L-Tenuazonic Acid, a New Inhibitor of Paenibacillus Larvae (original) (raw)
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The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with an LT50 of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of G. mellonella larvae and caused mortality of Acheta domesticus adults (LT50 7 days) at a concentration of 250 µg/g o...
Spanish Journal of Agricultural Research
Aim of study: To evaluate the potential bactericidal activity of natural molecules against Paenibacillus larvae. Moreover, we investigated if molecules that exhibit antimicrobial activity were able to inhibit the proteolytic activity of the bacterium.Area of study: Isolates S1 and S2 were from Balcarce, Buenos Aires province, strain S3 from Rio Cuarto, Cordoba province, strain S4 from Concordia, Entre Rios province, strain S5 and S8 from Necochea, Buenos Aires, strain S6 and S7 from Mar del Plata, Buenos Aires, strain S9 from Modena, Italy and strain S10 from Emilia Reggio, Italy.Material and methods: Bacterial isolates identification was carried out by amplification of a specific 16S rRNA gene fragment of P. larvae) using primers PL5 and PL4. Screening of the antimicrobial activity of thirteen molecules against four P. larvae isolates was conducted by the agar diffusion technique. The antimicrobial activity of selected molecules was evaluated by broth microdilution method.Main resu...
Activity of selected plant extracts against honey bee pathogen Paenibacillus larvae
Apidologie, 2018
The present study focuses on the antibacterial activity of selected plant extracts against Paenibacillus larvae , the causal agent of American foulbrood disease of honey bees. A gas chromatography-mass spectrometry method was used to analyze six diethyl ether extracts of two white birch species, black poplar and common aspen buds, as well as n-hexane, diethyl ether, and methanol extracts of young twigs from downy and silver birches. Among the identified extract constituents were flavonoids, phenylpropenoids, triterpenoids, and glucosides. In spite of significant differences in qualitative and quantitative composition, all tested in vitro extracts demonstrated high anti-P. larvae activity at minimal inhibitory concentration levels between < 1.0 and 125 μg/mL. To examine the cause of such disparity, the anti-P. larvae activity of some individual constituents naturally present in plant extract compounds was determined. A higher susceptibility of P. larvae (ERIC I) to relatively poorly polar triterpenoid levels compared to polar compounds, flavonoids, and glucosides was demonstrated.
Paenibacillus larvae, a Gram-positive and spore-forming bacterium is responsible for American foulbrood disease in bees. The antimicrobial activity of different plant extracts and phenolic phytochemical was evaluated on Paenibacillus larvae bacteria. In addition possible correlation with antioxidant activity of the same plant extracts was studied. Extracts of the following plants were utilized: Achillea millefolium (yarrow), Ocimum basilicum (basil), Thymus vulgaris (thyme) and Urtica dioica (nettle). The extracts that showed antimicrobial activity were later tested to determine the Minimal Inhibitory Concentration (MIC). Although nettle present the lowest polyphenolic content compared with the other plant extracts, exhibit the highest antimicrobial activity, measured as the inhibition zone using Mueller-Hinton agar plates. Basil presented both polyphenolic content and antimicrobial activity at higher levels, while thyme had the lowest antimicrobial activity, even it present high am...
New anti-Paenibacillus larvae substances purified from propolis
Apidologie, 2012
Propolis plays an important role in the exogenous defense of honeybee colony against pathogens. However, the studies dealing with the activity of propolis against bee pathogens are scarce. Poplar propolis extracts demonstrated promising activity against Paenibacillus larvae, the causative agent of American foulbrood. From the same propolis, five individual components and a mixture of caffeates were isolated, and their structures confirmed by spectroscopic data. Among the isolated propolis constituents are flavonoids, ferulic acid esters, and the oxylipin 9-oxo-10(E)-12(Z)-octadecadienoic acid, newly identified as propolis component. These substances were tested for their activity against P. larvae strains. The most active constituents were pinocembrin, 3-O-acetyl pinobanksin, and the caffeate mixture. This is the first communication of antimicrobial activity of individual propolis constituents against P. larvae; their important advantage is the fact that they are naturally present in the hive.
Journal of chemical ecology, 2018
Social insects are frequently observed in symbiotic association with bacteria that produce antimicrobial natural products as a defense mechanism. There is a lack of studies on the microbiota associated with stingless bees and their antimicrobial compounds. To the best of our knowledge, this study is the first to report the isolation of Paenibacillus polymyxa ALLI-03-01 from the larval food of the stingless bee Melipona scutellaris. The bacterial strain was cultured under different conditions and produced (L)-(-)-3-phenyllactic acid and fusaricidins, which were active against entomopathogenic fungi and Paenibacillus larvae. Our results indicate that such natural products could be related to colony protection, suggesting a defense symbiosis between P. polymyxa ALLI-03-01 and Melipona scutellaris.
Anais da Academia Brasileira de Ciências, 2015
American foulbrood (AFB) is a serious worldwide spreading disease in bees caused by Paenibacillus larvae. Plants extracts are known to decrease or inhibit the growth of these bacteria. The purpose of this study was to evaluate the antimicrobial activity of Calendula. officinalis, Cariniana domestica, and Nasturtium officinale extracts against the P. larvae and to evaluate the toxicity of the extracts in bees. In vitro activity against P. larvae of the extracts was evaluated by micro dilution method and the minimal inhibitory concentrations (MICs) were also determined. The concentrations used in the toxicity test were established based on the MIC values and by the spraying application method. The P. larvae was susceptible to the evaluated crude extract of C. officinalis and N. officinale. To C. domestica, only the ethyl acetate (EtAc) fraction and n-butanol (BuOH) fractions had activity against P. larvae. Toxicity analysis in bees showed no toxicity for N. officinale crude extract an...
Antibiotics, 2021
Honey bees (Apis mellifera) perform pollination service for many agricultural crops and contribute to the global economy in agriculture and bee products. However, honey bee health is an ongoing concern, as illustrated by persistent local population decline, caused by some severe bee diseases (e.g., nosemosis, AFB, EFB, chalkbrood). Three natural recipes are in development based on the bioactive compounds of different plants extract (Agastache foeniculum, Artemisia absinthium, Evernia prunastri, Humulus lupulus, Laurus nobilis, Origanum vulgare and Vaccinium myrtillus), characterised by HPLC-PDA. The antimicrobial activity of these recipes was tested in vitro against Paenibacillus larvae, Paenibacillus alvei, Brevibacillus laterosporus, Enterococcus faecalis, Ascosphaera apis and in vivo against Nosema ceranae. A mix of 20% blueberry, 40% absinthium, 10% oakmoss, 10% oregano, 10% Brewers Gold hops, 5% bay laurel and 5% anise hyssop extract showed the strongest antibacterial and antif...
Microorganisms
Honey bees coexist with fungi that colonize hive surfaces and pollen. Some of these fungi are opportunistic pathogens, but many are beneficial species that produce antimicrobial compounds for pollen conservation and the regulation of pathogen populations. In this study, we tested the in vitro antimicrobial activity of Talaromyces purpureogenus strains isolated from bee bread against Paenibacillus alvei (associated with European foulbrood disease) and three Aspergillus species that cause stonebrood disease. We found that methanol extracts of T. purpureogenus strains B18 and B195 inhibited the growth of P. alvei at a concentration of 0.39 mg/mL. Bioactivity-guided dereplication revealed that the activity of the crude extracts correlated with the presence of diketopiperazines, a siderophore, and three unknown compounds. We propose that non-pathogenic fungi such as Talaromyces spp. and their metabolites in bee bread could be an important requirement to prevent disease. Agricultural prac...