scholarly journals Fibrinogen Induces Biofilm Formation by Streptococcus suis and Enhances Its Antibiotic Resistance

2008 ◽  
Vol 74 (15) ◽  
pp. 4969-4972 ◽  
Author(s):  
Laetitia Bonifait ◽  
Louis Grignon ◽  
Daniel Grenier
Keyword(s):  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Culture Medium ◽  
Streptococcus Suis ◽  
Penicillin G ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Dose Dependent

ABSTRACT In this study, we showed that supplementing the culture medium with fibrinogen induced biofilm formation by Streptococcus suis in a dose-dependent manner. Biofilm-grown S. suis cells were much more resistant to penicillin G than planktonic cells. S. suis bound fibrinogen to its surface, a property that likely contributes to biofilm formation.

scholarly journals In vitro activities of cellulase and ceftazidime, alone and in combination against Pseudomonas aeruginosa biofilms

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Esmat Kamali ◽  
Ailar Jamali ◽  
Ahdieh Izanloo ◽  
Abdollah Ardebili
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Glycoside Hydrolase ◽  
Dependent Manner ◽  
Wound Infections ◽  
Persistent Infections ◽  
Novel Strategy ◽  
Dose Dependent

Abstract Background Biofilms are a main pathogenicity feature of Pseudomonas aeruginosa and has a significant role in antibiotic resistance and persistent infections in humans. We investigated the in vitro activities of antibiotic ceftazidime and enzyme cellulase, either alone or in combination against biofilms of P. aeruginosa. Results Both ceftazidime and cellulase significantly decreased biofilm formation in all strains in a dose-dependent manner. Combination of enzyme at concentrations of 1.25, 2.5, 5, and 10 U/mL tested with 1/16× MIC of antibiotic led to a significant reduction in biofilm biomass. Cellulase showed a significant detachment effect on biofilms at three concentrations of 10 U/mL, 5 U/mL, and 2.5 U/mL. The MIC, MBC, and MBEC values of ceftazidime were 2 to 4 µg/mL, 4 to 8 µg/mL, and 2048 to 8192 µg/mL. When combined with cellulase, the MBECs of antibiotic showed a significant decrease from 32- to 128-fold. Conclusions Combination of the ceftazidime and the cellulase had significant anti-biofilm effects, including inhibition of biofilm formation and biofilm eradication in P. aeruginosa. These data suggest that glycoside hydrolase therapy as a novel strategy has the potential to enhance the efficacy of antibiotics and helps to resolve biofilm-associated wound infections caused by this pathogen.

scholarly journals In VitroAnalyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells

2011 ◽  
Vol 56 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Marisa H. Miceli ◽  
Stella M. Bernardo ◽  
T. S. Neil Ku ◽  
Carla Walraven ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Metabolic Activity ◽  
Biofilm Formation ◽  
High Dose ◽  
Dependent Manner ◽  
Planktonic Cells ◽  
Content Type ◽  
Heparin Sodium ◽  
The Individual

ABSTRACTInfections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin onCandida albicansbiofilms and planktonic cells have not been previously studied. Therefore, we sought to determine thein vitroeffect of a heparin sodium preparation (HP) on biofilms and planktonic cells ofC. albicans. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformedC. albicansbiofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (P< 0.0001). Pure-H, MP, and PP each inhibitedC. albicansbiofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H havein vitroantifungal activity againstC. albicansmature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention ofC. albicansbiofilms is warranted.

Papaya shoot tip associated endophytic bacteria isolated from in vitro cultures and host–endophyte interaction in vitro and in vivo

2007 ◽  
Vol 53 (3) ◽  
pp. 380-390 ◽  
Author(s):  
Pious Thomas ◽  
Sima Kumari ◽  
Ganiga K. Swarna ◽  
T.K.S. Gowda
Keyword(s):  
Culture Medium ◽  
Carica Papaya ◽  
In Vitro Cultures ◽  
Dependent Manner ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Single Organism ◽  
Dose Dependent

Fourteen distinct bacterial clones were isolated from surface-sterilized shoot tips (~1 cm) of papaya (Carica papaya L. ‘Surya’) planted on Murashige and Skoog (MS)-based papaya culture medium (23/50 nos.) during the 2–4 week period following in vitro culturing. These isolates were ascribed to six Gram-negative genera, namely Pantoea ( P. ananatis ), Enterobacter ( E. cloacae ), Brevundimonas ( B. aurantiaca ), Sphingomonas , Methylobacterium ( M. rhodesianum ), and Agrobacterium ( A. tumefaciens ) or two Gram-positive genera, Microbacterium ( M. esteraromaticum ) and Bacillus ( B. benzoevorans ) based on 16S rDNA sequence analysis. Pantoea ananatis was the most frequently isolated organism (70% of the cultures) followed by B. benzoevorans (13%), while others were isolated from single stocks. Bacteria-harboring in vitro cultures often showed a single organism. Pantoea, Enterobacter, and Agrobacterium spp. grew actively on MS-based normal papaya medium, while Microbacterium, Brevundimonas, Bacillus, Sphingomonas, and Methylobacterium spp. failed to grow in the absence of host tissue. Supplying MS medium with tissue extract enhanced the growth of all the organisms in a dose-dependent manner, indicating reliance of the endophyte on its host. Inoculation of papaya seeds with the endophytes (20 h at OD550 = 0.5) led to delayed germination or slow seedling growth initially. However, the inhibition was overcome by 3 months and the seedlings inoculated with Pantoea, Microbacterium, or Sphingomonas spp. displayed significantly better root and shoot growths.

scholarly journals Glyoxalase I is a novel nitric-oxide-responsive protein

1999 ◽  
Vol 344 (3) ◽  
pp. 837-844 ◽  
Author(s):  
Atsushi MITSUMOTO ◽  
Kwi-Ryeon KIM ◽  
Genichiro OSHIMA ◽  
Manabu KUNIMOTO ◽  
Katsuya OKAWA ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Culture Medium ◽  
Molecular Mechanisms ◽  
Peptide Mapping ◽  
Glyoxalase I ◽  
Dependent Manner ◽  
Human Endothelial Cells ◽  
Native Form ◽  
No Donors ◽  
Dose Dependent

To clarify the molecular mechanisms of nitric oxide (NO) signalling, we examined the NO-responsive proteins in cultured human endothelial cells by two-dimensional (2D) PAGE. Levels of two proteins [NO-responsive proteins (NORPs)] with different pI values responded to NO donors. One NORP (pI 5.2) appeared in response to NO, whereas another (pI 5.0) disappeared. These proteins were identified as a native form and a modified form of human glyoxalase I (Glox I; EC 4.4.1.5) by peptide mapping, microsequencing and correlation between the activity and the isoelectric shift. Glox I lost activity in response to NO, and all NO donors tested inhibited its activity in a dose-dependent manner. Activity and normal electrophoretic mobility were restored by dithiothreitol and by the removal of sources of NO from the culture medium. Glox I was selectively inactivated by NO; compounds that induce oxidative stress (H2O2, paraquat and arsenite) failed to inhibit this enzyme. Our results suggest that NO oxidatively modifies Glox I and reversibly inhibits the enzyme's activity. The inactivation of Glox I by NO was more effective than that of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), another NO-sensitive enzyme. Thus Glox I seems to be a novel NO-responsive protein that is more sensitive to NO than G3PDH.

scholarly journals Efficacy of Synthetic Furanones on Listeria monocytogenes Biofilm Formation

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 647 ◽  
Author(s):  
Pedro Rodríguez-López ◽  
Andrea Emparanza Barrenengoa ◽  
Sergio Pascual-Sáez ◽  
Marta López Cabo
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Epifluorescence Microscopy ◽  
Dependent Manner ◽  
Antifouling Activity ◽  
Aisi 316 ◽  
Novel Strategy ◽  
And Control ◽  
Acylated Homoserine Lactones ◽  
Dose Dependent

Furanones are analogues of acylated homoserine lactones with proven antifouling activity in both Gram-positive and Gram-negative bacteria though the interference of various quorum sensing pathways. In an attempt to find new strategies to prevent and control Listeria monocytogenes biofilm formation on stainless steel (SS) surfaces, different concentrations of six synthetic furanones were applied on biofilms formed by strains isolated from food, environmental, and clinical sources grown onto AISI 316 SS coupons. Among the furanones tested, (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone and 3,4-Dichloro-2(5H)-furanone significantly (p < 0.05) reduced the adhesion capacity (>1 log CFU cm−2) in 24 h treated biofilms. Moreover, individually conducted experiments demonstrated that (Z-)-4-Bromo-5-(bromomethylene)-2(5H)-furanone was able to not only significantly (p < 0.05) prevent L. monocytogenes adhesion but also to reduce the growth rate of planktonic cells up to 48 h in a dose-dependent manner. LIVE/DEAD staining followed by epifluorescence microscopy visualisation confirmed these results show an alteration of the structure of the biofilm in furanone-treated samples. Additionally, it was demonstrated that 20 µmol L−1 of 3,4-Dichloro-2(5H)-furanone dosed at 0, 24 and 96 h was able to maintain a lower level of adhered cells (>1 log CFU cm−2; p < 0.05). Since furanones do not pose a selective pressure on bacteria, these results represent an appealing novel strategy for the prevention of L. monocytogenes biofilm grown onto SS.

scholarly journals Uric Acid Secretion from Adipose Tissue and Its Increase in Obesity

2013 ◽  
Vol 288 (38) ◽  
pp. 27138-27149 ◽  
Author(s):  
Yu Tsushima ◽  
Hitoshi Nishizawa ◽  
Yoshihiro Tochino ◽  
Hideaki Nakatsuji ◽  
Ryohei Sekimoto ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Uric Acid ◽  
Acid Secretion ◽  
Acid Production ◽  
Culture Medium ◽  
Dependent Manner ◽  
Obese Mice ◽  
Subsequent Increase ◽  
Dose Dependent ◽  
Uric Acid Secretion

Obesity is often accompanied by hyperuricemia. However, purine metabolism in various tissues, especially regarding uric acid production, has not been fully elucidated. Here we report, using mouse models, that adipose tissue could produce and secrete uric acid through xanthine oxidoreductase (XOR) and that the production was enhanced in obesity. Plasma uric acid was elevated in obese mice and attenuated by administration of the XOR inhibitor febuxostat. Adipose tissue was one of major organs that had abundant expression and activities of XOR, and adipose tissues in obese mice had higher XOR activities than those in control mice. 3T3-L1 and mouse primary mature adipocytes produced and secreted uric acid into culture medium. The secretion was inhibited by febuxostat in a dose-dependent manner or by gene knockdown of XOR. Surgical ischemia in adipose tissue increased local uric acid production and secretion via XOR, with a subsequent increase in circulating uric acid levels. Uric acid secretion from whole adipose tissue was increased in obese mice, and uric acid secretion from 3T3-L1 adipocytes was increased under hypoxia. Our results suggest that purine catabolism in adipose tissue could be enhanced in obesity.

scholarly journals Regulation of steroidogenesis in fetal bovine ovaries: differential effects of LH and FSH

2016 ◽  
Vol 57 (4) ◽  
pp. 275-286 ◽  
Author(s):  
J J Allen ◽  
S L Herrick ◽  
J E Fortune
Keyword(s):  
Culture Medium ◽  
Fetal Life ◽  
Dependent Manner ◽  
Ovarian Steroid ◽  
Steroid Production ◽  
Steroid Synthesis ◽  
Primordial Follicles ◽  
Preovulatory Follicles ◽  
Fetal Bovine ◽  
Dose Dependent

In cattle, primordial follicles form before birth. Fetal ovarian capacity to produce progesterone and estradiol is high before follicle formation begins and decreases around the time follicles first appear (around 90 days of gestation). However, mechanisms that regulate steroid production during this time remain unclear. We hypothesized that LH stimulates progesterone and androgen production and that FSH stimulates aromatization of androgens to estradiol. To test this, we cultured pieces from fetal bovine ovaries for 10 days without or with exogenous hormones and then measured the accumulation of steroids in the culture medium by RIA. LH (100 ng/mL) alone increased the accumulation of progesterone, androstenedione, testosterone and estradiol. FSH (100 ng/mL) alone increased both progesterone and estradiol accumulation, but had no effect on androgens. Exogenous testosterone (0.5 µM) alone greatly increased estradiol accumulation and the combination of testosterone + FSH, but not testosterone + LH, increased estradiol relative to testosterone alone. Interestingly, exogenous testosterone and estradiol decreased progesterone accumulation in a dose-dependent manner. Because the highest dose of estradiol (0.5 µM) decreased progesterone accumulation, but increased both pregnenolone and androstenedione in the same cultures, endogenous estradiol may be a paracrine regulator of steroid synthesis. Together, these results confirm our initial hypotheses and indicate that LH stimulates androgen production in fetal bovine ovaries via the Δ5 pathway, whereas FSH stimulates aromatization of androgens to estradiol. These results are consistent with the two-cell, two-gonadotropin model of estradiol production by bovine preovulatory follicles, which suggests that the mechanisms regulating ovarian steroid production are established during fetal life.

Investigation of the antibiotic resistance and biofilm formation of Staphylococcus aureus strains isolated from gangrenous mastitis of ewes

2012 ◽  
Vol 60 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Osman Tel ◽  
Özkan Aslantaş ◽  
Oktay Keskin ◽  
Ebru Yilmaz ◽  
Cemil Demir
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Virulence Factor ◽  
Resistance Genes ◽  
Biofilm Formation ◽  
Antibiotic Resistance Genes ◽  
Penicillin G ◽  
Beta Lactamase ◽  
Potential Virulence Factor ◽  
Amoxicillin Clavulanic Acid

In this study,Staphylococcus aureusstrains (n = 110) isolated from seven ewe flocks in Sanliurfa, Turkey were screened for antibiotic resistance and biofilmforming ability as well as for genes associated with antibiotic resistance and biofilm-forming ability. All isolates were found to be susceptible to oxacillin, gentamicin, clindamycin, cefoxitin, tetracycline, vancomycin, amoxicillin-clavulanic acid, ciprofloxacin and sulphamethoxazole-trimethoprim. The percent proportions of strains resistant to penicillin G, ampicillin and erythromycin were 27.2% (n = 30), 25.4% (n = 28) and 6.3% (n = 7), respectively. Regarding the antibiotic resistance genes, 32 (29%) isolates carried theblaZ and 8 (7.2%) theermC gene. Other resistance genes were not detected in the isolates. All isolates showed biofilm-forming ability on Congo red agar (CRA), while 108 (98.18%) and 101 (91.81%) of them were identified as biofilm producers by the use of standard tube (ST) and microplate (MP) methods, respectively. All isolates carried theicaA andicaD genes but none of them harboured thebapgene. The results demonstrated thatS. aureusisolates from gangrenous mastitis were mainly resistant to penicillins (which are susceptible to the staphylococcal beta-lactamase enzyme), and less frequently to erythromycin. Furthermore, all of theS. aureusisolates produced biofilm which was considered a potential virulence factor in the pathogenesis of staphylococcal mastitis.

scholarly journals A Dose-Response Study of Antibiotic Resistance inPseudomonas aeruginosa Biofilms

2000 ◽  
Vol 44 (3) ◽  
pp. 640-646 ◽  
Author(s):  
Alexei Brooun ◽  
Songhua Liu ◽  
Kim Lewis
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Molecular Mechanisms ◽  
Bacterial Biofilms ◽  
Bacterial Cells ◽  
Planktonic Cells ◽  
Dose Response Study ◽  
Dose Dependent ◽  
Very High

ABSTRACT Bacterial biofilms show enormous levels of antibiotic resistance, but little is known about the underlying molecular mechanisms. Multidrug resistance pumps (MDRs) are responsible for the extrusion of chemically unrelated antimicrobials from the bacterial cell. Contribution of the MDR-mediated efflux to antibiotic resistance ofPseudomonas aeruginosa biofilms was examined by using strains overexpressing and lacking the MexAB-OprM pump. Resistance ofP. aeruginosa biofilms to ofloxacin was dependent on the expression of MexAB-OprM but only in the low concentration range. Unexpectedly, biofilm resistance to ciprofloxacin, another substrate of MexAB-OprM, did not depend on the presence of this pump. Dose-dependent killing indicated the presence of a small “superresistant” cell fraction. This fraction was primarily responsible for very high resistance of P. aeruginosa biofilms to quinolones. Bacterial cells recovered from a biofilm and tested under nongrowing conditions with tobramycin exhibited higher resistance levels than planktonic cells but lower levels than cells of an intact biofilm.

Are ovine Leydig cells able to aromatize androgens?

1997 ◽  
Vol 9 (2) ◽  
pp. 193 ◽  
Author(s):  
Barbara Biliska ◽  
Marcin Le´sniak ◽  
Barbara Schmalz
Keyword(s):  
Aromatase Inhibitor ◽  
Incubation Period ◽  
Immunohistochemical Staining ◽  
Leydig Cells ◽  
Culture Medium ◽  
Aromatase Activity ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Testosterone Synthesis

The conversion of testosterone into oestradiol by ovine Leydig cells culturedin vitrowas studied using the non-steroidal aromatase inhibitor CGS 16949A. Additionally, aromatase activity was detected by immunohistochemical staining of cultured Leydig cells or cryosections. The cells were obtained from testes of Polish Mountain rams 5–6 months old (immature) or 12–15 months old (mature). Leydig cells were cultured alone (controls) or incubated for 6 h in the presence of testosterone. Aromatase inhibitor was then added to the cultures which were incubated for a further 18 h. After a 24-h incubation period, testosterone and oestradiol secretion were determined by testing the culture medium using radioimmunological methods. The addition of testosterone to the culture medium enhanced oestradiol synthesis, suggesting that exogenous testosterone could also be aromatized to oestradiol by ovine Leydig cells in vitro. In the presence of CGS 16949A, the conversion of testosterone to oestradiol was significantly suppressed in a dose-dependent manner. All Leydig cells obtained from testes of mature rams and stained immunohistochemically were positive for aromatase, whereas Leydig cells from immature males were negative. The localization of immunoreactive aromatase appeared to be dependent on the age of the donor ram. It is suggested therefore, that mature Leydig cells in the ram are not only the site for testosterone synthesis, they are also capable of converting androgens into oestrogens.

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