Significant Antagonistic Activity Research Articles

Estrogen agonistic/antagonistic activity of brominated parabens.

The estrogen agonistic/antagonistic activity of 16 brominated by-products of parabens was assessed by using a yeast two-hybrid assay transfected with the human estrogen receptor α. Characterization of synthetic compounds including novel brominated parabens was performed using 1H-NMR spectroscopy and high-resolution mass spectrometry. For the agonist assay, five C3-C4 alkylparabens exhibited significant activity (P < 0.05) relative to that of 17β-estradiol, ranging from 3.7 × 10-5 to 7.1 × 10-4. In contrast, none of the brominated alkyl parabens exhibited agonistic activity. In the antagonist assay, 12 brominated alkylparabens and butylparaben exhibited significant antagonistic activity (P < 0.05). Their antagonistic activity relative to 4-hydroxytamoxifen ranged from 0.11 to 2.5. The antagonist activity of C1-C4 alkylparabens increased with the number of bromine substitutions. Benzylparaben exhibited both agonistic and antagonistic activity, and these activities dissipated or were weakened with increased bromination. Thus, increased bromination appeared to attenuate the estrogen agonistic activity of most parabens such that it resulted in increased antagonistic activity, a feature of parabens that had not been previously described.

Suppression of Alternaria blight disease and plant growth promotion of mustard (Brassica juncea L.) by antagonistic rhizosphere bacteria

Indian mustard (Brassica juncea L.) is an important oilseed crop. Alternaria brassicae causes blight disease on this crop leading to 10–70% yield losses. Rhizobacterial isolates were tested in this study for use as biological control agent for suppression of the disease. Three hundred and eighty-three rhizobacterial isolates were screened for the antagonistic activity and 20.88% isolates inhibited the growth of fungi Alternaria brassicae on modified LB medium plates. Six rhizobacterial isolates HMM44, HMM89, HMR25, HMR32, HMR33 and HMR70 showed significant antagonistic activity. Antagonistic rhizobacterial isolates were analyzed for their disease suppression and plant-growth promoting activities such as production of ALA, IAA, HCN and siderophore. Maximum IAA production was shown by isolate HMR48 and high ALA production was observed in isolates HMM21 and HMM49. Five isolates i.e. HMR25, HMR29, HMR52, HMR69 and HMR73 showed HCN production. Under pot-house conditions, inoculation of isolates HMR25, HMR48 and WHA64 with fungi caused 100, 80.0 and 80.0% disease control, respectively at 50 DAS (days after sowing). Inoculation of rhizobacterial isolates HMR70, HMR48 and HMR25 with A. Brassicae caused 83.33, 83.33 and 100.0% disease control, respectively at 75 days of plant growth. Rhizobacterial isolates HMR48 and HMR25 also showed stimulation of mustard growth. These rhizobacterial isolates could further be assessed for their disease control and plant growth promotion potential under field conditions for their subsequent use as biofertilizer and biocontrol agents.

Isolation and characterization of Bacillus sp. strain BC01 from soil displaying potent antagonistic activity against plant and fish pathogenic fungi and bacteria.

Fungal and bacterial pathogens infect a diverse range of hosts including various plant and animal species. Fungal and bacterial diseases, especially of plants and aquatic animals, such as fish, lead to significant damage to crops and aquaculture, respectively, worldwide. The present study was conducted to isolate and characterize potent Bacillus strains with significant antagonistic activity against the major plant and fish pathogenic fungi and bacteria. We randomly collected 22 isolates of Bacillus from the soil, rhizosphere, and sediment from different parts of Bangladesh. Initial characterization, based on in vitro antagonistic activity on the culture plate, resulted in the selection of four gram-positive Bacillus sp. isolates. Among these, the isolate BC01, obtained from soil demonstrated the highest broad-spectrum anti-bacterial and anti-fungal activities. We confirmed the genus of BC01 to be Bacillus by morphological and biochemical tests as well as using molecular data analysis tools, including the study of 16s rDNA, phylogenetic relationship, and evolutionary divergence scores. The isolate significantly inhibited the mycelial growth of the plant pathogen, Penicillium digitatum and fish pathogen, Aphanomyces invadans in vitro. The anti-bacterial effect of the isolate was also evaluated against Pseudomonas spp. and Xanthomonas spp., the two deadliest plant pathogens, and Aeromonas veronii, Pseudomonas fluorescens, and Streptococcus iniae, three major fish pathogens that are primarily responsible for global aquaculture loss. The results of the present study could pave the way for developing potent drugs to combat microbial infection of plants and fish.

Antagonistic Activity of Lactic Acid Bacteria Lactobacillus spp. against Clinical Isolates of Klebsiella pneumoniae

The screening of three strains of lactic acid bacteria identified as Lactobacillus rhamnosus, Lactobacillus reuteri, and Lactobacillus helveticus showed significant antagonistic activity against Klebsiella pneumoniae strains characterized by multiple antibiotic resistance. Lactobacilli cocultivated with the Klebsiella strains inhibited their growth 20 to 86% on the first and second days, respectively. Exoproteome analysis of L. rhamnosus cocultivated with K. pneumoniae revealed the induction of peptidoglycan hydrolases, including extracellular lytic transglycosylases, family II (MltA), and endopeptidases capable of disrupting the peptidoglycan bacterial cell wall.

Kefir: composition and evaluation of in situ antagonistic activity against Staphylococcus aureus and Escherichia coli.

The aim of this study was to investigate whether produced kefir meets the identity and quality standards for fermented milks, to check the possibility of assigning a nutrition declaration, and to evaluate the antagonistic activity of the fermented milk against Staphylococcus aureus and Escherichia coli. Two different formulations of kefir (Kefir 1 and Kefir 2) were prepared to determine the percentage composition, minerals, pH, total lactic acid bacteria, and antagonistic activity against Staphylococcus aureus and Escherichia coli. The results of the physicochemical evaluation indicated a statistically significant difference between the formulations, except for the percentage of lipids, Ca, K, Mg and Na. The formulations met the parameters of identity and quality in the fermented milks under evaluation. Possible nutrition declarations for Kefir 1 are ‘source of proteins’ and ‘reduced calorie’, and for Kefir 2, ‘high protein content’ and ‘high zinc content’. The fermented milks showed significant antagonistic activity against the tested microorganisms (> 24 h), with no activity seen after this period. Further studies involving kefir are suggested, exploring its potential as a probiotic food, and its inclusion in the diet of the population.

Antagonistic assessment of Trichoderma spp. by producing volatile and non-volatile compounds against different fungal pathogens

Trichoderma spp. are well-known biological agents that have significant antagonistic activity against several plant pathogenic fungi. In the present study, Trichoderma spp. were tested in vitro for their antagonistic activity against different spp. of Fusarium and Alternaria viz. Alternaria alternata, A. brassicae, A. solani, Fusarium oxysporum and F. solani using dual plate assay and by the production of volatile and non-volatile compounds. The results obtained revealed that Trichoderma harzianum and T. viride effectively inhibited the growth and spore production of different spp. of Fusarium and Alternaria. The highest growth inhibition was found in A. alternata 62.50% and 60.00% by non-volatile compounds of T. harzianum and T. viride, respectively. Similarly, the volatile compounds inhibit the maximum growth of A. alternata 40.00% and 35.00% by T. harzianum and T. viride, respectively. Volatile and non-volatile compounds of Trichoderma spp. were analysed by GC-MS technique and the properties of distinguished compounds showed antifungal, antimicrobial and antibiotic activities. Volatile compounds of T. harzianum and T. viride showed highest percent abundance for glacial acetic acid (45.32%) and propyl-benzene (41.75%), respectively. In case of non-volatile compounds, T. harzianum and T. viride showed D-Glucose, 6-O-α-D-galactopyranosyl- (38.45%) and 17-Octadecynoic acid (36.23%), respectively. The results of present study confirmed that T. harzianum can be used as a promising biological control agent against Alternaria and Fusarium spp. that cause diseases in various vegetables and crops.

Identification and evaluation of potential bio-control fungal endophytes against Ustilagonoidea virens on rice plants.

False smut disease of rice is posing an increasing concern for production, not only because of the hiking epidemic occurrence in rice production, but also because of the challenging specific pathogenesis of the disease. The aim of this work was to evaluate the potential of five fungal endophytes to reduce negative effects of rice false smut fungus (Ustilagonoidea virens) on rice plants, in both the laboratory and greenhouse. Though all the fungal isolates showed the ability to inhibit the growth of U. virens with varying degrees, isolate E337 showed significant antagonistic activity against the pathogenic fungi. The isolate E337 was identified as Antennariella placitae by molecular and morphological data analysis including 18S rDNA sequence analysis. This isolate showed a significant in vitro inhibition of mycelial growth of U. virens by dual culture method and it was subsequently tested for its in vivo biocontrol potential on false smut disease on rice plants. Greenhouse experiments confirmed that applications of conidia of A. placitae protected rice plants by improving rice yield and by decreasing the severity of false smut disease on susceptible rice plants. This is the first report where A. placitae has been identified as a biocontrol organism.

Escherichia coli GutM4 produces 2,5-diketopiperazines and inhibits human pathogens in vitro

It has been a very common practice to use probiotics or their metabolites as alternative antimicrobial strategies for the treatment and prevention of infections as rampant and indiscriminate use of antibiotics causes the development of antibiotic-resistant pathogens. The objective of this study was to select a potential antimicrobial probiotic strain of Escherichia coli from the human gastrointestinal tract and investigate the production of diketopiperazines that contribute to the antimicrobial activity. E. coli GutM4 was isolated from the feces of a healthy adult. E. coli GutM4 showed significant antagonistic activity against 10 indicator pathogens, and this activity was no less than that of the reference strain E. coli Nissle 1917 against eight of the indicator pathogens. Moreover, E. coli GutM4 produced antagonistic substances containing trypsin-targeted peptide bonds because the inhibitory effects of E. coli GutM4 supernatant significantly decreased upon treatment with trypsin. Consistent with the antagonistic activity and peptide compounds of E. coli GutM4, 14 2,5-diketopiperazines were isolated from the fermented broth of E. coli GutM4, including 12 cyclo(Pro-Phe), 3 cyclo(Pro-Tyr), and 5 cyclo(4-hydroxyl-Pro-Leu), which are reported to have antipathogenic activity. E. coli GutM4 produces 2,5-diketopiperazines that are partly involved in antagonistic action against human pathogens in vitro.

Determination of Antibacterial and Technological Properties of Vaginal Lactobacilli for Their Potential Application in Dairy Products.

Functional foods could differently affect human health in relation to the gender. Recent studies have highlighted the anti-Candida and anti-Chlamydia activities of some Lactobacillus strains isolated from the vagina of healthy women. Considering these important beneficial activities on women's health, the preparation of functional food containing active vaginal lactobacilli can represent a great scientific challenge for the female gender. In this context, the aim of this work was to study some functional and technological properties of 17 vaginal strains belonging to the species Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus vaginalis in the perspective to include them in dairy products. The antagonistic activities against the pathogenic and spoilage species associated to food products and against the principal etiological agents of the genitourinary tract infections were evaluated. Moreover, the vaginal lactobacilli were characterized for their antibiotic resistance, and for their fermentation kinetics and viability during the refrigerated storage in milk. Finally, the volatile molecule profiles of the obtained fermented milks were determined. The results showed that several strains, mainly belonging to the species Lactobacillus crispatus, exhibited a significant antagonistic activity against spoilage and pathogenic microorganisms of food interest, as well as against urogenital pathogens. All the vaginal lactobacilli showed antimicrobial activity against strains belonging to the foodborne pathogenic species Listeria monocytogenes, Listeria innocua, Eenterococcus faecalis and Escherichia coli. In addition, most of the Lactobacillus strains were active toward the main pathogens responsible of vaginal and urinary tract infections including Staphylococcus aureus, Enterococcus faecium, Gardnerella vaginalis, and Proteus mirabilis. The antimicrobial activity can be attributed to the high production of organic acids. The fermentation kinetics in milk indicated the unsuitability of these lactobacilli as fermentation starters for the industrial production of dairy products. However, some strains, belonging to the species Lactobacillus crispatus and Lactobacillus gasseri, maintained a high viability in pasteurized milk at 4°C for over a month, showing their potential application as adjunct cultures for the production of female gender foods. These data represent a first step for the set-up of a new functional dairy product, directed to the women well-being, contributing also to innovate the dairy sector.

Endophytic fungi associated with Monarda citriodora, an aromatic and medicinal plant and their biocontrol potential

Context: The Food and Agriculture Organization has estimated that every year considerable losses of the food crops occur due to plant diseases. Although fungicides are extensively used for management of plant diseases, they are expensive and hazardous to the environment and human health. Alternatively, biological control is the safe way to overcome the effects of plant diseases and to sustain agriculture. Since Monarda citriodora Cerv. ex Lag. (Lamiaceae/Labiatae) is known for its antifungal properties, it was chosen for the study. Objective: The isolation of endophytic fungi from M. citriodora and assessing their biocontrol potential. Material and methods: The isolated endophytes were characterized using ITS-5.8 S rDNA sequencing. Their biocontrol potential was assessed using different antagonistic assays against major plant pathogens. Results: Twenty-eight endophytes representing 11 genera were isolated, of which, around 82% endophytes showed biocontrol potential against plant pathogens. MC-2 L (Fusarium oxysporum), MC-14 F (F. oxysporum), MC-22 F (F. oxysporum) and MC-25 F (F. redolens) displayed significant antagonistic activity against all the tested pathogens. Interestingly, MC-10 L (Muscodor yucatanensis) completely inhibited the growth of Sclerotinia sp., Colletotrichum capsici, Aspergillus flavus and A. fumigatus in dual culture assay, whereas MC-8 L (A. oryzae) and MC-9 L (Penicillium commune) completely inhibited the growth of the Sclerotinia sp. in fumigation assay. Conclusions: Endophytes MC-2 L, MC-14 F, MC-22 F and MC-25 F could effectively be used to control broad range of phytopathogens, while MC-10 L, MC-8 L and MC-9 L could be used to control specific pathogens. Secondly, endophytes showing varying degrees of antagonism in different assays represented the chemo-diversity not only as promising biocontrol agents but also as a resource of defensive and bioactive metabolites.

Biological potency and characterization of antibacterial substances produced by Lactobacillus pentosus isolated from Hentak, a fermented fish product of North-East India.

Lactic acid bacteria (LAB) isolated from various foods are important due to their potential to inhibit microorganisms, including drug-resistant bacteria. The objectives of this investigation were to isolate and identify antibacterial substances producing LAB from Hentak, a traditional fermented fish product of Manipur (North-East India), and to optimize the production of antagonistic substances present in cell free neutralized supernatant (CFNS) against enteric bacterial pathogens using the ‘one factor at a time’ (OFAT) method. Out of 10 LAB, the most potent bacterium producing antibacterial substances was isolated and identified as Lactobacillus pentosus strain LAP1 based upon morphological, biochemical and molecular characterization. MRS (de Man, Ragosa and Sharpe) medium was determined to provide better bactericidal activity (AU/ml) than other tested media against the indicator enteric bacteria, including Staphylococcus epidermidis MTTC 3615, Micrococcus luteus MTCC 106, Shigella flexneri MTCC 1457, Yersinia enterocolitica MTCC 840 and Proteus vulgaris MTCC 1771. The culture conditions (pH: 5, temperature: 30 °C and inoculum volume: 1 %) and medium components (carbon source: lactose and nitrogen source: ammonium chloride) were observed to be the most influential parameters of significant antagonistic activity of CFNS against the enteric pathogens. MRS medium supplemented with Tween20 effectively stimulated the yield of antibacterial substances. The CFNS of strain LAP1 exhibited sensitivity to proteolytic enzyme (pepsin) treatment and heat treatment (60 °C for 60 min, 100 °C for 30 min and 121 °C for 15 min) and lost its inhibitory properties. The CFNS was active at an acidic (pH 3.0) to neutral pH (pH 7.0) but lost its antagonistic properties at an alkaline pH. The CFNS obtained from strain LAP1 scavenges the DPPH (1,1-diphenyl-2 picrylhydrazyl) significantly in a concentration-dependent manner within the range of 8.8 ± 0.12–57.35 ± 0.1 %. The OFAT-based approach revealed the baseline for statistical optimization, the scale-up process and efficient production of CFNS by L. pentosus strain LAP1, which could be used as a potential antibacterial and free radical scavenging agent.

Two imide substances from a soil-isolated Streptomyces atratus strain provide effective biocontrol activity against grapevine downy mildew

ABSTRACTGrapevine downy mildew (Plasmopara viticola) is a devastating disease of grapevine. In this study, 151 actinomycete isolates were obtained and tested for antagonistic activity against P. viticola. The assay suggested that 28 isolates displayed antagonistic effects to varying degrees. The greatest reduction in disease severity was observed with isolate PY-1, which reduced disease severity by 92.13% in the detached leaf assay, and by 83% in a field assay. It was identified as Streptomyces atratus using the 16S rDNA sequence analysis. To elucidate the antagonistic mechanism of PY-1 against P. viticola, scanning electron microscopy showed that major damage to the pathogens sporangia and sporangiophores was observed after treatment for PY-1. Furthermore, PY-1 showed antagonistic activity against other pathogens, including: Botrytis cinerea, Colletotrichum orbiculare, Fusarium oxysporum, Phytophthora capsici and Phytophthora infestans. Two imide compounds were purified from the fermentation liquid using silica gel chromatography and high-performance liquid chromatography and identified as 5-acetoxycycloheximide and cycloheximide using nuclear magnetic resonance. Both compounds showed significant antagonistic activity against P. viticola, determining a reduction in disease severity by 65% and 84%, respectively. In conclusion, 5-acetoxycycloheximide and cycloheximide were identified for the first time in a new S. atratus strain able to effectively control grapevine downy mildew.

Efficiency of Specific Biopreparations in Organic Waste Management

Background: Biological approach is becoming more popular in the protection of the environment by organic waste of agricultural holdings due to economic efficiency and absence of additional damage to the ecosystem. Microorganisms of biopreparations possess significant fermentative properties and high antagonistic activity against of many pathogenic and opportunistic bacteria and toxigenic filamentous fungi. In our study we have isolated millions of coliform bacteria and Enterococci, thousands of Salmonella, Proteus and Staphylococci in 1 g of initial substrate. After the usage of biopreparations the quantity of coliform bacteria and Enterococci was less than 10 cells/g, and no Salmonella, Staphylococcus or Proteus were found. Application of the biopreparations has prevented the loss of nutrients. Therefore, nitrogen content was higher by 50-60% than in the control. The quantity of nitrifying, ammonifying and cellulose-fermenting microorganisms increased by 15.9%, 6.6% and 15.4%, respectively. Productivity of grain and vegetable crops increased by 10-20%. An important advantage of the biopreparations usage, that also we found, is the elimination of specific odor within a couple days due to the ability of their microorganisms to assimilate nitrogen from urea and neutralize the substrate against the bacteria causing putrefaction, anaerobic processes and the emission of ammonia and hydrogen sulphide. Conclusion: The application of developed new biopreparations will allow producing high-quality environmentally friendly agricultural products.

Identification and partial characterization of potential probiotic lactic acid bacteria in freshwaterLabeo rohitaandCirrhinus mrigala

Carps are the most diversified freshwater fish belonging to family Cyprinidae. Numerous probiotic and pathogenic lactic acid bacteria (LAB) have been characterized from carps. However, the diversity of these ecologically important bacteria is entirely unknown in freshwater fish of Pakistan. The present study aimed to characterize and identify the lactic acid bacteria from two carps viz. Laboe rohita and Cirrhinus mrigala and determine their antagonistic activity. Seventeen bacterial isolates were purified from the gastrointestinal tract and gills of these fish and characterized morphologically. Initially, seven isolates were screened as LAB using agar supplemented with CaCO3. Subsequently, only two isolates CILB2 and RIL10 were selected as LAB after high-performance liquid chromatography analysis for lactic acid production. Isolates CILB2 and RIL10 were genetically identified as Enterococcus faecalis and Weissella sp., respectively after 16S rRNA gene sequence analysis. Both strains exhibited significant antagonistic activity against common fish pathogens Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli. Enterococcus faecalis CILB2 and Weissella sp. RIL10 were also found negative for haemolysis and gelatinase activities and were sensitive to ampicillin, amoxicillin, doxycycline, erythromycin, chloramphenicol and co-trimoxazole antibiotics. The identified LAB strains may further be investigated for their potential probiotic application in fish feed and food preservation techniques.

A Comparative Study on the Biopolymer Functionalized Iron Oxide Nanocomposite for Antimicrobial Activity

Compared with bulk materials, nanoparticles have many outstanding properties, like optical, electronic, catalytic, and magnetic properties. Here the magnetite (Fe3O4) nanoparticles and biopolymer functionalized magnetite nanoparticles were synthesized by simple co-precipitation by using an aqueous solution containing ferrous (Fe2+) and ferric (Fe3+) ion salts in an alkaline media with poly (ethylene glycol) (PEG 400) as the surfactant. Both bare and Chitosan-coated iron oxide nanoparticles (IONPs) were subsequently characterized and evaluated for their antibacterial activity against Escherichia coli KL226. The XRD result indicates the formation of Fe3O4 nanoparticles and Chitosan (CS) coated Fe3O4 nanoparticles. Fourier transform infrared spectroscopy (FT-IR) studies confirm the bonding of the Chitosan polymer with Fe3O4 nanoparticles. The magnetic properties of the samples were measured by vibration sample magnetometer that confirmed ferromagnetic behaviour of magnetite nanoparticles at room temperature. The antibacterial test showed inhibition against E. coli with significant antagonistic activity.

Synthesis, characterisation and antimicrobial activity of nano sized hematite (α-Fe&lt;SUB align="right"&gt;2O&lt;SUB align="right"&gt;3) using bio and organic templates

Hematite nanoparticles were synthesised by chemical co-precipitation method using biomaterials, DNA and STARCH as templates. Structural characterisation was carried out using XRD. The samples were also characterised by TEM. Colour changes are observed in the samples with variation of templates. The hematite nanoparticles were tested for antibacterial activity against some bacterial species. Antimicrobial test showed the inhibition against Escherichia coli, Salmonella typhimurium, Shigella flexneri and Candida albicans with significant antagonistic activity. The results were also compared with hematite nanoparticles prepared using organic templates (EDTA and CTAB) and found some significant changes in many aspects.

Antibiotic Potential of Endophytic Actinomycetes of Medicinal Herbs Against Human Pathogenic Bacteria

Endophytic actinomycetes were isolated from six medicinal herbs viz., Abrus precatorius L., Aloe vera (L.) Burm. f., Asparagus racemoses Willd., Adhatoda vasica Nees, Catharanthus roseus (L.) G. Don. and Plumbago zeylanica L. which are known for their ethno botanical properties. A total of 34 endophytic actinomycetes were isolated through surface sterilization procedures. In the present study, procedure I for sterilization was effective for isolation of endophytic actinomycetes. All the medicinal herbs were positive for the endophytic actinomycetes. Maximum number of isolates of endophytic actinomycetes were obtained from Aloe vera (L.) Burm. f. The isolates obtained from roots (55.88 %) dominated over leaf (32.35 %) and stem (11.76 %). All these isolates were assessed for their antibacterial activity against human pathogenic bacteria. Thirteen actinobacterial isolates exhibited antagonistic activity through cross streak assay. The isolates, Streptomyces chromofuscus (Ck-S3) from stem and Streptomyces anulatus (Ck-L2) from leaf portion of Plumbago zeylanica L., showed significant antagonistic activity against all the tested human pathogenic bacteria. Out of 13 isolates, six (46.15 %) isolates obtained from root portion of Aloe vera (L.) Burm. f. and Abrus precatorius L. exhibited antibacterial activity against at least one of the tested pathogenic bacteria in agar well diffusion method.

In vitro antifungal activities of Actinomyces species isolated from soil samples against Trichophyton mentagrophytes.

Background and Purpose:Cutaneous infections arise from a homogeneous group of keratinophilic fungi, known as dermatophytes. Since these pathogenic dermatophytes are eukaryotes in nature, use of chemical antifungal agents for treatment may affect the host tissue cells. In this study, we aimed to evaluate the antifungal activity of Actinomyces species against Trichophyton mentagrophytes (abbreviated as T. mentagrophytes). The isolates were obtained from soil samples and identified by polymerase chain reaction (PCR) technique.Material and Methods:In total, 100 strains of Actinomyces species were isolated from soil samples in order to determine their antagonistic activities against T. mentagrophytes in Kerman, Iran. The electron microscopic study of these isolates was performed, based on the physiological properties of these antagonists (e.g., lipase, amylase, protease and chitinase), using relevant protocols. The isolates were identified using gene 16S rDNA via PCR technique. Results: Streptomyces flavogriseus, Streptomyces zaomyceticus strain xsd08149 and Streptomyces rochei were isolated and exhibited the most significant antagonistic activities against T. mentagrophytes. Images were obtained by an electron microscope and some spores, mycelia and morphology of spore chains were identified. Molecular, morphological and biochemical characteristics of these isolates were studied, using the internal 16S rDNA gene. Active isolates of Streptomyces sequence were compared to GenBank sequences. According to nucleotide analysis, isolate D5 had maximum similarity to Streptomyces flavogriseus (99%).Conclusion:The findings of this study showed that Streptomyces isolates from soil samples could exert antifungal effects on T. mentagrophytes.

Determination of the structure of the O-antigen and the lipid A from the entomopathogenic bacterium Pseudomonas entomophila lipopolysaccharide along with its immunological properties

The structure and the immunology of the lipopolysaccharide (LPS) of Pseudomonas entomophila, an entomopathogenic bacterium isolated from the fruit fly Drosophila melanogaster, was characterized. The O-antigen portion was established and resulted to be built up of a repetitive unit constituted by four monosaccharide residues, all L configured, all deoxy at C-6 and with an acetamido function at C-2:→3)-α-l-FucNAc-(1→4)-α-l-FucNAc-(1→3)-α-l-FucNAc-(1→3)-β-l-QuiNAc-(1→The structural analysis of lipid A, showed a mixture of different species. The diphosphorylated glucosamine backbone carries six fatty acids consistent with the composition C10:0 3(OH), C12:0 2(OH) and C12:0 3(OH), whereas other species differs by the number of phosphates and/or of fatty acids. The immunology experiments demonstrated that the LPS structure of P. entomophila displayed a low ability to engage the TLR4-mediated signaling correlated to a significant antagonistic activity toward hexa-acylated LPS structures.

Discovery of phenoxybutanoic acid derivatives as potent endothelin antagonists with antihypertensive activity

A series of phenoxybutanoic acid derivatives were synthesized and tested for their antagonistic activity on the contraction of the rat thoracic aortic ring induced by endothelin-1. Preliminary screening results showed that 6e and 6g with benzoheterocycles demonstrated significant antagonistic activities when compared to the reference compound BQ123. The results from additional assays for the binding affinity and selectivity for endothelin receptors showed that 6e was a selective ETA antagonist with a nanomolar IC50. Moreover, 6e was effective in relieving hypoxia-induced pulmonary arterial hypertension and right ventricular weight ratio. Therefore, 6e may have potential for further development as a therapeutic agent for the treatment of cardiovascular diseases.