Recombinant Strain of Bacillus thuringiensis Producing Cyt1A, Cry11B, and the Bacillus sphaericus Binary Toxin

A novel recombinant Bacillus thuringiensis subsp. israelensis strain that produces the B. sphaericus binary toxin, Cyt1Aa, and Cry11Ba is described. The toxicity of this strain (50% lethal concentration [LC₅₀] = 1.7 ng/ml) against fourth-instar Culex quinquefasciatus was higher than that of B. thuringiensis subsp. israelensis IPS-82 (LC₅₀ = 7.9 ng/ml) or B. sphaericus 2362 (LC₅₀ = 12.6 ng/ml).     

Production of Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus strain 1593 on media using a byproduct from a monosodium glutamate factory

Two newly developed media, H4 and H7, were found to be highly suitable for culturing Bacillus thuringiensis subsp. israelensis and B. sphaericus, respectively. These media contained 0.05% K₂HPO₄ and 4% HDL (H4 medium) or 0.05% K₂HPO₄ and 7% HDL (H7 medium); HDL is the by-product from a monosodium glutamate factory. Tests to compare endospore formation and toxicity values of B. thuringiensis subsp. israelensis in H4 medium and nutrient broth supplemented with salts and glucose (NBSG) medium were carried out in a 3-liter fermentor. The viable cell count and LC₅₀ value of B. thuringiensis subsp. israelensis in H4 medium at 48 hr were 2.5 × 10⁸ cells/ml and 10^?7.2 (dilution), respectively, while those in NBSG medium were 1.6 × 10⁸ cells/ml and 10^?6.5, respectively. In the case of B. sphaericus grown in H7 medium, the number of cells and LC₅₀ value were found to be 1.4 × 10⁹ cells/ml and 10^?7.8, respectively. B. sphaericus grown in nutrient broth supplemented with salt and yeast extract (NBSY) were found to produce 6.4 × 10⁸ cells/ml and an LC₅₀ value of 10^?6.8. The toxicity of B. thuringiensis subsp. israelensis was tested against Aedes aegypti larvae, while that of B. sphaericus was tested against Culex quinquefasciatus. The cost of 10 liters of medium for production of B. thuringiensis subsp. israelensis and in B. sphaericus and H4 and H7 was $0.02 and $0.03, respectively. The cost of these newly developed media was much less than that of NBSG medium ($7.05 per 10 liters) for cultivation of B. thuringiensis subsp. israelensis and NBSY medium ($11.67 per 10 liters) for cultivation of B. sphaericus.     

Mtx Toxins Synergize Bacillus sphaericus and Cry11Aa against Susceptible and Insecticide-Resistant Culex quinquefasciatus Larvae

Two mosquitocidal toxins (Mtx) of Bacillus sphaericus, which are produced during vegetative growth, were investigated for their potential to increase toxicity and reduce the expression of insecticide resistance through their interactions with other mosquitocidal proteins. Mtx-1 and Mtx-2 were fused with glutathione S-transferase and produced in Escherichia coli, after which lyophilized powders of these fusions were assayed against Culex quinquefasciatus larvae. Both Mtx proteins showed a high level of activity against susceptible C. quinquefasciatus mosquitoes, with 50% lethal concentrations (LC₅₀) of Mtx-1 and Mtx-2 of 0.246 and 4.13 μg/ml, respectively. The LC₅₀s were 0.406 to 0.430 μg/ml when Mtx-1 or Mtx-2 was mixed with B. sphaericus, and synergy improved activity and reduced resistance levels. When the proteins were combined with a recombinant Bacillus thuringiensis strain that produces Cry11Aa, the mixtures were highly active against Cry11A-resistant larvae and resistance was also reduced. The mixture of two Mtx toxins and B. sphaericus was 10 times more active against susceptible mosquitoes than B. sphaericus alone, demonstrating the influence of relatively low concentrations of these toxins. These results show that, similar to Cyt toxins from B. thuringiensis subsp. israelensis, Mtx toxins can increase the toxicity of other mosquitocidal proteins and may be useful for both increasing the activity of commercial bacterial larvicides and managing potential resistance to these substances among mosquito populations.     

Studies on the culicine mosquito host range of Bacillus sphaericus and Bacillus thuringiensis var. israelensis with notes on the effects of temperature and instar on bacterial efficacy

Toxicity tests of three strains of Bacillus sphaericus against late instars of 12 culicine mosquito species indicated a wide range of susceptibility. Culex pipiens and C. salinarius were highly susceptible (LC₅₀s < 10⁴ spores/ml) to strain 1593, and C. pipiens and C. restuans were highly susceptible to strain 2013-4. The potency of strain SSII-1 was approximately one-tenth that of strains 1593 and 2013-4 against C. pipiens. Susceptibility of Aedes species to strain 1593 was highly variable. At temperatures ≥ 20°C, A. fitchii, A. intrudens, A. stimulans, and A. vexans were moderately to highly susceptible (LC₅₀s 6 × 10³−4 × 10⁴ spores/ml), A. triseriatus was only slightly susceptible (LC₅₀ > 10⁶ spores/ml), and A. aegypti was refractory. Susceptibility of Aedes mosquitoes to strain SSII-1 was less variable, with LC₅₀s against A. aegypti, A. canadensis, A. stimulans, and A. triseriatus all being between 10⁴ and 10⁶ vegetative cells + spores/ml. All species of mosquitoes tested were, in general, highly susceptible to B. thuringiensis var. israelensis (LC₅₀s 2.3 × 10³−2.5 × 10⁴ spores/ml). In B. sphaericus toxicity tests, decreased temperatures resulted in up to a 16-fold increase in LC₅₀ and a substantial reduction in probit line slope. First-instar A. aegypti larvae were more susceptible to B. sphaericus strain SSII-1 than the three later instars, which were approximately equally susceptible; however, no significant difference was observed in the susceptibility of the four instars of A. triseriatus.     

Efficacy of dry powders from Bacillus sphaericus: RB 80, a potent reference preparation for biological titration

Larvicidal potency of three primary powders based on Bacillus sphaericus strains 1593 and 1881 was studied on mosquito larvae. Two acetone powders, P 1593 and P 1881, were very toxic for Anopheles stephensi larvae. The potency of a third lyophilized powder RB 80 made from 1593 strain compared even better when tested against Anopheles stephensi and Culex pipiens pipiens larvae. LC₅₀'s after 48 hr were 0.15 and 0.003 mg/ml, respectively. After storage of RB 80 aqueous suspensions over 2 years or after heat exposure of RB 80 powder, larvicidal potency was still high, indicating an excellent stability. The use of RB 80, because of all its qualities, is suggested as a first experimental standard for titration of B. sphaericus preparations.     

Laboratory and simulated-field bioassays for assessing mixed cultures of <Emphasis Type="Italic">Lysinibacillus sphaericus</Emphasis> against <Emphasis Type="Italic">Aedes aegypti</Emphasis> (Diptera: Culicidae) larvae resistant to temephos

Aedes aegypti (L.) is the main vector of tropical diseases such as dengue, chikungunya and Zika. Due to the overuse of insecticides, Ae. aegypti resistant populations have increased. Biological control with Lysinibacillus sphaericus (Ahmed) has been used against Culex sp. and Anopheles sp. Although Ae. aegypti is refractory to the binary toxin of L. sphaericus spores, vegetative cells have been shown to be effective against Ae. aegypti larvae. In this work, the effect of L. sphaericus vegetative cells on Ae. aegypti temephos-resistant larvae was assessed under lab and simulated field conditions. L. sphaericus caused about 90% mortality of insecticide-resistant Ae. aegypti larvae under simulated field conditions. Likewise, Ae. aegypti larvae were more sensitive to mixed cultures of L. sphaericus than to individual strains; then, the most effective mixed culture exhibited an LC₅₀ of 1.21 × 10⁵ CFU/mL with Rockefeller larvae and 8.04 × 10⁴ CFU/mL with field-collected larvae. Additionally, we found that mixed cultures composed of two L. sphaericus strains were more effective than a culture formed by the three strains. Our results suggest that mixed cultures comprising L. sphaericus vegetative cells could be useful for controlling temephos-resistant populations of Ae. aegypti, as evidenced by the effectiveness demonstrated under laboratory and simulated field conditions.     

Efficient mosquitocidal toxin production by Bacillus sphaericus using cheese whey permeate under both submerged and solid state fermentations

Whey permeate (WP) was used efficiently for production of mosquitocidal toxin by Bacillus sphaericus 2362 (B. sphaericus 2362) and the Egyptian isolate, B. sphaericus 14N1 (B. sphaericus 14N1) under both submerged and solid state fermentation conditions. Under submerged fermentation, high mosquitocidal activity was produced by B. sphaericus 2362 and B. sphaericus 14N1 at 50-100% and 25-70% WP, respectively. Initial pH of WP was a critical factor for toxin production by both tested organisms. The highest toxicity was obtained at initial pH 7. Egyptian isolate, B. sphaericus 14N1 was tested for growth and toxin production under solid state fermentation conditions (SSF) by using WP as moistening agent instead of distilled water. The optimum conditions for production of B. sphaericus 14N1 on wheat bran-WP medium were 10 g wheat bran/250 ml flask moistened with 10-70% WP at 50% moisture content, inoculum size ranged between 17.2 × 10⁷ and 34.4 × 10⁷ and 6 days incubation under static conditions at 30 °C. Preliminary pilot-scale production of B. sphaericus 14N1 under SSF conditions in trays proved that wheat bran-WP medium was efficient and economic for industrial production of mosquitocidal toxin by B. sphaericus.     

Biological activity in extracts of ascidians (Tunicata, Ascidiacea) from the northeastern Brazilian coast

Ascidians are marine animals with a great ability to synthesize bioactive substances. This study examined the cytotoxic potential of 10 ascidians found in the coastal waters of Northeast Brazil. Samples of the species Eudistoma vannamei Millar, 1977, Eudistoma sp., Didemnum ligulum Monniot F., 1983, Didemnum psammatodes (Sluiter, 1895), Didemnum sp., Polysyncraton sp., Trididemnum sp., Cystodytes dellechiajei (Della Valle, 1877), Euherdmania sp., and an unidentified species belonging to the Holozoidae family were extracted in methanol 5:1 (v/w). The extracts were tested for cytotoxicity using the brine shrimp lethality assay, sea urchin egg development assay, hemolysis assay, and MTT assay using tumor cell lines. The extract of E. vannamei showed the highest toxicity in brine shrimp (LD₅₀=34.7 μg/ml) and in all tumor cell lines tested, with an IC₅₀ of <2 μg/ml for CEM, 11.2 μg/ml for HL-60, 23.8 μg/ml for B16, and 14.3 μg/ml for HCT-8. In sea urchin eggs, it inhibited the cell cycle progression mainly at the blastula stage (IC₅₀=74.8 μg/ml). The extract of Euherdmania sp. also exhibited some toxicity in these assays, but at a lower potency than that of E. vannamei. The extracts of D. psammatodes and Polysyncraton sp. showed a strong inhibition of the sea urchin egg cell cycle during both phases examined, first cleavage and blastula, with a possible action on the cell microfilament apparatus. The extract of D. ligulum showed selective toxicity toward HCT-8 cells (IC₅₀=35.3 μg/ml). The extract from the Holozoidae was the only one that possessed a hemolytic effect, with an IC₅₀ of 175.2 μg/ml. Further studies are necessary for a better characterization of the active principles of these extracts and a possible elucidation of the mechanisms of action.     

Overproduction of a mosquitocidal chloramphenicol-resistant Lysinibacillus sphaericus mutant obtained through UV irradiation

A highly active mosquitocidal mutant UV-chloramphenicol-resistant mutant (UCR-146) of Lysinibacillus sphaericus 2362 was isolated by UV irradiation and selected through resistance to chloramphenicol which was inhibitory for growth of the parent strain. The growth of UCR-146 in NYSMCL at different concentrations of chloramphenicol (20–100 µg/ml) showed high mosquitocidal activity against Culex pipiens larvae with the optimum concentration of 35µg/ml. At this level, LC₅₀ of UCR-146 was decreased about five times from that of L. sphaericus 2362. Comparative efficiency of mosquitocidal activity of UCR-146 and L. sphaericus 2362 within 28 days of consecutive growth exhibited notable stability of both cultures through seven cycles of growth in their optimal media. UCR-146 was grown in industrial by-products media for production of the binary toxin under economic conditions. Offal medium at 2% showed the highest mosquitocidal activity of UCR-146 with LC₅₀ of 0.53 PPM which was 16.6, 13, 12.3 and 3.4 times less than that produced with L. sphaericus 2362 grown in NYSM, L. sphaericus 2362 grown in offal, UCR-146 grown in NYSM and UCR-146 grown in NYSMCL, respectively. Hence, the mosquitocidal activity of L. sphaericus 2362 increased several times through ultraviolet (UV) irradiation followed by chloramphenicol resistance selection and then growth in 2% offal medium. Finally, this procedure for selecting UV-chloramphenicol-resistant mutant and the medium used could potentially be a simple and cost effective approach for obtaining and producing a highly active mosquitocidal mutant.     

Indole and aminoimidazole moieties appear as key structural units in antiplasmodial molecules

From a library of compounds of natural sources, a big series of molecules was chosen by random sampling to evaluate their in vitro antimalarial activity against Plasmodium falciparum and their antifungal activity against Candida sp. From 184 molecules tested, no molecules were active against Candida sp. (MIC > 10 μg/ml) whereas 13 clearly showed high antiplasmodial activity in vitro, with an IC₅₀ less than 1 μg/ml against the chloroquine-resistant strain of P. falciparum FcM29-Cameroon. The molecules with the best antiplasmodial efficacy were 10-hydroxy-ellipticin (IC₅₀: 0.08 μg/ml), tchibangensin (IC₅₀: 0.13 μg/ml), ellipticin hydrochloride (IC₅₀: 0.17 μg/ml), usambarensin (IC₅₀: 0.23 μg/ml), 7S,3S-ochropposinine oxindole (IC₅₀: 0.25 μg/ml), 3,14-dihydro-ellipticin (IC₅₀: 0.25 μg/ml), tetrahydro-4′,5′,6′17-usambarensin 17S (IC₅₀: 0.26 μg/ml), ellipticine (IC₅₀: 0.28 μg/ml), aricin (IC₅₀: 0.3 μg/ml), 10-methoxy-ellipticin (IC₅₀: 0.32 μg/ml), aplysinopsin (IC₅₀: 0.43 μg/ml), descarbomethoxydihydrogambirtannin (IC₅₀: 0.46 μg/ml) and ochrolifuanin A (IC₅₀: 0.47 μg/ml). Among these 13 promising molecules, all except descarbomethoxydihydrogambirtannin, ochrolifuanine A and usambarensine presented here novel biological activities since they had never been described in the literature for their antiplasmodial activity. In spite of the large diversity of the molecules which have been tested, it is interesting to note that the ones active against Plasmodium are all indole derivatives (and one is both indolic and aminoimidazolic). To find new antiplasmodial compounds, ethnopharmacological approaches studying traditional medicine treatments for malaria is largely used but random research produced here an interesting yield (7%) of new antiplasmodial hits and appears therefore complementary to the traditional medicine way.     

Mosquito larvicidal activity of Aloe vera (Family: Liliaceae) leaf extract and Bacillus sphaericus,against Chikungunya vector,Aedes aegypti

The bio-efficacy of Aloe vera leaf extract and bacterial insecticide, Bacillus sphaericus larvicidal activity was assessed against the first to fourth instars larvae of Aedes aegypti, under the laboratory conditions. The plant material was shade dried at room temperature and powdered coarsely. A. vera and B. sphaericus show varied degrees of larvicidal activity against various instars larvae of A. aegypti. The LC₅₀ of A. vera against the first to fourth instars larvae were 162.74, 201.43, 253.30 and 300.05 ppm and the LC₉₀ 442.98, 518.86, 563.18 and 612.96 ppm, respectively. B. sphaericus against the first to fourth instars larvae the LC₅₀ values were 68.21, 79.13, 93.48, and 107.05 ppm and the LC₉₀ values 149.15, 164.67, 183.84, and 201.09 ppm, respectively. However, the combined treatment of A. vera + B. sphaericus (1:2) material shows highest larvicidal activity of the LC₅₀ values 54.80, 63.11, 74.66 and 95.10 ppm; The LC₉₀ values of 145.29, 160.14, 179.74 and 209.98 ppm, against A. aegypti in all the tested concentrations than the individuals and clearly established that there is a substantial amount of synergist act. The present investigation clearly exhibits that both A. vera and B. sphaericus materials could serve as a potential larvicidal agent. Since, A. aegypti is a container breeder vector mosquito this user and eco-friendly and low-cost vector control strategy could be a viable solution to the existing dengue disease burden. Therefore, this study provides first report on the mosquito larvicidal activity the combined effect of A. vera leaf extract and B. sphaericus against as target species of A. aegypti.     

A cost-effective medium for the large-scale production of Bacillus sphaericus H5a5b (VCRC B42) for mosquito control

Bacillus sphaericus has been widely used in mosquito control programs, but the large-scale production of this bacterium is expensive because of the high cost of the medium. In this study, we attempted to develop a cost-effective medium, based on inexpensive, locally available raw materials including soybean flour (Glycine max) and peanut cake powder (Arachis hypogea) by using 100-l bioreactor. Sporulation, toxicity and biomass were satisfactory after B. sphaericus was produced on both media. Use of the soybean culture medium resulted in “maximum” toxicity (LC₅₀ 14.02 ng/ml against third instar Culex quinquefasciatus larvae), highest spore count (3.7 × 10⁹ spores/ml) and maximum biomass (4.6 g/l) within a short fermentation time of 21 h. Hence, this soybean-based culture medium was considered most economical for the large-scale industrial production of B. sphaericus.     

Antifeedant and larvicidal activity of bioactive compounds isolated from entomopathogenic fungi Penicillium sp. for the control of agricultural and medically important insect pest (Spodoptera litura and Culex quinquefasciatus)

The use of chemical insecticides in agriculture has posed several challenges to environment and ecosystem health. Pesticides of biological origin are considered to be suitable for sustainable environment. In the present study bioactive compounds from Penicillium sp. was isolated and tested for insecticidal activity on Spodoptera litura and Culex quinquefasciatus larvae. Ethyl acetate extract of Penicillium sp. were characterized using GC–MS and FT-IR analysis. GC–MS analysis showed 20 different bioactive compounds namely, Propanoic acid, ethyl ester, Acetic Acid, Propyl Ester, Isopentyl Acetate, Acetic Acid, 2-Methylpropyl Ester, Behenic alcohol, 1-Hexadecene, 1-Octadecene, 1-Hexacosanol, n-Hexadecanoic acid, 1-Tetradecanol, 1-Dodecene, Tetrydamine, and Octadecanoic acid. The presence of functional groups such as, chloroalkanes, sulfonates, phosphines, amines, carboxylic acid, alkanes, and isocyanates was identified by using FTIR. Ethyl acetate extract of Penicillium sp., were tested for larvicidal activity on Spodoptera litura and Culex quinquefasciatus larvae showed significant larval mortality after 48 h of exposure with LC₅₀: 72.205 mg/ml: LC₉₀: 282.783 mg/ml and LC₅₀: 94.701 mg/ml: LC₉₀:475.049 mg/ml respectively. High antifeedant activity was observed in 300 μg/ml at 48 h of crude extract exposure. The present study concludes that Penicillium sp., secondary metabolites are effective for control of Spodoptera litura and Culex quinquefasciatus larvae.     

The comparative persistence of toxicity of Bacillus sphaericus strain 1593 and Bacillus thuringiensis serotype H-14 against mosquito larvae in different kinds of environments

Bacillus sphaericus strain 1593 and B. thuringiensis serotype H-14 were evaluated for persistence of toxicity against two species of mosquito larvae, Culex quinquefasciatus and Aedes aegypti, in a selected simulating plot in Bangkok. Both strains of bacteria demonstrated larvicidal activity towards both species of mosquito larvae. In tap water, the toxicity of B. sphaericus strain 1593 was found to be greater towards C. quinquefasciatus larvae than A. aegypti larvae, whereas the toxicity of B. thuringiensis serotype H-14 was found to be greater towards A. aegypti larvae than C. quinquefasciatus larvae. The persistence of toxicity of these two bacteria was found to be different. The lethal concentration of B. thuriengiensis H-14 against A. aegypti decreased from LC₉₀ to below LC₅₀ in about 15 weeks when tested in tap water. The decrease was faster in polluted water. The toxicity of B. sphaericus 1593 towards C. quinquefasciatus larvae persisted for at least 9 months in tap water and 6 months in polluted water. The multiplication of bacteria was indicated only in populations of B. sphaericus 1593 tested with C. quinquefasciatus larvae.     

Evaluation of in vitro free radical scavenging potential of Streptomyces sp. AM-S1 culture filtrate

The present study was carried out to determine the free radical scavenging potential of culture filtrate of Streptomyces sp. AM-S1. Antioxidant activity of culture filtrate, lyophilized culture filtrate and ethyl acetate extract of Streptomyces sp. AM-S1 was determined by various in vitro assays such as ferric reducing power assay, phosphomolybdenum reduction, DPPH and ABTS radical scavenging activities. The results revealed that the culture filtrate of Streptomyces sp. AM-S1 effectively scavenged DPPH (IC₅₀ 90.2 μl/ml) and ABTS (IC₅₀ 13.2 μl/ml) radicals in a concentration dependent manner. In all the assays, ethyl acetate extract registered higher antioxidant activity when compared with the lyophilized culture filtrate (LCF). In addition, ethyl acetate extract (1123.4 μmole Fe(II)/mg extract) exhibited higher ferric reducing activity than the standard BHA (814.4 μmole Fe(II)/mg extract). Further works are needed on the isolation and identification of antioxidant molecules from the ethyl acetate extract of Streptomyces sp. AM-S1 culture filtrate.     

Comparative research of chemical constituents,antifungal and antitumor properties of ether extracts of Panax ginseng and its endophytic fungus

The chemical compositions and bioactivities of ether extracts of an endophytic fungus Paecilomyces sp. isolated from Panax ginseng were reported, and the comparative analysis of the constituents, antifungal and antitumor properties of the ether extracts from this fungus and its host ginseng were also conducted. By means of GC/MS technique, 51 compounds of Panax ginseng and 38 compounds of Paecilomyce sp. were determined. It is attractive that the extracts derived from Paecilomyce sp. and ginseng samples contained the same compound falcarinol, a natural pesticide and anti-cancer agent. The ether extracts of Paecilomyce sp., tested at 7.8 μg/ml, completely inhibited the visible growth of Pyricularia oryzae. Furthermore, both extracts were tested against four human pathogenic fungi and showed the IC₈₀ of Paecilomyce sp. was 4 μg/ml against Trichophyton rubrum, equally to the control. Finally, the in vitro antitumor experience showed that the most of the IC₅₀ values were all being below 20 μg/ml.     

Study on bioactivity of extracts from marine sponges in Chinese Sea

The bioactivity screening of fractions from two inter-tidal sponges collected from the north of China Yellow Sea and one sponge collected from the South Chinese Sea was reported in this study. In sponge Hymeniacidon perleve there were 9 fractions out of 15 from CHCl₃ extract with anti Staphylococcus aureus activity, 9 fractions out of 19 from BuOH extract with anti Escherichia coli activity, and three fractions from CHCl₃ extract which had moderate to strong activity in inhibiting Bacillus subtilis, Candida albicans, and Aspergilus niger. The fractions of Reniochalina sp. showed bioactivity against bacteria and fungi. The fractions of Acanthella acuta Schmidt showed bioactivity against S. aureus and fungi. One compound from H. perleve obtained by the bioactively directing isolation was tested for bioactivity against the human hepatoma cell line Qgy7701 (IC₅₀ 10.1 μg/ml), Burkitt's lymphoma cell line Raji (IC₅₀ 9.76 μg/ml) and chronic myelogenous leukemia K562 (IC₅₀ 1.90 μg/ml).     

Production of mosquitocidal <Emphasis Type="Italic">Bacillus sphaericus</Emphasis> by solid state fermentation using agricultural wastes

In this study, Bacillus sphaericus NRC 69 was grown in culture media, in which 12 agricultural wastes were tested as the main carbon, nitrogen and energy sources under solid state fermentation. Of the 12 tested agricultural by-products, wheat bran was the most efficient substrate for the production of B. sphaericus mosquitocidal toxins against larvae of Culex pipiens (LC₅₀ 1.2 ppm). Mixtures of tested agricultural wastes separately with wheat bran enhanced the produced toxicity several folds and decreased LC₅₀ between 3.7- and 50-fold in comparison with that of agricultural wastes without mixing. The toxicity of B. sphaericus grown in wheat bran/rice hull at 8/2 (g/g) and wheat bran/barley straw at 1/4 (g/g) showed the same toxicity as that in wheat bran medium (LC₅₀ decreased 17- and 16-fold, in comparison with that in rice hull or barely straw media, respectively). In wheat bran medium, the maximum toxicity of the tested organism obtained at 50% moisture content, inoculum size 84 × 10⁶ CFU/g wheat bran and incubation for 6 days at 30°C. Addition of cheese whey permeate at 10% to wheat bran medium enhanced the toxicity of B. sphaericus NRC 69 about 46%.     

In Vitro α-Glucosidase Inhibition and Antioxidative Potential of an Endophyte Species (Streptomyces sp. Loyola UGC) Isolated from Datura stramonium L

Endophytic actinomycetes isolated from Datura stramonium L. was evaluated for its effects against in vitro α-glucosidase inhibition, antioxidant, and free radical scavenging activities. Based on microbial cultural characteristic and 16S rRNA sequencing, it was identified as Streptomyces sp. loyola UGC. The methanolic extract of endophytic actinomycetes (MeEA) shows remarkable inhibition of α-glucosidase (IC₅₀ 730.21 ± 1.33 μg/ml), scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC₅₀ 435.31 ± 1.79 μg/ml), hydroxyl radical (IC₅₀ 350.21 ± 1.02 μg/ml), nitric oxide scavenging (IC₅₀ 800.12 ± 1.05 μg/ml), superoxide anion radical (IC₅₀ 220.31 ± 1.47 μg/ml), as well as a high and dose-dependent reducing power. The MeEA also showed a strong suppressive effect on rat liver lipid peroxidation. Antioxidants of β-carotene linoleate model system revels significantly lower than BHA. The total phenolic content of the extract was 176 mg of catechol equivalents/gram extract. Perusal of this study indicates MeEA can be used as natural resource of α-glucosidase inhibitor and antioxidants.     

Isolation of marine bacteria with antimicrobial activities from cultured and field-collected soft corals

Bacteria associated with eight field-collected and five cultured soft corals of Briareum sp., Sinularia sp., Sarcophyton sp., Nephtheidae sp., and Lobophytum sp. were screened for their abilities in producing antimicrobial metabolites. Field-collected coral samples were collected from Nanwan Bay in southern Taiwan. Cultured corals were collected from the cultivating tank at National Museum of Marine Biology and Aquarium. A total of 1,526 and 1,138 culturable, heterotrophic bacteria were isolated from wild and cultured corals, respectively; seawater requirement and antimicrobial activity were then assessed. There is no significant difference between the ratio of seawater-requiring bacteria on the wild and cultured corals. The ratio of antibiotic-producing bacteria within the seawater-requiring bacteria did not differ between the corals. Nineteen bacterial strains that showed high antimicrobial activity were selected for 16S rDNA sequencing. Three strains could be assigned at the family level (Rhodobacteraceae). The remaining 16 strains belong to eight genera: Marinobacterium (2 strains), Pseudoalteromonas (1), Vibrio (5), Enterovibrio (1), Tateyamaria (1), Labrenzia (2), and Pseudovibrio (4). The crude extract from bacteria strains CGH2XX was found to have high cytotoxicity against the cancer cell line HL-60 (IC₅₀?=?0.94???g/ml) and CCRF-CEM (IC₅₀?=?1.19???g/ml). Our results demonstrate that the marine bacteria from corals have great potential in the discovery of useful medical molecules.