scholarly journals Comment on “A commensal strain of Staphylococcus epidermidis protects against skin neoplasia” by Nakatsuji et al.

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw3915
Author(s):  
Stanislav G. Kozmin ◽  
Igor B. Rogozin ◽  
Elizabeth A. Moore ◽  
Mariah Abney ◽  
Roel M. Schaaper ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Staphylococcus Epidermidis ◽  
Recent Article ◽  
Antitumor Activities ◽  
Base Form ◽  
Commensal Strain ◽  
Mutagenic Effects ◽  
Mutagenic Compound ◽  
Skin Neoplasia

A recent article in Science Advances described the striking discovery that the commensal Staphylococcus epidermidis strain MO34 displays antimicrobial and antitumor activities by producing a small molecule, identified as the nucleobase analog 6-N-hydroxylaminopurine (6-HAP). However, in contradiction to the literature, the authors claimed that 6-HAP is nonmutagenic and proposed that the toxic effect of 6-HAP results from its ability to inhibit, in its base form, DNA synthesis. To resolve the discrepancy, we proved by genetic experiments with bacteria and yeast that extracts of MO34 do contain a mutagenic compound whose effects are identical to chemically synthesized 6-HAP. The MO34 extract induced the same mutation spectrum as authentic 6-HAP. Notably, the toxic and mutagenic effects of both synthetic and MO34-derived 6-HAP depended on conversion to the corresponding nucleotide. The nucleobase 6-HAP does not inhibit DNA synthesis in vitro, and we conclude that 6-HAP exerts its biological activity when incorporated into DNA.

scholarly journals Response to Comment on “A commensal strain of Staphylococcus epidermidis protects against skin neoplasia” by Nakatsuji et al.

2019 ◽  
Vol 5 (9) ◽  
pp. eaay5611
Author(s):  
Teruaki Nakatsuji ◽  
William Fenical ◽  
Richard L. Gallo
Keyword(s):  
Staphylococcus Epidermidis ◽  
Model Systems ◽  
Inhibit Tumor Growth ◽  
Antitumor Activities ◽  
In Vitro Techniques ◽  
Commensal Strain ◽  
The Common ◽  
Skin Bacterium ◽  
Skin Neoplasia

Kozmin et al. contend that observations previously reported regarding the antimicrobial and antitumor activities of 6-N-hydroxy aminopurine (6-HAP) were incorrect. Their conclusions rely on poorly characterized reagents and focus strictly on in vitro techniques without validation in relevant mammalian model systems. We are pleased to be able to illuminate the weaknesses in their technical comment. The totality of current results continues to support our original conclusion that a strain of the common human commensal skin bacterium, Staphylococcus epidermidis, produces 6-HAP that can inhibit tumor growth.

Scanning Electron Microscopy of Staphylococcus Epidermidis Adherence to Continuous Ambulatory Peritoneal Dialysis Catheters

1985 ◽  
Vol 43 ◽  
pp. 520-521
Author(s):  
William J. Lamoreaux ◽  
David L. Smalley ◽  
Larry M. Baddour ◽  
Alfred P. Kraus
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Peritoneal Dialysis ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
Staphylococcus Epidermidis ◽  
Sterile Saline ◽  
Intravascular Devices ◽  
Capd Patient ◽  
Scanning Electron

Infections associated with the use of intravascular devices have been documented and have been reported to be related to duration of catheter usage. Recently, Eaton et al. reported that Staphylococcus epidermidis may attach to silastic catheters used in continuous ambulatory peritoneal dialysis (CAPD) treatment. The following study presents findings using scanning electron microscopy (SEM) of S. epidermidis adherence to silastic catheters in an in vitro model. In addition, sections of polyvinyl chloride (PVC) dialysis bags were also evaluated by SEM.The S. epidermidis strain RP62A which had been obtained in a previous outbreak of coagulase-negative staphylococcal sepsis at local hospitals was used in these experiments. The strain produced surface slime on exposure to glucose, whereas a nonadherent variant RP62A-NA, which was also used in these studies, failed to produce slime. Strains were grown overnight on blood agar plates at 37°C, harvested from the surface and resuspended in sterile saline (0.85%), centrifuged (3,000 rpm for 10 minutes) and then washed twice in 0.1 M phosphate-buffered saline at pH 7.0. Organisms were resuspended at a concentration of ca. 106 CFU/ml in: a) sterile unused dianeal at 4.25% dextrose, b) sterile unused dianeal at 1.5% dextrose, c) sterile used dialysate previously containing 4.25% dextrose taken from a CAPD patient, and d) sterile used dialysate previously containing 1.5% dextrose taken from a CAPD patient.

Investigating Non-Therapeutic Pharmaceutical Substances for Improving In-Vitro Efficacy of Clindamycin Phosphate Against MRSA and Staphylococcus Epidermidis

2020 ◽  
Vol 18 (2) ◽  
pp. 63-72
Author(s):  
Mohd Aftab Alam ◽  
Fahad I. Al-Jenoobi ◽  
Khaled A. Alzahrani ◽  
Mohammad H. Al-Agamy ◽  
Abdullah M. Al-Mohizea
Keyword(s):  
Fusidic Acid ◽  
Staphylococcus Epidermidis ◽  
Sorbic Acid ◽  
Tween 80 ◽  
Lauryl Sulfate ◽  
Individual Substance ◽  
Dependent Effect ◽  
Pharmaceutical Excipients ◽  
Active Substances

The aim of present study was to investigate the effect of pharmaceutical excipients and other active substances on antimicrobial efficacy of standard antibiotic against resistant and susceptible microorganisms. Pharmaceutical excipients (sodium lauryl sulfate [SLS], Tween-80, citric acid, NaOH, NaCl) and active substances (fusidic acid, sorbic acid) were investigated to check in-vitro efficacy and their effect on the efficacy of standard antibiotic. Clindamycin was selected as standard antibiotic. Clindamycin was found to be ineffective against methicillin-resistant Staphylococcus aureus (MRSA). Fusidic acid and SLS showed concentration dependent effect against MRSA. Other tested substances were also ineffective against MRSA, and also failed to improve the susceptibility of MRSA towards clindamycin. The clindamycin + fusidic acid (0.05 µg, 0.1 µg), and clindamycin + SLS (0.5 mg, 1 mg) showed concentration dependent effect on Staphylococcus epidermidis (S. epidermidis). Clindamycin combinations with fusidic acid or SLS showed better inhibition of S. epidermidis, than individual substance. At lower concentration of clindamycin (2 µg), the sorbic acid (25 µg) improves its effectiveness. SLS (0.5 mg, 1 mg) and clindamycin (4 µg, 10 µg) showed almost equal zone of inhibition against S. epidermidis, respectively. Present findings showed that certain pharmaceutical excipients (e.g. SLS) are effective against resistant and susceptible microbes, and suggested that more excipients should be screened for their antimicrobial potential and their ability to improve the efficacy of standard antibiotics.

Synthesis and Antitumor Activity Evaluation of New Phenanthrene-Based Tylophorine Derivatives

2019 ◽  
Vol 16 (6) ◽  
pp. 462-467
Author(s):  
Songtao Li ◽  
Hongling Zhao ◽  
Zhifeng Yin ◽  
Shuhua Deng ◽  
Yang Gao ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Cell Lines ◽  
Antitumor Activities ◽  
Human Carcinoma ◽  
Carcinoma Cell Lines ◽  
Structure Activity ◽  
Human Carcinoma Cell ◽  
Ic50 Values ◽  
Relationship Of

A series of new phenanthrene-based tylophorine derivatives (PBTs) were synthesized in good yield and their structures were characterized by 1H-NMR spectroscopy and ESI MS. In vitro antitumor activity of these compounds against five human carcinoma cell lines, including HCT116 (colorectal), BGC-823 (gastric), HepG-2 (hepatic), Hela (cervical) and H460 (lung) cells, was evaluated by MTT assay. Among these PBTs, compound 6b showed the highest antitumor activities against HCT116 and HepG-2 cell lines with IC50 values of 6.1 and 6.4 μM, respectively, which were comparable to that of adriamycin hydrochloride. The structure-activity relationship of these compounds was also discussed based on the results of their antitumor activity.

Complement (C5b-9) induces DNA synthesis in rat mesangial cells in vitro

2001 ◽  
Vol 59 (3) ◽  
pp. 905-912
Author(s):  
William G. Couser ◽  
Jeffrey W. Pippin ◽  
Stuart J. Shankland
Keyword(s):  
Dna Synthesis ◽  
Mesangial Cells

scholarly journals The bactericidal effect of vancomycin is not altered by tranexamic acid, adrenalin, dexamethasone, or lidocaine in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christiane Schwerdt ◽  
Eric Röhner ◽  
Sabrina Böhle ◽  
Benjamin Jacob ◽  
Georg Matziolis
Keyword(s):  
Staphylococcus Aureus ◽  
Tranexamic Acid ◽  
Total Joint Arthroplasty ◽  
Staphylococcus Epidermidis ◽  
Joint Infection ◽  
Bactericidal Effect ◽  
Joint Arthroplasty ◽  
Zone Of Inhibition ◽  
Agar Diffusion Test

AbstractOne of the most challenging complications of total knee arthroplasty (TKA) is periprosthetic joint infection (PJI). There is growing evidence of a good anti-infective effect of intrawound vancomycin powder in total joint arthroplasty. At the same time, various different locally applied substances have become popular in total joint arthroplasty. The objective of this study was therefore to investigate a possible inhibition of the bactericidal effect of vancomycin by tranexamic acid, adrenalin, lidocaine, or dexamethasone. The bactericidal effect of vancomycin was quantified using the established method of the agar diffusion test. The plates were incubated with Staphylococcus aureus or Staphylococcus epidermidis and four wells were stamped out. The wells were filled with vancomycin alone, the tested substance alone or a mixture of the two. The fourth well remained empty as a control. The plates were incubated overnight at 37 °C and the zone of inhibition in each field was measured on the next day. All tests were run three times for each pathogen and mean values and standard deviations of the measurements were calculated. Differences between the substances were tested using the t-test at a level of significance of 0.05. The bacterial growth was homogeneous on all plates. The baseline value for the zone of inhibition of vancomycin was on average 6.2 ± 0.4 mm for Staphylococcus aureus and 12 ± 0.3 mm for Staphylococcus epidermidis. In all other substances, no inhibition was detected around the well. The combination of vancomycin and each other substance did not show any different result compared to vancomycin alone. The bactericidal effect of vancomycin on staphylococci is not altered by tranexamic acid, adrenalin, dexamethasone, or lidocaine in vitro.

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