Streptococcus pneumoniae undergoes spontaneous phase variation between a transparent and an opaque colony phenotype, the latter being more virulent in a murine model of sepsis. Opaque pneumococci have previously been shown to express lower amounts of C polysaccharide (cell wall teichoic acid) and in this study were shown to have a higher content of capsular polysaccharide by immunoelectron microscopy. This report then examined the relationship between expression of these two cell surface carbohydrate structures and their relative contribution to the increased virulence of opaque variants. Comparison of genetically related strains showed that the differential content of capsular polysaccharide did not affect the amount of teichoic acid as measured by a capture enzyme-linked immunosorbent assay (ELISA). In contrast, when the teichoic acid structure was altered by replacing choline in the growth medium with structural analogs, the quantity of capsular polysaccharide as measured by a capture ELISA was decreased, demonstrating a linkage in the expression of the two surface carbohydrate structures. A standardized assay was used to assess the relative contribution of cell surface carbohydrates to opsonophagocytosis. The opaque variants required 1.2- to 30-fold more immune human serum to achieve 50% opsonophagocytic killing than did related transparent variants (types 6B and 9V). The opsonophagocytic titer was proportional to the quantity of capsular polysaccharide rather than teichoic acid. The major factor in binding of the opsonin, C-reactive protein (CRP), was also the amount of capsular polysaccharide rather than the teichoic acid ligand. Only for the transparent variant (type 6B), which bound more CRP, was there enhanced opsonophagocytic killing in the presence of this serum protein. Increased expression of capsular polysaccharide, therefore, appeared to be the major factor in the decreased opsonophagocytic killing of opaque pneumococci.

Our previous studies have shown that licochalcone A, an oxygenated chalcone, has antileishmanial and antimalarial activities, and alters the ultrastructure and function of the mitochondria of Leishmania spp. parasites. The present study was designed to investigate the antileishmanial activity and the mechanism of action of a group of new oxygenated chalcones. The tested oxygenated chalcones inhibited the in-vitro growth of Leishmania major promastigotes and Leishmania donovani amastigotes. Treatment of hamsters infected with L. donovani with intraperitoneal administration of two oxygenated chalcones resulted in a significant reduction of parasite load in the liver and the spleen compared with untreated control animals. The oxygenated chalcones also inhibited the respiration of the parasite and the activity of mitochondrial dehydrogenases. Electron microscopic studies illustrated that they altered the ultrastructure of the mitochondria of L. major promastigote. The data clearly indicate that this group of oxygenated chalcones has a strong antileishmanial activity and might be developed into a new antileishmanial drug. The antileishmanial activity of oxygenated chalcones might be the result of interference with function of the parasite mitochondria.

Our previous studies have shown that licochalcone A, an oxygenated chalcone, has antileishmanial (M. Chen, S.B. Christensen, J. Blom, E. Lemmich, L. Nadelmann, K. Fich, T.G. Theander, and A. Kharazmi, Antimicrob, Agents Chemother. 37:2550-2556, 1993; M. Chen, S.B. Christensen, T.G. Theander, and A. Khrazmi, Antimicrob. Agents Chemother. 38:1339-1344, 1994) and antimalarial (M. Chen, T.G. Theander, S.B. Christensen, L. Hviid, L. Zhai, and A. Kaharazmi, Antimicrob. Agents Chemother. 38:1470-1475, 1994) activities. We have observed that licochalcone A alters the ultrastructure of the mitochondria of Leishmania promastigotes (Chen et al., Antimicrob. Agents Chemother. 37:2550-2556, 1993). The present study was designed to examine this observation further and investigate the mechanism of action of antileishmanial activity of licochalcone A. Electron microscopic studies showed that licochalcone A altered the ultrastructure of Leishmania major promastigote and amastigote mitochondria in a concentration-dependent manner without damaging the organelles of macrophages or the phagocytic function of these cells. Studies on the function of the parasite mitochondria showed that licochalcone A inhibited the respiration of the parasite by the parasites. Moreover, licochalcone A inhibited the activity of the parasite mitochondrial dehydrogenase. The inhibition of the activity of the parasite mitochondrial enzyme correlated well with the changes in the ultrastructure of the mitochondria shown by electron microscopy. These findings demonstrate that licochalcone A alters the ultrastructure and function of the mitochondria of Leishmania parasites.

The original two strains of Mycoplasma genitalium were isolated from the human urogenital tract. No other strains have been isolated from this site since then. We have recently succeeded in propagating a third strain from a urogenital specimen from a patient with urethritis in Vero cell cultures. By electron microscopy mycoplasmas were demonstrated intracellularly in about 10% of the examined Vero cells. Various stages of penetration into the cells could be observed. The flask-shaped organisms seemed to penetrate into the cells by the tip-end which included a rodlike structure. The intracellular location of normal mycoplasmas were in membrane-bound vacuoles very close to the nucleus, occasionally together with a few disintegrated organisms. In a few cells additional material was entangling the mycoplasmas in the cytoplasmic vacuoles. The potential for intracellular survival of M. genitalium may help the organism to evade the defence mechanisms of the human body. This trait may be considered a pathogenic property which supports the presumption that M. genitalium has clinical importance.

The first 2 cases of infection with Enterocytozoon bieneusi in Denmark and Scandinavia are reported. Both patients were women and to the best of our knowledge this is the first report of E. bieneusi in female AIDS patients. Both had late stage AIDS, and both had complained of intermittent diarrhoea for more than 1 year. At the time microsporidiosis was diagnosed, no other pathogens causing diarrhoea were found. Immunodeficient patients with chronic unexplained diarrhoea should be investigated for intestinal microsporidiosis, especially as treatment is now available.

Licochalcone A, an oxygenated chalcone isolated from the roots of Chinese licorice plant, inhibited the growth of both Leishmania major and Leishmania donovani promastigotes and amastigotes. The structure of the licochalcone A was established by mass and nuclear magnetic resonance spectroscopies and by synthesis, and its purity was verified by high-pressure liquid chromatography. The 50% inhibition of growth of logarithmic- and stationary-phase promastigotes of L. major, as measured by [3H]thymidine uptake, were 4 and 2.5 micrograms/ml, respectively. The growth of L. major promastigotes was totally inhibited after a 20-h incubation period with licochalcone A at 5 micrograms/ml. At a concentration of 0.5 microgram/ml, licochalcone A markedly reduced the infection rate of human peripheral blood monocyte-derived macrophages and U937 cells with L. major promastigotes and exhibited a strong intracellular killing of the parasite. These data show that intracellular Leishmania amastigotes are more susceptible than promastigotes to licochalcone A. Results of studies on the site of action of licochalcone A indicate that the target organelle appears to be the parasite mitochondria. These findings demonstrate that licochalcone A in concentrations that are nontoxic to host cells exhibits a strong antileishmanial activity and that appropriate substituted chalcones might be a new class of antileishmanial drugs.

Sjögren's syndrome (SS) is a connective tissue disease characterized by general affection of exocrine glands. The three main components of SS are: dry eyes, dry mouth, and other connective tissue disease. When only two of these, dry eyes and dry mouth, are present, the disease is designated primary SS. In the presence of the third component, most commonly SLE or RA, with one or both of the two first components the disease is designated secondary SS. In murine transplantation chimeras, we have demonstrated the development of both primary and secondary SS depending upon the mouse strains used. We transferred large numbers of viable leucocytes from homozygotic donors to heterozygotic recipients. When DBA/2 mice were used as donors, a full-developed SLE-syndrome, with autoantibodies against native DNA, nuclear antigens, and red blood cells was observed. We found immune deposits in skin ("lupus band") and kidneys, immune complex glomerulonephritis (ICGN), proteinuria, ascites, and hepatosplenomegaly. In later stages, we found a generalized dacryoadenitis. In the kidneys we found interstitial nephritis, and occasionally "half-moon" nephritis. In skin, immune deposits were demonstrated in intercellular spaces. These findings are similar to those found in patients with Sjögren's syndrome secondary to SLE. The murine transplantation chimera is therefore an experimental model for spontaneous autoimmune diseases.

The in situ attachment of capsular polysaccharide of type 6A pneumococci was examined by immunoelectron microscopy using anti-type 6A monoclonal antibody. The result discloses an asymmetrical cross-section of pneumococcal cell walls because capsular polysaccharides are located on the outer surface of the walls only, in contrast to the cell wall polysaccharide, which has been shown to be located on both surfaces.

The presence or absence of a polysaccharide capsule on the human pathogen Neisseria (N.) gonorrhoeae is still a topic of controversy. For this reason we compared the results obtained by light microscopy (dry India ink-Fuchsin stain) and electron microscopy (Alcian blue-lanthanum nitrate stain) of encapsulated strains of N. meningitidis and Streptococcus (S.) pneumoniae and of non-encapsulated strains of S. pneumoniae and Escherichia (E.) coli with those obtained using the same methods on strains of pilliated and non-pilliated N. gonorrhoeae. After staining with India ink-Fuchsin no capsules could be demonstrated on any of the N. gonorrhoeae strains studied. If present the capsules on these cells are too delicate to be identified by light microscopy. After treatment with Alcian blue-lanthanum nitrate sections of cells of N. meningitidis and S. pneumoniae generally showed the presence of a capsular layer. Sections of cells of the non-encapsulated strain of S. pneumoniae which possess C (common)-polysaccharide also showed surface associated capsule-like material. Similarly the surface of the cells of the E. coli strain showed material which appeared to be tufts of pili and/or M (mucoid)-antigen. In experiments where the N. gonorrhoeae cells were harvested as early as after six hours of growth a capsule-like material was demonstrated on cells of all strains studied.

The localization of pneumococcal capsular and cell wall antigens was examined by immunoelectron microscopy. C polysaccharide (C-Ps), a common component of all pneumococci, was uniformly distributed on both the inside and outside of the cell walls. The thickness of the C-Ps varied with the strain. Encapsulated strains were covered by varied amounts of capsular polysaccharide concealing the C-Ps of the bacteria so as to render it inaccessible to anti-C-Ps antibodies. In addition to C-Ps, protein antigens were demonstrable on the surface of nonencapsulated pneumococci. The proteins were not masked by the C-Ps layer. An extra layer on the cell walls was conspicuous on electron micrographs of both rough and encapsulated pneumococci. The nature of this extra layer has not been disclosed. F antigen, another common antigen of pneumococci, was uniformly distributed on the surface of the plasma membranes. During the course of the experimental work a reproducible method of gold labeling immunoglobulins was developed.

Two antibiotic-susceptible and two multi-resistant strains of diphtheroid rods of the group JK, obtained from clinical specimens in Denmark and from CDC in the U.S. were studied. The cells of all four strains presented an ordinary Gram-positive cell wall and an additional surface layer. Septum formation in dividing cells appeared to result in a "snapping-like" dividing mechanism, thus corroborating the relationship of the JK cells to the genus Corynebacterium. A significantly increased thickness of the surface layer of the multi-resistant strains was observed when cells were treated with ruthenium red. It is suggested that such a structural difference on the exterior of the cell-wall among JK bacteria may affect the cell-wall's permeability to antibiotics.

Selected functions (i.e. phagocytosis and chemotaxis of circulating blood monocytes were studied on cells obtained from 20 patients with untreated multiple myeloma (MM) and the results were compared with those obtained on cells from 60 healthy persons. The mean number of circulating monocytes was only slightly increased over the normal value although a marked monocytosis was demonstrated in all of the 4 patients with M-components of the lambda light chain type. Plasma cells isolated from peripheral blood and from bone marrow of patients with MM were found to possess a strong alpha-naphthyl acetate esterase activity. No differences were observed in the phagocytic activity of monocytes from patients compared with those of the controls, whereas the chemotactic responsiveness of the monocytes from the patients was slightly increased.

The morphology of lymph node tissue from normal hamsters and from hamsters experimentally infected with Treponema pertenue Gauthier was compared by means of light and electron microscopy. The capsules of the lymph nodes from infected hamsters showed an increased thickness in comparison with those of the non-infected animals. The infected lymph nodes differed from normal lymph nodes by small accumulations of neutrophilic leucocytes in the cortical areas. In addition, the amount of intercellular collagenous matrix present between large elongated cells was greatly increased in lymph nodes from infected animals. Electron microscopy of thin sections of infected lymph nodes showed intercellularly located treponemes in the leucocyte infiltration areas. These regions also showed the increased amounts of the collagenous matrix. Treponemes were occasionally found intracellularly in macrophages. These treponemes did not show their typically helical shape, but were present as spherical forms or cysts.

Five patients with a serum M component were shown to possess plasma cells containing Russell bodies. Four of the patients suffered from multiple myeloma, whereas the fifth probably had a different disease or was in a premyeloma stage. The Russell bodies stained blue with the May-Grünwald-Giemsa stain and were found both in the nuclei and in the cytoplasm of the plasma cells. Ultrastructural studies showed that the Russell bodies were osmophilic and those located in the cytoplasm were always situated within the cisternae of the rough endoplasmic reticulum. The intranuclear Russell bodies were always surrounded by a triple layered membrane, and some evidence was obtained that these bodies were first formed within the perinuclear space of the cells. Immunofluorescence studies using anti-L chain conjugates showed a positive marginate straining of the intranuclear as well as the cytoplasmic Russell bodies of the cells from all patients. Only one patient had cells with Russell bodies which also stained their location in the plasma cells. It is concluded that some plasma cells in multiple myeloma may produce an excessive amount of L chains which, in combination with a failure in the secretion of immunoglobulin molecules, may lead to the formation of Russell bodies.

Negatively stained preparations of 30 different strains of gram-negative rods representing 20 different taxa were examined in the electron microscope. Thirteen of the strains studied exhibited twitching and six of the strains exhibited motility. Additionally, non-twitching substrains of two of the twitching strains and a non-gliding substrain of one of the gliding strains were examined. A variety of cultural media, preparations for negative straining and negative strains were used. It was found that all strains with twitching motility possessed fimbriae, the diameter of which was approximately 50 A in all but one strain; the fimbriae of this strain had a diameter of approximately 40 A. The fimbriae were judged to be of polar origin in all cases where the origin could be determined with certainty. On none of the strains without twitching motility could fimbriae be demonstrated. Only one of the six strains with gliding motility possessed fimbriae.

The morphological response of E. coli to a new antibiotic, 6β-[(hexahydro-1H-azepin-1-yl)-methyleneamino]-penicillanic acid (FL 1060), has been investigated and compared with the response to benzylpenicillin and ampicillin. At high concentrations of FL 1060 (1000 μg/ml) in osmotically stabilized media, E. coli responds in the same way as to penicillins by forming “rabbit ears” and spheroplasts. At lower concentrations down to the IC50 value (0.02 μg/ml), the cells, even in unstabilized media, first become ellipsoidal and later spherical. After 2–3 hours, lysis of the cells occurs. This is rather late, as compared to the early lysis obtained with penicillins. Electron microscopical investigations show no characteristic changes in the subcellular pattern. During the second hour of treatment, the bacterial culture contains a considerable number of cells presenting asymmetrical cell divisions. During the same period, nuclear stainings show abnormal nuclear regions with impaired segregation, resulting in chromatine bridges and horseshoe-shaped chromatine regions. The results support the conception that, on cells in the pre-lytic stage, FL 1060 interferes with the balance between lengthwise growth and cell division through cross wall formation.

Acta Pathologica Microbiologica Scandinavica Section B Microbiology and ImmunologyVolume 81B, Issue 1 p. 176-178 MYCOPLASMOSIS: EXPERIMENTAL SEMINAL VESICULITIS ELECTRON MICROSCOPY OF INFECTED TISSUE J. Blom, J. Blom Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark. Department of Biophysics, Statens Serum-institut, Amager Boulevard 80, DK-2300 Copenhagen S, Denmark.Search for more papers by this authorH. Ernø, H. Ernø Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark.Search for more papers by this authorA. Birch-Andersen, A. Birch-Andersen Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark.Search for more papers by this author J. Blom, J. Blom Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark. Department of Biophysics, Statens Serum-institut, Amager Boulevard 80, DK-2300 Copenhagen S, Denmark.Search for more papers by this authorH. Ernø, H. Ernø Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark.Search for more papers by this authorA. Birch-Andersen, A. Birch-Andersen Department of Biophysics, Statens Seruminstitut, Copenhagen FAO/WHO International Reference Centre for Animal Mycoplasmas, Institute of Medical Microbiology, University of Aarhus, Denmark.Search for more papers by this author First published: September 1973 https://doi.org/10.1111/j.1699-0463.1973.tb02202.x AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume81B, Issue1September 1973Pages 176-178 RelatedInformation