Virulence Increasing of <Emphasis Type="Italic">Salmonella typhimurium</Emphasis> in Balb/c Mice After Heat-Stress Induction of Phage Shock Protein A

Salmonella typhimurium is a potentially intracellular pathogen and is responsible for thousands of reported cases of acute gastroenteritis and diarrhea each year. Although many successful physiological and genetic approaches have been taken to conclude the key virulence determinants encoded by this organism, the total number of uncharacterized reading frames observed within the S. typhimurium genome suggests that many virulence factors remain to be discovered. This study was conducted to evaluate the role of heat induced phage shock protein A (PspA), in the pathogenicity of S. typhimurium. The stress proteins detected on sodium dodecyl sulfate-polyacrylamide gel electrophoresis were identified specifically by immunoblotting with polyclonal antibody against PspA. PspA was produced in response to heat stress at 45°C and it was over-expressed at 65°C. At this temperature, the stressed bacterial cells producing PspA were more virulent (16 folds greater) to female 6–8 week-old Balb/c mice. Correspondency between decrease in LD₅₀ and increase in PspA production during heat stress and lower pathogenicity in non-producing cells that emerged during stress at 55°C represents PspA as an important virulence factor in heat stressed S. typhimurium.     

Comparison of Cytokine Induction by Lipopolysaccharide of Bacteroides fragilis with Salmonella typhimurium in Mice

Comparison of cytokine stimulation by lipopolysaccharide (LPS) of Bacteroides fragilis and Salmonella typhimurium was done to study the early events occurring in vivo. Mice injected intraperitoneally with either LPS demonstrated endogenous production of all the cytokines studied (tumor necrosis factor-alpha, interferon-gamma and interleukin-6) within 6 hr in the bloodstream. However induction of all the cytokines by B. fragilis LPS (50 μg/mouse) was much weaker compared with S. typhimurium LPS (50 μg/mouse). Even a dose of S. typhimurium LPS 40 times smaller (1.2 μg/mouse) induced cytokines more strongly compared with B. fragilis LPS. Thus, a weak biological response to B. fragilis LPS as evidenced by chick embryo lethality, limulus lysate gelation, LD₅₀ for mice and rabbit pyrogenicity could be due to weak induction of bioactive mediators by LPS.     

Outer membrane protein OmpV mediates Salmonella enterica serovar typhimurium adhesion to intestinal epithelial cells via fibronectin and α1β1 integrin

Salmonella typhimurium is an invasive Gram‐negative enteric bacterium, which causes salmonellosis, a type of gastroenteritis in humans and typhoid‐like symptoms in mice. Upon entering through the contaminated food and water, S. typhimurium adheres, colonises, and invades intestinal epithelial cells (IECs) of the small intestine. In this study, we have shown that upon deletion of the outer membrane protein OmpV, there is a significant decrease in adherence of S. typhimurium to the IECs, indicating that OmpV is an important adhesin of S. typhimurium. Further, our study showed that OmpV binds to the extracellular matrix component fibronectin and signals through α1β1 integrin receptor on the IECs and OmpV‐mediated activation of α1β1, resulting in the activation of focal adhesion kinase and F‐actin modulation. Actin modulation is crucial for bacterial invasion. To the best of our knowledge, this is the first report of an adhesin mediated its effect through integrin in S. typhimurium. Further, we have observed a decrease in pathogenicity in terms of increased LD₅₀ dose, lesser bacterial numbers in stool, and less colonisation of bacteria in different organs of mice infected with Δompv mutant compared with the wild‐type bacteria, thus confirming the crucial role of OmpV in the pathogenesis of S. typhimurium.     

Immunobiology of Lipopolysaccharide (LPS) and LPS-Derived Immunoconjugates Vaccinate Mice against Salmonella typhimurium

The immunobiology of lipopolysaccharide (LPS) of Salmonella typhimurium LT2–71 was studied in its native, modified and conjugated states using mice as the experimental model. An alkali-treated detoxified fraction of LPS (D-LPS) was found to be not only non-toxic but also equally immunogenic, like LPS. In addition D-LPS alone or conjugated with enterotoxin or hemolysin was also non-pyrogenic and non-indurogenic. The immunoprophylactic activity of D-LPS conjugates to a 100 ID₅₀ challenge dose of S. typhimurium was also higher than that of detoxified LPS or native LPS.     

Role of anaerobiosis in virulence of Salmonella typhimuirium

Intestinal pathogens are exposed to various stress conditions during their infectious cycle. Anaerobiosis, one of such hostile condition, is offered by the host within gut and intestinal lumen, where survival, multiplication and entry into intestinal epithelial cells is priority for the invading pathogen. In the present study, a virulent strain of S. typhimurium (1402/84) was grown under anaerobic conditions and its virulence characteristics such as host cell binding, penetration and intracellular survival were compared with aerobic S. typhimurium. Anaerobically grown S. typhimurium showed significantly higher binding to immobilized mice enterocytes and intestinal mucus as compared to bacteria grown aerobically. Anaerobic bacteria also showed an early penetration of mucus and subsequent binding to underlying immobilized enterocytes, in vitro. Anaerobic S. typhimurium exhibited increased intracellular survival within spleen macrophages of mice and caused significantly higher fluid accumulation in ligated rabbit ileal loops as compared to aerobic bacteria. LD₅₀ of anaerobic S. typhimurium was also observed to be 2 fold lower when compared to aerobic bacteria. Cell surface hydrophobicity of anaerobic S. typhimurium was also found to be significantly higher than aerobic bacteria. Thus, it appears that exposure of S. typhimurium to anaerobiosis results in its enhanced virulence, adhesion and penetration of host cells.     

Variation in endoplasmic-reticulum-associated glycoproteins of carrot cells cultured in vitro

Glycoproteins extracted from microsomes of in-vitro-cultured cells of Daucus carota L. cv. US-Harumakigosun were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and detected by peroxidase-conjugated concanavalin A. The appearance of a glycoprotein with M_r 31 000 (GP 31) was correlated with the ability of cells to form somatic embryos. GP 31 appeared in embryogenic cells cultured in 2,4-dichlorophenoxyacetic acid (2,4-D)-containing medium, but not in somatic embryos and non-embryogenic cells; it disappeared when the cultures were transferred to auxin-free medium. Another glycoprotein with M_r 32 000 (GP 32) was detected only in non-embryogenic cells, regardless of the presence or absence of 2,4-D. Both glycoproteins, GP 31 and GP 32, were associated with the rough endoplasmic reticulum and were extractable with 0.05% deoxycholate.Abbreviations Con A concanavalin A - 2,4-D 2,4-dichlorophenoxyacetic acid - ER endoplasmic reticulum - GP 31, GP 32 a glycoprotein with an apparent molecular mass of 31 or 32 kdalton - kDa kilodalton - MS Murashige and Skoog - M_r apparent molecular mass - SDS-PAGE sodium dodecylsulfate-polyacrylamide gel electrophoresis     

Cell wall and sheath constituents of the cyanobacterium Gloeobacter violaceus

Sheaths isolated from Gloeobacter violaceus were found to be composed of a major polysaccharide moiety (glucose, galactose, rhamnose, mannose, arabinose), a protein moiety, and negatively charged components (glucuronic acids, phosphate, sulfate). Outer membrane polypeptide patterns were dominated by two major peptidoglycan-associated proteins (M_r 62,000 and 53,000). Lipopolysaccharide constituents were glucosamine, 3-hydroxy fatty acids (3-OH-14:0, anteiso-3-OH-15:0, 3-OH-16:0, 3-OH-18:0), carbohydrates, and phosphate. A1-type peptidoglycan and non-peptidoglycan components (mannosamine, glucose, mannose, and glucosamine) indicated the presence of a peptidoglycan-polysaccharide complex in the cell walls of Gloeobacter violaceus.Abbreviations A₂pm diaminopimelic acid - ATCC American Type Culture Collection - CE cell envelope - CM cytoplasmic membrane - CW cell wall - dOcla 3-deoxy-d-manno-2-octulosonic acid - GalN galactosamine - GlcN glucosamine - GlcUA glucuronic acid - HF hydrofluoric acid - LPS lipopolysaccharide - ManN mannosamine - M relative molecular mass - MurN muramic acid - MurN-6-P muramic acid-6-phosphate - OMe O-methyl - PAGE polyacrylamide gel electrophoresis - PCC Pasteur Culture Collection - SDS sodium dodecyl sulfate - SH sheath     

Capsule polysaccharide-protein-peptidoglycan complex in the cell envelope of Rhodobacter capsulatus

The capsule polysaccharide-protein-peptidoglycan complex (insoluble in boiling sodium dodecyl sulfate and hot phenol-water) from cell envelopes of Rhodobacter capsulatus St. Louis was characterized. Hydrofluoric, hydrochloric acid or alkaline hydrolysis solubilized the polysaccharide moiety, whereas the protein-peptidoglycan moiety remained insoluble. On treatment of the protein-peptidoglycan moiety with lysozyme, the protein with peptidoglycan-residues bound was solubilized. It showed a single, broad peptide band (M _r=about 17,000) on sodium dodecyl sulfate polyacrylamide gel-electrophoresis. The same protein was obtained by lysozyme digestion (without preceding hydrofluoric or hydrochloric acid treatment) of the protein-peptidoglycan complex of the phage-resistant mutant Rhodobacter capsulatus St. Louis RC1^-, in which the capsule polysaccharide is present in a free form. A protein-peptidoglycan complex was isolated also from the capsulefree Rhodobacter capsulatus 37b4. Covalent binding between the protein and peptidoglycan moieties is likely for all three strains as is the lipoprotein nature of the protein moiety. The polysaccharide moiety of the complete complex from the wild-type Rhodobacter capsulatus St. Louis was at least partly removable from the complex in the presence of high salt concentrations or ethylene diamine tetraacetate. A specific amino acid pattern (with Ser, Gly, Glu, and Ala dominating) remained constantly associated with the capsule polysaccharide moiety independent of the separation procedure.Abbreviations A₂pm diaminopimelic acid - Cetavlon cetyltrimethyl-ammonium bromide - EDTA ethylene-diaminetetraacetate, disodium salt - HF hydrofluoric acid - HPLC high-performance liquid chromatography - PAGL polyacrylamide gel-electrophoresis - SDS sodium dodecyl sulfate - TCA trichloroacetic acid     

Salmonella–Macrophage Interactions upon Manganese Supplementation

Various studies indicate the role of manganese (Mn) in the virulence of pathogens. Salmonella is an intracellular pathogen which is able to multiply within the macrophages. The present study was therefore, designed to assess the effect of Mn supplementation on Salmonella–macrophage interactions particularly in reference to Salmonella virulence and macrophage functions. A 50-fold decrease in the lethal dose 50 (LD₅₀) of Salmonella typhimurium was observed when mice were infected with Salmonella grown in the presence of Mn as compared to the LD₅₀ in the absence of Mn indicating an increase in the virulence of the organism. A significant increase was observed in the levels of superoxide dismutase (SOD) of S. typhimurium grown in presence of manganese. Upon Mn supplementation, macrophage functions were also found to be altered. Decreased phagocytic activity of macrophages interacted with Salmonella was observed in presence of Mn as compared to the activity in the absence of Mn. A significant increase was observed in the extent of lipid peroxidation along with significant decreases in the activities of SOD and catalase as well as nitrite levels of macrophages interacted with S. typhimurium upon supplementation with Mn. These observations indicate that Mn supplementation might have increased the expression of Mn transporters in Salmonella resulting in increased levels of its superoxide dismutase. The altered Salmonella function in turn might have been responsible for inhibiting phagocytosis and impairing the balance between the oxidant and antioxidant profile of macrophages, thus protecting itself by exhibiting exalted virulence.     

Purification of an autocatalytic protein-glycosylating enzyme from cell suspensions of Daucus carota L.

A glycosyltransferase was identified in the 174 000 · g membrane pellet and the supernatant from extracts of cell suspensions of Daucus carota L. The enzyme from the supernatant was enriched 475-fold, and sodium dodecyl sulfate-gel electrophoresis and fluorography of this purified sample showed that the only enriched protein band (40 000 Da) was simultaneously an enzyme and a glucose-acceptor. Gel filtration and electrophoresis under non-denaturing conditions proved that in vivo this protein provides the subunits for a very large molecule. Radio-gas-liquid chromatography demonstrated that only one glucosyl moiety was transferred from UDP-glucose to the protein.Abbreviations DEAE diethylaminoethyl - GT IsU glycosyltransferase I, soluble, substrate UDPglucose - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis     

Chemical and Biological Properties of Lipopolysaccharide from a Marine Bacterium,Photobacterium phosphoreum PJ-1

The chemical and biological properties of the lipopolysaccharide (LPS) isolated from a marine bacterium, Photobacterium phosphoreum PJ-1, were studied. This LPS consists of 40.6% carbohydrate, 27.3% fatty acid, 0.2% 2-keto-3-deoxyoctonate (KDO) and other components. One characteristic of this LPS is its small amount of KDO, the basic component of the usual LPS. Electrophoresis in sodium dodecylsulfate polyacrylamide gel revealed at least two staining bands for carbohydrates. These bands were continuous and broad, and showed rapid electrophoretic mobility which corresponded closely to the fastest moving band of LPS from Salmonella typhimurium. This LPS preparation had adjuvant activity, lethality for ddY mice, and the ability to gel Limulus amebocyte lysate, and the strength of these activities corresponded closely to those of LPS preparations from Escherichia coli 0111:B4 and S. typhimurium. In the test for lethality of the LPS for ddY mice, the lethal action appeared in two phases depending on the dose used for intravenous (i.v.) injection : the early lethal action appeared within 30 min after injection of 250 μg or less, and the late lethal action occurred gradually after 16 hr at doses of 500 μg or more. The total (both phases) LD50 of this LPS (i.v.) for ddY mice was 265 μg per mouse and in only the late phase it was 500 μg. These results show that in spite of structual differences in regard to KDO content, LPS from P. phosphoreum PJ-1 has some biological properties similar to those of LPS from E. coli 0111:B4 and S. typhimurium but it shows no immunological cross-reaction with other LPS.     

The antimutagenic effect of selenium on 7,12-dimethylbenz(a)anthracene and metabolites in the amesSalmonella/microsome system

The antimutagenic effect of selenium as sodium selenite, sodium selenate, selenium dioxide, and seleno-methionine was studied in the AmesSalmonella/microsome mutagenicity test using 7,12-dimethylbenz(a)anthracene (DMBA) and some of its metabolites. Selenium (20 ppm) as sodium selenite reduced the number of histidine revertants on plates containing up to 100 μg DMBA/plate. Increasing concentrations of selenium as sodium selenite, sodium selenate, and selenium dioxide up to 40 ppm Se progressively decreased the number of revertants caused by 50 μg DMBA. DMBA and its metabolites 7-hydroxymethyl-12-methylbenz(a)anthracene, 12-hydroxymethyl-7-methylbenz(a)anthracene, and 3-hydroxy-7,12-dimethylbenz(a)anthracene were mutagenic forSalmonella typhimurium TA100 in the presence of an S-9 mixture. Selenium supplementation as Na₂SeO₃ reduced the number of revertants induced by these metabolites to background levels. The antimutagenic effect of inorganic selenium compounds cannot be explained by toxicity of selenium as determined by viability tests withSalmonella typhimurium TA100. Selenium supplementation in all forms examined, except sodium selenate, decreased the rate of spontaneous reversion. Selenium as sodium selenate was slightly mutagenic at concentrations of 4 ppm or less. Higher concentration of Na₂SeO₄ inhibited the mutagenicity of DMBA. The present studies support the anticarcinogenic potential of selenium and indicate that form and concentration are important factors in this trace element's efficacy.     

Experimental Salmonellosis Immunizing Effect of Live Vaccine Prepared from Various Mutants of Salmonella Having Different Cell Wall Polysaccharides

Immunizing potencies of vaccines prepared from various strains of Salmonella were graded by comparing the mortality rate of immunized mice after challenge with highly virulent strains of either Salmonella enteritidis or S. typhimurium. The resistance against this challenge infection was shown to be conferred by joint immunization with a specific factor, which was represented by O specific lipopolysaccharide of smooth strains, and cross-protection factor, which was a major potent factor in live vaccine. The distribution of this cross-protection factor in rough mutants of S. typhimurium was found to be limited to strains which possessed a polysaccharide chain longer than that of glucose₁-less mutant. The potency conferring cross-resistance was found to be maintained partly in formalin-killed cells and cell walls of the strains harboring cross-protection factor but not in lipopolysaccharide extracted from such strains.     

Purification of GP57, and auxin-regulated extracellular glycoprotein of carrots,and its immunocytochemical localization in dermal tissues

A glycoprotein (GP57) was purified by ion-exchange and hydroxylapatite column chromatography from the 70%-ethanol precipitate of culture medium of non-embryogenic carrot cells (Daucus carota L.) grown with 2,4-dichlorophen-oxyacetic acid (2,4-D). Its apparent molecular mass (M _r) was estimated to be 57000 by sodium dodecylsulfate-polyacrylamide gel electrophoresis and 50000 by gel filtration. GP57 contained 14% (w/w) carbohydrate; the M _r of the peptide portion was estimated to be 55000 after deglycosylation by trifluoromethanesulfonic acid. GP57 is composed of two polypeptides with the same M_r and with very similar amino-acid composition but different pI values, 8.8 and 9.5. Both are rich in aspartic acid, serine and threonine, and may possess N-linked oligosaccharide chains, including fucose and xylose. A monoclonal antibody (MAb) against the purified GP57 reacted with both the pI 8.8 and the 9.5 components, as well as the deglycosylated GP57. Immunoblotting with the MAb indicated that GP57 is synthesized in and released from cultured cells which have been supplied with auxin. In immunocytochemical studies, GP57 was found in the space between the embryo and the endosperm of dry seeds, and its content decreased during germination. GP57 was also found in the endodermis and epidermis of young roots, the periderm of mature taproots, and the epidermis of petioles and young leaves.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - GP57 M _r-57000 glycoprotein - GP65 M _r-65000 glycoprotein - MAb monoclonal antibody - M _r apparent molecular mass - SDS-PAGE sodium dodecylsulfate-polyacrylamide gel electrophoresis - TFMS trifluoromethanesulfonic acid     

Antitumor therapeutic effects of Salmonella typhimurium containing Flt3 Ligand expression plasmids in melanoma-bearing mouse

An attenuated strain of Salmonella typhimurium has been tested in animals and clinically as an anticancer agent due to its in vivo tumor-targeting and tumoricidal properties. We exploited a genetically-engineered S. typhimurium harboring Flt3 Ligand (Flt3L) expression vectors as a tumoricidal agent to enhance its therapeutic efficacy. Flt3L showed tumoricidal effects when expressed in tumor cells in vitro. When melanoma-bearing mice were treated locally with Salmonella, S. typhimurim with Flt3L expression vectors inhibited tumor growth more than Salmonella controls (50% vs. 0% in tumor regression rates). Moreover, it prolonged survivals of animals without induction of memory antitumor protective responses to a parental tumor re-challenge (50% vs. 0% in survival rates). These results suggest that a genetically engineered S. typhimurium with Flt3L expression vectors has the potential to be applicable as a safer and more effective tumor-targeting and tumoricidal agent.     

Studies on the regulation of 1-aminocyclopropane-1-carboxylate synthase in tomato using monoclonal antibodies

A partially purified preparation of 1-aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14) from tomato (Lycopersicon esculentum (Mill.) fruit tissue was used to generate monoclonal antibodies (MAb) specific for the two different MAbs yielded a 50-kDa polypeptide as shown by sodium dodecylsulfate-polyacrylamide gel electrophoresis. An enzyme-linked immunosorbent assay (ELISA) capable of detecting <1 ng of antigen was developed. The ELISA system was used to demonstrate that two of the MAbs recognized different epitopes on the ACC-synthase protein. Wound-induced increases in ACC-synthase activity in tomato fruit tissue were correlated with changes in ELISA-detectable protein. In-vivo labeling of wounded tissue with [³⁵S]methionine followed by extraction and immunopurification in the presence of various protease inhibitors yielded one major radioactive band of 50 kDa molecular mass. Pulse labeling with [³⁵S]methionine at various times after wounding indicated that the wound-induced increase in ACC-synthase activity involved de-novo synthesis of a rapidly turning over 50-kDa polypeptide.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - ELISA enzyme-linked immunosorbent assay - MAb monoclonal antibody - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis     

Effects of pantolactone and butyrolaectone on the pleiotropic phenotypes of lon mutants and on thermal induction of the SOS phenomena in a tif mutant of Escherichia coli K12

Hydrophobic and charge-charge interactions of Salmonella typhimirium and Serratia marcescens were determined and related to their content of fimbriae and lipopolysaccharide (LPS). The cell surface structures were characterized with hydrophobic interaction chromatography (HIC), electrostatic interaction chromatography (ESIC) and particle electrophoresis measurements. The degree of interaction at the air-water interface was tested using a monolayered lipid film applied to an aqueous surface. The cell surface hydrophobicity of S. typhimurium in the presence of fimbriae was less in smooth than in rought bacteria. Examination of a series of rough mutants of S. typhimurium indicates that reduction of the O-side chain and core oligosaccharides was correlated with increased cell hydrophobicity. The enrichment factors at the air-water interface were significantly higher for fimbriated than for non-fimbriated S. typhimurium cells. Fimbriated S. marcescens cells were less hydrophobic and adhered to a lesser degree at the air-water surface than non-fimbriated counterparts. Electrophoretic measurements and adsorption to ion exchangers gives different information about the surface charge of bacteria. The latter technique gives the interaction between localized charged surfaces.Abbreviations HIC hydrophobic interaction chromatography - ESIC electrostatic interaction chromatography - LPS lipopolysaccharide - PBS phosphate buffered saline solution     

Amino acid metabolism in the thermophilic phototroph,Chloroflexus aurantiacus: properties and metabolic role of two l-threonine (l-serine) dehydratases

Two l-threonine (l-serine) dehydratases (EC 4.2.1.16) of the thermophilic phototrophic bacterium Chloroflexus aurantiacus Ok-70-fl were purified to electrophoretic homogeneity by procedures involving anion exchange and hydrophobic interaction chromatography. Only one of the two enzymes was sensitive to inhibition by l-isoleucine (K _i=2 M) and activation by l-valine. The isoleucine-insensitive dehydratase was active with l-threonine (K _m=20 mM) as well as with l-serine (K _m=10 mM) whereas the other enzyme, which displayed much higher affinity to l-threonine (K _m=1.3 mM), was inactivated when acting on l-serine. Both dehydratases contained pyridoxal-5-phosphate as cofactor. When assayed by gel filtration techniques at 20 to 25° C, the molecular weights of both enzymes were found to be 106,000±6,000. In sodium dodecylsulfate-polyacrylamide gel electrophoresis, the two dehydratases yielded only one type of subunit with a molecular weight of 55,000±3,000. The isoleucine-insensitive enzyme was subject to a glucose-mediated catabolite repression.Abbreviations A absorbance - ile isoleucine - PLP pyridoxal-5-phosphate - SDS sodium dodecyl sulfate - TDH threonine dehydratase - U unit     

Isolation and Partial Properties of a Porin-Like Protein from Vibrio parahaemolyticus Cell Envelope

The cell envelope of Vibrio parahaemolyticus pilot strain K-11 contains a major protein with an apparent molecular weight of 35,000 which was not solubilized with 2% sodium dodecyl sulfate (SDS) at 50 C for 30 min and was resistant to trypsin. The protein was extracted from the SDS-insoluble envelope with SDS containing 0.4 m NaCl and purified by acetone precipitation and gel filtration. The purified protein was completely dissociated into a monomer with a molecular weight of 35,000 in SDS at 60 C. The amino acid composition of the protein was nearly the same as that of porins from Escherichia coli and Salmonella typhimurium. Thus the protein seems to be porin-like.     

Sheath and outer membrane components from the cyanobacterium Fischerella sp. PCC 7414

A purified sheath fraction and an outer membrane fraction were obtained from the cyanobacterium Fischerella sp. PCC 7414. The sheath had a fine structure with osmiophilic fibers running in parallel to the cell surface in two distinct layers. The sheath fraction contained mainly neutral sugars (Glc, Man, Gal, Xyl, Fuc, 2-O-methylhexose), GlcN, uronic acids, and minor components such as amino acids, sulfate, phosphate, and fatty acids. The protein moiety was removable from the sheath fraction by treatment with boiling sodium dodecyl sulfate. The presence of three different 3-hydroxy fatty acids (3-OH-14:0, 3-OH-16:0, 3-OH-18:0) in addition to GlcN indicated the presence of lipopolysaccharide in the outer membrane. One major (M_r 50,000) and two minor (M_r 54,000 and 65,000) proteins were detected as constituents of the outer membrane.Abbreviations A₂pm diaminopimelic acid - GLC gas-liquid chromatography - GlcN glucosamine - Ino inositol - MurN muramic acid - PAGE polyacrylamide gel electrophoresis - SDS sodium dodecyl sulfate