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Search Results (160)

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Keywords = Gram-positive to Gram-negative bacteria ratio

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18 pages, 3792 KiB  
Article
Porcine β-Defensin 2 Expressed in Pichia pastoris Alleviates Enterotoxigenic Escherichia coli-Induced Intestinal Injury and Inflammatory Response in Mice
by Shuaiyang Wang, Huaixia Li, Yaxue Huang, Wenxiao Zhuo, Tingting Li, Tingting Jiang, Qi Huang and Rui Zhou
Animals 2025, 15(10), 1389; https://doi.org/10.3390/ani15101389 - 11 May 2025
Viewed by 698
Abstract
Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the [...] Read more.
Enterotoxigenic Escherichia coli (ETEC), a common intestinal pathogen, can colonize the intestines and induce diarrhea in piglets, which brings great economic losses to the swine industry. Antibiotics are recommended to the treatment for diarrhea caused by ETEC in weaned piglets. However, with the emergence and spread of multidrug-resistant ETEC, there is an urgent need to develop alternatives to antibiotics. Due to the unique antibacterial mechanism of targeting bacterial membranes, antimicrobial peptides (AMPs) are promising candidates. In this study, the activity of crude recombinant porcine β-defensin 2 (rPBD2) expressed in Pichia pastoris (P. pastoris) was measured in vitro. Mice infected with ETEC were orally administered 16, 8, and 4 AU crude rPBD2 for 7 consecutive days to evaluate its anti-infective activity in vivo. The results showed that in addition to broad antibacterial activity against Gram-positive and -negative bacteria, crude rPBD2 displayed high tolerance to temperatures ranging from 20 to 60 °C, a broad range of pH, trypsin, pepsin, and physiological concentrations of salts. In an ETEC-induced mouse model, the oral administration of crude rPBD2 decreased diarrhea scores and the intestinal/carcass ratio and alleviated body weight loss. Additionally, crude rPBD2 decreased bacterial loads in stools and the colon (HP group), and the levels of serum pro-inflammatory cytokines IL-6 (HP group) and TNF-α (HP and MP groups), and increased the villus height and the ratio of villus height to crypt depth (VH/CD) in the ileum (HP and MP groups). Our study provides a cost-effective way for PBD2 production and identifies it as a promising candidate to combat ETEC-induced infection. Full article
(This article belongs to the Section Pigs)
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15 pages, 1902 KiB  
Article
Rice-Fish Co-Culture Promotes Soil Carbon Sequestration Through Alterations in Soil Microbial Community Structure
by Daolin Sun, Hongjun Zheng, Zhaoji Shi, Jiaen Zhang, Qi Jia, Xing Liu, Min Zhao, Yuting Chen, Qi Chen and Mingzhu Luo
Agronomy 2025, 15(5), 1054; https://doi.org/10.3390/agronomy15051054 - 27 Apr 2025
Viewed by 485
Abstract
The high-input production mode of rice monoculture (RM) has caused severe soil degradation and biodiversity loss, necessitating a transition toward more sustainable practices. The traditional rice-fish co-culture (RF) may provide valuable insights for this situation. However, it remains elusive how long-term RF system [...] Read more.
The high-input production mode of rice monoculture (RM) has caused severe soil degradation and biodiversity loss, necessitating a transition toward more sustainable practices. The traditional rice-fish co-culture (RF) may provide valuable insights for this situation. However, it remains elusive how long-term RF system influences soil microbial community structure, enzyme activities, and carbon (C) sequestration. Here, a study was conducted at two representative RF areas in Lianshan Zhuang and Yao Autonomous County. At Shatian (P1), three treatments included rice monoculture (RM1) and 2-year and 5-year RF (RF2, RF5). At Gaoliao (P2), the experimental treatments included rice monoculture (RM2) and 15 and 30 years of RF (RF15, RF30). We collected the surface layer (0–20 cm) soils. Then, we analyzed the chemical properties, phospholipid fatty acids (PLFA), and enzyme activities to investigate the effects of their variation on soil C sequestration. The results showed that RF treatments significantly increased soil organic C (SOC) content. Specifically, RF2 and RF5 treatments promoted the SOC content by 4.82% and 13.60% compared with RM1 treatment at P1, respectively; RF15 and RF30 treatments increased the SOC content by 23.41% and 31.93% compared with RM2 treatment at P2, respectively. Additionally, RF5 treatment significantly increased the biomass of the soil microbial community in comparison with RM1 treatment, as did RF15 treatment and RF30 treatment compared with RM2 treatment, including the contents of total PLFA and the PLFA of gram-positive bacteria (G+), gram-negative bacteria (G−), actinomycetes, fungi, and bacteria. Activities of β-glucosidase, cellobiohydrolase, β-1,4-N-acetylglucosaminidase, and urease significantly increased in RF5 and RF30 treatments. The piecewise SEM results indicated that the changes of total PLFA content and the PLFA content ratio of fungi to bacteria were related to contents of dissolved organic C (DOC) and total N (TN) under different RF durations, which are key indicators affecting SOC content. Overall, SOC storage increases with the RF durations, and soil microbial community structure may drive soil C sequestration under long-term RF, which provides a scientific significance and practical value in promoting the sustainability of agricultural ecosystems, enhancing the potential of soil as a carbon sink, and addressing global climate change. Full article
(This article belongs to the Section Farming Sustainability)
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17 pages, 3974 KiB  
Article
Development of a Population Pharmacokinetic Model of Levofloxacin in Healthy Adults and Identification of Optimal Dosing Regimens
by Yun-Jung Lee, Gaeun Kang, Dae-Young Zang and Dong-Hwan Lee
Pharmaceuticals 2025, 18(5), 621; https://doi.org/10.3390/ph18050621 - 25 Apr 2025
Viewed by 579
Abstract
Background/Objectives: Levofloxacin dosing guidelines recommend adjustments only when the creatinine clearance (CrCl) is <50 mL/min. We hypothesized that further dose stratification based on CrCl could improve therapeutic outcomes, even when the CrCl ≥ 50 mL/min. This study aimed to develop a population [...] Read more.
Background/Objectives: Levofloxacin dosing guidelines recommend adjustments only when the creatinine clearance (CrCl) is <50 mL/min. We hypothesized that further dose stratification based on CrCl could improve therapeutic outcomes, even when the CrCl ≥ 50 mL/min. This study aimed to develop a population pharmacokinetic (PK) model of levofloxacin in healthy adults and identify optimal dosing regimens. Methods: In this prospective, open-label study, 12 healthy adults received a single dose of levofloxacin. Plasma concentrations were measured using liquid chromatography–tandem mass spectrometry. A population PK model was developed with nonlinear mixed-effects modeling, and Monte Carlo simulations were performed to identify optimal dosing regimens. Results: A two-compartment model with first-order kinetics best described the levofloxacin PK profiles. The CrCl was associated with a variation in clearance and lean body mass, with a variation in peripheral volume of distribution. Simulations identified optimal regimens, defined as those achieving a probability of target attainment of at least 90% for the target unbound 24-hour area under the curve at steady state to minimum inhibitory concentration ratio (fAUC/MIC), which differed by pathogen (≥30 for Gram-positive bacteria; ≥100 for Gram-negative bacteria). For the ratio fAUC/MIC ≥ 30 and an MIC of 0.5 mg/L, 500 mg daily was optimal for patients with a CrCl of 50–89 mL/min. For the ratio fAUC/MIC ≥ 100, 1000 mg daily was required in the same CrCl range and MIC value. Conclusions: The population PK model incorporating CrCl and lean body mass improved the prediction of levofloxacin PKs. Refining current dosing recommendations by incorporating stratified CrCl and MIC values could optimize therapeutic outcomes, particularly for patients with a CrCl ≥ 50 mL/min. Full article
(This article belongs to the Special Issue Population Pharmacokinetics and Pharmacogenetics)
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17 pages, 443 KiB  
Article
Incidence, Compliance, and Risk Factor Associated with Central Line-Associated Bloodstream Infection (CLABSI) in Intensive Care Unit (ICU) Patients: A Multicenter Study in an Upper Middle-Income Country
by Arulvani Rajandra, Nor’azim Mohd Yunos, Chin Hai Teo, Anjanna Kukreja, Nur Alwani Suhaimi, Siti Zuhairah Mohd Razali, Sazali Basri, Cindy Shuan Ju Teh, Chee Loon Leong, Ismaliza Ismail, Azureen Azmel, Nor Hafizah Mohd Yunus, Giri Shan Rajahram, Abdul Jabbar Ismail, Shanti Rudra Deva, Pei Wei Kee, TRGS Working Group and Sasheela Sri La Sri Ponnampalavanar
Antibiotics 2025, 14(3), 271; https://doi.org/10.3390/antibiotics14030271 - 7 Mar 2025
Cited by 2 | Viewed by 3769
Abstract
Background: Despite significant prevention efforts, the incidence of central line-associated bloodstream infection (CLABSI) in intensive care units (ICUs) is rising at an alarming rate. CLABSI contributes to increased morbidity, mortality, prolonged hospital stays and elevated healthcare costs. This study aimed to determine the [...] Read more.
Background: Despite significant prevention efforts, the incidence of central line-associated bloodstream infection (CLABSI) in intensive care units (ICUs) is rising at an alarming rate. CLABSI contributes to increased morbidity, mortality, prolonged hospital stays and elevated healthcare costs. This study aimed to determine the incidence rate of CLABSI, compliance with the central venous catheter (CVC) care bundle and risk factors associated with CLABSI among ICU patients. Method: This prospective observational study was conducted in one university hospital and two public hospitals in Malaysia between October 2022 to January 2023. Adult ICU patients (aged > 18 years) with CVC and admitted to the ICU for more than 48 h were included in this study. Data collected included patient demographics, clinical diagnosis, CVC details, compliance with CVC care bundle and microbiological results. All data analyses were performed using SPSS version 23. Results: A total of 862 patients with 997 CVCs met the inclusion criteria, contributing to 4330 central line (CL) days and 18 CLABSI cases. The overall incidence rate of CLABSI was 4.16 per 1000 CL days. The average of overall compliance with CVC care bundle components was 65%. The predominant causative microorganisms isolated from CLABSI episodes were Gram-negative bacteria (78.3%), followed by Gram-positive bacteria (17.4%) and Candida spp. (2.0%). Multivariate analysis identified prolonged ICU stay (adjusted odds ratio (AOR): 1.994; 95% confidence interval (CI): 1.092–3.009), undergoing surgery (AOR: 2.02, 95% CI: 1.468–5.830) and having had multiple catheters (AOR: 3.167, 95% CI: 1.519–9.313) as significant risk factors for CLABSI. Conclusions: The findings underscore the importance of robust surveillance, embedded infection-control and -prevention initiatives, and strict adherence to the CVC care bundle to prevent CLABSI in ICUs. Targeted interventions addressing identified risk factors are crucial to improve patient outcomes and reduce healthcare costs. Full article
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25 pages, 8148 KiB  
Article
Copper Nanoparticles Synthesized by Chemical Reduction with Medical Applications
by Alexandra Pricop, Adina Negrea, Bogdan Pascu, Nicoleta Sorina Nemeş, Mihaela Ciopec, Petru Negrea, Cătălin Ianăşi, Paula Svera, Delia Muntean, Alexandra Ivan and Iustina Mirabela Cristea
Int. J. Mol. Sci. 2025, 26(4), 1628; https://doi.org/10.3390/ijms26041628 - 14 Feb 2025
Cited by 3 | Viewed by 2303
Abstract
Copper nanoparticles (CuNPs) have attracted attention due to their low cost and high specific surface area. In this work, a simple and inexpensive two-step synthesis method was proposed to prepare highly stable and well-dispersed spherical CuNPs in solution with a particle size of [...] Read more.
Copper nanoparticles (CuNPs) have attracted attention due to their low cost and high specific surface area. In this work, a simple and inexpensive two-step synthesis method was proposed to prepare highly stable and well-dispersed spherical CuNPs in solution with a particle size of approximately 37 nm. Synthesis of CuNPs was carried on in the presence of complexing agent trisodium citrate (TSC), while for the chemical reduction step, sodium borohydride (NaBH4) was used. Taking into account the potential of this type of nanoparticles, their synthesis and characterization represent a current and relevant topic in the field. The ability to control the size, shape and properties of CuNPs by adjusting the synthesis parameters (pH, precursor:stabilizer:reductant ratio, homogenization time, temperature) offers extraordinary flexibility in the development of these materials. The combination of characterization techniques such as SEM, EDX, UV–Vis, Raman, FT-IR and AFM provides a thorough understanding of the structure and properties of CuNPs, allowing the modulation of the properties of the obtained nanoparticles in the desired direction. Based on the studies, the copper reduction mechanism was proposed. For the theoretical verification of the size of the experimentally obtained spherical CuNPs, Mie theory was applied. A stability study of the synthesized CuNPs in optimal conditions was performed using UV–Vis analysis at specific time intervals (1, 3, 30 and 60 days), the sample being kept in the dark, inside a drawer at 25 °C. The CuNPs obtained after setting the optimal synthesis parameters (Cu(II):TSC:BH4+ = 1:1:0.2, pH = 5, homogenization time 60 min and temperature 25 °C) were then tested to highlight their antibacterial effect on some reference bacterial strains. The obtained CuNPs demonstrated very good antimicrobial efficacy compared to traditional antimicrobials, for both Gram-negative and Gram-positive bacteria. This may reduce the development of antimicrobial resistance, an urgent medical issue. After evaluating the cytotoxic effects of CuNPs on the SKBR3 cancer cell line, a significant decrease in cell proliferation was observed at the 0.5 mg/mL concentration, with a reduction of 89% after 60 h of cultivation. Higher concentrations of CuNPs induced a more rapid cytotoxic effect, leading to an accelerated decline in cell viability. Full article
(This article belongs to the Section Molecular Nanoscience)
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20 pages, 9546 KiB  
Article
Biofabrication of Silver Nanoparticles Using Pergularia tomentosa Extract and Evaluation of Their Antibacterial, Antioxidant, and Cytotoxic Properties
by Munirah F. Aldayel
Life 2024, 14(12), 1639; https://doi.org/10.3390/life14121639 - 10 Dec 2024
Viewed by 1202
Abstract
The biosynthesis of silver nanoparticles using plant extracts is a promising field of research because of the useful biomedical applications of metal nanoparticles. In this study, the antibacterial and antioxidant properties of silver nanoparticles biosynthesized with the aqueous leaf extract of Pergularia tomentosa [...] Read more.
The biosynthesis of silver nanoparticles using plant extracts is a promising field of research because of the useful biomedical applications of metal nanoparticles. In this study, the antibacterial and antioxidant properties of silver nanoparticles biosynthesized with the aqueous leaf extract of Pergularia tomentosa were defined using a simple, eco-friendly, consistent, and cost-effective method. The leaf extract of Pergularia tomentosa (PT) served as a capping and reducing agent to biosynthesize silver nanoparticles. The effects of several parameters, such as the concentration of AgNO3, ratio of AgNO3 to extract, pH, and incubation time, were examined to optimize the synthesis process. In total, 5 mM of AgNO3, a 1:0.06 ratio of AgNO3 to Pergularia tomentosa extract, pH 9.0, and reaction mixture incubation for 24 h were found to be the ideal parameters for biosynthesizing silver nanoparticles (AgNPs). UV–visible spectroscopy, X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and scanning electron microscopy were used to characterize the biosynthesized Pergularia tomentosa silver nanoparticles (PT-AgNPs). Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (Salmonella enteritides and Escherichia coli) were used to test the PT-AgNPs’ antibacterial activity. The presence of different functional groups was determined using FTIR. The AgNPs were hexagon shaped. The nanoparticles were more toxic against S. enteritides than both B. cereus and E. coli. In antioxidant analyses, the AgNPs were found to be as strong at free radical scavenging as gallic acid (standard), with IC50 values of 0.69 and 22.30 μg/mL for DPPH and ABTS radicals, respectively. Interestingly, the PT-AgNPs displayed increased anti-inflammatory activity compared with the P. tomentosa leaf extract (79% vs. 59% at 500 µg/mL). The PT-AgNPs did not display any cytotoxicity against the MCF-7 cell line at the MIC. In conclusion, silver nanoparticles fortified with Pergularia tomentosa extract exhibited potential as effective antibacterial, anti-inflammatory, and antioxidant agents, suggesting their viability as alternatives to commercially available products. Full article
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29 pages, 6688 KiB  
Article
Bioactive Potential of Chitosan–Oleic Acid Nanoparticles Loaded with Lemon Peel Essential Oil for Topical Treatment of Vulvovaginal Candidiasis
by Faten M. Ibrahim, Eman Samy Shalaby, Mohamed F. Abdelhameed, Radwa H. El-Akad, Kawkab A. Ahmed, Mohamed S. Abdel-Aziz, El Sayed El Habbasha, Cristina V. Rodrigues and Manuela Pintado
Molecules 2024, 29(23), 5766; https://doi.org/10.3390/molecules29235766 - 6 Dec 2024
Cited by 3 | Viewed by 1705
Abstract
The rising incidence of vulvovaginal candidiasis (VVC) has been leading to the development of alternative antifungal therapies. This study aimed to develop a topical chitosan–oleic acid nanoparticle (CH-OA-NP) cream loaded with lemon peel essential oil (LPEO) for VVC treatment. The characterization of the [...] Read more.
The rising incidence of vulvovaginal candidiasis (VVC) has been leading to the development of alternative antifungal therapies. This study aimed to develop a topical chitosan–oleic acid nanoparticle (CH-OA-NP) cream loaded with lemon peel essential oil (LPEO) for VVC treatment. The characterization of the optimal nanoparticle formulation (F4: 10 g/L CH, 2:1 OA/LPEO ratio) showed high encapsulation efficiency, stability, and controlled release. Moreover, it was characterized regarding its particle size, polydispersity index, zeta potential, and chemical/morphological profile. LPEO-related compounds (e.g., eriodictyol) were identified through LC-ESI-QqTOF-HRMS in the cream matrix, suggesting the preservation of LPEO potential bioactivities after formulation. In silico docking of 12 LPEO metabolites revealed that compounds such as citronellic acid exerted inhibitory effects against several inflammation-associated enzymes (e.g., 14-α-Demethylase). In vitro antimicrobial tests demonstrated remarkable activity against Candida albicans, Gram-negative (e.g., Escherichia coli), and Gram-positive (e.g., Staphylococcus aureus) bacteria. In vivo studies in a rat model of VVC revealed significant antifungal, anti-inflammatory, and immunomodulatory effects of the LPEO-CH-OA-NP cream (5% and 10%), leading to reduced MDA, MPO, and IL-1β levels and increased GSH activity. This novel formulation potentially offers a promising alternative therapy for VVC, addressing the current antifungal therapies’ limitations, counteracting drug resistance. Full article
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20 pages, 2665 KiB  
Article
Biosynthesis of Palladium Nanoparticles by Using Aqueous Bark Extract of Quercus dalechampii, Q. frainetto, and Q. petraea for Potential Antioxidant and Antimicrobial Applications
by Nastaca-Alina Coman, Mihai Babotă, Alexandru Nicolescu, Alexandra Nicolae-Maranciuc, Lavinia Berta, Adrian Man, Dan Chicea, Lenard Farczadi and Corneliu Tanase
Plants 2024, 13(23), 3390; https://doi.org/10.3390/plants13233390 - 3 Dec 2024
Cited by 1 | Viewed by 1445
Abstract
This study aimed to synthesize palladium nanoparticles (PdNPs) using bioactive compounds from aqueous extracts of Quercus species (Quercus dalechampii, Quercus frainetto, and Quercus petraea) with potential biomedical applications. To optimize PdNPs biosynthesis, various parameters were explored, including the concentration [...] Read more.
This study aimed to synthesize palladium nanoparticles (PdNPs) using bioactive compounds from aqueous extracts of Quercus species (Quercus dalechampii, Quercus frainetto, and Quercus petraea) with potential biomedical applications. To optimize PdNPs biosynthesis, various parameters were explored, including the concentration of PdCl2, the extract-to-PdCl2 ratio, and the pH of the solution. The nanoparticles were characterized using ultraviolet/visible spectroscopy (UV/Vis), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). Total polyphenol content was measured using the Folin–Ciocâlteu method, while antioxidant capacity was evaluated through radical neutralization assays, including ABTS and DPPH, and through iron and copper reduction tests. Antimicrobial activity was tested against Gram-positive and Gram-negative bacteria, as well as Candida species. Phenolic compounds and flavonoids from the extracts were essential for the reduction in palladium ions and the stabilization of the nanoparticles. UV/Vis spectroscopy showed a distinct surface plasmon resonance peak, indicating the successful formation of PdNPs. FTIR analysis confirmed the interaction between the bioactive compounds and PdNPs, revealing characteristic peaks of phenolic groups. DLS analysis indicated a hydrodynamic diameter of 63.9 nm for QD-PdNPs, 48 nm for QF-PdNPs, and 63.1 nm for QP-PdNPs, highlighting good dispersion and stability in solution. Although the PdNPs did not exhibit strong antioxidant properties, they demonstrated selective antimicrobial activity, especially against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). PdNPs also exhibited significant antifungal activity against Candida krusei, with a minimum inhibitory concentration (MIC) of 0.63 mg/mL, indicating their ability to compromise fungal cell integrity. This study contributes to developing eco-friendly biosynthesis methods for metallic nanoparticles and underscores the potential of PdNPs in various applications, including in the biomedical field. Full article
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18 pages, 4231 KiB  
Article
Green Synthesis of Terminalia ferdinandiana Exell-Mediated Silver Nanoparticles and Evaluation of Antibacterial Performance
by W. Hansi S. Alwis, Vinuthaa Murthy, Hao Wang, Roshanak Khandanlou and Pappu Kumar Mandal
Biomolecules 2024, 14(12), 1516; https://doi.org/10.3390/biom14121516 - 27 Nov 2024
Cited by 1 | Viewed by 1261
Abstract
This study uses a novel method in which extracts from different parts of a single plant are used to synthesize well-defined silver nanoparticles (AgNPs) to address the lack of capping agents in certain plant extracts. We focused on synthesizing AgNPs with enhanced biomedical [...] Read more.
This study uses a novel method in which extracts from different parts of a single plant are used to synthesize well-defined silver nanoparticles (AgNPs) to address the lack of capping agents in certain plant extracts. We focused on synthesizing AgNPs with enhanced biomedical activity using aqueous leaves and fruit extracts of Terminalia ferdinandiana Exell, a plant native to northern Australia that is known for its high phenolic content and associated health benefits. The impact of using parameters such as the Ag+ ion-to-extract ratio and pH on AgNP synthesis was examined. The formation of AgNPs was confirmed using UV–visible spectrophotometry, transmission electron microscopy, and dynamic light scattering. The AgNPs synthesized at a pH of 8 and 1:25 Ag+/extract ratio exhibited the lowest particle size and polydispersity index. The AgNPs synthesized with leaf extract (AgKL) were monodisperse and exhibited a smaller hydrodynamic diameter (37 nm) compared to the fruit extract nanoparticles (AgKP), which were polydisperse and larger (147 nm). Phytochemicals in T. ferdinandiana aqueous leaf extract act as effective capping and stabilizing agents, enabling the synthesis of small-sized and homogenous AgNPs, which the fruit extract alone could not achieve. The in vitro bioactivity was evaluated using antioxidant and antibacterial assays and compared with the crude extract. Both the AgNPs and T. ferdinandiana extracts demonstrated strong 2,2 diphenyl-1-picrylhydrazyl radical scavenging activity. However, only AgKL showed excellent antibacterial activity against Gram-negative and Gram-positive bacteria based on minimum inhibitory and bactericidal results. Mixing 50% leaf extract with fruit extract resulted in well-stabilized NPs (AgKPL) with a hydrodynamic diameter of 33.4 nm and superior antibacterial properties. These results indicate that AgKL and AgKPL have significant potential for pharmaceutical and biomedical applications. Full article
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23 pages, 74396 KiB  
Article
Antimicrobial and Oxidative Activities of Different Levels of Silver-Exchanged Zeolites X and ZSM-5 and Their Ecotoxicity
by Elitsa L. Pavlova, Elena P. Nenova, Lyubomira D. Yocheva, Iliana A. Ivanova and Peter A. Georgiev
Pharmaceuticals 2024, 17(12), 1586; https://doi.org/10.3390/ph17121586 - 25 Nov 2024
Cited by 1 | Viewed by 1114
Abstract
Objectives: The antimicrobial, oxidative activities, and ecotoxicity of synthesized silver-loaded zeolites (X and ZSM-5(MFI), Si-to-Al ratios 12 and 25) were studied, linking antimicrobial properties to material structure and released active silver species. Methods: The materials were characterized by SEM, EDX, TEM, and XRPD. [...] Read more.
Objectives: The antimicrobial, oxidative activities, and ecotoxicity of synthesized silver-loaded zeolites (X and ZSM-5(MFI), Si-to-Al ratios 12 and 25) were studied, linking antimicrobial properties to material structure and released active silver species. Methods: The materials were characterized by SEM, EDX, TEM, and XRPD. All materials, with a silver content of 1–3%wt for the Ss and about 35%wt for the X-zeolites, were tested against Escherichia coli and Staphylococcus aureus. Redox activity was studied in physiological (pH 7.4/37 °C) and optimal (pH 8.5/37 °C) conditions in chemiluminescent model systems. In the ecotoxicity tests, we used Daphnia magna. Results: A proportional correlation was observed between the bactericidal effect of and the silver content in the zeolites. AgX with a Si/Al ratio of ~1.23 and 35% silver showed a higher antimicrobial efficiency, particularly against Gram-negative E. coli versus Gram-positive S. aureus. The concentration thresholds were as follows: AgXas had a bactericidal effect at 0.003 g/L−1, with an MIC at 0.0015 m/L−1 for E. coli; SA25-Ag, AgXcl, AgXrc had a bactericidal effect at 2.5 g/L−1. The bacteria were more resilient than Daphnia magna, which showed a 90–100% lethality at Ag–zeolite concentrations of 0.00625 to 0.0125 g/L−1. AgXas and AgXrc demonstrated strong reactive oxygen species generation at both the physiological and optimal pH, explaining their bactericidal effects. In general, the tested materials showed an inhibition of the generated reactive oxygen species depending on the model system and conditions. Conclusions: The silver species leached from the new materials explain their higher oxidation and bactericidal activity. While suitable for stringently controlled biological applications, their release into the environment, in concentrations higher than 0.01g/L−1, should be avoided. Full article
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20 pages, 2713 KiB  
Article
Integrated Rice-Snail-Crayfish Farming System Shapes Soil Microbial Community by Enhancing pH and Microbial Biomass in South Subtropical China
by Wenxiang Wu, Xuesong Du, Zhiwei Qin, Qingrong Liu and Fujing Pan
Agriculture 2024, 14(12), 2133; https://doi.org/10.3390/agriculture14122133 - 25 Nov 2024
Viewed by 1184
Abstract
Within the framework of sustainable agriculture, the integrated rice-snail-crayfish farming system has been recognized as a highly efficient agroecological approach that enhances crop production while minimizing the application of chemical fertilizers and pesticides. Nonetheless, the mechanisms by which this system influences soil microbial [...] Read more.
Within the framework of sustainable agriculture, the integrated rice-snail-crayfish farming system has been recognized as a highly efficient agroecological approach that enhances crop production while minimizing the application of chemical fertilizers and pesticides. Nonetheless, the mechanisms by which this system influences soil microbial community composition to achieve these benefits remain unknown. In this study, we focused on traditional rice farming (TR), the integrated rice-snail-crayfish (R-S-C) farming system, and mono-rice farming (CK), and systematically examined the impacts of these farming systems on soil chemical properties, microbial biomass, enzyme activity, and microbial community composition. Our results showed that the R-S-C significantly increased soil pH, microbial biomass carbon (MBC), and the MBC/microbial biomass phosphorus (MBP) ratio compared to TR, as well as the peroxidase activity. Moreover, the R-S-C significantly increased soil total phospholipid fatty acid (PLFA), bacterial PLFAs, Gram-negative bacterial (GN) PLFAs, anaerobic bacteria PLFAs, arbuscular mycorrhizal fungi (AMF) abundances, and the bacteria/fungi ratio compared to the other two systems. However, the soil microbial α-diversity indices, including Shannon–Wiener index (H), Simpson index (D), and Pielou evenness index (J), were significantly lower in the R-S-C system than in the other two systems. Further exploration suggested that soil pH, microbial biomass nitrogen (MBN), the MBN/total nitrogen (TN) ratio, and the MBC/MBP ratio were critical factors governing microbial community composition under the three farming practices. Notably, soil pH alone accounted for 64.5% of the observed variation in microbial community composition. Path analysis using partial least squares structural equation modeling further revealed the pathways by which the R-S-C system enhanced total PLFAs, AMF, and gram-positive bacteria by regulating the soil pH and MBN/TN ratio. This study provides insights into the regulatory mechanisms driving soil microbial communities in the R-S-C system and offers a theoretical foundation for developing sustainable agricultural management practices. Full article
(This article belongs to the Section Agricultural Systems and Management)
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38 pages, 3303 KiB  
Article
Antimicrobial Effectiveness of Ribes nigrum L. Leaf Extracts Prepared in Natural Deep Eutectic Solvents (NaDESs)
by Maria-Beatrice Solcan, Ana-Maria Vlase, Gabriel Marc, Dana Muntean, Tibor Casian, George Cosmin Nadăș, Cristiana Ștefania Novac, Daniela-Saveta Popa and Laurian Vlase
Antibiotics 2024, 13(12), 1118; https://doi.org/10.3390/antibiotics13121118 - 22 Nov 2024
Cited by 2 | Viewed by 1329
Abstract
Background: Blackcurrant (Ribes nigrum L.) leaves are valuable sources of bioactive compounds, including phenolic acids, flavonoids, and tannins, which contribute to their potent antioxidant, anti-inflammatory, and antimicrobial properties. Objectives: The overall aim of this study was to investigate the antimicrobial potential of [...] Read more.
Background: Blackcurrant (Ribes nigrum L.) leaves are valuable sources of bioactive compounds, including phenolic acids, flavonoids, and tannins, which contribute to their potent antioxidant, anti-inflammatory, and antimicrobial properties. Objectives: The overall aim of this study was to investigate the antimicrobial potential of extracts rich in bioactive compounds from blackcurrant leaves prepared in natural deep eutectic solvents (NaDESs). The objectives included the optimization of polyphenols extraction in NaDESs, characterization of the phytochemical composition by liquid chromatography–mass spectrometry (LC-MS), explanation of the chemical interactions between solvent systems and the main bioactive compound (chlorogenic acid) by molecular dynamics simulations, and evaluation of biological efficacy through antimicrobial tests. Methods: Two hydrogen-bond acceptors (HBAs) and three hydrogen-bond donors (HBDs) were tested. The experimental design included variables such as the HBA:HBD molar ratio, water percentage, extraction time, and extraction techniques used, specifically ultrasound-assisted extraction (UAE) and ultra-turrax extraction (UTE). The evaluated responses included the total polyphenol content, total flavonoid content, and total antioxidant activity. Antimicrobial assays were performed on four Gram-positive and three Gram-negative bacterial species, as well as one fungus, Candida albicans. Results: The extracts obtained by UAE showed higher concentrations of polyphenols and increased antioxidant potential. LC-MS analysis revealed the predominant presence of chlorogenic acid. The extracts showed significant activities against Gram-positive bacteria and Candida albicans. Conclusions: This study highlights the antioxidant and antimicrobial potentials of blackcurrant leaves extracts prepared in NaDESs, confirming that this type of solvent enhances polyphenols extraction and offers perspectives for new therapeutic formulations. Full article
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19 pages, 8932 KiB  
Article
Physico-Chemical Characterizations of Composited Calcium-Ortho-Phosphate Porous Particles and Their Controlled Release Behavior of Clindamycin Phosphate and Amikacin Sulfate
by Namfon Khamkaew, Sorada Kanokpanont, Jirun Apinun, Chalika Wangdee, Antonella Motta and Siriporn Damrongsakkul
Polymers 2024, 16(22), 3144; https://doi.org/10.3390/polym16223144 - 12 Nov 2024
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Abstract
The porous particles prepared from composited calcium–ortho-phosphate (biphasic), Thai silk fibroin, gelatin, and alginate, with an organic to inorganic component ratio of 15.5:84.5, were tested for their abilities to control the release of the commercialized antibiotic solutions, clindamycin phosphate (CDP) and amikacin sulfate [...] Read more.
The porous particles prepared from composited calcium–ortho-phosphate (biphasic), Thai silk fibroin, gelatin, and alginate, with an organic to inorganic component ratio of 15.5:84.5, were tested for their abilities to control the release of the commercialized antibiotic solutions, clindamycin phosphate (CDP) and amikacin sulfate (AMK). The in vitro biodegradability tests complying to the ISO 10993-13:2010 standard showed that the particles degraded <20 wt% within 56 days. The drugs were loaded through a simple adsorption, with the maximum loading of injection-graded drug solution of 43.41 wt% for CDP, and 39.08 wt% for AMK. The release profiles from dissolution tests of the drug-loaded particles varied based on the adsorption methods used. The drug-loaded particles (without a drying step) released the drug immediately, while the drying process after the drug loading resulted in the sustained-release capability of the particles. The model-fitting of drug release profiles showed the release driven by diffusion with the first-ordered kinetic after the initial burst release. The released CDF and AMK from particles could sustain the inhibition of Gram-positive bacteria and Gram-negative bacteria, respectively, for at least 72 h. These results indicated the potential of these composited particles as controlled-release carriers for CDP and AMK. Full article
(This article belongs to the Section Polymer Applications)
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15 pages, 1605 KiB  
Article
Investigation of the Complexation Activity of 2,4-Dithiouracil with Au(III) and Cu(II) and Biological Activity of the Newly Formed Complexes
by Petya Marinova, Dimitar Stoitsov, Nikola Burdzhiev, Slava Tsoneva, Denica Blazheva, Aleksandar Slavchev, Evelina Varbanova and Plamen Penchev
Appl. Sci. 2024, 14(15), 6601; https://doi.org/10.3390/app14156601 - 28 Jul 2024
Cited by 2 | Viewed by 1378
Abstract
The goal of this study is to synthesize, determine the structure, and examine the antimicrobial properties of novel Cu(II) and Au(III) complexes of 2,4-dithiouracil and its derivatives. These complexes were obtained by mixing aqueous solutions of the corresponding metal salts with the ligand [...] Read more.
The goal of this study is to synthesize, determine the structure, and examine the antimicrobial properties of novel Cu(II) and Au(III) complexes of 2,4-dithiouracil and its derivatives. These complexes were obtained by mixing aqueous solutions of the corresponding metal salts with the ligand dissolved in DMSO and aqueous NaOH, using a metal-to-ligand ratio of 1:4:2. The structures of the new compounds were analyzed by melting point determination, microwave plasma atomic emission spectrometry (MP-AES) for Cu and Au, inductively coupled plasma optical emission spectrometry (ICP-OES) for S, attenuated total reflection (ATR), solution and solid-state NMR, and Raman spectroscopy. The data for 2,4-dithiouracil obtained from the 1H NMR, 13C NMR, distortionless enhancement by polarization transfer spectrum (DEPT-135), proton–proton homonuclear correlation spectrum (1H-1H COSY), long-range 1H-13C heteronuclear multiple bond correlation experiment (HMBC), and heteronuclear single quantum coherence spectra (HSQC) aided the interpretation of the NMR data for the gold and copper complexes. Furthermore, the antimicrobial effect of the free ligands and their complexes was assessed against Gram-positive and Gram-negative bacteria, as well as yeasts. Full article
(This article belongs to the Section Chemical and Molecular Sciences)
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14 pages, 3987 KiB  
Article
Silver Nanoparticles Conjugated with BK510Lys Endolysin for Gram-Negative Bacteria Inhibition
by Diana Ramírez Saenz, Juan Carlos Martínez Espinosa, Andrea Guadalupe Valdivia Mancillas, Alma Arianna Lechuga Arana, Rocío Alejandra Silva Contreras and Abner Josué Gutiérrez Chávez
Appl. Sci. 2024, 14(15), 6493; https://doi.org/10.3390/app14156493 - 25 Jul 2024
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Abstract
In the last decade, the problems caused by the excessive use of antibiotics and the emergence of multi-resistant patterns in Gram-negative bacteria caused the generation of several alternatives and/or replacements, including endolysins and the use of silver nanomaterials (AgNPs). It has been shown [...] Read more.
In the last decade, the problems caused by the excessive use of antibiotics and the emergence of multi-resistant patterns in Gram-negative bacteria caused the generation of several alternatives and/or replacements, including endolysins and the use of silver nanomaterials (AgNPs). It has been shown that the AgNPs help overcome the bacterial lipopolysaccharide barrier and allow the endolysins to reach the cell wall; therefore, in the present investigation, conjugates of BK510 commercial endolysins (BK510Lys) with metallic nanoparticles were made, which eliminated the obstacle that represents the outer membrane of Gram-negative bacteria. AgNPs were produced by green synthesis using Lepidium virginicum extract as a reducing agent, and diameters of 16.06 ± 4.23 nm were obtained. The endolysins BK510Lys and AgNPs were used to generate conjugates that were characterized and evaluated against gram-negative and gram-positive bacteria of veterinary interest. The results indicated that using the conjugates at a concentration of 0.01 mg/mL, a 2:1 ratio, a temperature of 40 °C, and at pH 5, the inhibitory effect was greater than that of AgNPs (0.5 µg/mL) in more than 65% of the Gram-negative bacteria analyzed. Furthermore, it was determined that for both BK510Lys and the AgNP-BK510Lys conjugate, the only factor that had a significant effect on the lytic activity was their concentration. Finally, we concluded that based on the promising results obtained, future follow-up can be conducted for the formulation of highly specific alternative drugs for super-resistant Gram-negative bacteria. Full article
(This article belongs to the Section Nanotechnology and Applied Nanosciences)
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