Pseudomonas cyclic lipopeptides suppress the rice blast fungus Magnaporthe oryzae by induced resistance and direct antagonism

Beneficial Pseudomonas spp. produce an array of antimicrobial secondary metabolites such as cyclic lipopeptides (CLPs). We investigated the capacity of CLP-producing Pseudomonas strains and their crude CLP extracts to control rice blast caused by Magnaporthe oryzae, both in a direct manner and via induced systemic resistance (ISR). In planta biocontrol assays showed that lokisin-, white line inducing principle (WLIP)-, entolysin- and N3-producing strains successfully induced resistance to M. oryzae VT5M1. Furthermore, crude extracts of lokisin, WLIP and entolysin gave similar ISR results when tested in planta. In contrast, a xantholysin-producing strain and crude extracts of N3, xantholysin and orfamide did not induce resistance against the rice blast disease. The role of WLIP in triggering ISR was further confirmed by using WLIP-deficient mutants. The severity of rice blast disease was significantly reduced when M. oryzae spores were pre-treated with crude extracts of N3, lokisin, WLIP, entolysin or orfamide prior to inoculation. In vitro microscopic assays further revealed the capacity of crude N3, lokisin, WLIP, entolysin, xantholysin and orfamide to significantly inhibit appressoria formation by M. oryzae. In addition, the lokisin and WLIP biosynthetic gene clusters in the producing strains are described. In short, our study demonstrates the biological activity of structurally diverse CLPs in the control of the rice blast disease caused by M. oryzae. Furthermore, we provide insight into the non-ribosomal peptide synthetase genes encoding the WLIP and lokisin biosynthetic machineries

Toxic effect of Raphia vinifera on fish leech (Piscicola geometra)

This study examines acute toxicity of Raphia vinifera on fish leech, Piscicola geometra. The leeches with a mean total length of (TL) 4.2+1.0cm were exposed to various concentrations of both crude powdered and ethanolic extracts of the botanical. Median lethal concentration (LC50) was determined with static-renewal tests using logarithmic and arithmetic graphic methods. The LC50 (for 96 hours of crude powdered (aqueous) extracts of the botanical on Piscicola geometra was 1.10 ppm arithmetically and 1.14ppm logarithmically. The 95% confidence limits was 0.10ppm arithmetically and 0.12ppm logarithmically. The LC50 of ethanolic extract of the poison at 96-h was 0.5ppm arithmetically and 0.48ppm logarithmically. The 95% confidence limits were less than 0.10ppm. The use of extracts of R. vinifera in the control of leeches in fish ponds is discusse

Specific nucleoside triphosphatases in crude extracts of escherichia coli

General properties and distribution of nucleoside triphosphatases in crude extracts of Escherichia col

Ekstraksi Dan Pengamatan Aktivitas Antioksidan Dan Antimikroba Dari Kulit Buah Pometia Pinnata

This study investigated the extraction of matoa (Pometia pinnata) fruit peels, a fruit in the family of Sapindaceae. The extraction was performed through maceration method using three kinds of solvent: acetone, ethanol and water. The extracts were tested for their antioxidant and antimicrobial activities. DPPH radical scavenging assay was used in evaluating the antioxidant activities. The antimicrobial activity was evaluated using disc-diffusion and broth dilution method. The highest antioxidant activity was showed by acetone crude extract with IC50 value at 15.323 ppm, followed by ethanol and water crude extract at 143.23 ppm and 451.306 ppm, respectively. The antioxidant activities of the crude extracts were compared to L-ascorbic acid and it was found that acetone crude extract exhibited half the strength of the antioxidant activity of L-ascorbic acid. Antimicrobial activity of matoa fruit peel extracts were tested against Escherichia coli, Bacillus cereus and Staphylococcus aureus. The results showed that all crude extracts showed antimicrobial activity with bacteriostatic characteristic. Therefore, Non-Inhibitory Concentration (NIC) was determined for all crude extracts. Acetone and ethanol crude extract possessed the strongest antimicrobial activity at NIC <0.5 ppm against all tested microorganisms, while water crude extract showed the weakest antimicrobial activity with NIC at 5 ppm. The total phenolic content of the crude extracts were measured using Folin-Ciocalteau method. Positive correlation between the antioxidant activities and the total phenolic content of the crude extracts was detected. Saponin and tannin test, as well as spectrometric analyses supported the presence of saponin, tannin and alkaloid in matoa fruit peel

Inhibition of Protease Activity in Muscle Extracts and Surimi from Pacific Whiting, Merluccius productus, and Arrowtooth Flounder, Atheresthes stomias

Muscle extracts of Pacific whiting, Merluccius productus, and arrowtooth flounder, Atheresthes stomias, were assayed for proteolytic activity using azocasein as a substrate. Pacific whiting extracts showed maximum activity at pH 5.0-5.2 and a temperature of 50°C, while arrowtooth flounder extracts had maximum activity at pH 5.5 and 55°C. Three sources of inhibitors (potatoes, egg white, beef plasma protein) were evaluated in vitro for inhibition of protease activity. All three were found to be effective inhibitors in crude muscle extracts. Further studies utilizing these inhibitors in surimi showed that potato was equivalent to both egg white and beef plasma protein in preserving the gel forming characteristics ofheated kamaboko in both species

Inhibition of \u3cem\u3eRhizobium etli\u3c/em\u3e Polysaccharide Mutants by \u3cem\u3ePhaseolus vulgaris\u3c/em\u3e Root Compounds

Crude bean root extracts of Phaseolus vulgaris were tested for inhibition of the growth of several polysaccharide mutants of Rhizobium etli biovar phaseoli CE3. Mutants deficient only in exopolysaccharide and some mutants deficient only in the O-antigen of the lipopolysaccharide were no more sensitive than the wild-type strain to the extracts, whereas mutants defective in both lipopolysaccharide and exopolysaccharide were much more sensitive. The inhibitory activity was found at much higher levels in roots and nodules than in stems or leaves. Inoculation with either wild-type or polysaccharide-deficient R. etli did not appear to affect the level of activity. Sequential extractions of the crude root material with petroleum ether, ethyl acetate, methanol, and water partitioned inhibitory activity into each solvent except methanol. The major inhibitors in the petroleum ether and ethyl acetate extracts were purified by C18 high-performance liquid chromatography. These compounds all migrated very similarly in both liquid and thin-layer chromatography but were distinguished by their mass spectra. Absorbance spectra and fluorescence properties suggested that they were coumestans, one of which had the mass spectrum and nuclear magnetic resonances of coumestrol. These results are discussed with regard to the hypothesis that one role of rhizobial polysaccharides is to protect against plant toxins encountered during nodule development

The effects of herbal plant extracts on the growth and sporulation of Colletotrhichum gloesporioides

Objectives: The antifungal activities of the leaf extracts of fifteen selected medicinal plants; Alpinia galanga L., Alstonia spatulata Blume., Annona muricata L., Blechnum orientale L., Blumea balsamifera L., Centella asiatica L., Dicranopteris linearis, Dillenia suffruticosa, Litsea garciae Vidal., Melastoma malabathricum L.,Momordica charantia L., Nephrolepis biserrata (Sw.)., Pangium edule Reinw., Piper betle L., and Polygonum minus Huds., were evaluated on the plant pathogenic fungus; C.loeosporioides isolated from mango. Methodology and results: Different antifungal assays were employed, i.e. Agar-Disc Dilution assay as primary screening assay, followed by determination of Minimum Inhibition Concentration (MIC), and the rate of sporulation assay. The antifungal assay was carried out in Potato Dextrose Media in five different treatments, i.e.; distilled water as negative control, crude extract of leaves in methanol, chloroform, acetone and Benomyl as positive control. A. galanga extracts were most effective and exhibited highest antifungal activities against C. gloeosporioides. Methanol crude extract reduced radial growth of C. gloeosporioides by 66.39%, followed by chloroform crude extract 63.26%, and 61.56% for acetone crude extracts. The exact concentrations that have definite potential to fully restrict the growth of C. gloeosporioides (MICs) for A.galanga is 15.00 mg/mL in methanol, 17.50 mg/mL in chloroform, and 17.50 mg/mL in acetone. The sporulation assay also revealed that A. galanga leaves crude extracts showed highest inhibition of spore germination of C. gloeosporioides overall at concentration of 10 mg/mL; with 68.89% inhibition by methanol extracts, 64.13% by chloroform extracts, and 62.86% by acetone extracts. Conclusion and application of findings: Numerous natural products of plant origin are pesticidal and have the potential to control fungal diseases of crops. Thus, considerable effort should be devoted to screening plants in order to develop new natural fungicides as alternative to existing. In this study, the leaf crude extracts of A. galanga exhibited effectiveness against C. gloeosporioides and should be considered for further evaluation

Mosquito Larvicidal Constituents from Lantana Viburnoides SP Viburnoides Var Kisi (A. rich) Verdc (Verbenaceae).

\ud \ud Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae. Twenty late III or early IV instar larvae of An. gambiae s.s. were exposed to various concentrations of the plant extracts, fractions, blends and pure compounds, and were assayed in the laboratory by using the protocol of WHO 1996. Mean mortalities were compared using Dunnett's test (p < 0.05) and lethal concentration calculated by Lackfit Inversel of the SAS programme. The crude extract (LC50 = 7.70 ppm in 72 h) and fractions exhibited different level of mosquito larvicidal activity with subtraction of some fractions resulting in activity enhancement. The active fractions contained furanonaphthaquinones regio-isomers (LC50 = 5.48-5.70 ppm in 72 h) and the lantadene triterpenoid camaric acid (LC50 = 6.19 ppm in 72 h) as active principles while the lupane triterpenoid betulinic acid (LC50 < 10 ppm in 72 h) was obtained from the least active fraction. Crude extracts and some fractions had higher or comparable larvicidal activity to the pure compounds. These results demonstrate that L. viburnoides sp viburnoides var kisi extracts may serve as larvicides for managing various mosquito habitats even in their semi-purified form. The isolated compounds can be used as distinct markers in the active extracts or plant materials belonging to the genus Lantana

Effect of spruce-derived phenolics extracted using microwave enhanced pyrolysis on the oxidative stability of biodiesel

An investigation has been carried out to characterize and evaluate phenolic compounds of bio-oils produced by the microwave enhanced pyrolysis of spruce woodchips (picea abies) for their potential application in stabilizing biodiesel from autoxidation. Four extracts were isolated from the bio-oil through multi-fractionation steps using a liquid-liquid extraction method: water-soluble, neutral, phenolic and organic acids extracts. The crude bio-oil and the isolated extracts were characterized by GC-MS, GC-FID, total phenols by Folin-Ciocalteu assay, ATR-IR and 13C NMR. The antioxidative effect of the crude bio-oil, its isolated extracts and two significant phenolic components (eugenol and catechol) of the crude bio-oil were also investigated using methyl linoleate as a biodiesel model by means of a high temperature (120°C) oxidation test. The results show that methyl linoleate induction time increased after blending small amounts (1.4-5.6% w/w) of either the crude bio-oil or the isolated extracts. However, the crude bio-oil showed higher induction times in comparison with its isolated extracts, which was significant because the crude bio-oil contained a lower concentration of phenolic species (23% w/w), especially in comparison to the phenolic concentration in the phenolic extract (49.6% w/w). Furthermore, catechol was found to be very effective and was similar to crude bio-oil in the inhibition of methyl linoleate autoxidation, unlike eugenol, which was less effective at equivalent molar concentrations. Also, the effect of catechol and the crude bio-oil on methyl linoleate induction time was approximately comparable with a commercial antioxidant (butylated hydroxytoluene) when treated at equivalent molar concentration of phenols

Ferric reducing antioxidant power of crude extracts from artocarpus species

This study was designed to determine antioxidant capacity based on ferric ions reducing abilities of 49 crude extracts from eight Artocarpus species. Artocarpus species are well known as the source of antioxidant metabolites such as flavonoids, xanthones and stilbenes. The leaves and heartwoods of Artocarpus anisophyllus, A. fulvicortex, A. gomeizianus, A. hispidus, A. integer, A. kemando, A. lowii and A. rigidus collected from several locations in Malaysia were extracted successively at room temperature using different polarity of solvents. The ability of Artocarpus crude extracts to reduce ferric ions was determined using ferric reducing antioxidant potential (FRAP) assay and expressed as mM FRAP equivalent to FeSO4.7H2O. The trend for ferric ions reducing power of these crude extracts varied according to the polarity of the solvents used. Methanol crude extract of the leaves of A. hispidus (AHLM) relatively showed strong ferric ion reducing power ranging from 0.69-7.32 mM FRAP equivalent followed by the methanol crude extracts of the barks of A. rigidus (ARBM; 0.36-4.13 mM FRAP equivalent) and followed by methanol crude extract of the heartwoods of A. fulvicortex (AFHM; 0.32-3.66 mM FRAP equivalent). These results were comparable with the positive standards tested ie. trolox (0.20-2.43 mM FRAP equivalent), BHT (0.09-1.89 mM FRAP equivalent) and BHA (0.02-8.81 mM FRAP equivalent)