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Microbiology Spectrum May 2024Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and...
Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and role in membrane dynamics. In this study, we demonstrate that TBSA production can be abrogated either by addition of pivalic acid to mycobacterial growth cultures or by a gene knockout encoding a flavin adenine dinucleotide (FAD)-binding oxidoreductase. subspecies () growth and TBSA production were inhibited in 0.5-mg/mL pivalic acid-supplemented cultures, but higher concentrations were needed to have a similar effect in other mycobacteria, including . While C-type strains, isolated from cattle and other ruminants, will produce TBSA in the absence of pivalic acid, the S-type strains, typically isolated from sheep, do not produce TBSA in any condition. A SAM-dependent methyltransferase encoded by and FAD-binding oxidoreductase are both required in the two-step biosynthesis of TBSA. However, S-type strains contain a single-nucleotide polymorphism in the gene, rendering the oxidoreductase enzyme vestigial. This results in the production of an intermediate, termed 10-methylene stearate, which is detected only in S-type strains. Fatty acid methyl ester analysis of a C-type knockout revealed the loss of TBSA production, but the intermediate was present, similar to the S-type strains. Collectively, these results demonstrate the subtle biochemical differences between two primary genetic lineages of and other mycobacteria as well as explain the resulting phenotype at the genetic level. These data also suggest that TBSA should not be used as a diagnostic marker for .IMPORTANCEBranched-chain fatty acids are a predominant cell wall component among species belonging to the genus. One of these is TBSA, which is a long-chain middle-branched fatty acid used as a diagnostic marker for . This fatty acid is also an excellent biolubricant. Control of its production is important for industrial purposes as well as understanding the biology of mycobacteria. In this study, we discovered that a carboxylic acid compound termed pivalic acid inhibits TBSA production in mycobacteria. Furthermore, strains from two separate genetic lineages (C-type and S-type) showed differential production of TBSA. Cattle-type strains of subspecies produce TBSA, while the sheep-type strains do not. This important phenotypic difference is attributed to a single-nucleotide deletion in sheep-type strains of . This work sheds further light on the mechanism used by mycobacteria to produce tuberculostearic acid.
Topics: Mycobacterium avium subsp. paratuberculosis; Animals; Paratuberculosis; Cattle; Bacterial Proteins; Sheep; Fatty Acids; Polymorphism, Single Nucleotide; Methyltransferases; Stearic Acids
PubMed: 38501867
DOI: 10.1128/spectrum.00508-24 -
ACS Omega Mar 2024Waste seashells from aquaculture are a massive source of biogenic calcium carbonate (bCC) that can be a potential substitute for ground calcium carbonate and...
Waste seashells from aquaculture are a massive source of biogenic calcium carbonate (bCC) that can be a potential substitute for ground calcium carbonate and precipitated calcium carbonate. These last materials find several applications in industry after a surface coating with hydrophobic molecules, with stearate as the most used. Here, we investigate for the first time the capability of aqueous stearate dispersions to coat bCC powders from seashells of market-relevant mollusc aquaculture species, namely the oyster , the scallop , and the clam . The chemical-physical features of bCC were extensively characterized by different analytical techniques. The results of stearate adsorption experiments showed that the oyster shell powder, which is the bCC with a higher content of the organic matrix, showed the highest adsorption capability (about 23 wt % compared to 10 wt % of geogenic calcite). These results agree with the mechanism proposed in the literature in which stearate adsorption mainly involves the formation of calcium stearate micelles in the dispersion before the physical adsorption. The coated bCC from oyster shells was also tested as fillers in an ethylene vinyl acetate compound used for the preparation of shoe soles. The obtained compound showed better mechanical performance than the one prepared using ground calcium. In conclusion, we can state that bCC can replace ground and precipitated calcium carbonate and has a higher stearate adsorbing capability. Moreover, they represent an environmentally friendly and sustainable source of calcium carbonate that organisms produce by high biological control over composition, polymorphism, and crystal texture. These features can be exploited for applications in fields where calcium carbonate with selected features is required.
PubMed: 38496946
DOI: 10.1021/acsomega.3c06186 -
Chemico-pharmacological evaluation of the methanolic leaf extract of : GC-MS/MS, , , and approaches.Frontiers in Pharmacology 2024Natural plant-based medicines have gained popularity recently as a major source of inventive, risk-free, and more potent secondary bioactive compounds with medicinal...
Natural plant-based medicines have gained popularity recently as a major source of inventive, risk-free, and more potent secondary bioactive compounds with medicinal potential. is a perennial shrub containing various indole alkaloids cultivated extensively for local medical purposes. This research is conducted to identify the phytocompounds present in the leaves of and its central and peripheral analgesic, thrombolytic, and membrane-stabilizing activities through tail immersion, acetic acid-induced writhing, human blood clot lysis, and erythrocyte lysis by heat and hypotonic solution methods, respectively. A total of 39 compounds were identified using GC-MS/MS techniques, including hexadecanoic acid, methyl ester (56.749%), methyl stearate (29.782%), carvacrol and its TBDMS derivative (12.586%), and 9-octadecenoic acid, methyl ester, (E)-] (9.297%) presented in high quantity. The highest tail immersion latency was observed for the 600 mg/kg extract of crude extract. Both 400 and 600 mg/kg doses of crude extract exhibited prominent peripheral analgesic activity. The maximum thrombolytic effect was observed by DCM soluble fraction extract by inhibiting 54.87% of the clot. However, the aqueous-soluble fraction of this extract manifested an excellent membrane-stabilizing effect by showing 73.98% and 87.51% hemolysis against heat- and hypotonic-induced hemolysis, respectively. Some of the compounds were identified as active agents against different receptors related to these diseases, which supported the findings of and tests. Further investigation needs to be conducted to specify and identify the exact mechanism of action of these compounds.
PubMed: 38495091
DOI: 10.3389/fphar.2024.1347069 -
Frontiers in Pharmacology 2024Plants and their extracts have been integral to the development of medicinal treatments throughout history, offering a vast array of compounds for innovative therapies....
Plants and their extracts have been integral to the development of medicinal treatments throughout history, offering a vast array of compounds for innovative therapies. Müll. Arg., commonly known as Rambai, is an evergreen tree with economic importance in the Old-World Tropics. The study investigates its phytochemical composition through Gas Chromatography-Mass Spectrometry (GC-MS) and evaluates its pharmacological properties, including antidiabetic, antidiarrheal, antimicrobial, and antidepressant effects. The GC-MS analysis revealed 15 bioactive compounds in the methanol extract, with Phenol, 3,5-bis(1,1-dimethylethyl)-, Methyl stearate, and Hexadecanoic acid, methyl ester being the predominant ones. The cytotoxicity assay demonstrated significant activity in the ethyl acetate fraction. Antimicrobial assays indicated mild to moderate antibacterial activity. studies on mice revealed significant hypoglycemic, antidiarrheal, and antidepressant properties. Molecular docking studies against EGFR, DHFR, GLUT-3, KOR, and MOA identified promising compounds with potential therapeutic effects. The identified compounds exhibited favorable ADME/T properties, emphasizing their potential for drug development. The study underscores the promising therapeutic potential of , showcasing its diverse bioactive compounds with significant medicinal properties. These findings lay the groundwork for future research, emphasizing the exploration of as a source of natural remedies for addressing prevalent health conditions.
PubMed: 38487168
DOI: 10.3389/fphar.2024.1359815 -
Materials (Basel, Switzerland) Feb 2024Nanosilica and diatomite are pozzolanic resources rich in SiO. In this study, the purpose of this study was to improve the moisture resistance of the specimen by...
Nanosilica and diatomite are pozzolanic resources rich in SiO. In this study, the purpose of this study was to improve the moisture resistance of the specimen by producing a mixed material using pozzolanic materials and calcium stearate and adding it to cement mortar while stirring. The results showed that the hydration reaction was not activated when calcium stearate adhered to the fine particles of nanosilica; it existed simply in the form of a filler inside the specimen. Diatomite, due to its atypical particles and porosity, may have greater water tightness than nanosilica because of the pozzolanic reaction in particles to which calcium stearate is not attached.
PubMed: 38473486
DOI: 10.3390/ma17051014 -
European Journal of Pharmaceutics and... May 2024External lubrication is an alternative to internal lubrication and its related detrimental effects on properties of tablets like tensile strength (TS). However, to date...
External lubrication is an alternative to internal lubrication and its related detrimental effects on properties of tablets like tensile strength (TS). However, to date there are hardly any systematic investigations on external lubrication of mini-tablets on rotary tablet presses. Aim of this study was the systematic investigation of the impact of parameters tableting pressure, tableting speed, dosing rate and air pressure on the TS of mini-tablets. Both studies, the Central Composite Design (CCD) with SMCC 90 and the subsequently executed D-optimal design with SMCC 50, exhibited that tableting pressure had the highest positive effect on TS. Tableting speed and dosing rate in the CCD presumably did not seem to influence the TS, air pressure represented a positive coefficient. An additional temporal factor seemed to impact the results, deduced from the negative effect of the experimental order on TS in the CCD and from the negative correlation along the execution order in the residual plots. Additional long runs support findings of a non-linear decrease of TS over time. An interplay between dosing rate level and performance of the dust extraction collector is assumed, making more magnesium stearate available in the tablet press and potentially causing gradual contamination of the powder over time.
Topics: Lubrication; Tensile Strength; Tablets; Drug Compounding
PubMed: 38423137
DOI: 10.1016/j.ejpb.2024.114236 -
Materials (Basel, Switzerland) Feb 2024The production of autoclaved aerated concrete via the autoclaving process incurs substantial energy consumption, posing a challenge to sustainable economic development....
The production of autoclaved aerated concrete via the autoclaving process incurs substantial energy consumption, posing a challenge to sustainable economic development. Herein, a novel nonautoclaved aerated concrete (NAAC) was prepared using sulfoaluminate cement as the primary raw material and aluminum powder as the aerating agent. The physicomechanical characteristics and pore structures of the sulfoaluminate-cement-based (SAC) NAAC (SAC-NAAC) were examined through X-ray diffraction, thermogravimetry, and scanning electron microscopy. The findings revealed that the optimal mechanical attributes of the SAC-NAAC were achieved at a water-cement ratio of 0.55, with a specific content ratio of polycarboxylate superplasticizer-borax-calcium stearate-sodium hydroxide at 0.24%:0.32%:0.36%:2.90%, along with 0.40% aluminum powder. The SAC-NAAC samples, with a bulk density range of 600-750 g/m, exhibited a compressive strength of 3.55-4.16 MPa, porosity of 45.9-63.5%, and water absorption rate of 60.2-74.4%. The weight loss in the SAC-NAAC with different aluminum powder contents ranged between 15.23% and 16.83%. The prismatic ettringite (AFt) crystals served as the main source of strength for the SAC-NAAC, and AH was attached to the AFt surfaces in a microcrystalline gel phase, thereby further enhancing the strength of the SAC-NAAC. Thus, the lightweight, high-strength SAC-NAAC has great potential as a nonautoclaved aerated concrete.
PubMed: 38399086
DOI: 10.3390/ma17040836 -
Polymers Jan 2024Natural rubber (NR) is extensively utilized in numerous industries, such as aerospace, military, and transportation, because of its exceptional elasticity and all-around...
Natural rubber (NR) is extensively utilized in numerous industries, such as aerospace, military, and transportation, because of its exceptional elasticity and all-around mechanical qualities. However, commercial NR made using various techniques typically has distinct mechanical characteristics. For instance, whole field latex rubber (SCR-WF) cured with accelerator 2-Mercaptobenzothiazole exhibits poor mechanical properties. This work attempts to enhance the mechanical property of SCR-WF via the addition of lanthanum stearate (LaSt). The influence of LaSt on strain-induced crystallization (SIC) and the mechanical properties of SCR-WF were investigated. The results of crosslinking density measured by the equilibrium swelling method demonstrate that the presence of LaSt significantly increases the crosslinking density of SCR-WF with lower loading of LaSt. The results of the mechanical properties show that the introduction of LaSt can enhance the tensile strength and fracture toughness of SCR-WF. To reveal the mechanism of LaSt improving the mechanical properties of SCR-WF, synchrotron radiation wide-angle X-ray diffraction (WAXD) experiments were used to investigate the SIC behaviors of SCR-WF. We found that the LaSt leads to higher crystallinity of SIC for the strain higher than 3.5. The tube model indicates the contribution of LaSt in both crosslinking and topological constraints. This work may provide an instruction for developing SCR-WF with superior mechanical properties.
PubMed: 38276684
DOI: 10.3390/polym16020276 -
International Journal of Biological... Mar 2024Glyceryl stearate and cassava starch (CS) composites were prepared by an esterification process. Formulations containing starch at various concentrations were prepared,...
Glyceryl stearate and cassava starch (CS) composites were prepared by an esterification process. Formulations containing starch at various concentrations were prepared, being 1, 1.5, 3, 5, 10, 15, 20, and 30 % by weight, respectively. The characteristics of pH, moisture content, FTIR, melting point, latent heat, thermal energy storage, and specific heat capacity of composites were elucidated. The optimal formulation contained 1 % w/w CS, this indicated that the composite was able to maintain its temperature for 9.4 ± 0.5 min, with a melting temperature of 51.9 ± 0.3 °C, solidification temperature of 36.1 ± 1.6 °C, latent heat of fusion of 120 ± 10 J/g, and latent heat of solidification of 126 ± 3 J/g, and specific heat capacity of 2.6 ± 0.2 J/g.K. New bonds were formed in the composite structure of glyceryl stearate and CS at these levels. The composite had a pH that was safe for contact with human skin and a moisture content that could be kept stable for a prolonged time. The innovation and the advantages of a composite materials: 1. The main components are derived from natural materials. 2. Costs effective 3. Sustainability 4. Safety, and 5. Efficacy. Therefore, composites have a high potential as are replacement for paraffin wax bath therapy.
Topics: Humans; Manihot; Stearates; Temperature; Starch; Hot Temperature; Glycerides
PubMed: 38272417
DOI: 10.1016/j.ijbiomac.2024.129681 -
Pharmaceutics Dec 2023Agglomerate formulations for dry powder inhalation (DPI) formed with fine particles are versatile means for the highly efficient delivery of budesonide. However,...
Agglomerate formulations for dry powder inhalation (DPI) formed with fine particles are versatile means for the highly efficient delivery of budesonide. However, uncontrolled agglomeration induces high deposition in the upper airway, causing local side effects due to high mechanical strength, worse deagglomeration, and poor fine-particle delivery. In the present study, fine lactose was mechanically dry-coated prior to particle agglomeration, and the agglomerates were then spheroidized via ultrasonic vibration to improve their aerosol performance. The results showed that the agglomerate produced with the surface-enriched hydrophobic magnesium stearate and ultrasonic vibration demonstrated improved aerosolization properties, benefiting from their lower mechanical strength, less interactive cohesive force, and improved fine powder dispersion behavior. After dispersion utilizing a Turbuhaler with a pharmaceutical cascade impactor test, a fine particle fraction (FPF) of 71.1 ± 1.3% and an artificial throat deposition of 19.3 ± 0.4% were achieved, suggesting the potential to improve the therapeutic outcomes of budesonide with less localized infections of the mouth and pharynx.
PubMed: 38258079
DOI: 10.3390/pharmaceutics16010068