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Scientific Reports Feb 2022In the present work, nonwoven cotton fabric was modified for antibacterial applications using low-cost and eco-friendly precursors. The treatment of fabric with alkali...
In the present work, nonwoven cotton fabric was modified for antibacterial applications using low-cost and eco-friendly precursors. The treatment of fabric with alkali leads to the formation of active sites for surface modification, followed by dip coating with silver nanoparticles and chitosan. The surface was chlorinated in the next step to transform amide (N-H) groups in chitosan into N-halamine (N-Cl). The modified and unmodified surfaces of the nonwoven cotton fabric have been characterized by FTIR, SEM, and XRD. The active chlorine loading is measured with iodine/sodium thiosulphate. The antimicrobial activity and cell toxicity assay were carried out with and without modifications of nonwoven cotton fabric. The antimicrobial efficacies of loaded fabric were evaluated against four bacterial species (Micrococcus luteus, Staphylococcus aureus, Enterobacter aerogenes, and E.coli). It was found that modified fabric exhibited superior efficiency against gram-positive and gram-negative bacterial strains as compared to their bulk counterparts upon exposure without affecting strength and integrity of fabric. The overall process is economical for commercial purposes. The modified fabric can be used for antimicrobial, health, and food packaging industries, and in other biomedical applications.
PubMed: 35169158
DOI: 10.1038/s41598-022-06391-5 -
Life (Basel, Switzerland) Jun 2022Despite the challenging conditions in the pre-Saharan areas of Algeria, such as weak plant cover and a harsh climate, beekeeping is being developed and spread. In the...
Despite the challenging conditions in the pre-Saharan areas of Algeria, such as weak plant cover and a harsh climate, beekeeping is being developed and spread. In the present work, honey samples collected from ten locations in the El Oued region were examined during the spring of 2021. A melissopalynological analysis was carried out, followed by a floristic investigation. The 10 honey samples were also investigated for their physicochemical properties and antioxidant and antibacterial activity against five strains: , , , and The floristic analysis found 65 species belonging to 33 botanical families, with a dominance of the Asteraceae family accounting for 18.461% of the total. The melissopalynological study revealed only one monofloral honey (), whereas the nine others were multi-floral. The honey's color changed from light to dark amber, and most tested honey was of high quality, fulfilling international criteria. The total phenol and flavonoid contents varied considerably amongst the various honey samples. Furthermore, LC-MS-MS phenolic profile analysis identified the presence of 20 chemicals, of which only three phenols were found in all honey types. Antioxidant capacity analyzed with FRAP test and antiradical activities against DPPH differed from one honey sample to another. Moreover, a significant correlation was recorded between the antioxidant activity, honey's color, polyphenol, and flavonoid contents. The strain was the most sensitive regarding honey antibacterial activity, while and strains were only moderately sensitive.
PubMed: 35888017
DOI: 10.3390/life12070927 -
Journal of Bacteriology Dec 2019Bacteria have remarkable mechanisms to survive severe external stresses, and one of the most enigmatic is the nonreplicative persistent (NRP) state. Practically, NRP...
Bacteria have remarkable mechanisms to survive severe external stresses, and one of the most enigmatic is the nonreplicative persistent (NRP) state. Practically, NRP bacteria are difficult to treat, and so inhibiting the proteins underlying this survival state may render such bacteria more susceptible to external stresses, including antibiotics. Unfortunately, we know little about the proteins and mechanisms conferring survival through the NRP state. Here, we report that a universal stress protein (Usp) is a primary regulator of bacterial survival through the NRP state in NCTC 2665, a biosafety level 1 (BSL1) mycobacterial relative. Usps are widely conserved, and bacteria, including , , and , have multiple paralogs with overlapping functions that have obscured their functional roles. A kanamycin resistance cassette inserted into the universal stress protein A 616 gene (Δ::) ablates the UspA616 protein and drastically impairs survival under even short-term starvation (survival, 83% wild type versus 32% Δ::) and hypoxia (survival, 96% wild type versus 48% Δ::). We observed no detrimental UspA616 knockout phenotype in logarithmic growth. Proteomics demonstrated statistically significant log-phase upregulation of glyoxylate pathway enzymes isocitrate lyase and malate synthase in Δ:: We note that these enzymes and the UspA616 homolog (Rv2623) are important in virulence and chronic infection, suggesting that Usps are important stress proteins across diverse bacterial species. We propose that UspA616 is a metabolic switch that controls survival by regulating the glyoxylate shunt. Bacteria tolerate severe external stresses, including antibiotics, through a nonreplicative persistent (NRP) survival state, yet the proteins regulating this survival state are largely unknown. We show a specific universal stress protein (UspA616) controls the NRP state in Usps are widely conserved across bacteria, but their biological function(s) has remained elusive. UspA616 inactivation renders susceptible to stress: bacteria die instead of adapting through the NRP state. UspA616 regulates malate synthase and isocitrate lyase, glyoxylate pathway enzymes important for chronic infection. These data show that UspA616 regulates NRP stress survival in and suggest a function for homologous proteins in other bacteria. Importantly, inhibitors of UspA616 and homologs may render NRP bacteria more susceptible to stresses, including current antibiotics.
Topics: Bacterial Proteins; Citric Acid Cycle; Glyoxylates; Heat-Shock Proteins; Micrococcus luteus; Stress, Physiological
PubMed: 31548273
DOI: 10.1128/JB.00497-19 -
Brazilian Journal of Biology = Revista... 2021Persea lingue Ness is a tree species that lives mainly in temperate forests of south-central Chile. Its leaves are used in ethnomedicine, the fruit is a drupe similar to...
Persea lingue Ness is a tree species that lives mainly in temperate forests of south-central Chile. Its leaves are used in ethnomedicine, the fruit is a drupe similar to that of the avocado and has not been studied. The aim of this study was to determine the cytotoxicity in leukemia cell and antibacterial activity, along with some chemical content characteristics of P. lingue fruit and leaf extracts. The antibacterial activity was determined by the inhibition of bacterial growth in liquid medium assay against Gram-positive and Gram-negative bacteria. The leukemia cell lines Kasumi-1 and Jurkat were used to evaluate the cytotoxic activity by using propidium iodide and AlamarBlue assays. Total phenolic, flavonoid, condensed tannin, alkaloid and lipid contents were evaluated in the fruit and in the leaf extracts. The antioxidant activity of both extracts were also elavaluated. Leaf extract presented the highest content of total phenols, condensed tannins and flavonoids, and also the highest antioxidant activity. While the fruit extract has a higher amount of lipids and alkaloids and the high antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus megaterium and Micrococcus luteus. The leaf extract only showed activity against M. luteus. Concerning the cytotoxic activity, only the fruit extract showed cytotoxicity against the cell lines Jurkat and Kasumi-1. P. lingue fruit extract is a potential source of biologically active molecules for the development of new drugs to be used in some types of leukemia, as well as antibacterial agent.
Topics: Anti-Bacterial Agents; Fruit; Gram-Negative Bacteria; Gram-Positive Bacteria; Lauraceae; Persea; Plant Extracts
PubMed: 34495162
DOI: 10.1590/1519-6984.248063 -
Graefe's Archive For Clinical and... Aug 2022Increased ophthalmology-specific risk of novel coronavirus 2019 (SARS-CoV-2) transmission is well-established, increasing the fear of infection and causing associated...
PURPOSE
Increased ophthalmology-specific risk of novel coronavirus 2019 (SARS-CoV-2) transmission is well-established, increasing the fear of infection and causing associated decreased rates of procedures known to save vision. However, the potential transmission from exposure to clinic instrumentation is unknown, including which additional pathogens may be spreading in this context. This study seeks to fill this gap by characterizing the microbiota of instrumentation in ophthalmology clinics during the COVID-19 pandemic and identifying potential sources of pathogenic spread encountered by patients and healthcare workers.
METHODS
Thirty-three samples were captured using standard cultures and media. Ten positive and negative controls were used to confirm proper technique. Descriptive statistics were calculated for all samples. Samples were collected from the retina (N = 17), glaucoma (N = 6), cornea (N = 6), and resident (N = 4) clinics with rigorous disinfection standards at a tertiary academic medical center. Standard media cultures and/or polymerase chain reaction (PCR) was performed for each sample.
RESULTS
From 33 samples, more than half (17/33, 51.5%) yielded bacterial growth. Using two different molecular methods, three samples (3/33, 9%) tested positive for SARS-CoV-2 (cycle thresholds 36.48, 37.14, and 37.83). There was no significant difference in bacterial growth (95% confidence interval [95% CI]: - 0.644-0.358, p = 0.076) among different clinics (retina, glaucoma, cornea, resident). Staphylococcus (S.) epidermidis grew most frequently (12/35, 34%), followed by S. capitis (7/35, 20%), Micrococcus luteus (2/35, 5.7%), Corynebacterium tuberculostearicum (2/35, 5.7%), and Cutibacterium ([C.], Propionibacterium) acnes (2/35, 5.7%). C. acnes growth was more frequent with imaging device forehead rests (2/7, 28.6%) than other surfaces (0/26, 0%, 95% CI: 0.019-0.619, p = 0.040). No samples isolated fungus or adenovirus.
CONCLUSIONS
Most samples across subspecialty clinic instrumentation grew bacteria, and several tested positive for SARS-CoV-2. Many isolated pathogens have been implicated in causing infections such as endophthalmitis, conjunctivitis, uveitis, and keratitis. The clinical implications of the ophthalmology microbiome for transmitting nosocomial infections warrant optimization of disinfection practices, strategies for mitigating spread, and additional study beyond the pandemic.
Topics: COVID-19; Glaucoma; Humans; Microbiota; Ophthalmology; Pandemics; SARS-CoV-2
PubMed: 35355117
DOI: 10.1007/s00417-022-05639-0 -
Dose-response : a Publication of... 2022The aim of this study was to evaluate antioxidant and antimicrobial potential of fruit. Ethanolic extract was prepared and phytochemical screening showed the presence...
The aim of this study was to evaluate antioxidant and antimicrobial potential of fruit. Ethanolic extract was prepared and phytochemical screening showed the presence of a lot of chemical compounds. Fourier transform infrared spectroscopy (FTIR) spectra indicated the presence of organic acids, hydroxyl and phenolic compounds, amino groups, aliphatic compounds, and functional groups such as amide, ketone, aldehyde, aromatics, and halogen compounds. Antioxidant activity of the ethanolic extract of by the DPPH method showed 71.4% inhibition, whereas IC ± SEM (μg/mL) was .406 ± .11. Antibacterial activity was performed against Maximum antibacterial activity was exhibited by , and it was Antifungal activity was performed against Ethanolic extract of showed antifungal activity against ± 1 mm) 4 ± 1 mm) Aspergillus ( ± 1 mm), whereas no activity was exhibited by . Further research is needed in order to evaluate the cytotoxic effects of as well.
PubMed: 36106057
DOI: 10.1177/15593258221126832 -
Journal of Functional Biomaterials Oct 2020An accumulating body of evidence reports the synthesis and biomedical applications of silver nanoparticles. However, the studies regarding the use of maleic acid and...
An accumulating body of evidence reports the synthesis and biomedical applications of silver nanoparticles. However, the studies regarding the use of maleic acid and citric acid in the synthesis of nano-sized silver particles (AgNPs) and micro-sized silver particles (AgMPs) as well as their antibacterial, antifungal, and anticancer activities have not been reported. In the current study, we synthesized AgNPs and AgMPs using maleic acid and citric acid as capping agents and have characterized them by UV-Vis, energy-dispersive X-Ray spectroscopy (EDS), X-Ray diffraction (XRD), and scanning electron microscope (SEM) analysis. The capped silver particles were examined for their antimicrobial activity and cytotoxicity against bacteria, fungi, and brine shrimp. Additionally, the anticancer activity of these particles was tested against human breast and liver cancer cell lines. The free radical scavenging activity of capped silver particles was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. SEM analysis revealed a round plate-like morphology of maleic acid capped particles with an average size of 39 ± 4 nm, whereas citric acid capped particles display flower-shaped morphology with rough surfaces and an average size of 250 ± 5 nm. The uncapped AgMPs were hexagonal with 500 ± 4 nm size. EDS and XRD analysis confirmed the presence of Ag and face-centered cubic crystalline nature, respectively. Functionally, capped silver particles exhibited antibacterial activity against Gram-positive ( and ) and Gram-negative bacteria ( and ). The bactericidal activity was more active against Gram-negative bacteria with minimum inhibitory concentration (MIC) as low as 5 ppm as compared to 25 ppm for Gram-positive. Similarly, the silver particles demonstrated antifungal activity by inhibiting the growth of five fungal strains ( and ) up to 50% at the concentration of 500 ppm. Additionally, these particles showed substantial toxicity against brine shrimp and also significantly inhibited the proliferation of breast cancer (MCF7) and liver cancer (HePG2) cell lines (IC 8.9-18.56 µM). Uncapped AgMPs were less effective, inhibiting only the proliferation of MCF7 cells with IC 46.54 µM. Besides cytotoxicity, these particles acted as potential antioxidants, showing free radical scavenging up to 74.4% in a concentration-dependent manner. Taken together, our results showed that the modifiers affect the shape and size of silver particles and may, in part, contribute to the antimicrobial and antioxidant activity of silver particles. However, the contribution of maleic acid and citric acid in enhancing the antimicrobial, anticancer, and antioxidant potential independent of silver nano and microparticles needs to be studied further. In vivo experiments may determine the therapeutic effectiveness of silver particles capped with these modifiers.
PubMed: 33113975
DOI: 10.3390/jfb11040076 -
Frontiers in Cellular and Infection... 2023In insects, antibacterial immunity largely depends on the activation of downstream signaling and effector responses, leading to the synthesis and secretion of soluble...
In insects, antibacterial immunity largely depends on the activation of downstream signaling and effector responses, leading to the synthesis and secretion of soluble effector molecules, such as antimicrobial peptides (AMPs). AMPs are acute infection response peptides secreted into the hemolymph upon bacterial stimulation. The transcription of innate immunity genes encoding for AMPs is highly dependent on several signaling cascade pathways, such as the Toll pathway. In the African malaria mosquito, , AMPs hold a special interest as their upregulation have been shown to limit the growth of malaria parasites, bacteria, and fungi. Most of the current knowledge on the regulation of insect AMPs in microbial infection have been obtained from . However, largely due to the lack of convenient assays, the regulation of antimicrobial activity in mosquito hemolymph is still not completely understood. In this study, we report a zone of inhibition assay to identify the contribution of AMPs and components of the Toll pathway to the antimicrobial activity of hemolymph. As a proof of principle, we demonstrate that challenge induces antimicrobial activity in the adult female mosquito hemolymph, which is largely dependent on defensin 1. Moreover, by using RNAi to silence , , and , we showed that kd induces antimicrobial activity in the mosquito hemolymph, whereas the antimicrobial activity in kd and kd is reduced after challenge. Finally, while injection itself is not sufficient to induce antimicrobial activity, our results show that it primes the response to bacterial challenge. Our study provides information that increases our knowledge of the regulation of antimicrobial activity in response to microbial infections in mosquitoes. Furthermore, this assay represents an medium throughput assay that can be used to determine the upstream regulatory elements of antimicrobial activity in hemolymph.
Topics: Animals; Female; Hemolymph; Myeloid Differentiation Factor 88; Anopheles; Malaria; Anti-Bacterial Agents
PubMed: 36779191
DOI: 10.3389/fcimb.2023.891577 -
Frontiers in Physiology 2023Biogenic amines are crucial signaling molecules that modulate various physiological life functions both in vertebrates and invertebrates. In humans, these...
Biogenic amines are crucial signaling molecules that modulate various physiological life functions both in vertebrates and invertebrates. In humans, these neurotransmitters influence the innate and adaptive immunity systems. In this work, we analyzed whether the aminergic neurotransmission of dopamine, serotonin, and octopamine could have an impact on the humoral innate immune response of . This is a powerful model system widely used to uncover the insect innate immunity mechanisms which are also conserved in mammals. We found that the neurotransmission of all these amines positively modulates the Toll-responsive antimicrobial peptide (AMP) () gene in adult flies infected with the bacterium. Indeed, we showed that either blocking the neurotransmission in their specific aminergic neurons by expressing shibire (Shi) or silencing the vesicular monoamine transporter gene () by RNAi caused a significantly reduced expression of the Toll-responsive gene. However, upon infection, the block of aminergic transmission did not alter the expression of AMP genes responding to the immune deficiency (Imd) and Toll pathways. Overall, our results not only reveal a neuroimmune function for biogenic amines in humoral immunity but also further highlight the complexity of the network controlling AMP gene regulation.
PubMed: 37693001
DOI: 10.3389/fphys.2023.1249205 -
Molecules (Basel, Switzerland) Apr 20221-pyrrole-2,5-dione derivatives are known for their wide range of pharmacological properties, including anti-inflammatory and antimicrobial activities. This study aimed...
1-pyrrole-2,5-dione derivatives are known for their wide range of pharmacological properties, including anti-inflammatory and antimicrobial activities. This study aimed to synthesize new 3,4-dimethyl--pyrrole-2,5-dione derivatives - in the reaction of -substituted amidrazones with 2,3-dimethylmaleic anhydride and evaluate their structural and biological properties. Compounds - were studied by the H-C NMR two-dimensional techniques (HMQC, HMBC) and single-crystal X-ray diffraction (derivatives and ). The anti-inflammatory activity of compounds - was examined by both an anti-proliferative study and a production study on the inhibition of pro-inflammatory cytokines (IL-6 and TNF-α) in anti-CD3 antibody- or lipopolysaccharide-stimulated human peripheral blood mononuclear cell (PBMC) cultures. The antibacterial activity of compounds against , , , , , , and strains was determined using the broth microdilution method. Structural studies of - revealed the presence of distinct and stereoisomers in the solid state and the solution. All compounds significantly inhibited the proliferation of PBMCs in anti-CD3-stimulated cultures. The strongest effect was observed for derivatives -. The strongest inhibition of pro-inflammatory cytokine production was observed for the most promising anti-inflammatory compound .
Topics: Anti-Bacterial Agents; Anti-Inflammatory Agents; Humans; Leukocytes, Mononuclear; Microbial Sensitivity Tests; Pyrroles; Staphylococcus aureus
PubMed: 35566243
DOI: 10.3390/molecules27092891