scholarly journals THE INHIBITION OF SURFACE PHAGOCYTOSIS BY THE CAPSULAR "SLIME LAYER" OF PNEUMOCOCCUS TYPE III

1949 ◽  
Vol 90 (1) ◽  
pp. 85-96 ◽  
Author(s):  
W. Barry Wood ◽  
Mary Ruth Smith

Five strains of type III pneumococcus have been shown to possess wide capsular slime layers during the logarithmic phase of growth in serum broth. The slime layer stains metachromatically with methylene blue and can be visualized under the electron microscope as a fuzzy halo which extends well beyond the surace of the capsule proper and causes centrifugates of the organism to be of extremely large volume. This outer capsular structure is most readily demonstrated in vivo and in nutrient broth containing glucose and serum. It disappears from the surface of the cell with aging of the culture, and is easily removed by dilute alkali, alcohol, and heat. Exposure of slime-covered type III pneumococci to homologous antibody and to type III polysaccharidase reveals that the slime layer contains the same type-specific polysaccharide that is present in the rest of the capsule. From a type III strain producing a prominent slime layer an intermediate mutant has been isolated which forms small non-mucoid colonies on blood agar and possesses a relatively small capsule with a barely discernible slime layer. The wide slime layer protects virulent type III pneumococci from surface phagocytosis. Whenever the type III cells lose their broad slime layer, whether from aging of the culture, from mutation, from exposure to injurious chemicals, or from the action of type III polysaccharidase, they become susceptible to phagocytosis by the surface mechanism. Once phagocyted the type III pneumococci are promptly destroyed, even in the absence of antibodies.

1937 ◽  
Vol 65 (4) ◽  
pp. 469-485 ◽  
Author(s):  
Madeleine E. Field ◽  
Morris F. Shaffer ◽  
John F. Enders ◽  
Cecil K. Drinker

Experiments are described which show that in rabbits infected intravenously with virulent Type III pneumococci, these organisms are found not only in the thoracic duct lymph, as previously reported, but also in lymph from the cervical and leg lymphatics. The nonmotile bacteria must have crossed both vascular and lymphatic endothelium in reaching the lymph. Intracellular transportation by phagocytes is apparently not the means by which this is effected. The intravenous and intraperitoneal injection of large amounts of homologous type-specific antibody fails even after many hours to terminate or permanently reduce the pneumococcal infection of the lymph. The failure of antiserum to sterilize the lymph is discussed.


1950 ◽  
Vol 92 (1) ◽  
pp. 85-100 ◽  
Author(s):  
W. Barry Wood ◽  
Mary Ruth Smith

Experimental pneumonia was produced with a highly virulent strain of type III pneumococcus which synthesizes, during rapid growth, large amounts of capsular polysaccharide. The type III pneumonia differed from that caused by pneumococcus I in that (a) death occurred more promptly in the type III infection, (b) the local pulmonary lesion became more heavily infected, and (c) frank suppuration was common even after otherwise effective chemotherapy. The greater pathogenicity of the type III organism was shown by special histologic techniques to be due primarily to its capsular slime layer which interferes with surface phagocytosis. Capsular polysaccharide shed from the organism during growth was also demonstrated in high concentration in certain parts of the pneumonic lesion. Removal of the excess polysaccharide from the alveoli resulted from (a) lymphatic drainage to regional lymph nodes and (b) phagocytosis, particularly by macrophages. The possible relationship of the free carbohydrate to the malignancy and the characteristically viscous exudate of type III pneumonia was discussed. The lung abscesses which resulted from type III infection were observed to occur in those areas in which the maximum number of organisms had accumulated. Evidence was obtained that suppuration was due, not to necrotoxic products peculiar to the type III pneumococcus, but rather to the survival of large numbers of bacteria in the tissues, brought about primarily by the antiphagocytic effect of the slime layer. When pneumonia was produced with an intermediate type III mutant lacking the protective slime layer, back mutation to the mucoid parent occurred during the course of the infection, and the mucoid form eventually predominated in the lung as a result of selective phagocytosis of the intermediate organisms. Similar mutation to the maximally virulent type III form was noted with a transformed intermediate type III strain grown from single cell preparations.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1917
Author(s):  
Guangpu Zhang ◽  
Rong Wo ◽  
Zhe Sun ◽  
Gazi Hao ◽  
Guigao Liu ◽  
...  

A magnetic metal−organic frameworks adsorbent (Fe3O4@MIL-53(Al)) was prepared by a typical solvothermal method for the removal of bisphenol A (BPA), tetracycline (TC), congo red (CR), and methylene blue (MB). The prepared Fe3O4@MIL-53(Al) composite adsorbent was well characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and fourier transform infrared spectrometer (FTIR). The influence of adsorbent quantity, adsorption time, pH and ionic strength on the adsorption of the mentioned pollutants were also studied by a UV/Vis spectrophotometer. The adsorption capacities were found to be 160.9 mg/g for BPA, 47.8 mg/g for TC, 234.4 mg/g for CR, 70.8 mg/g for MB, respectively, which is superior to the other reported adsorbents. The adsorption of BPA, TC, and CR were well-fitted by the Langmuir adsorption isotherm model, while MB followed the Freundlich model, while the adsorption kinetics data of all pollutants followed the pseudo-second-order kinetic models. The thermodynamic values, including the enthalpy change (ΔH°), the Gibbs free energy change (ΔG°), and entropy change (ΔS°), showed that the adsorption processes were spontaneous and exothermic entropy-reduction process for BPA, but spontaneous and endothermic entropy-increasing processes for the others. The Fe3O4@MIL-53(Al) was also found to be easily separated after external magnetic field, can be a potential candidate for future water treatment.


2021 ◽  
Vol 129 (5) ◽  
pp. 053301
Author(s):  
Eric Freund ◽  
Lea Miebach ◽  
Ramona Clemen ◽  
Michael Schmidt ◽  
Amanda Heidecke ◽  
...  

PLoS ONE ◽  
2010 ◽  
Vol 5 (5) ◽  
pp. e10505 ◽  
Author(s):  
Rong Lu ◽  
Shaoping Wu ◽  
Xingyin Liu ◽  
Yinglin Xia ◽  
Yong-guo Zhang ◽  
...  

2011 ◽  
Vol 286 (41) ◽  
pp. 36098-36107 ◽  
Author(s):  
Xiu-Jun Yu ◽  
Mei Liu ◽  
Steve Matthews ◽  
David W. Holden

Type III secretion systems (T3SSs) of bacterial pathogens involve the assembly of a surface-localized needle complex, through which translocon proteins are secreted to form a pore in the eukaryotic cell membrane. This enables the transfer of effector proteins from the bacterial cytoplasm to the host cell. A structure known as the C-ring is thought to have a crucial role in secretion by acting as a cytoplasmic sorting platform at the base of the T3SS. Here, we studied SsaQ, an FliN-like putative C-ring protein of the Salmonella pathogenicity island 2 (SPI-2)-encoded T3SS. ssaQ produces two proteins by tandem translation: a long form (SsaQL) composed of 322 amino acids and a shorter protein (SsaQS) comprising the C-terminal 106 residues of SsaQL. SsaQL is essential for SPI-2 T3SS function. Loss of SsaQS impairs the function of the T3SS both ex vivo and in vivo. SsaQS binds to its corresponding region within SsaQL and stabilizes the larger protein. Therefore, SsaQL function is optimized by a novel chaperone-like protein, produced by tandem translation from its own mRNA species.


1984 ◽  
Vol 99 (5) ◽  
pp. 1696-1705 ◽  
Author(s):  
P C Marchisio ◽  
D Cirillo ◽  
L Naldini ◽  
M V Primavera ◽  
A Teti ◽  
...  

The cell-substratum interaction was studied in cultures of osteoclasts isolated from the medullary bone of laying hens kept on low calcium diet. In fully spread osteoclasts, cell-substratum adhesion mostly occurred within a continuous paramarginal area that corresponded also to the location of a thick network of intermediate filaments of the vimentin type. In this area, regular rows of short protrusions contacting the substratum and often forming a cup-shaped adhesion area were observed in the electron microscope. These short protrusions showed a core of F-actin-containing material presumably organized as a network of microfilaments and surrounded by a rosette-like structure in which vinculin and alpha-actinin were found by immunofluorescence microscopy. Rosettes were superposable to dark circles in interference-reflection microscopy and thus represented circular forms of close cell-substratum contact. The core of ventral protrusions also contained, beside F-actin, fimbrin and alpha-actinin. Villin was absent. This form of cell-substratum contact occurring at the tip of a short ventral protrusion differed from other forms of cell-substratum contact and represented an osteoclast-specific adhesion device that might also be present in in vivo osteoclasts as well as in other normal and transformed cell types.


1991 ◽  
Vol 114 (4) ◽  
pp. 773-786 ◽  
Author(s):  
P D Kouklis ◽  
T Papamarcaki ◽  
A Merdes ◽  
S D Georgatos

To identify sites of self-association in type III intermediate filament (IF) proteins, we have taken an "anti-idiotypic antibody" approach. A mAb (anti-Ct), recognizing a similar feature near the end of the rod domain of vimentin, desmin, and peripherin (epsilon site or epsilon epitope), was characterized. Anti-idiotypic antibodies, generated by immunizing rabbits with purified anti-Ct, recognize a site (presumably "complementary" to the epsilon epitope) common among vimentin, desmin, and peripherin (beta site or beta epitope). The beta epitope is represented in a synthetic peptide (PII) modeled after the 30 COOH-terminal residues of peripherin, as seen by comparative immunoblotting assays. Consistent with the idea of an association between the epsilon and the beta site, PII binds in vitro to intact IF proteins and fragments containing the epsilon epitope, but not to IF proteins that do not react with anti-Ct. Microinjection experiments conducted in vivo and filament reconstitution assays carried out in vitro further demonstrate that "uncoupling" of this site-specific association (by competition with PII or anti-Ct) interferes with normal IF architecture, resulting in the formation of filaments and filament bundles with diameters much greater than that of the normal IFs. These thick fibers are very similar to the ones observed previously when a derivative of desmin missing 27 COOH-terminal residues was assembled in vitro (Kaufmann, E., K. Weber, and N. Geisler. 1985. J. Mol. Biol. 185:733-742). As a molecular explanation, we propose here that the epsilon and the beta sites of type III IF proteins are "complementary" and associate during filament assembly. As a result of this association, we further postulate the formation of a surface-exposed "loop" or "hairpin" structure that may sterically prevent inappropriate filament-filament aggregation and regulate filament thickness.


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