scholarly journals Manganese transport by Streptococcus sanguinis in acidic conditions and its impact on growth in vitro and in vivo

2021 ◽  
Author(s):  
Tanya Puccio ◽  
Seon‐Sook An ◽  
Alexander C. Schultz ◽  
Claudia A. Lizarraga ◽  
Ashley S. Bryant ◽  
...  
Keyword(s):  
Streptococcus Sanguinis ◽  
Acidic Conditions ◽  
Manganese Transport

scholarly journals Manganese transport by Streptococcus sanguinis in acidic conditions and its impact on growth in vitro and in vivo

2021 ◽  
Author(s):  
Tanya Puccio ◽  
Alexander C Schultz ◽  
Claudia A Lizarraga ◽  
Ashley S Bryant ◽  
David J Culp ◽  
...  
Keyword(s):  
Streptococcus Sanguinis ◽  
Manganese Uptake ◽  
Zip Family ◽  
Oral Environment ◽  
Colonization Model ◽  
Acidic Conditions ◽  
Oral Colonization ◽  
Manganese Transport

Streptococcus sanguinis is an oral commensal and an etiological agent of infective endocarditis. Previous studies have identified the SsaACB manganese transporter as essential for endocarditis virulence; however, the significance of SsaACB in the oral environment has never been examined. Here we report that a ΔssaACB mutant of strain SK36 exhibits reduced growth and manganese uptake under acidic conditions. Further studies revealed that these deficits resulted from the decreased activity of TmpA, shown in the accompanying paper to function as a ZIP-family manganese transporter. Transcriptomic analysis of fermentor-grown cultures of SK36 WT and ΔssaACB strains identified pH-dependent changes related to carbon catabolite repression in both strains, though their magnitude was generally greater in the mutant. In strain VMC66, which possesses a MntH transporter, loss of SsaACB did not significantly alter growth or cellular manganese levels under the same conditions. Interestingly, there were only modest differences between SK36 and its ΔssaACB mutant in competition with Streptococcus mutans in vitro and in a murine oral colonization model. Our results suggest that the heterogeneity of the oral environment may provide a rationale for the variety of manganese transporters found in S. sanguinis and point to strategies for enhancing the safety of oral probiotics.

scholarly journals Doxorubicin loaded magnetism nanoparticles based on cyclodextrin dendritic-graphene oxide inhibited MCF-7 cell proliferation

2021 ◽  
Vol 12 (1) ◽  
pp. 8-15
Author(s):  
Ainaz Mihanfar ◽  
Niloufar Targhazeh ◽  
Shirin Sadighparvar ◽  
Saber Ghazizadeh Darband ◽  
Maryam Majidinia ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Anticancer Drug Delivery ◽  
Release Studies ◽  
Anti Cancer ◽  
Acidic Conditions ◽  
Mcf 7

Abstract Doxorubicin (DOX) is an effective chemotherapeutic agent used for the treatment of various types of cancer. However, its poor solubility, undesirable side effects, and short half-life have remained a challenge. We used a formulation based on graphene oxide as an anticancer drug delivery system for DOX in MCF-7 breast cancer cells, to address these issues. In vitro release studies confirmed that the synthesized formulation has an improved release profile in acidic conditions (similar to the tumor microenvironment). Further in vitro studies, including MTT, uptake, and apoptosis assays were performed. The toxic effects of the nanocarrier on the kidney, heart and liver of healthy rats were also evaluated. We observed that the DOX-loaded carrier improved the cytotoxic effect of DOX on the breast cell line compared to free DOX. In summary, our results introduce the DOX-loaded carrier as a potential platform for in vitro targeting of cancer cells and suggest further studies are necessary to investigate its in vivo anti-cancer potential.

scholarly journals Small Molecule Modifiers of In Vitro Manganese Transport Alter Toxicity In Vivo

2018 ◽  
Vol 188 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Tanara V. Peres ◽  
Kyle J. Horning ◽  
Julia Bornhorst ◽  
Tanja Schwerdtle ◽  
Aaron B. Bowman ◽  
...  
Keyword(s):  
Small Molecule ◽  
Manganese Transport

scholarly journals Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro

2019 ◽  
Vol 10 (4) ◽  
pp. 54 ◽  
Author(s):  
Joseph Lazraq Bystrom ◽  
Michael Pujari-Palmer
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Ionic Concentration ◽  
Strong Adhesion ◽  
Acidic Conditions ◽  
Rapid Transformation ◽  
Comparable Mass

Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of αTCP based PMCs. PMCs were significantly stronger than unmodified cement (38–49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.

Developmental Changes in the PH of Enamel Fluid and Its Effects On Matrix-Resident Proteinases

1996 ◽  
Vol 10 (2) ◽  
pp. 159-169 ◽  
Author(s):  
C.E. Smith ◽  
M. Issid ◽  
H.C. Margolis ◽  
E.C. Moreno
Keyword(s):  
Acetic Acid ◽  
Protein Extraction ◽  
Maturation Stage ◽  
Activity Levels ◽  
Freeze Dried ◽  
Mineral Components ◽  
Acidic Conditions ◽  
Pre Treatment

The objectives of this study were to measure pH in developing enamel at progressively older (more mature) stages of amelogenesis in vivo, and then to formulate synthetic enamel fluid mixtures that approximated these pH values for in vitro studies. The ultimate goal was to characterize the molecular weights of proteinases visualized by enzymograms incubated in synthetic enamel fluid using gelatin and casein as substrates. For most experiments. the proteinases were extracted en masse from small freeze-dried enamel strips directly into a non-reducing sample preparation buffer. In some experiments, we pre-treated the enamel strips with acetic acid to determine if this common method for demineralization and protein extraction caused any changes in the activity levels of the enamel proteinases. In other experiments, we first soaked enamel strips in synthetic enamel fluid to determine solubility of the proteinases within an aqueous phase. The results indicated that the pH of developing enamel remained fairly constant near pH 7.23 across the secretory stage, but it was generally more acidic (6.93) and fluctuated in focal areas between mildly acidic (6.2-6.8) and near-neutral (7.2) conditions across the maturation stage. The pH then slowly rose to near 7.35 when the enamel was almost mature (hard). The acidic conditions were generally inhibitory to most enamel proteinases, but there were some caseinase activities in mid-maturation-stage enamel near 23-30 kDa which appeared to be activated by weakly acidic conditions (pH 6.28). Pre-treatment of enamel samples with 0.5 M acetic acid markedly altered the overall profile of enamel proteinases, causing activation of some latent proteinase activities and permanent inhibition of other activities. Most proteinases in whole homogenates were insoluble in synthetic enamel fluid. This suggests that they may be tightly bound, directly or indirectly, to matrix proteins or mineral components in situ.

scholarly journals Lymphatic absorption of α-linolenic acid in rats fed flaxseed oil-based emulsion

2010 ◽  
Vol 105 (7) ◽  
pp. 1026-1035 ◽  
Author(s):  
Leslie Couëdelo ◽  
Carole Boué-Vaysse ◽  
Laurence Fonseca ◽  
Emeline Montesinos ◽  
Sandrine Djoukitch ◽  
...  
Keyword(s):  
Linolenic Acid ◽  
Area Under The Curve ◽  
Flaxseed Oil ◽  
Lymphatic Absorption ◽  
Oil Emulsion ◽  
Emulsion Group ◽  
Lymph Duct ◽  
Acidic Conditions

The bioavailability of α-linolenic acid (ALA) from flaxseed oil in an emulsified formv.a non-emulsified form was investigated by using two complementary approaches: the first one dealt with the characterisation of the flaxseed oil emulsion inin vitrogastrointestinal-like conditions; the second one compared the intestinal absorption of ALA in rats fed the two forms of the oil. Thein vitrostudy on emulsified flaxseed oil showed that decreasing the pH from 7·3 to 1·5 at the physiological temperature (37°C) induced instantaneous oil globule coalescence. Some phase separation was observed under acidic conditions that vanished after further neutralisation. The lecithin used to stabilise the emulsions inhibited TAG hydrolysis by pancreatic lipase. In contrast, lipid solubilisation by bile salts (after lipase and phospholipase hydrolysis) was favoured by preliminary oil emulsification. Thein vivoabsorption of ALA in thoracic lymph duct-cannulated rats fed flaxseed oil, emulsified or non-emulsified, was quantified. Oil emulsification significantly favoured the rate and extent of ALA recovery as measured by the maximum ALA concentration in the lymph (Cmax = 14 mg/ml at 3 h in the emulsion groupv.9 mg/ml at 5 h in the oil group;P < 0·05). Likewise, the area under the curve of the kinetics was significantly higher in the emulsion group (48 mg × h/ml for rats fed emulsionv.26 mg × h/ml for rats fed oil;P < 0·05). On the whole, ALA bioavailability was improved with flaxseed oil ingested in an emulsified state. Data obtained from thein vitrostudies helped to partly interpret the physiological results.

scholarly journals MdMYB3 helps regulate anthocyanin accumulation in apple calli under moderately acidic conditions

2018 ◽  
Author(s):  
Yi-Cheng Wang ◽  
Jing-Jing Sun ◽  
Yan-Fen Qiu ◽  
Xiao-Jun Gong ◽  
Li Ma ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Myb Transcription Factor ◽  
Anthocyanin Content ◽  
Anthocyanin Accumulation ◽  
Mobility Shift ◽  
In The Wild ◽  
Acidic Conditions ◽  
Electrophoretic Mobility Shift Assays

AbstractAnthocyanins are the key factors controlling the coloration of plant tissues. However, the molecular mechanism underlying the effects of environmental pH on the synthesis of apple anthocyanins is unclear. In this study, we analyzed the anthocyanin contents of apple calli cultured in media at different pHs (5.5, 6.0, and 6.5). The highest anthocyanin content was observed at pH 6.0. Additionally, the moderately acidic conditions up-regulated the expression of MdMYB3 as well as specific anthocyanin biosynthesis structural genes (MdDFR and MdUFGT). Moreover, the anthocyanin content was higher in calli overexpressing MdMYB3 than in the wild-type controls at different pHs. Yeast one-hybrid assay results indicated that MdMYB3 binds to the MdDFR and MdUFGT promoters in vivo. An analysis of the MdDFR and MdUFGT promoters revealed multiple MYB-binding sites. Meanwhile, electrophoretic mobility shift assays confirmed that MdMYB3 binds to the MdDFR and MdUFGT promoters in vitro. Furthermore, GUS promoter activity assays suggested that the MdDFR and MdUFGT promoter activities are enhanced by acidic conditions, and the binding of MdMYB3 may further enhance activity. These results implied that an acid-induced apple MYB transcription factor (MdMYB3) promotes anthocyanin accumulation by up-regulating the expression of MdDFR and MdUFGT under moderately acidic conditions.

scholarly journals The Helicobacter pylori UreI Protein Is Not Involved in Urease Activity but Is Essential for Bacterial Survival In Vivo

1998 ◽  
Vol 66 (9) ◽  
pp. 4517-4521 ◽  
Author(s):  
Stéphane Skouloubris ◽  
Jean-Michel Thiberge ◽  
Agnès Labigne ◽  
Hilde De Reuse
Keyword(s):  
Helicobacter Pylori ◽  
Urease Activity ◽  
Saline Solution ◽  
Integral Membrane Protein ◽  
Bacterial Survival ◽  
Acidic Conditions ◽  
H Pylori ◽  
Phosphate Buffered Saline

ABSTRACT We produced defined isogenic Helicobacter pylori ureImutants to investigate the function of UreI, the product of one of the genes of the urease cluster. The insertion of a catcassette had a strong polar effect on the expression of the downstream urease genes, resulting in very weak urease activity. Urease activity, measured in vitro, was normal in a strain in which ureI was almost completely deleted and replaced with a nonpolar cassette. In contrast to previous reports, we thus found that the product ofureI was not necessary for the synthesis of active urease. Experiments with the mouse-adapted H. pylori SS1 strain carrying the nonpolar ureI deletion showed that UreI is essential for H. pylori survival in vivo and/or colonization of the mouse stomach. The replacement of ureIwith the nonpolar cassette strongly reduced H. pylorisurvival in acidic conditions (1-h incubation in phosphate-buffered saline solution at pH 2.2) in the presence of 10 mM urea. UreI is predicted to be an integral membrane protein and may therefore be involved in a transport process essential for H. pylori survival in vivo.

Influence of Streptococcus mitis and Streptococcus sanguinis on virulence of Candida albicans: in vitro and in vivo studies

2018 ◽  
Vol 64 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Ana Luiza do Rosário Palma ◽  
Nádia Domingues ◽  
Patrícia Pimentel de Barros ◽  
Graziella Nuernberg Back Brito ◽  
Antônio Olavo Cardoso Jorge
Keyword(s):  
Candida Albicans ◽  
In Vivo Studies ◽  
Streptococcus Mitis ◽  
Streptococcus Sanguinis

scholarly journals Identification of Streptococcus sanguinis Genes Required for Biofilm Formation and Examination of Their Role in Endocarditis Virulence

2008 ◽  
Vol 76 (6) ◽  
pp. 2551-2559 ◽  
Author(s):  
Xiuchun Ge ◽  
Todd Kitten ◽  
Zhenming Chen ◽  
Sehmi P. Lee ◽  
Cindy L. Munro ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Dental Plaque ◽  
Biofilm Formation ◽  
Bacterial Colonization ◽  
Abundant Species ◽  
Oral Biofilm ◽  
Streptococcus Sanguinis ◽  
Streptococcal Species

ABSTRACT Streptococcus sanguinis is one of the pioneers in the bacterial colonization of teeth and is one of the most abundant species in the oral biofilm called dental plaque. S. sanguinis is also the most common viridans group streptococcal species implicated in infective endocarditis. To investigate the association of biofilm and endocarditis, we established a biofilm assay and examined biofilm formation with a signature-tagged mutagenesis library of S. sanguinis. Four genes that have not previously been associated with biofilm formation in any other bacterium, purB, purL, thrB, and pyrE, were putatively identified as contributing to in vitro biofilm formation in S. sanguinis. By examining 800 mutants for attenuation in the rabbit endocarditis model and for reduction in biofilm formation in vitro, we found some mutants that were both biofilm defective and attenuated for endocarditis. However, we also identified mutants with only reduced biofilm formation or with only attenuation in the endocarditis model. This result indicates that the ability to form biofilms in vitro is not associated with endocarditis virulence in vivo in S. sanguinis.

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