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PubMed1993

Glucose stimulates cAMP accumulation in the oral bacterium Actinomyces viscosus.

Actinomyces viscosus T14V, a Gram-positive bacterium found in the oral cavity, was found to be insensitive to glucose-mediated catabolite repression. Basal levels of beta-galactosidase (18-26 U) were observed at all phases of growth regardless of the culture conditions. Further, beta-galactosidase could not be induced with lactose, or with a known inducer of the enzyme, isopropyl-beta-D-thiogalactoside, or with dibutyryl cAMP. Glucose, on the other hand, stimulated cAMP accumulation in a concentration-dependent manner. Fructose and sucrose mimicked the effects of glucose on cAMP accumulation, whereas galactose, mannose and maltose had lesser stimulatory effects. Other carbon sources, i.e., lactose, alpha-methylglucoside, ribose, xylose and succinate were without effect. Glucose and alpha-methylglucoside were found to stimulate cAMP accumulation in toluene-permeabilized cells, in the presence of the phosphodiesterase inhibitor, theophylline. Glucose did not stimulate cAMP levels in other Gram-positive bacteria including Streptococcus mutans, S. sanguis and S. salivarius but did cause cAMP accumulation in other strains of A. viscosus. The results suggest that glucose effects on cAMP metabolism are independent of the induction of beta-galactosidase as presently defined for Escherichia coli, and that the effects appear to be selective to the A. viscosus bacteria. The results also suggest that glucose stimulates cAMP accumulation via activation of adenylate cyclase.

Actinomyces viscosus↗
PubMed1989

Phylogenetic evidence for the relationship between the genera Mobiluncus and Actinomyces.

Partial reverse transcriptase sequencing of 16S rRNA from Mobiluncus curtisii and M. mulieris clearly indicate that the genus Mobiluncus is not a member of the Bacteroidaceae but belongs to the order Actinomycetales. The highest degree of relationship is found with the genus Actinomyces which is supported by the presence of common physiological properties.

Actinomyces↗
PubMed1995

Characterization of levJ, a sucrase/fructanase-encoding gene from Actinomyces naeslundii T14V, and comparison of its product with other sucrose-cleaving enzymes.

A library of Actinomyces naeslundii T14V DNA was constructed in plasmid pUC18 and from this several sucrose-positive clones were isolated. Evidence was obtained that all these clones contained the same gene. One clone, which carried a plasmid that was named pPNG102, was chosen for further study. It was found that the enzyme specified by this plasmid hydrolyzed sucrose, raffinose, inulin and levan, but not dextran, and did not synthesize fructan or glucan from sucrose. The sequence of the insert in pPNG102 was determined and was found to contain a large ORF that specifies a polypeptide of 99,319 Da with similarity to other sucrases. This gene was named levJ. The deduced amino acid (aa) sequence contained both a potential signal sequence and potential C-terminal cell envelope attachment domain. Alignments revealed an internal 331-aa domain not present in other levanases and sucrases. A neighbour-joining tree showed that sucrases of eukaryotic origin form a cluster with eubacterial sucrase/fructanases, and this cluster does not include other eubacterial sucrases. It is postulated that certain eukaryotic sucrase-encoding genes are of eubacterial origin.

Actinomyces↗
PubMed1996

Identification and partial characterization of an Actinomyces pyogenes hemolysin.

Twenty-two Actinomyces pyogenes isolates were recovered from hepatic abscesses in cattle and evaluated for hemolysin production. Hemolysin was collected from supernatant of cultures grown in 6% CO2 in brain heart infusion (BHI) broth. The effect of oxidizing and reducing agents, enzymes, temperatures and pH on hemolytic activity were studied using sheep erythrocytes as the target cells. Our study showed that A. pyogenes hemolysin is oxygen stable; sensitive to treatment by protease, trypsin, and amylase; and destroyed by treatment at extreme temperatures (56 and 100 degrees C) and pH (pH 3 and 11). Production of hemolysin was studied in BHI, RPMI-1640, and a defined serum-free A. pyogenes medium under aerobic and anaerobic conditions. Maximum hemolysin was produced in BHI incubated aerobically in 6% CO2 and to a lesser degree anaerobically in RPMI-1640. No hemolysin was produced in the defined A. pyogenes medium. Differential filtration, isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis identified two hemolysin proteins with pI values of 3.40 and 9.45 and estimated molecular masses of 62 and 58 kDa, respectively. Cell-free supernatant samples positive for hemolysin activity also were screened for leukotoxin activity. Significant levels of leukotoxin were detected in all samples screened.

Actinomyces↗
PubMed2004

Human minor and major gland saliva proteins and ability to mediate Actinomyces naeslundii adherence.

Bacteria-binding components and the ability to mediate bacterial adhesion to the tooth surface have been thoroughly studied in major salivary gland secretions. Our knowledge on the bacteria binding activity in minor gland saliva is, however, limited. In this study, proteins were examined in parallel in minor (palatal, buccal and labial) and major (parotid and submandibular/sublingual) salivary gland secretions in one subject using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The adherence of early colonizing Actinomyces naeslundii to pellicles formed from the secretions on hydroxyapatite beads was also examined. Amylase, IgA, proline-rich proteins and the high-molecular-weight glycoproteins, agglutinins, were detected in all saliva tested. Carbohydrate-reactive antibodies recognized the low-molecular weight mucin, MUC 7 in submandibular/sublingual saliva only. A. naeslundii strain 12104 adhered to all pellicles and especially to the buccal gland saliva pellicles. Strain LY7 adhered in highest numbers to the submandibular/sublingual saliva pellicles. It also bound in considerable numbers to parotid and palatal saliva pellicles but not to the ones formed from buccal and labial gland saliva. Our findings indicate that several bacteria-binding components are secreted in both minor and major gland saliva. The adherence-promoting ability of the various gland secretions differs, however.

Actinomyces↗
PubMed2004

Chronic postoperative endophthalmitis caused by Actinomyces neuii.

Uneventful phacoemulsification with implantation of a foldable, acrylic posterior chamber intraocular lens was performed in the right eye of a 73-year-old white man. Postoperatively, the patient developed a chronic, low-grade intraocular inflammation. Cultures from the aqueous specimen grew Actinomyces neuii, an unusual gram-positive bacillus. The low-grade intraocular inflammation persisted with intensive topical steroid-antibiotic medication and systemic antibiotics. A diagnostic, 3-port, pars plana vitrectomy was performed, and aqueous aspirate specimens were sent for culture and sensitivity and to look for abnormal cells. Intracameral antibiotics were not injected. The specimens were sterile to culture, and chronic inflammatory cells were reported on the vitreous specimen. On examination 6 months later, inflammation had not recurred and the best corrected visual acuity was 6/18.

Actinomyces↗
PubMed2006

Characterization of the Actinomyces naeslundii ureolysis and its role in bacterial aciduricity and capacity to modulate pH homeostasis.

Ammonia production from urea by ureolytic oral bacteria is believed to have a significant impact on oral health and ecological balance of oral microbial populations. Actinomyces naeslundii is an important ureolytic organism in the oral cavity. In this study, we aimed to investigate the substrate affinity and pH optimum for ureolysis of A. naeslundii (ATCC12104), and expression of urease under different environmental factors. In addition, in vitro acid killing and pH drop experiments were used to detect the role of ureolysis in bacterial aciduricity and capacity to modulate pH homeostasis. We observed the K(s) value of the ureolytic activity was 7.5mM and a pH optimum near 6.5. Urease expression by A. naeslundii (ATCC12104) was affected by multiple factors, including environmental pH, glucose and nitrogen availability. The cells could be protected against acid killing through hydrolysis of physiologically relevant concentrations of urea. A. naeslundii (ATCC12104) demonstrated a significant capacity to temper glycolytic acidification in vitro at urea concentrations normally found in the oral cavity.

Actinomyces↗
PubMed2004

Steroid profiles of transgenic tobacco expressing an Actinomyces 3-hydroxysteroid oxidase gene.

Previously, we have shown that the expression of a 3-hydroxysteroid-oxidase gene in transgenic tobacco initiated a series of biochemical events leading to the conversion of sterol to stanol. As a result, the plants maintained a diminished sterol pool and a modified relative sterol ratio but demonstrated no observable morphological abnormalities. The maintenance of normal higher plant physiology in the absence of particular sterols or in the presence of modified sterol ratios is controversial. In this report, we present additional biochemical and physiological characteristics of transgenic tobacco expressing an Actinomyces 3-hydroxysteroid-oxidase gene. The total steroid accumulated in the transgenic plants is 6-fold higher than in control plants and consists of sterol, 3-ketosteroid and stanol. The relative abundance of sterols within whole plant and individual organs is grossly altered as ethylated side chain sterols account for 99% of the total sterol pool in the transgenic tobacco. Stigmasterol is readily apparent in all tissues and cholesterol is found at measurable levels in specific organs, while campesterol and sitosterol are detected at trace levels in the transgenic plants. Stanols and 3-ketosteroids accumulate in all tissues and represent 77% of the measurable steroid pool in the transgenic plants. The sum of sterol, the respective 3-ketosteroid plus stanol provide a relative abundance of steroid, which is similar to the abundance of sterol accumulated in control tissue. In vitro photosynthetic electron transport measurements demonstrate altered activity of chloroplasts under a variety of reaction conditions, indicating a link between the modified steroid pool and a modulation of chloroplast membrane function.

3-Hydroxysteroid Dehydrogenases↗
PubMed1985

Actinomyces and the intrauterine contraceptive device: aspects of the fluorescent antibody stain.

Using fluorescein-conjugated globulins specific for Actinomyces israelii and Arachnia propionica, we observed large dispersed actinomycete populations in vaginal smears of several asymptomatic women. Mycelial granules, commonly revealed by the Papanicolaou stain, were not seen. These observations are discussed in regard to the threat of infection and sensitivity of the fluorescent stain.

Actinomyces↗
PubMed2003

Genetic diversity of Actinomyces naeslundii genospecies 2 in mother-child pairs.

Actinomyces naeslundii genospecies 2 (gsp-2) are members of the autochthonous oral flora. Chromosomal DNA fingerprinting (CDF) with SmaI revealed extensive genetic diversity among A. naeslundii gsp-2 strains within individual mothers and children. There was a low prevalence of genotype match among A. naeslundii gsp-2 strains between all mother and child pairs.

Actinomyces↗
PubMed1998

Experimental chronic infection induced in mice by Actinomyces israelii entrapped in alginate gel.

Tissue responses to experimentally induced actinomycotic lesions were investigated in mice by both light and transmission electron microscopy. Micro-organisms of Actinomyces israelii were entrapped in alginate gel and injected into the subcutaneous tissue over the periosteum of the mouse cranium. One day after the injection (initial stage), a non-stained amorphous structure was located in the core of the lesion, corresponding to the injected gel with bacteria. Numerous neutrophils surrounded the core region and phagocytized the injected complex actively. At days 3-7 (intermediate stage), the lesion became well developed. The core structure became eosinophilic and separated to form island-like structures. No lesion was recognized in the control group (gel without bacteria) until day 14. After 30 days (late stage), the lesions displayed more static features, similar to the "sulphur granules" characteristic of actinomycotic lesions. At the late stage, foamy cells increased in number and took the place of neutrophils in the alginate islands. By transmission electron microscopy these foamy cells were seen to be filled with lysosomal vesicles containing electron-dense foreign material. Thus, these cells appeared to be macrophages that had phagocytized degenerated neutrophils containing bacteria. Along with the active phagocytosis by foamy cells that progressed in the late stage, a collagenous capsule became conspicuous and separated the lesion from the intact tissue. The bacteria remained in the gel islands until at least day 60, although they considerably decreased in number with time. Serum IgG antibody titres began to rise within 24 h of the injection, reached a peak concentration at day 14 and remained a significantly high (p < 0.01, vs 0 time) until day 120. These results suggest that this animal model is useful for inducing experimental chronic infectious lesions.

Actinomyces↗
PubMed2000

The incidence of actinomyces-like organisms in Papanicolaou-stained smears of copper- and levonorgestrel-releasing intrauterine devices.

Actinomyces-like organisms (ALOs) are a common finding in Papanicolaou-stained cervico-vaginal smears (PAP smears) of women using an intrauterine device (IUD). The incidence of ALOs positive PAP smears depends on the type of IUD. Pelvic actinomycosis is a severe disease that may require hysterectomy and salpingo-oophorectomy. In a retrospective study we compared the incidence of ALOs positive PAP smears in users of the new levonorgestrel-releasing intrauterine device (LNG-IUD) (n = 52) with the incidence in Multiload Copper IUD (ML375) users (n = 104). All IUDs had been inserted from 1996-1998. Women with a follow-up period of more than 9 months were included into the final analysis (LNG-IUD: n = 34; ML375: n = 65). The incidence of ALOs in LNG-IUD users (2.9%) was significantly lower than in ML375 users (20%). Clinical consequences of ALOs positive PAP smears are discussed controversially. The low incidence in the LNG-IUD users probably leads to less IUD-removals, reinsertions and less pelvic-inflammatory-diseases.

Actinomyces↗
PubMed1995

Pulmonary intravascular macrophages in the pathogenesis of bovine pulmonary lesions caused by Actinomyces pyogenes.

Rabbit antisera raised against somatic antigens from two strains of Actinomyces pyogenes reacted specifically in a peroxidase anti-peroxidase technique which was developed for the location of the bacteria in formalin-fixed tissues. The technique was applied on experimental murine and spontaneous bovine lesions caused by A. pyogenes. By electron microscopy and immunohistochemistry it was demonstrated that pulmonary intravascular macrophages play a role in the uptake of A. pyogenes from the blood, and in the production of pyaemic pulmonary lesions.

Actinomyces↗
PubMed2004

Soft-tissue abscess involving Actinomyces odontolyticus and two Prevotella species in an intravenous drug abuser.

Skin and soft-tissue infections in intravenous users comprise a variety of microorganisms and anaerobic bacteria are frequently involved in these suppurative infections. A case of subcutaneous abscess into anterior femoral muscles involving Actinomyces odontolyticus and two Prevotella species (Prevotella buccae and Prevotella melaninogenica) in an intravenous drug abuser is presented. This combination of microorganisms has not previously been described in soft-tissue infections. The patient volunteering that he licked his hypodermic needle prior to cocaine injection supports that the implicating bacteria originated from the oral cavity. Eventually, the patient recovered and at a 6-month follow-up a gradual improvement of his subcutaneous infection was noticed.

Abscess↗
PubMed1988

Actinomyces pyogenes bacteraemia in a patient with carcinoma of the colon.

A patient with carcinoma of the colon adherent to the pelvis developed Actinomyces pyogenes bacteraemia after uterine curettage but recovered with antibiotic treatment. This organism is a Gram-positive cocco-bacillus, beta-haemolytic when growing on blood agar and reactive with Lancefield group G antiserum. These features could easily lead to its misidentification as a streptococcus. Reports of human infection with A. pyogenes are summarised.

Actinomyces↗
PubMed1988

Mutanolysin-induced lysis of actinomyces pyogenes determined by aggregometry.

The lytic activity of mutanolysin from Streptomyces globisporus on 42 cultures of Actinomyces pyogenes could be effectively analyzed in an aggregometer. It was expressed as increase of transmittance at 546 nm after 20 min and 2 h at 37 degrees C. The A. pyogenes cultures revealed no uniform lysis pattern. Most of the cultures were lyzed within 20 to 40 min at 37 degrees C, others were lyzed only moderately or weakly within 2 h of incubation. The lytic activity was optimal at low (0.01 mol/l) molarity of the lysis buffer between pH 5.7 and 7 and could be inhibited by HgCl2.A. pyogenes was not lyzed by lysostaphin or lysozyme.

Actinomyces↗