Efficacy of sodium polyanethol sulfonate on herpes simplex virus-1 infection in vitro.

Objective: To investigate the effect of sodium polyanethol sulfonate (SPS) on herpes simplex virus type 1 (HSV-1) infection in vitro. Methods: Human corneal epithelial (HCE-T) cells and Vero cells were infected with HSV-1 [HSV-1 f strain, HSV-1f; HSV-1-H129 with green fluorescent protein (GFP) knock-in, HSV-1g]. SPS was added to the culture medium at various concentrations in time-of-addition assay. Experiments including photography of fluorescence in HSV-1g or plaque formation by HSV-1f, western blot assays, real-time RT-PCR assays, cytopathic effect inhibition assays, cytotoxicity assays, and viral absorption and penetration assays were performed to explore the antiviral effect and mechanism of the compounds. Results: We identified that SPS reduced the replication of HSV-1 in HCE-T and Vero cells in a dose-dependent manner. HSV-1g fluorescence was reduced by 66.3% and 65.4% in HCE-T and Vero cells, respectively, after treatment with 0.4 µg/ml SPS. Furthermore, the viral fluorescence intensities were inhibited by SPS in a dose-dependent manner when the viruses or cells were preincubated with SPS. Relative levels of the ICP4 protein and VP16 mRNA were decreased by SPS in a dose-dependent manner. Moreover, the IC50 values of SPS for HSV-1g and HSV-1f in HCE-T cells were 0.69±0.09 µg/ml and 1.63±0.44 µg/ml, respectively. Even 10,000 µg/ml SPS had no obvious cytotoxicity toward HCE-T and Vero cells. Importantly, viral absorption and penetration assays showed that the relative fluorescence intensity of HSV-1g was significantly reduced by SPS in a dose-dependent manner in the absorption test, but no change was observed in the penetration test. Conclusions: SPS inhibits HSV-1 replication in HCE-T and Vero cells, indicating that SPS has the potential for treating HSV-1 infection, particularly HSV-1 keratitis.

SPS-neutralization in tissue samples for efficacy testing of antimicrobial peptides.

BACKGROUND: Accurate determination of the efficacy of antimicrobial agents requires neutralization of residual antimicrobial activity in the samples before microbiological assessment of the number of surviving bacteria. Sodium polyanethol sulfonate (SPS) is a known neutralizer for the antimicrobial activity of aminoglycosides and polymyxins. In this study, we evaluated the ability of SPS to neutralize residual antimicrobial activity of antimicrobial peptides [SAAP-148 and pexiganan; 1% (wt/v) in PBS], antibiotics [mupirocin (Bactroban) and fusidic acid (Fucidin) in ointments; 2% (wt/wt))] and disinfectants [2% (wt/wt) silver sulfadiazine cream (SSD) and 0.5% (v/v) chlorhexidine in 70% alcohol]. METHODS: Homogenates of human skin models that had been exposed to various antimicrobial agents for 1 h were pipetted on top of Methicillin-resistant Staphylococcus aureus (MRSA) on agar plates to determine whether the antimicrobial agents display residual activity. To determine the optimal concentration of SPS for neutralization, antimicrobial agents were mixed with PBS or increasing doses of SPS in PBS (0.05-1% wt/v) and then 105 colony forming units (CFU)/mL MRSA were added. After 30 min incubation, the number of viable bacteria was assessed. Next, the in vitro efficacy of SAAP-148 against various gram-positive and gram-negative bacteria was determined using PBS or 0.05% (wt/v) SPS immediately after 30 min incubation of the mixture. Additionally, ex vivo excision wound models were inoculated with 105 CFU MRSA for 1 h and exposed to SAAP-148, pexiganan, chlorhexidine or PBS for 1 h. Subsequently, samples were homogenized in PBS or 0.05% (wt/v) SPS and the number of viable bacteria was assessed. RESULTS: All tested antimicrobials displayed residual activity in tissue samples, resulting in a lower recovery of surviving bacteria on agar. SPS concentrations at ≥0.05% (wt/v) were able to neutralize the antimicrobial activity of SAAP-148, pexiganan and chlorhexidine, but not of SSD, Bactroban and Fucidin. Finally, SPS-neutralization in in vitro and ex vivo efficacy tests of SAAP-148, pexiganan and chlorhexidine against gram-positive and gram-negative bacteria resulted in significantly higher numbers of CFU compared to control samples without SPS-neutralization. CONCLUSIONS: SPS was successfully used to neutralize residual activity of SAAP-148, pexiganan and chlorhexidine and this prevented an overestimation of their efficacy.

Sodium Polyanethol Sulfonate Modulates Natural Transformation of SigH-Expressing Staphylococcus aureus.

Expression of genes required for natural genetic competence in Staphylococcus aureus is controlled by an alternative transcription sigma factor, SigH. However, even in the SigH-expressing cells, the DNA transformation efficiency varies depending on culture conditions. We report here that cells grown in the competence-inducing medium (CS2 medium) exhibit enlarged morphology with disintegrated cell walls. Notably, an autolysis inhibitor, Sodium Polyanethol Sulfonate (SPS), facilitated transformation in CS2 medium in a dose-dependent manner, suggesting the involvement of the cell wall metabolism in transformation. However, the transformation efficiency of cells grown in TSB was not improved by physical or enzymatic damage on the cell walls.

Stripe-like Clay Nanotubes Patterns in Glass Capillary Tubes for Capture of Tumor Cells.

Here, we used capillary tubes to evaporate an aqueous dispersion of halloysite nanotubes (HNTs) in a controlled manner to prepare a patterned surface with ordered alignment of the nanotubes . Sodium polystyrenesulfonate (PSS) was added to improve the surface charges of the tubes. An increased negative charge of HNTs is realized by PSS coating (from -26.1 mV to -52.2 mV). When the HNTs aqueous dispersion concentration is higher than 10%, liquid crystal phenomenon of the dispersion is found. A typical shear flow behavior and decreased viscosity upon shear is found when HNTs dispersions with concentrations higher than 10%. Upon drying the HNTs aqueous dispersion in capillary tubes, a regular pattern is formed in the wall of the tube. The width and spacing of the bands increase with HNTs dispersion concentration and decrease with the drying temperature for a given initial concentration. Morphology results show that an ordered alignment of HNTs is found especially for the sample of 10%. The patterned surface can be used as a model for preparing PDMS molding with regular micro-/nanostructure. Also, the HNTs rough surfaces can provide much higher tumor cell capture efficiency compared to blank glass surfaces. The HNTs ordered surfaces provide promising application for biomedical areas such as biosensors.

Sodium polyanethol sulfonate (SPS) falsifies protein staining and quantification and how to solve this problem.

Sodium polyanethol sulfonate (SPS) is an anionic detergent with a broad range of activities and applications. While studying the excretion of cytoplasmic proteins in Staphylococcus aureus SPS was used as cell lysis inhibitor. When investigating the protein pattern of culture supernatants from cells grown in the absence or presence of SPS by Coomassie blue stained polyacrylamide gel the amount of protein bands was significantly decreased in the presence of SPS, suggesting that this effect was due to inhibition of cell lysis. However, various control studies showed that the apparent decreased protein secretion was an artifact due to the interference of SPS with Coomassie blue- and silver-staining. The only alternative method that was uninfluenced by SPS was imidazole-SDS-zinc staining. This is the method of choice particularly when protein interfering compounds are present in the extracts. For protein quantification in liquid samples the bicinchoninic acid (BCA) assay appeared to be the method of choice in the presence of SPS. The assay is based on neutral peptide bonds and is therefore rather insensitive to interfering compounds. This study shows that SPS and most likely also related detergents might falsify conventional protein staining and quantification methods.

Heat transfer within hydrodissection fluids: An analysis of thermal conduction and convection using liquid and gel materials.

Interventional oncology procedures such as thermal ablation are becoming widely used for many tumours in the liver, kidney and lung. Thermal ablation refers to the focal destruction of tissue by generating cytotoxic temperatures in the treatment zone. Hydrodissection - separating tissues with fluids - protects healthy tissues adjacent to the ablation treatment zone to improve procedural safety, and facilitate more aggressive power application or applicator placement. However, fluids such as normal saline and 5% dextrose in water (D5W) can migrate into the peritoneum, reducing their protective efficacy. As an alternative, a thermo-gelable poloxamer 407 (P407) solution has been recently developed to facilitate hydrodissection procedures. We hypothesise that the P407 gel material does not provide convective heat dissipation from the ablation site, and therefore may alter the heat transfer dynamics compared to liquid materials during hydrodissection-assisted thermal ablation. The purpose of this study was to investigate the heat dissipation mechanics within D5W, liquid P407 and gel P407 hydrodissection barriers. Overall it was shown that the gel P407 dissipated heat primarily through conduction, whereas the liquid P407 and D5W dissipated heat through convection. Furthermore, the rate of temperature change within the gel P407 was greater than liquid P407 and D5W. Testing to evaluate the in vivo efficacy of the fluids with different modes of heat dissipation seems warranted for further study.

Colitis isquémica secundaria a poliestireno sulfonato cálcico (Kalimato) no asociado a sorbitol / Colonic necrosis due to calcium polystyrene sulfonate (Kalimate) not suspended in sorbitol

Las resinas de intercambio iónico forman parte del tratamiento habitual de la hiperkaliemia, especialmente en pacientes con insuficiencia renal crónica. Estas resinas se han asociado en muchas ocasiones a lesiones del tracto digestivo, especialmente en el caso del poliestireno sulfonato sódico (Kayexalato) asociado a sorbitol. Presentamos el caso de un paciente con una hemorragia digestiva secundaria a colitis isquémica asociada a cristales de poliestireno sulfonato cálcico (Kalimato) sin sorbitol (AU)

Cation-exchange resins are used in the management of hyperkalemia, particularly in patients with end-stage renal disease. These resins were associated with gastrointestinal tract lesions, especially sodium polystyrene sulfonate (Kayexalate) mixed with sorbitol. We present a case of colonic necrosis after the administration of calcium polystyrene sulfonate (Kalimate) not suspended in sorbitol (AU)

Expanding the diagnostic use of PCR in leptospirosis: improved method for DNA extraction from blood cultures.

BACKGROUND: Leptospirosis is a neglected zoonosis of ubiquitous distribution. Symptoms are often non-specific and may range from flu-like symptoms to multi-organ failure. Diagnosis can only be made by specific diagnostic tests like serology and PCR. In non-endemic countries, leptospirosis is often not suspected before antibiotic treatment has been initiated and consequently, relevant samples for diagnostic PCR are difficult to obtain. Blood cultures are obtained from most hospitalized patients before antibiotic therapy and incubated for at least five days, thus providing an important source of blood for PCR diagnosis. However, blood cultures contain inhibitors of PCR that are not readily removed by most DNA-extraction methods, primarily sodium polyanetholesulfonate (SPS). METHODOLOGY/PRINCIPAL FINDINGS: In this study, two improved DNA extraction methods for use with blood cultures are presented and found to be superior in recovering DNA of Leptospira interrogans when compared with three previously described methods. The improved methods were easy and robust in use with all tested brands of blood culture media. Applied to 96 blood cultures obtained from 36 patients suspected of leptospirosis, all seven patients with positive convalescence serology were found positive by PCR if at least one anaerobic and one aerobic blood culture, sampled before antibiotic therapy were tested. CONCLUSIONS/SIGNIFICANCE: This study suggests that a specific and early diagnosis can be obtained in most cases of severe leptospirosis for up to five days after initiation of antimicrobial therapy, if PCR is applied to blood cultures already sampled as a routine procedure in most septic patients.

Sodium polyanethole sulfonate as an inhibitor of activation of complement function in blood culture systems.

Sodium polyanethole sulfonate (SPS; trade name, Liquoid) is a constituent in culture media used to grow bacteria from blood samples from patients suspected of bacteremia. SPS prevents the killing of bacteria by innate cellular and humoral factors. We analyzed the effect of SPS on the three complement activation pathways: the classical, alternative, and lectin pathways, respectively. Inhibition of complement activity by SPS is caused by a blocking of complement activation and is not a result of complement consumption. The classical pathway is inhibited at SPS concentrations greater than 0.1 mg/ml, and complete inhibition is seen at 0.4 mg/ml. An SPS concentration of 0.5 mg/ml completely inhibits the binding of C1q and subsequent incorporation of C3, C4, and C9. The same was observed for the alternative pathway with an inhibition at SPS concentrations from 0.1 mg/ml and a complete inhibition from 0.4 mg/ml. Here, properdin binding was completely absent, and no incorporation of C3 and C9 was observed. In contrast, the lectin complement pathway remains unaffected at these SPS concentrations, and inhibition is first observed from 0.7 mg/ml. A complete inhibition required concentrations greater than 1 mg/ml. SPS is used in growth media (e.g., BACTEC and BacT/Alert) at concentrations from 0.3 to 0.5 mg/ml. The well-known finding that certain bacteria are growth inhibited by blood factors could therefore be a consequence of the lectin pathway, which is not inhibited at these concentrations. In addition, our findings also open up the possibility of a new assay for the assessment of the functional capacity of the lectin complement pathway.

Anticoagulant carryover may influence clot formation in direct tube coagulase tests from blood cultures.

The tube coagulase test (TCT) performed directly from positive blood culture bottles has been used to reduce the turnaround time for identifying Staphylococcus aureus. Most reports have shown the test to be specific but often lacking sufficient sensitivity to be useful. In a prospective study of blood culture bottles (BCB) signaling positive, with a Gram-stained smear showing gram-positive cocci resembling staphylococci, the sensitivity of the direct TCT was improved by diluting the BCB broth 1:10 in saline before inoculating 0.1 ml into 1.0 ml of 10% pooled human plasma. It was hypothesized that the improved sensitivity might be explained by reduced carryover of the anticoagulant sodium polyanetholesulfonate (SPS) used in blood culture media. By titrating the inoculum size and the concentration of SPS in an in vitro checkerboard assay, it was shown that concentrations of SPS >0.0008% prevented plasma coagulation. The 1:10 dilution of blood culture broth reduced the amount of residual SPS carried over to the TCT to a level (0.0005%) that did not impair plasma coagulation. The direct TCT inoculated with a 1:10 saline dilution of blood culture broth achieved 100% specificity and sensitivity within 4 h of inoculation without reducing the quality or quantity of coagulum.

Staphylococcus aureus requires increased level of Ca(2+) or Mn(2+) to grow normally in a high-NaCl/low-Mg(2+) medium.

Mg2+-availability in Staphylococcus aureus cells decreased significantly with increasing NaCl concentration in growth media. Cells grew in a NaCl-free, Chelex resin-treated complex medium only if the medium was supplemented with 50 microM MgCl2, while, growth was limited when the medium was further supplemented with 1.0 M NaCl. Cells grown in such a high-NaCl/low-Mg2+ medium exhibited the morphologic abnormality of larger than normal cells. Both sufficient growth and normal cell morphology were restored by increasing Mg2+ concentration in a high-NaCl medium, or by supplementation with either CaCl2 or MnSO4 in a high-NaCl/low-Mg2+ medium. Supplementing with BaCl2, SrCl2 or FeSO4, however, had no effect. These results indicate that Ca2+ and Mn2+ might play some essential role in the growth of Staphylococcus aureus in a high-NaCl/low-Mg2+ environment.

Efecto negativo de los componentes del sistema lisis-centrifugación en el crecimiento de micobacterias en los medios líquidos mgit y septi- chek afb / Negative effect of the components in the lysis- centrifugation system for mycobacterial growth in fluid media MGIT and Septi-Check AFB

Fundamento. El sistema lisis-centrifugación (Isolator system) es una técnica con excelentes resultados en la recuperación de micobacterias en muestras de sangre. Este sistema está compuesto fundamentalmente por saponina (SAP), polipropilenglicol (PPG) y polianetol sulfonato de sodio (SPS). El objetivo de este estudio fue determinar el efecto de SAP, PPG y SPS sobre el crecimiento de Mycobacterium avium, M. kansasii, M. tuberculosis y M. xenopi en los medios de cultivo líquidos MGIT y Septi-Chek AFB. Métodos. Se prepararon en dos concentraciones SAP, PPG y SPS, y se añadieron en cantidad de 0,1 ml (individualmente, en parejas y en combinación los tres) en los medios líquidos MGIT y Septi-Chek AFB. Posteriormente los medios de cultivo líquidos fueron inoculados individualmente con dos concentraciones diferentes (103 y 105 unidades formadoras de colonias [UFC]/ml) de cada una de las cuatro micobacterias utilizadas en este estudio. Los medios fueron incubados a 37ºC y diariamente se vigiló el crecimiento. Resultados. SAP, PPG y SPS no anularon el crecimiento de las micobacterias, pero sí lo retardaron (mayor tiempo en la detección del crecimiento con relación al control positivo). Las concentraciones finales de SAP, PPG y SPS que retardaron el crecimiento de las micobacterias fueron variables, dependiendo de la especie e inóculo micobacteriano, e igualmente del medio líquido utilizado. Conclusiones. Las sustancias que componen el sistema lisis-centrifugación (SAP, PPG y SPS) en forma individual y combinada retardaron el crecimiento de M. avium, M. kansasii, M, tuberculosis y M. xenopi en concentraciones de 103 y 105 UFC/ml, en los medios de cultivo líquidos MGIT y Septi-Chek AFB. Estos resultados sugieren la necesidad de plantear estrategias para disminuir las concentraciones de estas tres sustancias, presentes en el sedimento de la sangre procesada por el sistema Isolator, que finalmente van a ser añadidas a los medios líquidos MGIT y Septi-Chek AFB (AU)

Necrosis intestinal asociada a la administración de sulfonato de poliestireno sódico: presentación de un caso / Intestinal necrosis associated with the administration of sodium polystyrene sulfonate: a case representation

Varias son las complicaciones gastrointestinales observadas en pacientes urémicos, que pueden aparecer además en relación a las medidas terapeúticas usadas. Se presenta el caso de un anciano en diálisis peritoneal durante varios años, con múltiples episodios de rectorragia. Se le diagnosticó angiodisplasia de ciego y se trató con láser y Resin sodio oral. A las 24 horas del posoperatorio presenta perforación ileal, con presencia de cristales de Resin sodio en la zona de necrosis intestinal (AU)

[Negative effect of the components of the lysis-centrifugation system in the growth of mycobacteria in MGIT and Septi-Chek AFB liquid media]. / Efecto negativo de los componentes del sistema lisis-centrifugación en el crecimiento de micobacterias en los medios líquidos MGIT y Septi-Chek AFB.

BACKGROUND: The lysis-centrifugation system (Isolator system) is a technique with excellent results in the recovery of mycobacteria from blood specimens. This system consists mainly of saponin (SAP), polypropylenglycol (PPG), and sodium polianthol sulfonate (SPS). The objective of this work was to determine the effect of SAP, PPG, and SPS on the growth of Mycobacterium avium, M. kansasii, M. tuberculosis, and M. xenopi in fluid culture media MGIT and Septi-Chek AFB. METHODS: Two concentrations each of SAP, PPG, and SPS were prepared, and were added in 0.1 ml amounts (alone, in pairs and in combination) to fluid media MGIT and Septi-Chek AFB. Fluid culture media were then in individually inoculated with two different concentrations (10(3) and 10(5) CFU/ml) of each of the four mycobacterial strains used in this study. Culture media were incubated at 37 degrees C and were checked for growth daily. RESULTS: SAP, PPG, and SPS did not inhibit growth of mycobacteria but growth of these strains was indeed retarded (a lengthier time was required for detection of bacterial growth compared with the positive control). Final concentrations of SAP, PPG, and SPS which retarded mycobacterial growth varied, depending upon species, mycobacterial inoculum size, and fluid culture media used. CONCLUSIONS: Components included in the lysy-centrifugation system (SAP, PPG, and SPS), either alone or in combination retarded growth of M. avium, M. kansasii, M. tuberculosis, and M. xenopi in 10(3) and 10(5) CFU/ml concentrations in fluid culture media MGIT and Septi-Chek AFB. These results suggest that strategies should be adopted to decrease the concentrations of these three components, present in the sediment of the processed blood by the Isolator System, which eventually are going to be added to fluid media MGIT and Septi-Check AFB.

Age-associated differences in neutrophil oxidative burst (chemiluminescence).

Phagocytic defensive functions consist of a sequence of events, including migration, phagocytosis, secretion, and the release of reactive oxygen species (ROS). The last of these (also called "oxidative burst") has not received due attention in the elderly, even though it can be considered the most important event in the process of killing an invading microorganism. The aim of the present study was to investigate the oxidative burst activity of polymorphonuclear neutrophil leukocytes (PMNs) in relation to age, using a technique that specifically identifies ROS production: luminol-amplified chemiluminescence (LACL). Besides the use of LACL, a particular feature of the study was the use of five rather than just one or two different stimulants: two particulate (Candida albicans and zymosan) and three soluble ones [N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol 12 myristate 13 acetate (PMA), and polyanetholesulfonate (liquoid)]. This approach allowed us to observe a dichotomy between the effects of Candida and zymosan (particulates), which were not significantly different in the elderly subjects compared to the young controls, and those of fMLP, PMA, and liquoid (solubles), which showed a significant reduction in LACL in the elderly group. Considering the different results obtained with the various stimulants adopted that are all believed to have NADPH oxidase as a common final target of oxidative burst, it may be postulated that aging can influence the different transductional pathways in different ways.

Improved amplification of microbial DNA from blood cultures by removal of the PCR inhibitor sodium polyanetholesulfonate.

Molecular methods are increasingly used to identify microbes in clinical samples. A common technical problem with PCR is failed amplification due to the presence of PCR inhibitors. Initial attempts at amplification of the bacterial 16S rRNA gene from inoculated blood culture media failed for this reason. The inhibitor persisted, despite numerous attempts to purify the DNA, and was identified as sodium polyanetholesulfonate (SPS), a common additive to blood culture media. Like DNA, SPS is a high-molecular-weight polyanion that is soluble in water but insoluble in alcohol. Accordingly, SPS tends to copurify with DNA. An extraction method was designed for purification of DNA from blood culture media and removal of SPS. Blood culture media containing human blood and spiked with Escherichia coli was subjected to an organic extraction procedure with benzyl alcohol, and removal of SPS was documented spectrophotometrically. Successful amplification of the extracted E. coli 16S rRNA gene was achieved by adding 5 microliter of undiluted processed sample DNA to a 50-microliter PCR mixture. When using other purification methods, the inhibitory effect of SPS could be overcome only by dilution of these samples. By our extraction technique, even uninoculated blood culture media were found to contain bacterial DNA when they were subjected to broad-range 16S rRNA gene consensus PCR. We conclude that the blood culture additive SPS is a potent inhibitor of PCR, is resistant to removal by traditional DNA purification methods, but can be removed by a benzyl alcohol extraction protocol that results in improved PCR performance.

Isolator component responsible for inhibition of Mycobacterium avium-M. intracellulare in BACTEC 12B medium.

We previously reported an inhibitory effect on Mycobacterium avium-M. intracellulare (MAI) when blood collected and processed with the Isolator system was placed in BACTEC 12B bottles for radiometric monitoring. We sought to identify the specific component(s) of the Isolator lysis-anticoagulant reagent (LAR) responsible for the inhibitory effect. We added the three components of the LAR, saponin, polyanetholesulfonate, and polypropylene glycol (PPG), to triplicate sets of BACTEC bottles separately and in various combinations. These bottles were then seeded with 10(2) CFU of MAI. The growth index (GI) was observed over a 42-day period and was compared with the GI for a growth control bottle set with no reagents and with the GI for a bottle set containing an equivalent volume of LAR. Growth in all growth control bottles and those bottles containing no PPG reached the maximum GI (GI = 999) within 8 to 10 days. Growth in bottles containing PPG never reached the maximum GI before day 14. In addition, the GIs of one bottle containing all three reagent components as well as all of the bottles containing actual Isolator LAR failed to reach the maximum within 42 days. Our data suggest that PPG is the main cause of the inhibitory effect, but that a secondary synergistic interaction between all three of the reagents may also be present.

Adherence of Mycoplasma pneumoniae to human alveolar macrophages.

The human pathogen Mycoplasma pneumoniac causes primary atypical-cold agglutinin-positive pneumonia. Since alveolar macrophages internalize mycoplasma as part of their immune defense, we studied characteristics of the human macrophage receptor for opsonized and nonopsonized M. pneumoniae. The glass-adhering subpopulation of M. pneumoniae attached more than the non-adherent subpopulation. The attachment was dose-dependent and enhanced by opsonization in the presence of human serum. It is inhibited by sulfated compounds such as dextran-sulfate and polyanetholsulfonic acid, but not by dextran or several monosaccharides, suggesting that sulfated glycolipids on the macrophage surface may act as receptors for M. pneumoniae binding. In addition, sialylated compounds, such as fetuin and alpha 1-acid glycoprotein, were found to be potent inhibitors of the attachment, also indicating the role of sialic acid residue in recognition and attachment of M. pneumoniae to human alveolar macrophages.

Salt-induced cell lysis of Staphylococcus aureus.

Cell lysis was efficiently induced in Staphylococcus aureus by the addition of 0.3 M NaCl to exponentially growing cultures at 30 degrees C. When cells harvested at the exponential phase were incubated in buffer with NaCl, autolysis occurred. Treatment with chloramphenicol failed to induce cell lysis by NaCl. The effects of NaCl on growing cells and harvested cells were inhibited by the addition of sodium polyanethole sulfonate, subtilisin, cardiolipin, and lipoteichoic acid. These agents diminished the activity of a cell wall-lytic enzyme liberated from the cells in the presence of NaCl. Lysis induced by salt appears to be catalyzed by a similar lytic enzyme in growing and harvested cells.