Leakage Of Contents Research Articles

Utilization of nanoemulsion to enhance antibacterial capacity of Zanthoxylum bungeanum pericarp essential oils against foodborne pathogenic bacteria

Essential oils (EOs) have promising applications as natural and environmentally friendly antimicrobial agents. Preparation of EOs into emulsions can improve the properties of EOs. The aim of this study was to investigate the mechanism underlying the antibacterial effects of Zanthoxylum bungeanum pericarp essential oil (ZBEO) against Staphylococcus aureus, Escherichia coli, Bacillus cereus, and Shigella boydii, and to determine the effect of nanoemulsions on antibacterial activity. ZBEO efficiently suppressed foodborne pathogenic bacteria, as determined by the minimum inhibitory concentration and survival rate. Based on analyses of bacterial morphology, the degree of leakage of proteins and nucleic acids, and lactate dehydrogenase activity, we found that ZBEO disrupted the integrity and permeability of cell membranes, resulting in the leakage of cellular contents and apoptotic cell death. Prepared ZBEO nanoemulsion (ZBEO-NE) had good dispersion and stability. Both ZBEO and ZBEO-NE inhibited the growth of S. aureus, E. coli, B. cereus, and Sh. boydii in mutton broth, and ZBEO-NE exhibited better inhibitory effects than those of ZBEO. These findings suggest that preparing EOs in the form of nanoemulsions improves the antibacterial properties of EOs, making them suitable for food applications.

Novel Insights into the Antimicrobial and Antibiofilm Activity of Pyrroloquinoline Quinone (PQQ); In Vitro, In Silico, and Shotgun Proteomic Studies.

Microbial infections pose a significant global health threat, affecting millions of individuals and leading to substantial mortality rates. The increasing resistance of microorganisms to conventional treatments requires the development of novel antimicrobial agents. Pyrroloquinoline quinone (PQQ), a natural medicinal drug involved in various cellular processes, holds promise as a potential antimicrobial agent. In the present study, our aim was, for the first time, to explore the antimicrobial activity of PQQ against 29 pathogenic microbes, including 13 fungal strains, 8 Gram-positive bacteria, and 8 Gram-negative bacteria. Our findings revealed potent antifungal properties of PQQ, particularly against Syncephalastrum racemosum, Talaromyces marneffei, Candida lipolytica, and Trichophyton rubrum. The MIC values varied between fungal strains, and T. marneffei exhibited a lower MIC, indicating a greater susceptibility to PQQ. In addition, PQQ exhibited notable antibacterial activity against Gram-positive and -negative bacteria, with a prominent inhibition observed against Staphylococcus epidermidis, Proteus vulgaris, and MRSA strains. Remarkably, PQQ demonstrated considerable biofilm inhibition against the MRSA, S. epidermidis, and P. vulgaris strains. Transmission electron microscopy (TEM) studies revealed that PQQ caused structural damage and disrupted cell metabolism in bacterial cells, leading to aberrant morphology, compromised cell membrane integrity, and leakage of cytoplasmic contents. These findings were further affirmed by shotgun proteomic analysis, which revealed that PQQ targets several important cellular processes in bacteria, including membrane proteins, ATP metabolic processes, DNA repair processes, metal-binding proteins, and stress response. Finally, detailed molecular modeling investigations indicated that PQQ exhibits a substantial binding affinity score for key microbial targets, including the mannoprotein Mp1P, the transcriptional regulator TcaR, and the endonuclease PvuRTs1I. Taken together, our study underscores the effectiveness of PQQ as a broad-spectrum antimicrobial agent capable of combating pathogenic fungi and bacteria, while also inhibiting biofilm formation and targeting several critical biological processes, making it a promising therapeutic option for biofilm-related infections.

Hepatotoxic Effects of an Oral Amiodarone in White Albino Rats: Sub-Acute Biochemical, and Histopathological Assessments

Amiodarone, potent antidysrhythmic, widely used drug that has been associated with hepatic toxicity in long-term or excessive use. In the presented study twelve rats were allocated into two groups and given daily doses via gastric gavage orally for two weeks as follows; The first group served as a control normal group, whereas the second got amiodarone at a dosage of 300mg/kg/day orally. Liver tissues were processed for light microscopy, and blood samples were examined for serum transaminases (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)) and phospholipase a2 enzyme (Pla2) (which are thought to be an indicator of phospholipidosis and lipid buildup). Amiodarone was shown to produce hepatic histological abnormalities such as blood vessel congestion, leucocytic infiltration, liver degeneration, and stages of steatosis and necrosis of hepatocytes. The biochemical assessments were revealed that there was an elevation in amiodarone group's ALT and AST levels as a result of hepatic necrosis leading to leakage of enzymes content, while serum Pla2 was lowered significantly. Also, histopathology indicates stages of steatosis (Lipid accumulation) in hepatocytes, which may lead to farther damage in the late stages of hepatotoxicity.

Antimicrobial activity of magnolol against Bacillus cereus and its application as food preservative

The aim of this study was to explore the antibacterial properties and mechanism of magnolol against Bacillus cereus. Our findings demonstrated that magnolol exhibited potent antimicrobial activity against B. cereus, with minimum inhibitory concentrations (MICs) of 2 μg/mL. Additionally, magnolol could inhibit spore germination and biofilm formation in a dose-dependent manner. Electron microscopy and membrane potential analysis indicated that the cytomembranes were disrupted, resulting in leakage of cellular contents. Transcriptomic profiling showed that magnolol treatment (1/2 × MIC) resulted in 585 differentially expressed genes (DEGs), including 295 down-regulated and 290 up-regulated genes. Bioinformatic analysis indicated that magnolol affected many potential cellular responses, including cellular metabolic process, locomotion, oxidative stress, and cell membranes. The pathway analysis revealed that DEGs mainly associated with flagellar assembly, bacterial chemotaxis, amino acids, and energy metabolism. Moreover, magnolol obviously reduced the amount of B. cereus in boiled rice and beef at 4 °C storage. These results provided insights into the molecular mechanism of magnolol against B. cereus and suggested that magnolol might be a promising natural antimicrobial agent for controlling the B. cereus in foods. Industrial relevanceBacillus cereus is considered as an important foodborne pathogenic microorganism that can exist as vegetative cells, spores, and biofilm in various food-processing environment, posing a big challenge for the food industry. Magnolol is a natural compound with potent antimicrobial activity against various pathogens and has been certified as safe by food safety organizations. Consequently, magnolol holds great promise as a natural antimicrobial agent for controlling B. cereus contaminations in foods.

The disruptive effect on the bacterial cell wall explored of the ultrasmall particle-sized Ag nanoparticles supported with Zn Cu-based hybrid nanoagents

The smaller the particle size of Ag nanoparticles, the higher their antibacterial activity against drug-resistant strains, and the greater their potential for application in living organisms. Therefore, preparing Ag nanoparticles with ultra-small particle sizes has become one of the greatest challenges at present. In this study, 1.75 nm Ag was uniformly anchored on the surface of a highly biocompatible carrier to synthesize Fe3O4/ZnO@Cu2S@Ag (FCA) nanocomposites. The antibacterial activity and mechanism of FCA were investigated, and the material was used to treat wound infections caused by bacteria. At a concentration of 175 μg/mL, the antibacterial rate of Escherichia coli, Staphylococcus aureus, and drug-resistant Salmonella was over 99.99 % within 45 min. The antibacterial activity is mainly composed of •OH and multiple cations. The antibacterial mechanism involves •OH and multiple cations synergistically targeting and damaging the bacterial cell wall, altering the secondary structure of the bacterial cell wall, leading to leakage of bacterial contents and bacterial death. Additionally, FCA exhibited high biocompatibility, curing bacterial infections within 7 days and completely eliminating bacterial burden. These findings elucidate the role of antibacterial activity in composite antibacterial materials and suggest that FCA has clinical application potential in treating bacterial infections.

Mechanism of Brevibacillus brevis strain TR-4 against leaf disease of Photinia×fraseri Dress.

Colletotrichum species are among the most common pathogens in agriculture and forestry, and their control is urgently needed. In this study, a total of 68 strains of biocontrol bacteria were isolated and identified from Photinia × fraseri rhizosphere soil. The isolates were identified as Brevibacillus brevis by 16S rRNA. The inhibitory effect of TR-4 on Colletotrichum was confirmed by an in vitro antagonistic experiment. The inhibitory effect of TR-4 was 98% at a concentration of 10 µl/ml bacterial solution, protection of the plant and inhibition of C. siamense was evident. Moreover, the secretion of cellulase and chitosan enzymes in the TR-4 fermentation liquid cultured for three days was 9.07 mol/L and 2.15 µl/mol, respectively. Scanning electron microscopy and transmission electron microscopy confirmed that TR-4 destroyed the cell wall of C. siamense, resulting in leakage of the cell contents, thus weakening the pathogenicity of the bacteria.

A 14-amino acid cationic peptide Bolespleenin334-347 from the marine fish mudskipper Boleophthalmus pectinirostris exhibiting potent antimicrobial activity and therapeutic potential

Antimicrobial peptides (AMPs) are an important component of innate immunity in both vertebrates and invertebrates, and some of the unique characteristics of AMPs are usually associated with their living environment. The marine fish, mudskipper Boleophthalmus pectinirostris, usually live amphibiously in intertidal environments that are quite different from other fish species, which would be an exceptional source of new AMPs. In the study, an AMP named Bolespleenin334-347 was identified, which was a truncated peptide derived from a new functional gene found in B. pectinirostris, that was up-regulated in response to bacterial challenge. Bolespleenin334-347 had only 14 amino acid residues, including five consecutive arginine residues. It was found that the peptide had broad-spectrum antibacterial activity, good thermal stability and sodium ion tolerance. Bolespleenin334-347 killed Acinetobacter baumannii and Staphylococcus aureus by disrupting the structural integrity of the bacterial membrane, leading to leakage of the cellular contents, and inducing accumulation of bacterial endogenous reactive oxygen species (ROS). In addition, Bolespleenin334-347 effectively inhibited biofilm formation of A. baumannii and S. aureus and long-term treatment did not lead to the development of resistance. Importantly, Bolespleenin334-347 maintained stable activity against clinically multi-drug resistant bacterial strains. In addition, it was noteworthy that Bolespleenin334-347 showed superior efficacy to LL-37 and vancomycin in a constructed mouse model of MRSA-induced superficial skin infections, as evidenced by a significant reduction in bacterial load and more favorable wound healing. This study provides an effective antimicrobial agent for topical skin infections with potential therapeutic efficacy for infections with drug-resistant bacteria, including MRSA.

Rapid Membrane-Penetrating Hybrid Peptides Achieve Efficient Dual Antimicrobial and Antibiofilm Activity through a Triple Bactericidal Mechanism.

Antimicrobial peptides (AMPs) are a type of biomaterial used against multidrug resistant (MDR) bacteria. This study reports the design of a peptide family rich in tryptophan and lysine obtained by optimizing a natural AMP using single factor modification and pheromone hybridization to expedite the penetration and improve the antimicrobial activity of AMPs. S-4, L-4, and P-4 showed α-helical structures, exhibited extremely fast membrane penetration rates in vitro, and could kill MDR bacteria efficiently within 30 min. Intracellular fluorescence localization suggested rapid membrane-penetrating of AMPs within 1 min, making it more difficult for bacteria to develop resistance. Furthermore, they could effectively inhibit and destroy bacterial biofilms with dual antimicrobial and antibiofilm activity. In the treatment of skin infections caused by MDR-Acinetobacter baumannii in vivo , AMPs could effectively alleviate inflammation without toxic side effects. Additionally, the triple antimicrobial damage of AMPs was described in detail. AMPs rapidly penetrate the cell membrane, inducing cell membrane damage, triggering oxidative damage with a storm of reactive oxygen species and leading to bacterial death through leakage of cellular contents by complexing with DNA. The multiple damage is an important means by which AMPs can prevent bacterial resistance adequately.

The inhibitory effects of monolauroyl-galactosylglycerol against spores of Bacillus cereus and its potential application in dairy

Bacillus cereus is a typical spore-forming strain that can transform into dormant spores to resist unfavorable growth conditions. Among the microorganisms that cause spoilage of dairy products, B. cereus accounts for a large proportion. In this study, we evaluated the inhibitory activity of monolauroyl-galactosylglycerol (MLGG) on B. cereus spores and explored its inhibitory mechanism. The minimum inhibitory spore concentration (MISC) and the minimum sporicidal concentration (MSC) of MLGG against B. cereus spores were 0.313 mg/mL and 2.5 mg/mL, respectively. Scanning electron microscopy was used to observe the changes in spore morphology after MLGG treatment. It was found that low concentrations of MLGG caused irregular spore shape, with a few spores slightly ruptured and high concentrations of MLGG increased the degree of spore rupture, resulting in significant leakage of spore contents. By measuring the effect of MLGG on spore structure, it could be determined that MLGG damaged the coat of the spores and weakened the resistance of the spores, but did not affect the activity of cortical lyases. Therefore, spores could not resume growth even with the addition of exogenous lytic enzymes. After propidium iodide (PI) staining of the spores, flow cytometry analysis revealed that the positive area gradually increased, indicating that the permeability of the inner membrane of the spores was disrupted, leading to dipicolinic acid (DPA) release. The amount of DPA release was proportional to the MLGG concentration, and the growth rate of the spores decreased under hypertonic conditions. These findings indicated that MLGG inactivated spores primarily by damaging the inner membrane of the spores.

A Clinical Approach for the Removal of a Large Antral Pseudocyst with Simultaneous Maxillary Sinus Augmentation: A Case Series.

For a large benign lesion within the maxillary sinus, such as an antral pseudocyst, maxillary sinus floor augmentation is more commonly performed using a two-stage approach. This involves first removing the lesion, and then, re-entry following several months of healing. In this case series, we described the "one-bony-window" approach, which is a technical surgical modification of the previous one-stage approach, for simultaneous cyst removal and maxillary sinus floor augmentation. Four patients with large maxillary antral pseudocysts were included. The "one-bony-window" approach involves the preparation of a large window opening of approximately 15 mm × 20 mm at the lateral wall. A mesiodistally extended intentional perforation was made in the upper part of the exposed membrane to enhance the access for instrumentation. The antral pseudocyst was removed in its entirety without being deformed to prevent rupture or leakage of the cystic contents. Subsequent detachment and elevation of the Schneiderian membrane at the sinus floor significantly reduced the perforation site, and bone grafting with implant placement was performed simultaneously. This alleviated the need to surgically repair the perforation. The lateral opening was either uncovered or repositioned using bony window lids. Healing abutments were connected after six months, and the final prosthesis was placed after two months. At the 1-year follow-up, the antral pseudocysts had resolved with no specific recurrence, and the stability of the augmented sinus was maintained with excellent implant survival. Within the limitations of our findings, the "one-bony-window" technique can be suggested for the simultaneous removal of large antral pseudocysts and maxillary sinus floor augmentation with favorable clinical outcomes.

A novel cathelicidin TS-CATH derived from Thamnophis sirtalis combats drug-resistant gram-negative bacteria in vitro and in vivo

Antimicrobial peptides are promising therapeutic agents for treating drug-resistant bacterial disease due to their broad-spectrum antimicrobial activity and decreased susceptibility to evolutionary resistance. In this study, three novel cathelicidin antimicrobial peptides were identified from Thamnophis sirtalis, Balaenoptera musculus, and Lipotes vexillifer by protein database mining and sequence alignment and were subsequently named TS-CATH, BM-CATH, and LV-CATH, respectively. All three peptides exhibited satisfactory antibacterial activity and broad antibacterial spectra against clinically isolated E. coli, P. aeruginosa, K. pneumoniae, and A. baumannii in vitro. Among them, TS-CATH displayed the best antimicrobial/bactericidal activity, with a rapid elimination efficiency against the tested drug-resistant gram-negative bacteria within 20 min, and exhibited the lowest cytotoxicity toward mammalian cells. Furthermore, TS-CATH effectively enhanced the survival rate of mice with ceftazidime-resistant E. coli bacteremia and promoted wound healing in meropenem-resistant P. aeruginosa infection. These results were achieved through the eradication of bacterial growth in target organs and wounds, further inhibiting the systemic dissemination of bacteria and the inflammatory response. TS-CATH exhibited direct antimicrobial activity by damaging the inner and outer membranes, resulting in leakage of the bacterial contents at super-MICs. Moreover, TS-CATH disrupted the bacterial respiratory chain, which inhibited ATP synthesis and induced ROS formation, significantly contributing to its antibacterial efficacy at sub-MICs. Overall, TS-CATH has potential for use as an antibacterial agent.

Primary Mesenteric Hydatid Cyst in Pediatric Patients: Case Report and Literature Review

Mesenteric hydatid cyst in children is not common, even in endemic areas. The primary or secondary origin of this site, especially in children, remains controversial. Secondary peritoneal hydatid cyst mainly results from spontaneous or traumatic rupture of concurrent liver cysts or leakage of cystic contents during surgery. The aim of our study is to present a mesenteric hydatid cyst in children. Our study focuses on a single case of a child with peritoneal hydatid cyst, who underwent surgery in 2021 in the pediatric surgery department of the Mohammed VI hospital in Marrakech. The diagnosis is based on abdominal ultrasound, computed tomography and hydatidosis serology. The treatment is surgical by open or laparoscopic excision, which can be associated with medical treatment.

Acorus calamus L. rhizome extract and its bioactive fraction exhibits antibacterial effect by modulating membrane permeability and fatty acid composition.

Ethnopharmacological relevanceIndia's ancient texts, the Charak Samhita and Sushruta Samhita, make reference to the traditional medicinal usage of Acorus calamus L. In India and China, it has long been used to cure stomach aches, cuts, diarrhea, and skin conditions. This ability of the rhizome is attributed to its antimicrobial properties. Research studies to date have shown its antimicrobial properties. However, scientific evidence on its mode of action is still lacking. Aim of the studyAcorus calamus L. rhizome extract and its bioactive fraction exhibits antibacterial effect by modulating membrane permeability and fatty acid composition. Material and methodThe secondary metabolites in the rhizome of A. calamus L. were extracted in hexane using Soxhlet apparatus. The ability of the extract to inhibit multidrug resistant bacterial isolates, namely Bacillus cereus, Escherichia coli, Acinetobacter baumannii, and Pseudomonas aeruginosa were evaluated using checkerboard assay. Further, the extract was purified using thin layer chromatography, gravity column chromatography, and combiflash chromatography. Structure elucidation of the active compound was done using GC-MS, FT-IR, and UV–Vis spectral scan. The mode of action of the bioactive fraction was determined. Bacterial membrane damage was analyzed using SEM, membrane permeability was determined using SYBR green I and PI dye, leakage of cytoplasmic contents were analyzed using Bradford assay and Fehling’s reagent. The ability to inhibit efflux pump of A. baumannii was determined using EtBr accumulation assay and β-lactamase inhibition was analyzed using nitrocefin as substrate. Also, the biofilm inhibition of B. cereus was determined using crystal violet dye. Moreover, the effect of the bioactive fraction on the fatty acid profile of the bacterial membrane was determined by GC-FAME analysis using 37 component FAME mix as standard. ResultsAcorus calamus L. rhizome hexane extract (AC-R-H) demonstrated broad-spectrum antibacterial activity against all the isolates tested. AC-R-H extract also significantly reduced the MIC of ampicillin against all tested bacteria, indicating its bacterial resistance modulating properties. The assay guided purification determined Asarone as the major compound present in the bioactive fraction (S-III-BAF). S-III-BAF was found to reduce the MIC of ampicillin against Escherichia coli (100–25 mg/mL), Pseudomonas aeruginosa (15–3.25 mg/mL), Acinetobacter baumannii (12.5–1.56 mg/ml), and Bacillus cereus (10–1.25 mg/mL). Further, it recorded synergistic activity with ampicillin against B. cereus (FICI = 0.365), P. aeruginosa (FICI = 0.456), and A. baumannii (FICI = 0.245). The mode of action of S-III-BAF can be attributed to its ability to disturb the membrane integrity, enhance membrane permeability, reduce biofilm formation, and possibly alter the fatty acid composition of the bacterial cell membranes. ConclusionThe bioactive fraction of AC-R-H extract containing Asarone as the active compound showed antibacterial activity and synergistic interactions with ampicillin against the tested bacterial isolates. Such activity can be attributed to the modulation of fatty acids present in bacterial membranes, which enhances membrane permeability and causes membrane damage.

Synthesis and Antifungal Activity of Coumarin Derivatives Containing Hydrazone Moiety.

Plant disease control mainly relies on pesticides. In this study, a series of coumarin derivatives containing hydrazone moiety were designed and synthesized. The synthesized compounds were characterized and used to evaluate the antifungal activity against four pathogens, Botrytis cinerea, Alternaria solani, Fusarium oxysporum, and Alternaria alternata. The results showed that the inhibition rate of some compounds at 100 μg/mL in 96 hours reached around 70 % against A. alternata, higher than that of the positive control. The corresponding EC50 values were found at around 30 μg/mL. Finally, the compound 3 b was screened out with the lowest EC50 value (19.49 μg/mL). The analysis of SEM and TEM confirmed that the compound 3 b can obviously damage the morphological structure of hyphae, resulting in the depletion of the cells by the destruction of morphological matrix and leakage of contents. RNA sequencing showed that compounds 3 b mainly affected the pentose phosphate pathway, which caused to destroy the layer of mitochondrial structure. Molecular docking showed that compounds 3 b fitted the binding pocket of yeast transketolase and interacted with lysine at the hydrazone structure. Our results suggested that the introduction of hydrazone was an effective strategy for the design of novel bioactive compounds.

Purification, characterization, and identification of a novel bacteriocin produced by Lacticaseibacillus casei KLS1, and its antimicrobial mechanism against Staphylococcus aureus

Staphylococcus aureus (S. aureus) and its biofilm were recognized as one of the major threats to food safety and human health. Bacteriocins produced by Lacticaseibacillus species have been demonstrated to inhibit the growth of foodborne pathogenic bacteria and their biofilm formation. Herein, a novel bacteriocin KLS1 from Lacticaseibacillus casei KLS1 was extracted by ethyl acetate and purified using an AKTA Pure 25 protein chromatography purification system. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses revealed that the molecular mass of bacteriocin KLSI was 3786.91 Da and the amino acid sequence was DTSASIASNKSETNDLLKQIEAANTEVINLNKQID. Bacteriocin KLS1 was stable at pH 2.0–6.0, sensitive to proteases, and showed excellent thermal stability. Furthermore, bacteriocin KLS1 exhibited broad-spectrum antimicrobial activity against both Gram-positive and Gram-negative bacteria, even fungi. The crystal violet staining assay indicated that bacteriocin KLS1 significantly reduced the relative percentage of S. aureus biofilm (P < 0.05). Meanwhile, bacteriocin KLS1 was found to significantly decrease the metabolic activity of S. aureus by Cell Counting Kit-8 assay (P < 0.05). In addition, scanning electron microscopy and confocal laser scanning microscope showed that bacteriocin KLS1 disrupted the structure of S. aureus biofilm and cell membrane integrity, leading to cell deformation and leakage of contents. These results suggested that bacteriocin KLS1 might have the potential to serve as a biological preservative in the food industry.

Antifungal mechanisms of binary combinations of volatile organic compounds produced by lactic acid bacteria strains against Aspergillusflavus

Aspergillus flavus（A. flavus）, a common humic fungus known for its ability to infect agricultural products, served as the subject of investigation in this study. The primary objective was to assess the antifungal efficacy and underlying mechanisms of binary combinations of five volatile organic compounds (VOCs) produced by lactic acid bacteria, specifically in their inhibition of A. flavus. This assessment was conducted through a comprehensive analysis, involving biochemical characterization and transcriptomic scrutiny. The results showed that VOCs induce notable morphological abnormalities in A. flavus conidia and hyphae. Furthermore, they disrupt the integrity of the fungal cell membrane and cell wall, resulting in the leakage of intracellular contents and an increase in extracellular electrical conductivity. In terms of cellular components, VOC exposure led to an elevation in malondialdehyde content while concurrently inhibiting the levels of total lipids, ergosterol, soluble proteins, and reducing sugars. Additionally, the impact of VOCs on A. flavus energy metabolism was evident, with significant inhibition observed in the activities of key enzymes, such as Na+/K+-ATPase, malate dehydrogenase, succinate dehydrogenase, and chitinase. And they were able to inhibit aflatoxin B1 synthesis. The transcriptomic analysis offered further insights, highlighting that differentially expressed genes (DEGs) were predominantly associated with membrane functionality and enriched in pathways about carbohydrate and amino acid metabolism. Notably, DEGs linked to cellular components and energy-related mechanisms exhibited down-regulation, thereby corroborating the findings from the biochemical analyses. In summary, these results elucidate the principal antifungal mechanisms of VOCs, which encompass the disruption of cell membrane integrity and interference with carbohydrate and amino acid metabolism in A. flavus.

Fabrication of Ti3C2Tx/ZnONPs composite with high antibacterial and antibiofilm activity

Microbial contamination poses a serious threat to human health and socioeconomics, and is a major problem for global public health. Herein, we fabricated Ti3C2Tx/ZnONPs composite by using Lactobacillus plantarum fermentation broth to reduce ZnONPs in situ on few-layer Ti3C2Tx MXene after etching and delamination treatment. Antibacterial experiments showed that the Ti3C2Tx/ZnONPs composite exhibited significant antibacterial and antibiofilm activity against both Gram-negative E. coli and Gram-positive S. aureus. Moreover, the exploration of the antibacterial mechanisms demonstrated that Ti3C2Tx/ZnONPs could inhibit and kill bacteria by disrupting bacterial cell wall/membrane, causing leakage of intracellular contents, interfering with metabolism and inducing oxidative stress. The synergistic effect of multiple antibacterial mechanisms can effectively prevent the evolution of resistance. Overall, as a novel inorganic antibacterial material, Ti3C2Tx/ZnONPs composite holds a promising application in the antimicrobial field.

A case of surgical treatment of neck phlegmon after gunshot wound complicated by total posterior mediastinitis using laparoscopic surgical techniques

The purpose of this article is to demonstrate the peculiarities of diagnosis and staged surgical treatment for neck phlegmon after gunshot wound complicated by total posterior mediastinitis using laparoscopic surgical techniques. Inflammatory complications in neck injuries are a serious complication with a rapid course. An important diagnostic method is multislice computed tomography. The use of multislice computed tomography in the dynamics of the postoperative period allows for timely detection of further spread of the mediastinal inflammatory process. In the surgical treatment of neck phlegmon, it is necessary to open all fascial spaces widely and perform drainage of the upper mediastinum. Laparoscopic access is a minimal trauma with good visualization of the posterior mediastinum (middle and lower), which allows for a complete revision, sanitation, and drainage of the posterior mediastinum. To prevent a leakage of purulent contents from the mediastinal cavity into the abdominal cavity, safety drains in both hypocostal areas are placed in subdiaphragmatic spaces to the oesophageal opening.

Synthesis, Characterization, and Antifungal Activity of Benzimidazole-Grafted Chitosan against Aspergillus flavus.

Aspergillus flavus contamination in agriculture and food industries poses threats to human health, leading to a requirement of a safe and effective method to control fungal contamination. Chitosan-based nitrogen-containing derivatives have attracted much attention due to their safety and enhanced antimicrobial applications. Herein, a new benzimidazole-grafted chitosan (BAC) was synthesized by linking the chitosan (CS) with a simple benzimidazole compound, 2-benzimidazolepropionic acid (BA). The characterization of BAC was confirmed by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H and 13C NMR). Then, the efficiency of BAC against A. flavus ACCC 32656 was investigated in terms of spore germination, mycelial growth, and aflatoxin production. BAC showed a much better antifungal effect than CS and BA. The minimum inhibitory concentration (MIC) value was 1.25 mg/mL for BAC, while the highest solubility of CS (16.0 mg/mL) or BA (4.0 mg/mL) could not completely inhibit the growth of A. flavus. Furthermore, results showed that BAC inhibited spore germination and elongation by affecting ergosterol biosynthesis and the cell membrane integrity, leading to the permeabilization of the plasma membrane and leakage of intracellular content. The production of aflatoxin was also inhibited when treated with BAC. These findings indicate that benzimidazole-derived natural CS has the potential to be used as an ideal antifungal agent for food preservation.

Coculture of Acinetobacter johnsonii and Shewanella putrefaciens Contributes to the ABC Transporter that Impacts Cold Adaption in the Aquatic Food Storage Environment.

Acinetobacter johnsonii and Shewanella putrefaciens were identified as specific spoilage organisms in aquatic food. The interactions among specific spoilage organisms under cold stress have a significant impact on the assembly of microbial communities, which play crucial roles in the spoilage and cold adaptation processes. The limited understanding of A. johnsonii and S. putrefaciens interactions in the cold adaptation mechanism hinders the elucidation of their roles in protein and metabolism levels. 4D quantitative proteomic analysis showed that the coculture of A. johnsonii and S. putrefaciens responds to low temperatures through ABC transporter proteins, resulting in phospholipid transport and inner membrane components. SapA and FtsX proteins were significantly upregulated, while LolC, LolD, LolE, PotD, PotA, PotB, and PotC proteins were significantly downregulated. Metabolome assays revealed that metabolites of glutathione and spermidine/putrescin were significantly upregulated, while metabolites of arginine/lysine/ornithine were significantly downregulated and involved in the ABC transporter metabolism. The results of ultramicroscopic analyses showed that the coculture of A. johnsonii and S. putrefaciens surface combined with the presence of the leakage of intracellular contents, suggesting that the bacteria were severely damaged and wrinkled to absorb metabolic nutrients and adapt to cold temperatures.