Study on Bacteriostatic Properties of Piroctone Olamine in Commonly Used Surfactants Systems

Piroctone olamine(OCT) was used as the main bacteriostatic component, the inhibition of OCT in different kinds and mass concentrations of surfactants were studied. Six surfactants commonly used in personal care products, i.e. sodium laureth sulfate(AES), cocamidopropyl betaine(CAB 35), sodium lauroyl sarcosinate(LS-30), sodium lauroyl glutamate(ULS-30S), alkyl glycoside(APG), cocamide methyl MEA(CMMEA),were used. The results showed that the bacteriostatic of OCT decreased with the increase of AES, which was suggested ≤ 5%. OCT has good bacteriostatic performance in the systems of amino acid surfactants and high dosage of amphoteric surfactants, 5% LS 30 and ≥ 10% CAB 35 was recommended. High dosage of nonionic surfactant could interfere the bacteriostatic performance of OCT, the recommended dosage was ≤ 2%.In addition, OCT has good bacteriostatic performance against Staphylococcus aureus, Escherichia coli and Candida albicans when pH was controlled less than 5.5.

In Vitro Bacteriostatic Activity of Five Chinese Herbal Medicines against Two Common Pathogens of Scylla serrata

[ Objective] To investigate the in vitro bacteriostatic activity of Chinese herbal medicines （ rhubarb, Baikal skullcap root, honeysuckle, eucommia bark and Chinese date） and their compounds against two common pathogens of Scylla serrata （ Vibrio parahaemolyticus and Aeromonas hydrophila）. [Method] Drug sensitivity of the bacteria was determined by paper method. Minimum inhibitory concentration （MIC） and minimum bactericidal concentration （MBC） were determined by dilution method and plate method, respectively. [Result] The bacteriostatic order of single medicines on V. parahaemolyticus were Baikal skullcap root 〉 honeysuckle 〉 rhubarb 〉 Chinese date 〉 eucommia bark. The bacteriostatic order of the compounds were A =B = C 〉 D. Among these medicines, the Baikal skullcap root and the compounds A, B, C and D had better bactericidal effects on V. parahaemolyticus. The bacteriostatic order of single medicines on A. hydrophila was rhubarb 〉 Baikal skullcap root 〉 honeysuckle 〉 Chinese date 〉 eucommia bark. The bacteriostatic order of the compounds were A 〉 B 〉 C = D, while the rhubarb and the compound C had better bactericidal effects on A. hydrophila. [ Conclusion] The Chinese herbal medicines including rhubarb, Baikal skullcap root, honeysuckle, eucommia bark and Chinese date have good bacteriostatic effects on V. parahaemolyticus and A. hydrophila, and they can be used to treat bacterial infection in Scylla serrata.

Bacteriostatic Effect of Extracts from 10 Kinds of Traditional Chinese Medicinal Materials and Garlic on Pectobacterium chrysanthemi

Pectobacterium chrysanthemi is one of the main pathogens of soft rot disease of Amorphophallus konjac.The bacteriostatic effect of extracts from 10 kinds of traditional Chinese medicine and garlic on Pectobacterium chrysanthemi was studied in this experiment.The results showed that the extracts of Coptis chinensis,garlic,Scutellaria baicalensis,Mume Fructus and Bupleurum had significant bacteriostatic effect.Among them,Coptis chinensis and garlic had the best bacteriostatic effect on Pectobacterium chrysanthemi,and the diameter of inhibition zone was 2.27 and 2.19 cm,respectively,followed by Scutellaria baicalensis,with the diameter of inhibition zone of 1.68 cm.The extracts of Coptis chinensis,Scutellaria baicalensis and garlic with good bacteriostatic effect were diluted by double dilution method,and the bacteriostatic effect was determined.The results showed that 2-fold dilution of Coptis chinensis and 2-fold and 4-fold dilution of Scutellaria baicalensis had significant bacteriostatic effect,but the bacteriostatic effect of garlic extract was not obvious after dilution.

Bacteriostatic Effects of Hyaluronan-Based Bioresorbable Membrane

Purpose: The purpose of this study is to determine the presence of bacteriostatic effects of hyaluronan-based bioresorbable membrane (HA/CMC) on selected major bacterial strains in digestive organs. Methods: We firstly evaluated the growth inhibition effect of HA/CMC for E. coli and S. aureus by determining the optical density (OD)650 in the incubation medium. At second, to determine the viable counts of bacteria, total adenosine triphosphate (ATP) were measured with five groups;several concentrations of HA/CMC and control. Results: OD curve gradually elevated and reached to plateau at 4 hours in E. coli. and 6 hours in S. aureus. After reaching plateau, the growth inhibition of both strains was statistically significantly correlated to the concentrations of HA/CMC. The ATP productions had statistically significant differences at 6 hours after incubation and inhibited in dose-dependence of a well-dissolved HA/CMC. Conclusion: HA/CMC may have dose-dependently bacteriostatic effects on S. aureus and E. coli.

Screening beneficial bacteriostatic lactic acid bacteria in the intestine and studies of bacteriostatic substances

Lactic acid bacteria(LAB)are a representative probiotic.As the dominant flora in the human intestinal tract,LAB can regulate the balance of human intestinal flora and improve host health.The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population,with excellent probiotics and high antibacterial activity.After 16S ribosomal RNA(rRNA)homology and phylogenetic tree analysis,potential probiotics were tested for their antibacterial activity,resistance to artificial gastrointestinal fluid and drugs,surface hydrophobicity,and safety.Three strains of LAB with acid resistance,bile salt resistance,epithelial cell adhesion,and no multidrug resistance were selected:Lactobacillus salivarius,Leuconostoc lactis,and Lactobacillus paracasei.Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L.lactis were organic acids,whereas those of L.salivarius and L.paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity.These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens.

Bacillus subtilis produces(p)ppGpp in response to the bacteriostatic antibiotic chloramphenicol to prevent its potential bactericidal effect

Antibiotics combat bacteria through their bacteriostatic(by growth inhibition)or bactericidal(by killing bacteria)action.Mechanistically,it has been proposed that bactericidal antibiotics trigger cellular damage,while bacteriostatic antibiotics suppress cellular metabolism.Here,we demonstrate how the difference between bacteriostatic and bactericidal activities of the antibiotic chloramphenicol can be attributed to an antibiotic-induced bacterial protective response:the stringent response.Chloramphenicol targets the ribosome to inhibit the growth of the Gram-positive bacterium Bacillus subtilis.Intriguingly,we found that chloramphenicol becomes bactericidal in B.subtilis mutants unable to produce(p)ppGpp.We observed a similar(p)ppGpp-dependent bactericidal effect of chloramphenicol in the Gram-positive pathogen Enterococcus faecalis.In B.subtilis,chloramphenicol treatment induces(p)ppGpp accumulation through the action of the(p)ppGpp synthetase RelA.(p)ppGpp subsequently depletes the intracellular concentration of GTP and antagonizes GTP action.This GTP regulation is critical for preventing chloramphenicol from killing B.subtilis,as bypassing(p)ppGpp-dependent GTP regulation potentiates chloramphenicol killing,while reducing GTP synthesis increases survival.Finally,chloramphenicol treatment protects cells from the classical bactericidal antibiotic vancomycin,reminiscent of the clinical phenomenon of antibiotic antagonism.Taken together,our findings suggest a role of(p)ppGpp in the control of the bacteriostatic and bactericidal activity of antibiotics in Gram-positive bacteria,which can be exploited to potentiate the efficacy of existing antibiotics.

Antibacterial Activity and Mechanisms of Ethanol Extracts from Scutellaria baicalensis Georgi and Magnolia officinalis against Phytophthora nicotianae

Phytophthora nicotianae causes substantial economic losses in most countries where tobacco is produced.At present,the control of P.nicotianae mainly depends on chemical methods,with considerable environmental and health issues.We investigated the effects of ethanol extracts from Scutellaria baicalensis Georgi(SBG)and Magnolia officinalis(MO).On mycelial growth,sporangium formation,and zoospore release of P.nicotianae.Both extracts inhibited the growth of P.nicotianae,with mycelial growth inhibition rates of 88.92%and 93.92%,respectively,at 40 mg/mL,and EC50 values of 5.39 and 5.74 mg/mL,respectively.The underlying mechanisms were the inhibition of sporangium formation,the reduction of zoospore number,and the destruction of the mycelium structure.At an SBG extract concentration of 16.17 mg/mL,the inhibition rates for sporangia and zoospores were 98.66%and 99.39%,respectively.At an MO extract concentration of 2.87 mg/mL,the production of sporangia and zoospores was completely inhibited.The hyphae treated with the two plant extracts showed different degrees of deformation and damage.Hyphae treated with SBG extract showed adhesion and local swelling,whereas treatment with MO extract resulted in broken hyphae.Mixture of the extracts resulted in a good synergistic effect.

Phytochemicals, polyphenols content, in vitro antioxidant and antibacterial activities of Albizia coriaria Welw ex. Oliver flowers

Albizia coriaria Welw ex.Oliver(hereafter A.coriaria)is a revered medicinal tree whose organs are used by indigenous African societies for managing various ailments.Herein,we assessed the secondary metabolites,total polyphenolics,free radical scavenging and antimicrobial activities of A.coriaria flowers.The dry powdered sample was extracted serially with ethyl acetate,ethanol and distilled water.Results of classical phytochemical screening showed that saponins,phenols,alkaloids,flavonoids,tannins and terpenes were the dominant phytochemicals.The highest total polyphenolic content(10.37±0.02 mg QE/g DW and 72.09±0.09 mg GAE/g DW)and free radical scavenging potential(IC50=24.23±0.04 mg/mL)were for the ethyl acetate extract.It also had a higher bacteriostatic activity than the ethanolic extract against Pseudomonas aeruginosa,Salmonella typhi,Escherichia coli and Staphylococcus aureus with diameters of inhibition ranging from 7.00±0.00 to 22.00±1.73 mm.The aqueous extract showed no appreciable antibacterial effect on the tested microorganisms.This is the first report which support the use of floral extracts of this species in the management of ailments in African traditional medicine.

Preparation of a Novel Highly Effective and Environmental Friendly Wheat Seed Coating Agent

A novel environmental friendly wheat seed coating agent was prepared from the natural polymer,biological pesticide,microfertilizer,microelements and other additives.The laboratory and field test results showed that it could enhance the yield up to 16% and reduce its input cost to 1/6 as compared with the conventional wheat seed coating agent.It is safe without causing any pollution and would have significant economic and environmental benefits.

Fungi with potential probiotic properties isolated from Fuzhuan brick tea

Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains from two types of FBT and identified these strains based on internal transcribed spacer(ITS)fragment sequence similarity to reference strains(sequence similarity>98%).Of the 18 strains,10 tolerated simulated human digestive conditions for sufficient periods in vitro:pH 2-3,0.3%-0.5%(m/V)bile salts,and artificial gastrointestinal juices.We then measured the antimicrobial activity of the remaining 10 strains against 5 enteropathogenic bacteria and tested the bacteriostatic effects of the thalli and fermentation broth extracts.Of the 6 strains with strong bacteriostatic effects,we eliminated Eurotium cristatum S-9 due to its low hydrophobicity of(26.12±0.35)%.Finally,2 exhibited good adhesion abilities to human cells(>100%).Notably,2 strains can survive in vivo,because they can be isolated from C57BL/6 mice feces.Thus,2 strains,Aspergillus cristatus H-1 and A.cristatus H-5,are herein identified as promising candidate probiotic strains.It may be put forward a novel research focus on evaluating potential probiotic fungi from FBT.

Screening and Identification of Biocontrol Strains against Potato Black Shank Disease,Pectobacterium atrosepticum

[Objective]The paper was to screen and identify biocontrol strains against potato black shank disease in Inner Mongolia.[Method]Totally 58 strains of Bacillus spp.preserved in the laboratory were used to screen and identify biocontrol agents against potato black shank disease,and the antagonistic activities of strains were determined by plate confrontation culture method.[Result]A total of 17 strains showed antagonistic activity against Pectobacterium atrosepticum in potato,accounting for 29.31%of the tested strains.Five strains with better antagonistic effect were obtained by further screening,namely Chi8-7,Genyun4-4,Gen7-4,Jing6-7,and S-7.Genyun4-4 had the most obvious bacteriostatic effect,and the average inhibition zone diameter reached 20.7 mm,significantly higher than those of other tested strains.Results of bioactivity determination also demonstrated that the strain had better bacteriostatic effect.Through morphological observation,molecular identification and physiological and biochemical characteristics determination,the strain Chi8-7 was identified as Bacillus amyloliquefaciens;the strain Genyun4-4 was identified as B.subtilis;and strains Gen7-4,Jing6-7 and S-7 were identified as B.methylotrophicus.[Conclusion]The results will lay a theoretical basis for biological control against potato black shank disease in Inner Mongolia.

Selection and Molecular Biological Identification of a Strain of Bacillus sp. Inhibiting the Growth of Saprolegnia ferax

Based on the theory of biological control of Saprolegnia ferax,antagonism test of nine strains of Bacillus sp. to S. ferax JL was carried out. Bacillus sp.BA1 was screened to have significantly inhibitory effects on the growth of S. ferax JL( P 【 0. 05). Then,the effects of Bacillus sp. BA1 on different sources of S. ferax were carried out. Results showed that BA1 also had significantly inhibitory effects on S. ferax 6#,10# and S2( P 【 0. 05). Sequence of 16 S r DNA of BA1 was analyzed; and homologous alignment analysis showed that BA1 had more than 99% similarity with Bacillus cereus. Therefore,it could be concluded that strain BA1 was B. cereus,which significantly inhibited the growth of S. ferax and could be used as the biological control agent for S. ferax diseases in aquaculture.

In-vitro Synthesis and Activity Identification of Antimicrobial Peptide from Aspergillus granifolium

[Objectives] This study was conducted to investigate the control effect of antimicrobial peptides to peanut aflatoxin contamination and achieve the purpose of biological control of peanut aflatoxin.[Methods]Bioinformatics methods were applied to screen antimicrobial peptides with strong antifungal activity in the antimicrobial peptide database and analyze their secondary structures and bacteriostatic characteristics,and the candidated peptide was then artificially synthesized,expressed and purified and detected for in-vitro activity.[Results] The antimicrobial peptide(AFP1) which was screened from Aspergillus granifolium exhibited strong antimicrobial activity against Aspergillus flavus.The inhibition rate of crude AFP1 at 3 mg/ml reached 58% for gram-positive bacteria,52% for gram-negative bacteria,and 62% for A.flavus.[Conclusions]This study provides a new approach for the prevention and control of various plant diseases including peanut disease,and a new idea for the biological prevention and control of plant diseases.

Development of a Construction Material for Indoor and Outdoor, Metakaolinite-Based Geopolymer, with Environmental Properties

Environmental problems that came from the human activity have many facets,since pollution of the atmosphere arises from vehicles,industrial emissions while pollution of water could be from organic compounds,pesticides etc.These can cause serious health effects,such as respiratory diseases,including asthma and lung cancer.Hence,in the present work,a kinetic study on the effective adsorption and photo degradation of methylene blue(MB)dye,under ultraviolet A(UVA)irradiation of an alkali activated inorganic polymer(geopolymer)with homogeneously dispersed titanium dioxide(TiO2)micro-particles is presented.In addition,antimicrobial testing of the alkali activated TiO2 material was performed showing a bacteriostatic effect.

Preparation and Quality Evaluation of Salicylic Acid Gel

Taking salicylic acid as the active ingredient and 10%sodium hydroxide aqueous solution as the neutralizer,the best matrix for preparing gel was screened,and the salicylic acid aqueous gel was prepared.The properties,pH value and viscosity were determined,and the stability,antibacterial activity and irritation were evaluated.The experimental results showed that the best gel matrix was cellulose,which had the best stability,could increase the solubility of salicylic acid in gel preparations,solved the problem of easy precipitation of salicylic acid crystals,enhanced the antibacterial activity,and reduced irritation,providing a reference for the application of salicylic acid in cosmetics.

乳杆菌功能改变与外阴阴道假丝酵母菌病

目的研究VVC患者阴道乳杆菌菌种构成与功能特点。方法从VVC患者和健康女性阴道分泌物中分离乳杆菌并鉴定。测定乳杆菌抑制白假丝酵母菌的能力。结果对照组女性阴道分泌物分离出64株乳杆菌,81.3%能抑制白假丝酵母菌增殖,VVC组分离出51株乳杆菌,70.6%能抑制白假丝酵母菌增殖。对照组常见菌种为卷曲乳杆菌、加氏乳杆菌和詹氏乳杆菌,VVC组常见菌种为阴道乳杆菌、发酵乳杆菌和德氏乳杆菌。对照组所有患者均能分离到具有抑制白假丝酵母菌功能的乳杆菌,VVC组仅42%的患者能分离到具有抑制白假丝酵母菌作用的乳杆菌。结论 VVC患者阴道乳杆菌菌种构成与健康女性存在差别。VVC组患者阴道乳杆菌抑制白假丝酵母菌能力较对照组弱。

Micro/nano-structured TiO2 surface with dual-functional antibacterial effects for biomedical applications

Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics.Given the global threat and increasing influence of antibiotic resistance,there is an urgent demand to explore novel antibacterial strategies other than using antibiotics.Recently,using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention.However,the clinical application of biomimetic nano-pillar array is not satisfactory,mainly because its antibacterial ability against Gram-positive strain is not good enough.Thus,the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application.Here,we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2.Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections.First,to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array,we systematically investigated its effects on bacterial adhesion,growth,proliferation,and viability in the dark without involving the photocatalysis of TiO2.The pillar array with sub-micron motif size can significantly inhibit the adhesion,growth,and proliferation of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array.Moreover,the pillar array is not lethal to S.aureus and E.coli in 24 h.Then,the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work.This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics.

Functional C1q is present in the skin mucus of Siberian sturgeon (Acipenser baerii)

The skin mucus of fish acts as the first line of self-protection against pathogens in the aquatic environment and comprises a number of innate immune components.However,the presence of the critical classical complement component C1q,which links the innate and adaptive immune systems of mammalians,has not been explored in a primitive actinopterygian fish.In this study,we report that C1q is present in the skin mucus of the Siberian sturgeon(Acipenser baerii).The skin mucus was able to inhibit the growth of Escherichia coli.The bacteriostatic activity of the skin mucus was reduced by heating and by pre-incubation with EDTA or mouse anti-human C1q antibody.We also detected C1q protein in skin mucus using the western blot procedure and isolated a cDNA that encodes the Siberian sturgeon C1qC,which had 44.7–51.4%identity with C1qCs in teleosts and tetrapods.A phylogenetic analysis revealed that Siberian sturgeon C1qC lies at the root of the actinopterygian branch and is separate from the tetrapod branch.The C1qC transcript was expressed in many tissues as well as in skin.Our data indicate that C1q is present in the skin mucus of the Siberian sturgeon to protect against water-borne bacteria,and the C1qC found in the sturgeon may represent the primitive form of teleost and tetrapod C1qCs.