Changes in the protonation state of lyophilized proteins can impact structural integrity, chemical stability, and propensity to aggregate upon reconstitution. When a buffer is chosen, the freezing/drying process may result in dramatic changes in the protonation state of the protein due to ionization shift of the buffer. In order to determine whether protonation shifts are occurring, ionizable probes can be added to the formulation. Optical probes (dyes) have shown dramatic ionization changes in lyophilized products, but it is unclear whether the pH indicator is uniform throughout the matrix and whether the change in the pH indicator actually mirrors drug ionization changes. In solid-state NMR (SSNMR) spectroscopy, the chemical shift of the carbonyl carbon in carboxylic acids is very sensitive to the ionization state of the acid. Therefore, SSNMR can be used to measure ionization changes in a lyophilized matrix by employing a small quantity of an isotopically-labeled carboxylic acid species in the formulation. This paper compares the apparent pH of six trehalose-containing lyophilized buffer systems using SSNMR and UV-Vis diffuse reflectance spectroscopy (UVDRS). Both SSNMR and UVDRS results using two different ionization probes (butyric acid and bromocresol purple, respectively) showed little change in apparent acidity compared to the pre-lyophilized solution in a sodium citrate buffer, but a greater change was observed in potassium phosphate, sodium phosphate, and histidine buffers. While the trends between the two methods were similar, there were differences in the numerical values of equivalent pH (pHeq) observed between the two methods. The potential causes contributing to the differences are discussed.
- MeSH
- fosfáty * chemie MeSH
- histidin * chemie MeSH
- koncentrace vodíkových iontů MeSH
- kyselina citronová chemie MeSH
- lyofilizace * metody MeSH
- magnetická rezonanční spektroskopie * metody MeSH
- pufry MeSH
- spektrofotometrie ultrafialová metody MeSH
- trehalosa * chemie MeSH
- Publikační typ
- časopisecké články MeSH
Plants form associations with different microbes; some promote their growth and protect from biotic and abiotic stresses in different ways. However, the biological role of fungi associated with the rhizosphere of medicinal plants is not well explored. In the present study, Colletotrichum gloeosporioides, and Aspergillus fumigatus isolated from the rhizosphere of Dillenia indica were screened for their phosphate solubilization and indole-3-acetic acid (IAA) production potential. The selected fungal strains were identified by macroscopic, microscopic, and molecular characteristics. Phosphate solubilization was qualitatively and quantitatively evaluated using Pikovskaya's (PVK) agar and PVK broth medium using different substrates such as AlPO4, Ca3(PO4)2, and FePO4. Colletotrichum gloeosporioides and Aspergillus fumigatus with respect to the phosphate source showed solubilization index (SI) of 1.7 ± 0.03 and 2.1 ± 0.04, and solubilized phosphate up to 138.8 ± 0.058 μg/mL and 121.6 ± 0.062 μg/mL. These fungal strains are also good producers of IAA and significantly enhance the growth of Vigna radiata and Cicer arietinum seedlings. This is the first report on A. fumigatus and C. gloeosporioides from the rhizosphere of Dillenia indica and their phosphate solubilization and IAA production ability.
This study evaluates the efficiency of Phosphate solubilizing bacteria isolated from Effluent Treatment Plant sludge of Paradeep Phosphate Limited, Odisha, India, to solubilize rock phosphate (RP) and the mechanism and structural changes during solubilization investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Out of 13 bacterial isolates, Bacillus cereus S0B4, Solibacillus isronensis S0B8, and Bacillus amyloliquefaciens S0B17 strains were found to be the best RP solubilizers. This is the first report on S. isronensis S0B8 with the ability to solubilize RP. In particular, the potent strain B. cereus S0B4 showed maximum soluble P (338.5 mg/L) on the 7th day. Negative correlations (r = -0.70; p ≤ 0.01) were observed between soluble P concentration and pH, whereas positive correlation exists with the growth of B. cereus S0B4 (r = 0.91, p ≤ 0.01), S. isronensis S0B8 (r = 0.75, p ≤ 0.01), and B. amyloliquefaciens S0B17 (r = 0.77, p ≤ 0.01) respectively. The P release kinetics followed the 1st order model well (R2 = 0.8001-0.8503). It seems that H+ ions and organic anions released from the organic acids are major factors responsible for RP solubilization. The SEM observations demonstrate that B. cereus S0B4 corroded the RP surface significantly due to the proton attack. The XRD analysis confirms that the intensity of all mineral peaks decreases after treatment with B. cereus S0B4. The FTIR analysis indicated a significant decrease of calcite and fluorapatite's vibrational bands with the disappearance of quartz.
- MeSH
- Bacteria MeSH
- fosfáty * chemie MeSH
- odpadní vody MeSH
- průmyslová hnojiva * MeSH
- půdní mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Indie MeSH
Amine-containing drugs often show poor pharmacological properties, but these disadvantages can be overcome by using a prodrug approach involving self-immolative linkers. Accordingly, we designed l-lactate linkers as ideal candidates for amine delivery. Furthermore, we designed linkers bearing two different cargos (aniline and phenol) for preferential amine cargo release within 15 min. Since the linkers carrying secondary amine cargo showed high stability at physiological pH, we used our strategy to prepare phosphate-based prodrugs of the antibiotic Ciprofloxacin. Therefore, our study will facilitate the rational design of new and more effective drug delivery systems for amine-containing drugs.
- MeSH
- aminy chemie MeSH
- antibakteriální látky chemie MeSH
- ciprofloxacin chemie MeSH
- fosfáty chemie MeSH
- koncentrace vodíkových iontů MeSH
- kyselina mléčná chemie MeSH
- léčivé přípravky chemie MeSH
- prekurzory léčiv chemie MeSH
- systémy cílené aplikace léků metody MeSH
- Publikační typ
- časopisecké články MeSH
Cyclic dinucleotides (CDNs) are second messengers that bind to the stimulator of interferon genes (STING) and trigger the expression of type I interferons and proinflammatory cytokines. Here we evaluate the activity of 3',3'-c-di(2'F,2'dAMP) and its phosphorothioate analogues against five STING allelic forms in reporter-cell-based assays and rationalize our findings with X-ray crystallography and quantum mechanics/molecular mechanics calculations. We show that the presence of fluorine in the 2' position of 3',3'-c-di(2'F,2'dAMP) improves its activity not only against the wild type (WT) but also against REF and Q STING. Additionally, we describe the synthesis of the acyloxymethyl and isopropyloxycarbonyl phosphoester prodrugs of CDNs. Masking the negative charges of the CDNs results in an up to a 1000-fold improvement of the activities of the prodrugs relative to those of their parent CDNs. Finally, the uptake and intracellular cleavage of pivaloyloxymethyl prodrugs to the parent CDN is rapid, reaching a peak intracellular concentration within 2 h.
- MeSH
- estery chemie farmakologie terapeutické užití MeSH
- fosfáty chemie metabolismus farmakologie terapeutické užití MeSH
- HEK293 buňky MeSH
- interferon gama metabolismus MeSH
- krystalografie rentgenová MeSH
- leukocyty mononukleární cytologie účinky léků metabolismus MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- membránové proteiny agonisté metabolismus MeSH
- prekurzory léčiv chemická syntéza chemie metabolismus farmakologie MeSH
- teorie funkcionálu hustoty MeSH
- TNF-alfa metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The international standard ISO 23317:2014 for the in vitro testing of inorganic biomaterials in simulated body fluid (SBF) uses TRIS buffer to maintain neutral pH. In our previous papers, we investigated the interaction of a glass-ceramic scaffold with TRIS and HEPES buffers. Both of them speeded up glass-ceramic dissolution and hydroxyapatite (HAp) precipitation, thereby demonstrating their unsuitability for the in vitro testing of highly reactive biomaterials. In this article, we tested MOPS buffer (3-[N-morpholino] propanesulfonic acid), another amino acid from the group of "Goods buffers". A highly reactive glass-ceramic scaffold (derived from Bioglass®) was exposed to SBF under static-dynamic conditions for 13/15 days. The kinetics and morphology of the newly precipitated HAp were studied using two different concentrations of (PO4 )3- ions in SBF. The pH value and the SiIV , Ca2+ , and (PO4 )3- concentrations in the SBF leachate samples were measured every day (AAS, spectrophotometry). The glass-ceramic scaffold was monitored by SEM/EDS, XRD, WD-XRF, and BET before and after 1, 3, 7, 11, and 13/15 days of exposure. As in the case of TRIS and HEPES, the preferential dissolution of the glass-ceramic crystalline phase (Combeite) was observed, but less intensively. The lower concentration of (PO4 )3- ions slowed down the kinetics of HAp precipitation, thereby causing the disintegration of the scaffold structure. This phenomenon shows that the HAp phase was predominately generated by the presence of (PO4 )3- ions in the SBF, not in the glass-ceramic material. Irrespective of this, MOPS buffer is not suitable for the maintenance of pH in SBF.
The antifouling, antimicrobial, elution behavior, skin irritant, and cytotoxicity properties of water-soluble phosphate glass on stainless steel were evaluated. Water-soluble phosphate glass samples with 35% Cu (mol/mol) were prepared by altering the network modifier (Na2O, K2O) and network former (P2O5, B2O3) compositions. The materials were melted at temperatures within the range of 850-950 °C. The melt was then quenched and ground into fine particles using a twin roll mill. The resulting water-soluble glasses were prepared as glass frit (size < 100 μm) using a sieve. The amorphous phase was determined by X-ray diffraction and differential thermal analysis. Water-soluble glasses with a reduced Cu ion elution rate of 1.2 ppm per week were formed because the chemical resistances of the formulated glasses improved as the P2O5 content decreased and the B2O3 content increased. To test its antifouling properties, the glass frit was mixed with paint and coated onto a STS316L sheet. The surface roughness was increased markedly from 1.4 to 19.2 nm, increasing the specific surface area for antimicrobial activity. It was demonstrated that the proposed method was able to form noncytotoxic, nonirritant, water-soluble glasses with 99.9% antimicrobial activity against Staphylococcus aureus. These results suggest that water-soluble phosphate glass on STS316L sheets could be useful in filtration plants.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- bioznečištění prevence a kontrola MeSH
- čištění vody přístrojové vybavení MeSH
- difrakce rentgenového záření MeSH
- filtrace přístrojové vybavení MeSH
- fosfáty chemie farmakologie MeSH
- králíci MeSH
- kůže účinky léků MeSH
- sklo chemie MeSH
- Staphylococcus aureus účinky léků růst a vývoj MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Iron oxide nanoparticles (IONPs) have biomedical and biotechnological applications in magnetic imaging, drug-delivery, magnetic separation and purification. The biocompatibility of such particles may be improved by covering them with coating. In presented paper the biochemical anomalies of liver and kidney occurring in animals exposed to d-mannitol-coated iron(III) oxide nanoparticles (M-IONPs) were examined with Fourier transform infrared (FTIR) microspectroscopy. The dose of IONPs used in the study was significantly lower than those used so far in other research. Liver and kidney tissue sections were analysed by chemical mapping of infrared absorption bands originating from proteins, lipids, compounds containing phosphate groups, cholesterol and cholesterol esters. Changes in content and/or structure of the selected biomolecules were evaluated by comparison of the results obtained for animals treated with M-IONPs with those from control group. Biochemical analysis of liver samples demonstrated a few M-IONPs induced anomalies in the organ, mostly concerning the relative content of the selected compounds. The biomolecular changes, following exposition to nanoparticles, were much more intense within the kidney tissue. Biochemical aberrations found in the organ samples indicated at increase of tissue density, anomalies in fatty acids structure as well as changes in relative content of lipids and proteins. The simultaneous accumulation of lipids, phosphate groups as well as cholesterol and cholesterol esters in kidneys of rats exposed to IONPs may indicate that the particles stimulated formation of lipid droplets within the organ.
- MeSH
- cholesterol chemie metabolismus MeSH
- fosfáty chemie metabolismus MeSH
- injekce intravenózní MeSH
- játra chemie účinky léků metabolismus MeSH
- ledviny chemie účinky léků metabolismus MeSH
- lipidy chemie MeSH
- magnetické nanočástice oxidů železa aplikace a dávkování chemie toxicita MeSH
- mannitol chemie MeSH
- metabolismus lipidů účinky léků MeSH
- potkani Wistar MeSH
- sekundární struktura proteinů MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
We have developed a robust solid-phase protocol which allowed the synthesis of chimeric oligonucleotides modified with phosphodiester and O-methylphosphonate linkages as well as their P-S and P-N variants. The novel O-methylphosphonate-derived modifications were obtained by oxidation, sulfurization, and amidation of the O-methyl-(H)-phosphinate internucleotide linkage introduced into the oligonucleotide chain by H-phosphonate chemistry using nucleoside-O-methyl-(H)-phosphinates as monomers. The H-phosphonate coupling followed by oxidation after each cycle enabled us to successfully combine H-phosphonate and phosphoramidite chemistries to synthesize diversely modified oligonucleotide strands.
Optical fibers have recently attracted a noticeable interest for biomedical applications because they provide a minimally invasive method for in vivo sensing, imaging techniques, deep-tissue photodynamic therapy or optogenetics. The silica optical fibers are the most commonly used because they offer excellent optical properties, and they are readily available at a reasonable price. The fused silica is a biocompatible material, but it is not bioresorbable so it does not decompose in the body and the fibers must be ex-planted after in vivo use and their fragments can present a considerable risk to the patient when the fiber breaks. In contrast, optical fibers made of phosphate glasses can bring many benefits because such glasses exhibit good transparency in ultraviolet-visible and near-infrared regions, and their solubility in water can be tailored by changing the chemical composition. The bioresorbability and toxicity of phosphate glass-based optical fibers were tested in vivo on male laboratory rats for the first time. The fiber was spliced together with a standard graded-index multi-mode fiber pigtail and an optical probe for in vitro pH measurement was prepared by the immobilization of a fluorescent dye on the fiber tip by a sol-gel method to demonstrate applicability and compatibility of the fiber with common fiber optics.
- MeSH
- fosfáty chemie metabolismus MeSH
- koncentrace vodíkových iontů MeSH
- krysa rodu rattus MeSH
- optická vlákna * MeSH
- oxid křemičitý chemie MeSH
- potkani Wistar MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
