In this research,microbiologically induced corrosion(MIC)performance of magnesium in tryptic soy broth with S.aureus or E.coli were systematically explored.The results showed that magnesium in biotic solution presente...In this research,microbiologically induced corrosion(MIC)performance of magnesium in tryptic soy broth with S.aureus or E.coli were systematically explored.The results showed that magnesium in biotic solution presented higher mass loss,thicker degradation product layer and more severe pitting corrosion compared to abiotic solution after 24 h of immersion.Electrochemical measurements including EIS spectra and polarization curve further suggested that the corrosion rate of Mg in biotic solution increased during the early stage owing to the decrease of p H,which was originated from the consumption of glucose and the resulting accumulation of acidic metabolites.However,corrosion rate subsequently decreased because of the reduction of acidic metabolites and production of alkaline compound as well as the corrosion protection provided by the corrosion product and biofilm.Moreover,the corrosion rate of magnesium in high concentration of S.aureus and E.coli solution was larger than that in low concentration of S.aureus and E.coli solution,respectively during the initial stage,but subsequently presented a reverse variation.In addition,more severe corrosion of magnesium was observed in S.aureus solution in comparison with E.coli solution.These results suggested that the MIC performance of magnesium was closely related to the concentration and species of bacteria.展开更多
Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of i...Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of its efficacy,safety,and relatively low cost.Ascorbic acid(vitamin C)is water-soluble monosaccharide antioxidant;it is essentially required by the body for its various biochemical and physiological processes.S.aureus is Gram-positive cocci;widely distributed in the environment,it is a member of the normal flora of the body.S.aureus is not always pathogenic;it is a common cause of skin infections including abscesses,respiratory infections such as sinusitis,and food poisoning.E.coli is Gram-negative bacteria,found in the environment,foods,and intestines.Most E.coli strains are harmless;it is part of the normal microbiota of the gut.However,some serotypes of E.coli cause serious food poisoning in their hosts;it can cause diarrhea,while others cause urinary tract infections,respiratory illness and pneumonia,and other illnesses.Method:Cup cut diffusion method was applied.Experiment I:is carried out to choose the concentration of vitamin C to be used in experiment II.The negative control is normal saline,added in cup in each plate,vitamin C(100 mg/mL,200 mg/mL,400 mg/mL)was added,the volume in each cup was 100μL.Experiment II:Eight groups of treatments were applied.The first is the negative control(1%normal saline),the second group is the positive control of vitamin C(200 mg/mL).The third,fourth and fifth groups are ciprofloxacin with different concentrations(10 mg/mL,20 mg/mL,40 mg/mL);the sixth,seventh and eighth are the combination of vitamin C with each concentration of ciprofloxacin(10 mg/mL,20 mg/mL,40 mg/mL).Each group includes six petri dishes.Bacterial plates were incubated at 37 oC for 24 h and 48 h.Zone of inhibition is measured in mm.Results and conclusion:Ciprofloxacin produces dose dependent increase in zone of inhibition of S.aureus and E.coli growth,after 24 and 48 hours incubation.While vitamin C in the concentration used produced inhibitory effect on the growth of S.aureus and E.coli,after 24 hours incubation,vitamin C effect was not changed after 48 hours incubation.After 24 hours incubation,vitamin C potentiated the effect of ciprofloxacin at low concentration(10 mg/mL);while vitamin C antagonized the effect of ciprofloxacin at higher concentrations(20 and 40 mg/mL)on S.aureus growth.In the same time,ciprofloxacin antagonized the inhibitory effect of vitamin C on S.aureus growth.After 48 hours incubation,S.aureus produced resistance against ciprofloxacin alone,and that combined with vitamin C compared to zone of inhibition after 24 hours.Ciprofloxacin produced dose dependent inhibition of E.coli growth after incubation for 24 and 48 hours.Vitamin C potentiated the inhibitory effect induced by ciprofloxacin(additive effect).The inhibitory effect of ciprofloxacin,vitamin C and the combination was not changed after 48 hours compared to 24 hours.展开更多
Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic s...Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic strains of Staphylococcus aureus(S.aureus).Methods:Methanol(MeOH)and aqueous extracts of plants were subjected to sensitivity test against S.aureus ATCC 25953 and two hospital isolated virulent strains of S.aureus SA1 and SA2 following disc diffusion assay to determine sensitivity and agar dilution method to test minimum inhibition concentration using Mueller-Hinton agar.Results:Potential antibacterial activity was recorded for MeOH extracts against test pathogens,while moderate antibacterial activity was observed in case of aqueous extracts.Out of 43 plant species,39 species were found sensitive to tested strains.Minimum inhibition concentration values of MeOH extracts were demonstrated at low concentration ranging from 15.5 mg/mL up to 45.5 mg/mL compared to aqueous extracts which were observed ranging from 30.0 mg/mL up to 95.0 mg/mL.Conclusions:The present findings strongly support traditional uses of these plants in the treatment of infectious maladies and further urge of phytochemical and pharmacological research to develop safer and cheaper drugs for the benefit of ailing humanity.展开更多
Background Subclinical mastitis,caused by many pathogens including Staphylococcus aureus(S.aureus)and Staphylococcus chromogenes(S.chromogenes),presents a major challenge to the dairy industry due to its associated ec...Background Subclinical mastitis,caused by many pathogens including Staphylococcus aureus(S.aureus)and Staphylococcus chromogenes(S.chromogenes),presents a major challenge to the dairy industry due to its associated economic losses and poor milk quality.The molecular regulatory mechanisms,including the role of small nucleolar RNAs(snoRNAs),of the host response to mastitis pathogens remain unclear.Therefore,this study investigated snoRNA expression and potential roles during subclinical mastitis.Milk somatic cells from cows with naturally occurring S.aureus(n=14)and S.chromogenes(n=3)subclinical mastitis,and healthy cows(n=4)were subjected to transcriptome sequencing and bioinformatics analyses.Results We identified 255 expressed snoRNAs including 21 differentially expressed(DE)in S.aureus-positive cows and 20 DE in S.chromogenes-positive cows.Prediction of ribosomal RNA(rRNA)modification sites found several 18S rRNA and 28S rRNA modification(pseudouridylation and 2′-O-methylation)target sites essential for ribosome function for DE snoRNAs,such as SNORA79(18S-1319,28S-3001),SNORA1(18S-1496,28S-1747),suggesting their roles in translation and immune modulation during subclinical mastitis.Correlation analysis identified DE snoRNAs-mRNAs(from the same samples)pairs with majority of the correlated mRNAs(e.g.,CXCL8,IL6R,IL2,IL1R,IL18R1,STAT3,NFKB2,MYD88,VEGFA,and CD40)having immune related functions.Functional enrichment of correlated genes of snoRNAs for S.aureus-positive group(regulation of defense/immune response,leukocyte differentiation,response to cytokine,NF-κB signaling pathway,JAK-STAT signaling pathway etc.)and S.chromogenes-positive group(e.g.,regulation of defense response,response to cytokine,regulation of immune response,NF-κB signaling pathway,TNF signaling pathway,and JAK-STAT signaling pathway)revealed involvement in immune and inflammatory processes.Some functional terms were common to both pathogens(e.g.,NF-κB,JAK-STAT signaling,immune system processes)and suggest common regulatory mechanisms used by both pathogens to contain infection.Furthermore,snoRNA-mRNA network construction identified 7 key(hub)snoRNAs each for S.aureus-positive group(SNORA66,novelsnoRNA_26_14905(also denoted as novelSnoRNA_86),SNORD107,SNORA1,SNORA63,SNORA79,SNORA76)and S.chromogenes-positive group(SNORD18,SNORA79,SNORA46,U2-19,SNORA66,SNORD37,SNORD49)that correlated with the most protein coding genes(|r|>0.9;≥30 mRNAs).Functional enrichment of correlated genes of hub snoRNAs reveals their involvement in immune related functions(75%of enriched terms)and metabolic processes(20%of enriched terms).Conclusion These data suggest potential regulatory roles for the DE snoRNAs and in particular,the 14 hub snoRNAs during subclinical mastitis.This study presents the first evidence linking snoRNAs to bovine subclinical mastitis and offers new insights into the molecular mechanisms underlying subclinical mastitis caused by S.aureus and S.chromogenes.展开更多
The practice of phage therapy,which uses bacterial viruses(phages)to treat bacterial infections,has been around for almost a century.The universal decline in the effectiveness of antibiotics has generated renewed inte...The practice of phage therapy,which uses bacterial viruses(phages)to treat bacterial infections,has been around for almost a century.The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice.Conventionally,phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection.Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins.Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections,suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments.Antibacterial therapies,whether phage-or antibiotic-based,each have relative advantages and disadvantages;accordingly,many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection.Although much about phages and human health is still being discovered,the time to take phage therapy serious again seems to be rapidly approaching.展开更多
Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)are the most typical pathogenic bacteria with a significantly high risk of bio-contamination,widely existing in hospital and public places.Recent studies on a...Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)are the most typical pathogenic bacteria with a significantly high risk of bio-contamination,widely existing in hospital and public places.Recent studies on antibacterial materials and the related mechanisms have attracted more interests of researchers.However,the antibacterial behavior of materials is usually evaluated separately on the single bacterial strain,which is far from the practical condition.Actually,the interaction between the polymicrobial communities can promote the growing profile of bacteria,which may weaken the antibacterial effect of materials.In this work,a 420 copper-bearing martensitic stainless steel(420 CuSS)was studied with respect to its antibacterial activity and the underlying mechanism in a co-culturing infection model using both E.coli and S.au reus.Observed via plating and counting colony forming units(CFU),Cu releasing,and material characterization,420 CuSS was proved to present excellent antibacterial performance against the mixed bacteria with an approximately 99.4%of antibacterial rate.In addition,420 CuSS could effectively inhibit the biofilm formation on its surfaces,resulting from a synergistic antibacterial effect of Cu ions,Fe ions,reactive oxygen species(ROS),and proton consumption of bacteria.展开更多
Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy(APDT)is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms.Among the photosensi...Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy(APDT)is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms.Among the photosensitizers(PSs),compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms.Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia.The aim of this work was to determine and test the most e®ective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms.It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria,including the methicillinresistant S.aureus strain.Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs.The e®ectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation.It was found that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors:the presence in the porphyrin macrocycle of a positive charge(+4),a central metal atom(Zn2þÞand hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen.The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins cannd wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT.展开更多
Cu-bearing stainless steel has been found to have obvious inhibition performance against encrustation in vitro. This study was aiming to further investigate the inhibitory effect of a Cu-bearing stainless steel（316 L...Cu-bearing stainless steel has been found to have obvious inhibition performance against encrustation in vitro. This study was aiming to further investigate the inhibitory effect of a Cu-bearing stainless steel（316 L-Cu SS） on the infectious encrustation based on its antimicrobial activity. The encrustation in presence of bacteria, antibacterial performance, urease production and Ca and Mg precipitation were examined by scanning electron microscopy, antibacterial assay, enzyme-linked immunosorbent assay and inductively coupled plasma-mass spectrometry, respectively. It was found that 316 L-Cu SS could inhibit the formation of bacterial biofilm due to the release of Cu^（2＋） ions and then decrease the urease amount splitting by bacteria, which produced a neutral environment with pH around 7. However, more encrustations coupled with bacterial biofilms on the surface of comparison stainless steel（316 L SS） with an alkaline environment were recorded. It can thus be seen that the 316 L-Cu SS highlights prominent superiority against encrustation in the presence of microorganisms.展开更多
The prevalence of enterotoxigenic Staphylococcus aureus was investigated among 200 participants working in three different food processing plants in Egypt. Using skin swabs, 75 (38%) of the 200 tested persons were pos...The prevalence of enterotoxigenic Staphylococcus aureus was investigated among 200 participants working in three different food processing plants in Egypt. Using skin swabs, 75 (38%) of the 200 tested persons were positive for the presence of S. aureus. Of the S. aureus positive persons, 28 (14%) harboured S. aureus produced staphylococcal enterotoxins. The serotypes of these enterotoxins were enterotoxin A (68%), enterotoxin B (36%), enterotoxin C (46%) and enterotoxin D (18%). Some of these isolates produced more than one type of enterotoxins namely AB, AC, BC, BD, ABC and ACD. Analysis of risk factors implicated in skin carriage of S. aureus as age, gender, marital status, education, duration in employment, frequency and method of hand wash and incidence of chronic skin infection revealed insignificant association with staphylococcal skin carriage. The obtained results put forth the risk of food contracting contamination with enterotoxigenic strains of S. aureus owing to skin colonization of S. aureus among food handlers.展开更多
With the increase in antimicrobial resistance,it has become necessary to explore alternative approaches for combating and preventing diseases.DB-cinnamaldehyde(CNM)and Benzyl4-amino(B4AM)are bioactive compounds derive...With the increase in antimicrobial resistance,it has become necessary to explore alternative approaches for combating and preventing diseases.DB-cinnamaldehyde(CNM)and Benzyl4-amino(B4AM)are bioactive compounds derived from chalcones but with restricted solubility in aqueous media.Nanoemulsions can enhance the solubility of compounds and can be a promising alternative in the development of novel antimicrobials,with reduced side effects and prolonged release.The objective of this study was to evaluate the stability of oil-in-water nanoemulsions loaded with two distinct types of chalcones at two different dosages,to propose a stable formulation with antimicrobial properties.Results showed that nanoemulsions presented high encapsulation efficiency,low polydispersity index(PDI)and particle size below 200 nm,indicating that emulsification was a suitable method for nanoemulsion preparation.Nanoemulsions with higher dosages exhibited significant antimicrobial effects when compared to free chalcones and positive controls.Notably,B4AM nanoemulsions at higher dosages showed expressive activity against Salmonella minnesota,with a 420%greater inhibitory response compared to the free form and showing equivalence to the positive control.CNM nanoemulsions showed excellent inhibitory activity at the highest dosage,equivalent to the positive control against S.minnesota and Staphylococcus aureus.The greater number of conjugated bonds in CNM increased the antimicrobial activity in comparison with B4AM,and the formation of nanometric domains enhanced the bioavailability,being a promising alternative for antimicrobial applications.展开更多
Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at d...Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.展开更多
基金the Science and Technology Innovation Commission of Shenzhen(Nos.JCYJ20210324120009026,JCYJ20210324102013036,JCYJ20210324101809026,and JCYJ20200109114620793)the Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110631)+2 种基金the SIAT Innovation Program for Excellent Young Researchers(No.E1G052)the National Natural Science Foundation of China(Nos.31870956 and U2001221)the Frontier Science Key Research Programs of CAS(No.QYZDB-SSWJSC030)for financially supporting this study。
文摘In this research,microbiologically induced corrosion(MIC)performance of magnesium in tryptic soy broth with S.aureus or E.coli were systematically explored.The results showed that magnesium in biotic solution presented higher mass loss,thicker degradation product layer and more severe pitting corrosion compared to abiotic solution after 24 h of immersion.Electrochemical measurements including EIS spectra and polarization curve further suggested that the corrosion rate of Mg in biotic solution increased during the early stage owing to the decrease of p H,which was originated from the consumption of glucose and the resulting accumulation of acidic metabolites.However,corrosion rate subsequently decreased because of the reduction of acidic metabolites and production of alkaline compound as well as the corrosion protection provided by the corrosion product and biofilm.Moreover,the corrosion rate of magnesium in high concentration of S.aureus and E.coli solution was larger than that in low concentration of S.aureus and E.coli solution,respectively during the initial stage,but subsequently presented a reverse variation.In addition,more severe corrosion of magnesium was observed in S.aureus solution in comparison with E.coli solution.These results suggested that the MIC performance of magnesium was closely related to the concentration and species of bacteria.
文摘Ciprofloxacin is a second-generation of fluoroquinolone,broad-spectrum antibiotic with bactericidal activity against Gram-positive and Gram-negative organisms.It is one of the most widely used antibiotics,because of its efficacy,safety,and relatively low cost.Ascorbic acid(vitamin C)is water-soluble monosaccharide antioxidant;it is essentially required by the body for its various biochemical and physiological processes.S.aureus is Gram-positive cocci;widely distributed in the environment,it is a member of the normal flora of the body.S.aureus is not always pathogenic;it is a common cause of skin infections including abscesses,respiratory infections such as sinusitis,and food poisoning.E.coli is Gram-negative bacteria,found in the environment,foods,and intestines.Most E.coli strains are harmless;it is part of the normal microbiota of the gut.However,some serotypes of E.coli cause serious food poisoning in their hosts;it can cause diarrhea,while others cause urinary tract infections,respiratory illness and pneumonia,and other illnesses.Method:Cup cut diffusion method was applied.Experiment I:is carried out to choose the concentration of vitamin C to be used in experiment II.The negative control is normal saline,added in cup in each plate,vitamin C(100 mg/mL,200 mg/mL,400 mg/mL)was added,the volume in each cup was 100μL.Experiment II:Eight groups of treatments were applied.The first is the negative control(1%normal saline),the second group is the positive control of vitamin C(200 mg/mL).The third,fourth and fifth groups are ciprofloxacin with different concentrations(10 mg/mL,20 mg/mL,40 mg/mL);the sixth,seventh and eighth are the combination of vitamin C with each concentration of ciprofloxacin(10 mg/mL,20 mg/mL,40 mg/mL).Each group includes six petri dishes.Bacterial plates were incubated at 37 oC for 24 h and 48 h.Zone of inhibition is measured in mm.Results and conclusion:Ciprofloxacin produces dose dependent increase in zone of inhibition of S.aureus and E.coli growth,after 24 and 48 hours incubation.While vitamin C in the concentration used produced inhibitory effect on the growth of S.aureus and E.coli,after 24 hours incubation,vitamin C effect was not changed after 48 hours incubation.After 24 hours incubation,vitamin C potentiated the effect of ciprofloxacin at low concentration(10 mg/mL);while vitamin C antagonized the effect of ciprofloxacin at higher concentrations(20 and 40 mg/mL)on S.aureus growth.In the same time,ciprofloxacin antagonized the inhibitory effect of vitamin C on S.aureus growth.After 48 hours incubation,S.aureus produced resistance against ciprofloxacin alone,and that combined with vitamin C compared to zone of inhibition after 24 hours.Ciprofloxacin produced dose dependent inhibition of E.coli growth after incubation for 24 and 48 hours.Vitamin C potentiated the inhibitory effect induced by ciprofloxacin(additive effect).The inhibitory effect of ciprofloxacin,vitamin C and the combination was not changed after 48 hours compared to 24 hours.
基金Supported by SERC Fast Track OYS Scheme,Department of Science and Technology,New Delhi,India[Grant No.304/2004(SR/FT/L-129/2004)].
文摘Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic strains of Staphylococcus aureus(S.aureus).Methods:Methanol(MeOH)and aqueous extracts of plants were subjected to sensitivity test against S.aureus ATCC 25953 and two hospital isolated virulent strains of S.aureus SA1 and SA2 following disc diffusion assay to determine sensitivity and agar dilution method to test minimum inhibition concentration using Mueller-Hinton agar.Results:Potential antibacterial activity was recorded for MeOH extracts against test pathogens,while moderate antibacterial activity was observed in case of aqueous extracts.Out of 43 plant species,39 species were found sensitive to tested strains.Minimum inhibition concentration values of MeOH extracts were demonstrated at low concentration ranging from 15.5 mg/mL up to 45.5 mg/mL compared to aqueous extracts which were observed ranging from 30.0 mg/mL up to 95.0 mg/mL.Conclusions:The present findings strongly support traditional uses of these plants in the treatment of infectious maladies and further urge of phytochemical and pharmacological research to develop safer and cheaper drugs for the benefit of ailing humanity.
基金Agriculture and Agri-Food Canada funded this research(grant number J-002223).
文摘Background Subclinical mastitis,caused by many pathogens including Staphylococcus aureus(S.aureus)and Staphylococcus chromogenes(S.chromogenes),presents a major challenge to the dairy industry due to its associated economic losses and poor milk quality.The molecular regulatory mechanisms,including the role of small nucleolar RNAs(snoRNAs),of the host response to mastitis pathogens remain unclear.Therefore,this study investigated snoRNA expression and potential roles during subclinical mastitis.Milk somatic cells from cows with naturally occurring S.aureus(n=14)and S.chromogenes(n=3)subclinical mastitis,and healthy cows(n=4)were subjected to transcriptome sequencing and bioinformatics analyses.Results We identified 255 expressed snoRNAs including 21 differentially expressed(DE)in S.aureus-positive cows and 20 DE in S.chromogenes-positive cows.Prediction of ribosomal RNA(rRNA)modification sites found several 18S rRNA and 28S rRNA modification(pseudouridylation and 2′-O-methylation)target sites essential for ribosome function for DE snoRNAs,such as SNORA79(18S-1319,28S-3001),SNORA1(18S-1496,28S-1747),suggesting their roles in translation and immune modulation during subclinical mastitis.Correlation analysis identified DE snoRNAs-mRNAs(from the same samples)pairs with majority of the correlated mRNAs(e.g.,CXCL8,IL6R,IL2,IL1R,IL18R1,STAT3,NFKB2,MYD88,VEGFA,and CD40)having immune related functions.Functional enrichment of correlated genes of snoRNAs for S.aureus-positive group(regulation of defense/immune response,leukocyte differentiation,response to cytokine,NF-κB signaling pathway,JAK-STAT signaling pathway etc.)and S.chromogenes-positive group(e.g.,regulation of defense response,response to cytokine,regulation of immune response,NF-κB signaling pathway,TNF signaling pathway,and JAK-STAT signaling pathway)revealed involvement in immune and inflammatory processes.Some functional terms were common to both pathogens(e.g.,NF-κB,JAK-STAT signaling,immune system processes)and suggest common regulatory mechanisms used by both pathogens to contain infection.Furthermore,snoRNA-mRNA network construction identified 7 key(hub)snoRNAs each for S.aureus-positive group(SNORA66,novelsnoRNA_26_14905(also denoted as novelSnoRNA_86),SNORD107,SNORA1,SNORA63,SNORA79,SNORA76)and S.chromogenes-positive group(SNORD18,SNORA79,SNORA46,U2-19,SNORA66,SNORD37,SNORD49)that correlated with the most protein coding genes(|r|>0.9;≥30 mRNAs).Functional enrichment of correlated genes of hub snoRNAs reveals their involvement in immune related functions(75%of enriched terms)and metabolic processes(20%of enriched terms).Conclusion These data suggest potential regulatory roles for the DE snoRNAs and in particular,the 14 hub snoRNAs during subclinical mastitis.This study presents the first evidence linking snoRNAs to bovine subclinical mastitis and offers new insights into the molecular mechanisms underlying subclinical mastitis caused by S.aureus and S.chromogenes.
基金Supported by Winkler Bacterial Overgrowth Research Fund(in part)
文摘The practice of phage therapy,which uses bacterial viruses(phages)to treat bacterial infections,has been around for almost a century.The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice.Conventionally,phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection.Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins.Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections,suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments.Antibacterial therapies,whether phage-or antibiotic-based,each have relative advantages and disadvantages;accordingly,many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection.Although much about phages and human health is still being discovered,the time to take phage therapy serious again seems to be rapidly approaching.
基金financially supported by the National Natural Science Foundation of China(Nos.51101154,51631009,51672184,and 51371168)the National Basic Research Program of China(No.2012CB619101)National Key R&D Program of China(No.2020YFC1107400)。
文摘Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)are the most typical pathogenic bacteria with a significantly high risk of bio-contamination,widely existing in hospital and public places.Recent studies on antibacterial materials and the related mechanisms have attracted more interests of researchers.However,the antibacterial behavior of materials is usually evaluated separately on the single bacterial strain,which is far from the practical condition.Actually,the interaction between the polymicrobial communities can promote the growing profile of bacteria,which may weaken the antibacterial effect of materials.In this work,a 420 copper-bearing martensitic stainless steel(420 CuSS)was studied with respect to its antibacterial activity and the underlying mechanism in a co-culturing infection model using both E.coli and S.au reus.Observed via plating and counting colony forming units(CFU),Cu releasing,and material characterization,420 CuSS was proved to present excellent antibacterial performance against the mixed bacteria with an approximately 99.4%of antibacterial rate.In addition,420 CuSS could effectively inhibit the biofilm formation on its surfaces,resulting from a synergistic antibacterial effect of Cu ions,Fe ions,reactive oxygen species(ROS),and proton consumption of bacteria.
基金the Decree of the Government of the Russian Federation No.220 of April 9,2010(Agreement No.075-15-2021-615 of June 4,2021).
文摘Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy(APDT)is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms.Among the photosensitizers(PSs),compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms.Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia.The aim of this work was to determine and test the most e®ective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms.It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria,including the methicillinresistant S.aureus strain.Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs.The e®ectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation.It was found that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors:the presence in the porphyrin macrocycle of a positive charge(+4),a central metal atom(Zn2þÞand hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen.The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins cannd wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT.
基金supported by the National Basic Research Program of China (973 Program, No. 2012CB619101)the National Natural Science Foundation of China (Nos. 51171186 and 51371168)the Foundation of Jiangsu Collaborative Innovation Center of Biomedical Functional Materials
文摘Cu-bearing stainless steel has been found to have obvious inhibition performance against encrustation in vitro. This study was aiming to further investigate the inhibitory effect of a Cu-bearing stainless steel（316 L-Cu SS） on the infectious encrustation based on its antimicrobial activity. The encrustation in presence of bacteria, antibacterial performance, urease production and Ca and Mg precipitation were examined by scanning electron microscopy, antibacterial assay, enzyme-linked immunosorbent assay and inductively coupled plasma-mass spectrometry, respectively. It was found that 316 L-Cu SS could inhibit the formation of bacterial biofilm due to the release of Cu^（2＋） ions and then decrease the urease amount splitting by bacteria, which produced a neutral environment with pH around 7. However, more encrustations coupled with bacterial biofilms on the surface of comparison stainless steel（316 L SS） with an alkaline environment were recorded. It can thus be seen that the 316 L-Cu SS highlights prominent superiority against encrustation in the presence of microorganisms.
基金Financial support for this research was provided by the Agencia Espanola de Cooperaci’on Internacional para el Desarrollo(A/019106/08,A/025113/09 and A1/035779/11).
文摘The prevalence of enterotoxigenic Staphylococcus aureus was investigated among 200 participants working in three different food processing plants in Egypt. Using skin swabs, 75 (38%) of the 200 tested persons were positive for the presence of S. aureus. Of the S. aureus positive persons, 28 (14%) harboured S. aureus produced staphylococcal enterotoxins. The serotypes of these enterotoxins were enterotoxin A (68%), enterotoxin B (36%), enterotoxin C (46%) and enterotoxin D (18%). Some of these isolates produced more than one type of enterotoxins namely AB, AC, BC, BD, ABC and ACD. Analysis of risk factors implicated in skin carriage of S. aureus as age, gender, marital status, education, duration in employment, frequency and method of hand wash and incidence of chronic skin infection revealed insignificant association with staphylococcal skin carriage. The obtained results put forth the risk of food contracting contamination with enterotoxigenic strains of S. aureus owing to skin colonization of S. aureus among food handlers.
基金supported by the National Council for Scientific Development-CNPQ/MCTI/FNDCT N18/2021,by the Concession of Research Funding Grant Number 406522/2021-9-1 to F.O.M.S.Abreu.Helcio Silva dos Santos acknowledges financial support from CNPq-PQ (Grant Number 306008/2022-0).
文摘With the increase in antimicrobial resistance,it has become necessary to explore alternative approaches for combating and preventing diseases.DB-cinnamaldehyde(CNM)and Benzyl4-amino(B4AM)are bioactive compounds derived from chalcones but with restricted solubility in aqueous media.Nanoemulsions can enhance the solubility of compounds and can be a promising alternative in the development of novel antimicrobials,with reduced side effects and prolonged release.The objective of this study was to evaluate the stability of oil-in-water nanoemulsions loaded with two distinct types of chalcones at two different dosages,to propose a stable formulation with antimicrobial properties.Results showed that nanoemulsions presented high encapsulation efficiency,low polydispersity index(PDI)and particle size below 200 nm,indicating that emulsification was a suitable method for nanoemulsion preparation.Nanoemulsions with higher dosages exhibited significant antimicrobial effects when compared to free chalcones and positive controls.Notably,B4AM nanoemulsions at higher dosages showed expressive activity against Salmonella minnesota,with a 420%greater inhibitory response compared to the free form and showing equivalence to the positive control.CNM nanoemulsions showed excellent inhibitory activity at the highest dosage,equivalent to the positive control against S.minnesota and Staphylococcus aureus.The greater number of conjugated bonds in CNM increased the antimicrobial activity in comparison with B4AM,and the formation of nanometric domains enhanced the bioavailability,being a promising alternative for antimicrobial applications.
基金Supported by the Scientific Research Projects of Basic Scientific Research Business Expenses of Undergraduate Universities in Heilongjiang Province(135309363)Fundamental Research Business Expenses of Heilongjiang Provincial Universities(Specialized Subjects of Plant Food Processing Technology)(YSTSXK201889)+2 种基金Heilongjiang General Undergraduate Universities Young Innovative Talents Training Plan(UNPYSCT-2018101)Natural Science Foundation of Heilongjiang Province(LH2019C067)Science and Technology Plan Project of Qiqihar City(NYGG-201915)。
文摘Onion(Allium cepa L.)is a common biennial herb,and contains allicin compounds which can kill harmful microorganism.The antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations on Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were studied.There were differences among the antibacterial effects of raw and mature onion juice of purple,yellow and white-skinned onions at different concentrations.What was more,the antibacterial effects of raw onion juice were better than those of the mature one.The antibacterial effects of high concentration onion juice were better than those of the low one.The content of the total flavonoids in raw purple onion was higher than that in mature onion,and reached extremely significant levels in 50%,75%and 100%,respectively.Through comparison,it was found that onion juice of purple-skinned had the best suppression effects on S.aureus(gram-positive bacterium)and E.coli(gram-negative bacterium),and gram-positive bacterium had better suppression effects than gram-negative bacterium.It wound provide the basis about bioactive function and antibacterial drugs.
