Crystal Violet Research Articles

Use of Pinus patula wood pellet biochar for the adsorptive elimination of crystal violet: optimization, isotherms, and kinetics

Use of Pinus patula wood pellet biochar for the adsorptive elimination of crystal violet: optimization, isotherms, and kinetics

Fabrication of Porous Fibrous Membranes with Rough Surfaces via PAN-H/PVP for Cation Dye Removal and Oil/Water Emulsion Separation.

The purification of organic dye pollutants and insoluble emulsified oils in wastewater has become a critical focus of environmental research. In this study, fibrous membranes were prepared through electrostatic spinning by first hydrolyzing polyacrylonitrile and then blending it with water-soluble polyvinylpyrrolidone (PVP). Subsequent hydrothermal treatment was applied to partially remove PVP from the fibers, creating rough and porous surfaces that exposed more functional carboxyl groups and increased the fibers' specific surface area. The resulting membranes exhibited superhydrophilicity (≈0°) and underwater superoleophobicity (≈157°), alongside excellent fouling resistance. The fibrous membranes, characterized by their carboxyl-rich surfaces, exhibited improved adsorption capabilities for cationic dyes, attaining capacities of 735.77 mg/g for malachite green, 429.31 mg/g for methylene blue, and 607.21 mg/g for crystal violet. The membranes achieved a remarkable separation efficiency of 99.8% for oil-in-water emulsions and maintained 98.5% efficiency after 10 cycles of separation and elution, highlighting their outstanding regeneration capability. In summary, this study demonstrates that these fibrous membranes are highly effective in removing cationic dyes and insoluble emulsified oils from wastewater. The membranes show great potential for applications in wastewater treatment, particularly for selective dye removal and oil-water separation.

A Monomeric Diarylstannanone with a Sn=O Double Bond: Synthesis and Characterization.

A series of diarylstannylenes, (Rind)2Sn: (1) [Rind = 1,1,7,7-tetra-R1-3,3,5,5-tetra-R2-s-hydrindacen-4-yl: EMind (a: R1 = Et, R2 = Me), Eind (b: R1 = R2 = Et), and MPind (c: R1 = Me, R2 = nPr)], has been obtained as purple to blue crystals by the reaction of SnX2·dioxane (X = Br or Cl) with two equiv of (Rind)Li. The less bulky EMind-based stannylene, (EMnd)2Sn: (1a), reacted with N2O gas to afford a 1,3,2,4-dioxadistannetane, (EMind)4Sn2(μ-O)2 (3a), through the dimerization of a stannanone, (EMind)2Sn=O (2a). In contrast, a similar oxidation reaction using the bulkier MPind-based stannylene, (MPind)2Sn: (1c), produced a hitherto unknown acid-base free monomeric diarylstannanone, (MPind)2Sn=O (2c), with an authentic Sn=O double bond. The stannanone 2c was highly sensitive to air and moisture but remained thermally stable at room temperature. Isolating 2c as a pure single crystalline material proved challenging due to its highly-reactive nature; however, its structural characteristics and bonding properties were discussed based on both experimental findings and computational results. The Sn=O double bond in 2c exhibits a weaker and more polarized character compared to the Ge=O double bond in the diarylgermanone, (Eind)2Ge=O (A).

Standardizing biofilm quantification: harmonizing crystal violet absorbance measurements through extinction coefficient ratio adjustment.

Precise quantification of biofilm is critical as the formation and persistence of biofilm have significant implications in the environmental, therapeutic and industrial contexts. The microtiter plate assay using crystal violet with 33% glacial acetic acid or 94-100% ethanol as the resolubilising agent is widely used for the categorisation of biofilms into weak, moderate and strong categories. But, the use of varying wavelengths for the measurement of biofilm resulted in discrepancies in categorisation across the studies due to the difference in the extinction coefficient of CV. This study emphasises the importance of measuring the biofilm at the absorbance maximum (λmax) of resolubilized CV, identified as 585nm for 33% acetic acid and 580nm for 94-100% ethanol. To address the challenge of harmonizing the results across studies, a method was developed to adjust the biofilm categorisation threshold based on the extinction coefficient ratios of CV at different wavelengths enabling consistent classification regardless of the wavelength used. Validation with E. coli and S. aureus demonstrated that the adjusted thresholds produced results similar to that obtained with the λmax. This standardised approach not only enables the researchers to obtain accurate and consistent results in the future studies, but also facilitates the comparison of previously published data on biofilm research, which is essential for the exploration of newer therapeutic strategies against biofilm related infections.

Innovative nanocomposite comprising of ZrO2, MnCO3, and CdCO3 for superior crystal violet dye adsorption: synthesis, characterization, and regeneration insights

Crystal violet dye, widely used in industries, poses environmental and human health hazards due to its persistence and toxicity. Effective removal methods are critical to mitigate these impacts. This study presents the synthesis of a novel ZrO2@MnCO3@CdCO3 nanocomposite for the efficient removal of crystal violet dye from aqueous solutions. The nanocomposite was synthesized using a precipitation method and characterized using XRD, SEM, EDX, and BET surface area analysis. Adsorption experiments were conducted under various conditions, including pH, contact time, concentration, and temperature. The ZrO2@MnCO3@CdCO3 nanocomposite exhibited a mesoporous structure (22.38 m2/g surface area, 0.0935 cm3/g total pore volume, and 8.79 nm average pore size) and an average crystallite size of 76.30 nm. The maximum adsorption capacity for crystal violet dye was 179.52 mg/g, following pseudo-second-order kinetics and the Langmuir isotherm. Thermodynamic studies revealed an exothermic, physical, and spontaneous adsorption process. Regeneration experiments demonstrated high reusability with desorption efficiency reaching 99.67% over five cycles.

Inhibitory Effect of Shikimic Acid on Biofilm Formation and the Expression of Critical Biofilm-associated Genes in Streptococcus agalactiae

Background Streptococcus agalactiae is well-known for causing adverse pregnancy outcomes, such as stillbirths and miscarriages, as well as being a major cause of newborn sepsis and meningitis. Aims This study sought to investigate how shikimic acid influences the expression of genes involved in the synthesis of biofilms. Methods A total of 181 specimens were obtained from pregnant women. Twenty-two isolates were bacteriologically recognized as S. agalactiae from these specimens. They were gathered from hospitals in the Al-Anbar province. These twenty-two isolates were identified as Group B streptococcus (GBS) based on their cultural and microscopical properties, as well as automated (VITEK-2 system) and molecular identification based on the atr gene, which is an essential gene expressed in all S. agalactiae isolates. Results GBS produced varying amounts of biofilm (weak, moderate, and strong). Shikimic acid (SA) was tested for its antibacterial effect against biofilm. Shikimic acid was incubated at various doses, and its effects on biofilm growth and formation were evaluated by MTT and crystal violet assay. SA greatly reduced the GBS inhibitory effects on GBS biofilms in pregnant women. Furthermore, it demonstrated a potent initial cell attachment, but it had less inhibitory effects on biofilms that had already been developed on polystyrene surfaces after eight hours. However, the Checkerboard approach produced a synergistic interaction between erythromycin and shikimic acid. Polymerase Chain Reaction (PCR) was used to verify the presence of pilA and PilB genes in the GBS strain. We detected these genes by PCR. The results revealed that pilA was found only in three isolates (13.63%), but pilB was found in all isolates (22/22;100%). Conclusion Quantitative real-time PCR was used to determine the effect of shikimic acid on the expression of genes (sag1407 and sag1408), and the results showed down-regulation of the expression of biofilm synthesis genes sag1407 and sag1408 when treated with Sub-MIC of shikimic acid.

Synthesis of Isatin-Schiff Base and 1,2,3-Triazole Hybrids as Anti-SARS-CoV-2 Agents: DFT, Molecular Docking, and ADMET Studies

This study focuses on discovering novel antiviral compounds to address challenges posed by viral mutations and drug resistance. In this work, 3-((3,5-dimethylphenyl)imino)-1-((1-substituted-1H-1,2,3-triazol-4-yl)methyl)indolin-2-one derivatives 16–21 were synthesized via two distinct routes. The first route involved click cycloaddition reactions of Schiff base 3 with various substituted azides, while the second utilized the condensation of pre-synthesized isatin hybrids 10–15 with 3,5-dimethylaniline. The structures of these newly synthesized compounds were confirmed using advanced spectroscopic techniques and elemental analysis. Furthermore, in vitro evaluations included cytotoxicity and antiviral assays against SARS-CoV-2. Cytotoxicity was assessed using crystal violet assays to determine the cytotoxic concentration (CC50) of the compounds on Vero E6 cells. Antiviral activity was also evaluated. Among the tested compounds, compound 21 exhibited moderate antiviral activity, with a CC50 of 135.3 µM and an IC50 of 44.1 µM, resulting in a safety index (SI) of 3.1. Computational studies such as molecular docking, DFT calculations, molecular dynamics simulations, and drug-likeness assessments confirmed the stability, favorable pharmacokinetics, and drug-like properties of compound 21. These findings highlight the promise of these compounds as candidates for further optimization and development as antiviral agents.

Nepenthes pitcher fluid for the green synthesis of silver nanoparticles with biofilm inhibition, anticancer and antioxidant properties

This is the first report of silver nanoparticles (AgNPs) synthesis utilizing the pitcher secretion from an insectivorous plant, specifically Nepenthes ventrata, through a microwave assisted green synthesis approach. The successful formation of AgNPs was validated through a comprehensive set of analyses, including UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, DLS analysis and Zeta potential measurements. In addition gas chromatography-high-resolution mass spectrometry and liquid chromatography-high-resolution mass spectrometry analyses were conducted to examine the components present in the pitcher secretion. These analyses aimed to identify the capping and stabilizing agents in the secretion that facilitate the synthesis and stability of AgNPs. The synthesized AgNPs significantly inhibited biofilm formation by Pseudomonas aeruginosa PAO1, as demonstrated by Crystal Violet staining and fluorescence microscopy. Additionally, these AgNPs showed promising antioxidant properties through a DPPH radical scavenging assay. Furthermore, the anticancer properties of the AgNPs were analyzed using an MTT assay, which measures cell metabolic activity as an indicator of cell viability, proliferation, and cytotoxicity. Collectively, these findings suggest that the biosynthesized AgNPs possess multifaceted biological applications, showcasing their utility as both antimicrobial and antioxidative agents, and highlighting their potential in medical and environmental applications.

Characterization and antibiofilm activity of carotenoids derived from marine Bacillus infantis against Staphylococcus aureus and Pseudomonas aeruginosa

ABSTRACT Antibiotic resistance and biofilm pose significant challenges in healthcare, impacting economic growth and human well-being. The quest must be conducted for plausible natural anti-biofilm agents. Liquid chromatography mass spectroscopy was used for identification of carotenoids. Thebiofilm inhibition and eradication activity were evaluated against P. aeruginosa and S. aureus using crystal violet, Congo Red agar, and Scanning electron microscopy (SEM). Along with apocarotenoids, di‐O‐demethylspirilloxanthin, dihydroxylycopene glucoside, 2,2’-dihydroxy astaxanthin, and all-trans-Rhodovibrin were detected. Carotenoids at a concentration of 200 µg/ml showed 89.42 ± 3.42%, and 44.72 ± 6.18% biofilm inhibition of S. aureus, and P. aeruginosa, respectively, and was able to eradicate 25.68 ± 1.87% preformed biofilm in S. aureus. SEM and Congo Red Agar confirmed that carotenoids inhibited bacterial growth, exopolysaccharide production and prevented biofilm formation. Our investigation indicated that carotenoids from B. infantis could be an effective inhibitor for biofilm formed by both organisms and also had good eradication activity against S. aureus.

Histamine Promotes Pseudomonas aeruginosa Biofilm Formation and Renders Pseudomonas aeruginosa Biofilms More Resistant to Gentamicin and Azithromycin.

Pseudomonas aeruginosa biofilms contribute to the persistent presence of this bacterium in the cystic fibrosis airways. P. aeruginosa produces histamine in vitro and expresses histamine receptors. We investigated whether histamine regulated P. aeruginosa biofilm formation in vitro and contributed to bacterial virulence in Galleria mellonella. P. aeruginosa biofilms were measured by staining bacteria adhered on polystyrene with crystal violet. Histamine concentrations were measured by ELISA. G. mellonella survival upon inoculation with P. aeruginosa was measured in the absence or presence of histamine. The concentration of histamine in the BHI broth was 140 ng/ml (1.3 M). Addition to the broth of diamine oxidase (DAO), an enzyme that catabolizes histamine, reduced by ~ 3-fold the concentration of histamine and by 2-fold PAO1 strain biofilms. Addition of histamine (10-9 M - 10-4 M) to the LB medium augmented P. aeruginosa biofilms. Maximum effects were observed with concentrations of 10-5 M and 10-8 M for the mucoid NH57388A strain and the PAO1 strain, respectively. DAO reduced mucoid NH57388A biofilms induced by histamine (10-4 M) added to the LB medium. Addition of histamine to 48 h formed biofilms reduced anti-biofilm activities of gentamicin and azithromycin. Inoculation of G. mellonella with the PAO1 strain led to augmented histamine concentration in the haemolymph. Inoculation of histamine (10-8 M) reduced the survival rate of G. mellonella infected with the PAO1 strain. Histamine produced during periods of infection may augment P. aeruginosa virulence by promoting the biofilm mode of life of this bacterium.

Plasmonic Slippery Surface for Surface-Enhanced Raman Spectroscopy and Protein Adsorption Inhibition.

Slippery liquid-infused porous surfaces (SLIPSs) are a class of surface that offers low contact angle hysteresis and low tilt angle for water droplet shedding. This property also endows the surface with pinning-free evaporation, which in turn has been exploited for analyte concentration enrichment for Surface Enhanced Raman Spectroscopic applications and antibiofouling. Herein, we demonstrate a facile approach for creating SLIPS with low contact angle hysteresis and low tilt angle for water shedding by coating the equal-volume mixture of polydimethylsiloxane (PDMS) and silicone oil. By exploiting the in situ plasmonic particle reduction capability of the PDMS, the surface is converted to plasmonic SLIPS, which illustrates its potential as a sensitive analytical platform via surface-enhanced Raman spectroscopy. The Raman spectroscopic studies using crystal violet as a reference sample show a limit of detection of 76 pM. Further, we have demonstrated that the fabricated plasmonic substrate is found to be more efficient in inhibiting proteins (bovine serum albumin) on the surface compared to pristine PDMS surfaces. Our fabricated plasmonic surface can find applications in ultrasensitive molecular detection for applications related to analytical chemistry, diagnostics, environmental monitoring, and national security and more importantly can control the nonspecific adsorption of proteins.

Eisenia bicyclis-Mediated Gold Nanoparticles Exhibit Antibiofilm and Antivirulence Activities Against Pseudomonas aeruginosa and Staphylococcus aureus.

Background/Objectives: Brown algae, particularly Eisenia bicyclis, produce various bioactive chemicals with significant application potential in the food, cosmetics, and pharmaceutical industries. This study aimed to evaluate the antibacterial, antibiofilm, and antivirulence properties of the ethyl acetate fraction (EA) of E. bicyclis and its synthesized gold nanoparticles (EA-AuNPs), with a focus on their potential applications against both Gram-positive and Gram-negative bacteria. Methods: The bioactive component in the ethyl acetate fraction was identified using a gas chromatography-mass spectroscopy (GC-MS) device and a liquid chromatography-mass spectrometer/mass spectrometry (LC-MS) system. The crystal violet method was utilized to evaluate the biofilm inhibition experiments. Several instruments, including dynamic light scattering, Fourier transform infrared, X-ray diffraction, field emission transmission electron microscopy, and energy-dispersive spectroscopy, were employed to completely characterize the produced EA-AuNPs. The cytotoxicity of the EA-AuNPs was determined using the MTT assay, and the expression of genes linked with biofilm and virulence in Pseudomonas aeruginosa and Staphylococcus aureus was investigated using real-time polymerase chain reaction (RT-PCR). Results: Various bioactive compounds were identified from the EA using GC-MS and LC-MS, including fatty acids and phlorotannins such as eckol, dieckol, 6,6'-bieckol, and phlorofucofuroeckol in high amounts, highlighting EA as a phlorotannin-rich fraction. The EA also demonstrated significant antibiofilm activity, with 79.86% inhibition at 512 μg/mL against P. aeruginosa and 87.00% at 64 μg/mL against S. aureus. EA was then used in the synthesis of gold nanoparticles (AuNPs) to improve their stability and safety. The synthesized EA-AuNPs were determined to have an average size of 165.04 nm, with a zeta potential of -29.86 mV, indicating good stability. In antibiofilm activity assays, EA-AuNPs demonstrated 45.76% inhibition against P. aeruginosa at 1024 μg/mL and 44.64% inhibition against S. aureus at 128 μg/mL. At sub-MIC levels, EA-AuNPs significantly inhibited biofilm formation and virulence factors, including the motility of P. aeruginosa and staphyloxanthin synthesis in S. aureus. The RT-PCR analysis revealed the downregulation of key genes involved in biofilm formation and virulence in P. aeruginosa and S. aureus. Conclusions: These findings highlight the potential of E. bicyclis solvent-soluble extracts and EA-AuNPs as effective antibacterial, antibiofilm, and antivirulence agents, with significant application potential in the pharmaceutical and food industries. To the best of our knowledge, this is the first report of antibiofilm activity against both Gram-positive and Gram-negative bacteria using EA-AuNPs.

Enhanced photocatalytic activity of Z-scheme ZrO2/V2O5 nanocomposite with graphite carbon nitride for effective degradation of amoxicillin and crystal violet under visible light

Enhanced photocatalytic activity of Z-scheme ZrO2/V2O5 nanocomposite with graphite carbon nitride for effective degradation of amoxicillin and crystal violet under visible light

Insights into the molecular self-assembly of urea-functionalized acetylenes

This study investigates simple acetylenes substituted with phenylurea as a constant H-bonding unit (Alk-R) and varied hydrophobic units (R = H, Phenyl (Ph), phenylacetylene (PA), Ph-NMe2) to understand self-assembly properties driven by synergistic non-covalent interactions. Our observations reveal hierarchical self-assembled fibrillar networks with luminescent needles, fibers, and flowers on nano- to micro-meter scales. Subtle changes in substituents led to significant differences: H, Ph, PA, and Ph-NMe2produced needle-like crystals, dendritic nanofibers, microflakes, and no self-assembly, respectively.Alk-Ph-NMe2likely did not self-assemble due to reduced hydrophobic interactions and steric hindrance. Interestingly,Alk-Phexhibited a uniform spherulitic pattern and effectively gelled organic solvents and water. This luminescent gel demonstrated multifunctionality, including white light emission when doped with rhodamine-B dye and adsorption of organic cationic dyes (methylene blue and crystal violet) from water. This study offers valuable insights into balancing interactions to achieve desired hierarchical networks and understand material properties, guiding future molecular design.

ZnCo Bimetallic Macro-Microporous Metal-Organic Frameworks for Efficient Adsorption of Dyes.

The significant threat posed by dye wastewater has driven the development of efficient adsorbents, such as metal organic frameworks (MOFs). Specifically, we explore the synthesis and application of ZnCo-based bimetallic zeolite imidazolate frameworks with a macro-microporous structure (SOM-ZnCo-ZIF), which exhibit enhanced adsorption capacity for dyes due to their large specific surface area and ordered porous arrangement. When SOM-ZnCo-ZIF is immersed in DMA solutions of methylene blue, methyl orange, crystal violet, and rhodamine B, due to its high specific surface area and the synergistic effect of ZnCo bimetallic clusters, SOM-ZnCo-ZIF significantly enhances dye adsorption. Notably, its adsorption capacity for Rhodamine B reaches an impressive 6798.9 mg/g, and within just 1 min, 0.5 g/L of SOM-ZnCo-ZIF can remove over 97% of Rhodamine B from a 60 mg/L solution. Moreover, it maintained a 92.8% dye removal efficiency in ten cycles without regeneration, demonstrating the effective adsorption capacity of SOM-ZnCo-ZIF. Density functional theory calculations have shown that the adsorption energy of ZnCo bimetallic ZIF for Rhodamine B is approximately twice that of a single metal. SOM-ZnCo-ZIF exhibits strong adsorption of Rhodamine B mainly due to its macro-microporous structure, which provides larger pore sizes (∼250 nm) allowing the dye molecules to infiltrate the porous network, and its ability to facilitate π-π stacking interactions between the benzene rings of Rhodamine B and the imidazole rings of the ZIF. Additionally, the interaction is further enhanced by strong coordination bonds and electrostatic interactions between the cationic dye and the negatively charged framework. This work not only proposes an effective adsorbent to remove Rhodamine B but also provides valuable insights for the rational design and synthesis of environmentally sustainable MOF structures.

Investigation of the optimal condition for the growth and biofilm development of Candida albicans on three dental materials

Background and Objectives: Candida albicans as pathogenic fungi cause conditions like oral candidiasis and dental caries. The critical role of biofilms in the pathogenicity of C. albicans necessitates the exploration of conditions that promote their growth and development. Our study aimed to delineate the optimal conditions conducive to the proliferation and biofilm production of C. albicans on prevalent dental materials. Materials and Methods: To approximate oral cavity conditions, culture media were enhanced with various glucose concen- trations to assess the growth and biofilm-forming capability of the fungus through growth curve analysis and crystal violet assays. Results: The findings suggest that YPG medium augmented with 4% glucose presents as an optimal environment for C. albicans growth. Biofilm formation was most effectively promoted in RPMI medium supplemented with the same concen- tration of glucose. Composite resin was identified as the substrate most susceptible to biofilm development by C. albicans under these conditions. Conclusion: This investigation highlights the necessity of accounting for microbial activity and material characteristics in the prevention and management of dental biofilm formation. Our research advances the understanding of in vitro cultivation of C. albicans, simulating the oral milieu more accurately and contributing to enhanced oral health management for individ- uals utilizing temporary dental fixtures.

Discovery of Biofilm-Inhibiting Compounds to Enhance Antibiotic Effectiveness Against M. abscessus Infections.

Background/Objectives: Mycobacterium abscessus (MAB) is a highly resilient pathogen that causes difficult-to-treat pulmonary infections, particularly in individuals with cystic fibrosis (CF) and other underlying conditions. Its ability to form robust biofilms within the CF lung environment is a major factor contributing to its resistance to antibiotics and evasion of the host immune response, making conventional treatments largely ineffective. These biofilms, encased in an extracellular matrix, enhance drug tolerance and facilitate metabolic adaptations in hypoxic conditions, driving the bacteria into a persistent, non-replicative state that further exacerbates antimicrobial resistance. Treatment options remain limited, with multidrug regimens showing low success rates, highlighting the urgent need for more effective therapeutic strategies. Methods: In this study, we employed artificial sputum media to simulate the CF lung environment and conducted high-throughput screening of 24,000 compounds from diverse chemical libraries to identify inhibitors of MAB biofilm formation, using the Crystal Violet (CV) assay. Results: The screen established 17 hits with ≥30% biofilm inhibitory activity in mycobacteria. Six of these compounds inhibited MAB biofilm formation by over 60%, disrupted established biofilms by ≥40%, and significantly impaired bacterial viability within the biofilms, as confirmed by reduced CFU counts. In conformational assays, select compounds showed potent inhibitory activity in biofilms formed by clinical isolates of both MAB and Mycobacterium avium subsp. hominissuis (MAH). Key compounds, including ethacridine, phenothiazine, and fluorene derivatives, demonstrated potent activity against pre- and post-biofilm conditions, enhanced antibiotic efficacy, and reduced intracellular bacterial loads in macrophages. Conclusions: This study results underscore the potential of these compounds to target biofilm-associated resistance mechanisms, making them valuable candidates for use as adjuncts to existing therapies. These findings also emphasize the need for further investigations, including the initiation of a medicinal chemistry campaign to leverage structure-activity relationship studies and optimize the biological activity of these underexplored class of compounds against nontuberculous mycobacterial (NTM) strains.

Recyclable Fe3O4 embedded Sterculia gum-graft-poly(acrylamide-co-vinyl acetate) hydrogel as a novel adsorbent for toxic cationic dyes remediation

In this study, a novel Fe3O4-embedded Sterculia gum (SG) crosslinked poly(acrylamide-co-vinyl acetate) hydrogel abbreviated as SG-cl-(PAAm-co-PVAc)@Fe3O4 was synthesized by in situ co-precipitation of Fe3O4 magnetic particles for enrichment of cationic dyes methylene blue (MB), crystal violet (CV) and Brilliant cresyl blue (BCB) from aqueous solutions. The surface morphology and composition of the fabricated hydrogel was analyzed and characterized by Fourier transform-infrared, differential thermal analysis, X-ray diffraction, field emission scanning electron microscopy, Brunauer–Emmett–Teller analysis and vibrating sample magnetometer studies. It was discovered that the highest sorption efficiency of 74.881 ± 1.5, 77.303 ± 1.7 and 67.751 ± 0.8 mg g−1 for MB, CV and BCB dyes respectively was achieved using SG-cl-(PAAm-co-PVAc)@Fe3O4 dose of 20 mg, a solution pH of 9.2, temperature of 303 K and at an initial dye concentration of 100 mg L−1. The pHpzc studies reveals surface of SG-cl-(PAAm-co-PVAc)@Fe3O4 hydrogel is predominantly negative at pH values higher than 3.36. The adsorption behavior for MB, CV and BCB dyes conformed well to Temkin isotherm model and followed pseudo-first-order kinetics. Thermodynamic studies revealed that adsorption process is exothermic (negative ΔH°), feasible and spontaneous with a negative value of entropy (ΔS°). Reusability results demonstrated that the hydrogel maintained adsorption efficiencies of 68.67 ± 1.7%, 70.15 ± 1.2%, and 59.53 ± 1.6% for cationic dyes MB, CV and BCB respectively even after three cycles underscoring its exceptional reusability and structural stability. Overall the study highlights the potential of SG based magnetic hydrogel as a promising solution for eliminating the toxic cationic dyes from water sources.

Phenotypic and genotypic screening of multidrug resistant Klebsiella pneumoniae isolated from ready to eat street food in Tanta, Egypt.

Ready-To-Eat-Street-Foods (RTESF)have food safety concerns, since they are prepared with less-structured food safety guidelines in small and roadside outlets.Klebsiella pneumoniae has become a dangerous foodborne-pathogen worldwide due to its virulence and resistance profile. This study aimed at evaluating the potential burden of antibiotic-resistant Klebsiella pneumoniae contaminating RTESF and assessing the microbiological quality of RTESF in Egypt. A total of 242 RTESF (green salad) samples was collected, different media were used for isolation of different bacterial species.Klebsiella pneumoniae isolates were identified biochemically and by Gram and capsular staining then isolates were assessed for antimicrobial resistance phenotypically. The ability of biofilm formation was assessed using crystal violet and molecular characterization of ESBLs and virulence genes was done using PCR. A total of 77/242(31.8%)of the recovered isolates was identified as Klebsiella pneumoniaeand the resistance percentages were as follow: cefuroxime and cephradine(100%, 77/77),amoxicillin-clavulanic acid (98.7%, 76/77), while (27.3%, 21/77)of the isolates were MDR. Biofilm assay revealed that (31/77, 41/77 and 5/77) isolates were strong, moderate, and weak biofilm-producers, respectively. Among ESBLs-encoding-genes, blaSHV was the most prevalent(71.4%)whileblaTEMand blaCTX-M-2were equally-present (55.8%).The most prevalent virulence genes were mrkD (92.2%) followed by K2 (63.3%). The contaminated RTESF could be a reservoir for Klebsiella pneumoniae, therefore much care must be taken during preparation and consumption to avoid dissemination of MDRKlebsiella pneumoniae leading to subsequent treatment challenges. Our finding indicating that RTESF, if not prepared under hygienic conditions, could be a source of serious Klebsiella pneumoniae infection.

Effective removal of crystal violet in the aqueous solution using magnetic composites originated from sugarcane bagasse

Effective removal of crystal violet in the aqueous solution using magnetic composites originated from sugarcane bagasse