An Efficient Strategy for Enhancement of Bioactive Compounds in the Fruit Body of Caterpillar Medicinal Mushroom, Cordyceps militaris (Ascomycetes), by Spraying Biotic Elicitors.

Cordyceps militaris is a mushroom species with high nutritive and medicinal values based on diverse bioactive metabolites. The contents of bioactive ingredients are indicative of the quality of commercially available fruit body of this fungus. Although the application of biotic elicitors has been an efficient strategy to induce the accumulation of valuable bioactive compounds in vivo, related research in C. militaris is rarely reported. In this study, five biotic elicitors in different concentrations (0.05, 0.5, 1, and 2 mg/mL), including chitosan (CHT), 2,4-dichlorophenoxyacetic acid (2,4-D), methyl jasmonate (MeJA), gibberellic acid (GA), and triacontanol (TRIA), were first introduced to enhance the production of 10 kinds of major bioactive components in the fruit body of C. militaris. Results showed that the effect of biotic elicitors on bioactive compounds in the fruit body of C. militaris was elicitor-specific and concentration-dependent. Overall, 1 mg/L CHT was considered the most favorable for the production of 10 bioactive ingredients in C. militaris fruit body, which could increase the content of protein, polysaccharides, polyphenol, triterpenoids, flavonoids, cordyceps acid, cordycepin, and anthocyanins by 20.38-, 1.41-, 0.7-, 0.47-, 11.90-, 1.09-, 0.34-, and 2.64-fold, respectively, compared with the control. The results of this study would provide an efficient strategy for the production of a superior quality fruit body of and contribute to further elucidation of the effects of biotic elicitors on metabolite accumulation in C. militaris.

Isolation and Characterization of Fengycins Produced by Bacillus amyloliquefaciens JFL21 and Its Broad-Spectrum Antimicrobial Potential Against Multidrug-Resistant Foodborne Pathogens.

The continuing emergence and development of pathogenic microorganisms that are resistant to antibiotics constitute an increasing global concern, and the effort in new antimicrobials discovery will remain relevant until a lasting solution is found. A new bacterial strain, designated JFL21, was isolated from seafood and identified as B. amyloliquefaciens. The antimicrobial substance produced by B. amyloliquefaciens JFL21 showed low toxicity to most probiotics but exhibited strong antimicrobial activities against multidrug-resistant foodborne pathogens. The partially purified antimicrobial substance, Anti-JFL21, was characterized to be a multiple lipopeptides mixture comprising the families of surfactin, fengycin, and iturin. Compared with commercially available polymyxin B and Nisin, Anti-JFL21 not only could exhibit a wider and stronger antibacterial activity toward Gram-positive pathogens but also inhibit the growth of a majority of fungal pathogens. After further separation through gel filtration chromatography (GFC), the family of surfactin, fengycin, and iturin were obtained, respectively. The results of the antimicrobial test pointed out that only fengycin family presented marked antimicrobial properties against the indicators of L. monocytogenes, A. hydrophila, and C. gloeosporioides, which demonstrated that fengycins might play a major role in the antibacterial and antifungal activity of Anti-JFL21. Additionally, the current study also showed that the fengycins produced by B. amyloliquefaciens JFL21 not only maintained stable anti-Listeria activity over a broad pH and temperature range, but also remained active after treatment with ultraviolet sterilization, chemical reagents, and proteolytic enzymes. Therefore, the results of this study suggest the new strain and its antimicrobials are potentially useful in food preservation for the biological control of the multidrug-resistant foodborne pathogens.

Arenibacter catalasegens sp. nov., isolated from marine surface sediment, and emended description of the genus Arenibacter.

A Gram-staining-negative, aerobic, non-motile, rod-shaped bacterium, designated as P308H10T, was isolated from surface sediment of the Southern Indian Ocean. Growth occurred at 4-36 °C (optimum 20-25 °C), pH 6.0-8.5 (optimum 7.5-8.0) and in the presence of 1-8 % (w/v) NaCl (optimum 2-3 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain P308H10T lies within the clade of members of the genus Arenibacter and is closely related to Arenibacterhampyeongensis HP12T (98.0 %), Arenibacterechinorum KMM 6032T (98.4 %), Arenibacterpalladensis LMG 21972T (97.9 %), Arenibactertroitsensis KMM 3674T (97.9 %) and 'Arenibacter algicola' TG409 (98.1 %). The average nucleotide identity and digital DNA-DNA hybridization values between strain P308H10T and the five reference strains were 85.9-80.6 % and 30.2-23.6 %, respectively. The major fatty acids (>10 %) of strain P308H10T were summed feature 3, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0. The major polar lipids comprised phosphatidylethanolamine, five unidentified aminolipids and four unidentified lipids. The only respiratory quinone was menaquinone-6. The genomic DNA G+C content was 38.2 mol%. On the basis of the phenotypic, phylogenetic and chemotaxonomic data presented, strain P308H10T represents a novel species of the genus Arenibacter, for which the name Arenibacter catalasegens sp. nov. is proposed. The type strain is P308H10T (=GDMCC 1.1230T=KCTC 52983T). An emended description of the genus Arenibacter is also proposed.

Antarcticibacterium flavum gen. nov., sp. nov., isolated from marine sediment.

A Gram-stain-negative, strictly aerobic, yellow-pigmented, non-gliding, oval to rod-shaped bacterial strain, designated JB01H24T, belonging to the family Flavobacteriaceae, was isolated from marine surface sediment collected from the Ross Sea, Antarctica. Strain JB01H24T grew at 4-40 °C (optimum 25-30 °C), pH 7.0-9.0 (optimum 7.5-8.0), and in the presence of 0-8 % NaCl (optimum 3 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JB01H24T formed an independent linkage within the family Flavobacteriaceae and was closely related with the genus Gillisia. Strain JB01H24T exhibited 16S rRNA gene sequence similarities of 95.3-91.5 % and 94.9-94.0 % to the type strains of the genera Gillisia and Salinimicrobium, respectively. The major fatty acids (>5 %) were iso-C15 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), anteiso-C15 : 0, iso-C15 : 1 G and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). The major polar lipids were phosphatidylethanolamine, seven unidentified lipids, two unidentified aminolipids and an unidentified aminophospholipid. Strain JB01H24T contained menaquinone-6 as the only ubiquinone. The DNA G+C content was 42.4 mol%. On the basis of phylogenetic, physiological and chemotaxonomic properties, strain JB01H24T is considered to represent a novel species of a new genus within the family Flavobacteriaceae, for which the name Antarcticibacterium flavum gen. nov., sp. nov. is proposed. The type strain of Antarcticibacterium flavum is JB01H24T (=GDMCC 1.1229T=KCTC 52984T).

Gramella antarctica sp. nov., isolated from marine surface sediment.

A Gram-stain-negative, aerobic, yellow-coloured, motile by gliding, rod-shaped bacterial strain, designated R17H11T, was isolated from surface sediment collected from the Ross Sea, Antarctica. Growth optimally occurred at 25-30 °C, at pH 7.0-7.5 and in the presence of 3 % NaCl (w/v). Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R17H11T clustered together with Gramella flava JLT2011T and fell within the genus Gramella. Strain R17H11T shared the highest 16S rRNA gene similarities (96.1 and 96.0 %) with the type strains of Gramella forsetii and G. flava, and 92.6-95.5 % similarities with those of other known Gramella species. Strain R17H11T contained menaquinone-6 as the only isoprenoid quinone. The major fatty acids (>5 %) were summed feature 3 (17.5 %, comprising C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 (14.0 %), summed feature 9 (11.8 %, comprising 10-methyl C16 : 0 and/or iso-C17 : 1ω9c), iso-C17 : 0 3-OH (11.8 %), iso-C16 : 0 (7.4 %), C17 : 1ω6c (6.9 %) and anteiso-C15 : 0 (5.1 %). The major polar lipids were phosphatidylethanolamine, four unidentified lipids, an unidentified aminolipid, an unidentified aminophospholipid and an unidentified glycolipid. The DNA G+C content of strain R17H11T was 38.6 mol%. On the basis of the phylogenetic, physiological and chemotaxonomic characteristics, strain R17H11T represents a novel species in the genus Gramella, for which the name Gramellaantarctica sp. nov. is proposed. The type strain of the novel species is R17H11T (=GDMCC 1.1208T=KCTC 52925T).

Aurantimonas aggregata sp. nov., isolated from deep-sea sediment.

A novel bacterium, designated R14M6T, was isolated from deep-sea sediment collected from the Ross Sea, Antarctica. Cells are Gram-stain-negative, aerobic, pale yellow, short-rod-shaped, polar-flagellated and aggregate-forming. Growth occurs at 4-36 °C, pH 6.0-8.3, and in 1-15 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain R14M6T clustered together with Aurantimonas endophytica EGI6500337T and fell within the genus Aurantimonas. The 16S rRNA gene sequence of strain R14M6T shared similarity with A. endophytica EGI6500337T (99.15 %), A. manganoxydans DSM 21871T (97.73 %), A. coralicida DSM 14790T (97.58 %) and 'A. litoralis' KCTC 12094 (97.51 %). The DNA-DNA relatedness values between strain R14M6T and A. endophytica EGI6500337T, A. coralicida DSM 14790T, A. manganoxydans DSM 21871T and 'A. litoralis' KCTC 12094 were 36.9±4.5, 27.6±2.8, 29.6±1.2 and 25.2±2.4 % respectively. The major fatty acid of strain R14M6T was C18 : 1ω7c. The major polar lipids were phosphatidylcholine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified aminolipid. Strain R14M6T contained Q-10 as the dominant isoprenoid quinone. The DNA G+C content of strain R14M6T was 67.4 mol%. Based on the phylogenetic, physiological and chemotaxonomic analyses, strain R14M6T represents a novel species of the genus Aurantimonas, for which the name Aurantimonas aggregata sp. nov. is proposed. The type strain is R14M6T (=GDMCC 1.1202T=KCTC 52919T).

Arenibacter antarcticus sp. nov., isolated from marine sediment.

A strictly aerobic, Gram-stain-negative, pale-golden, rod-shaped bacterium, designated as R18H21T, was isolated from marine sediment collected from the Ross Sea, Antarctica. Strain R18H21T grew at 4-40 °C (optimum 25 °C), at pH 6.3-9.2 (optimum 7.5-8.5) and in 0.5-6 % (w/v) NaCl (optimum 2 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain R18H21T belonged to the genus Arenibacter, with the highest similarity to two type strains, Arenibacter latericius KMM 426T (96.6 %) and Arenibacter certesii KMM 3941T (96.6 %), and lower similarities (95.2-95.9 %) to five other members of the genus Arenibacter. The major fatty acids were iso-C17 : 0 3-OH, Summed Feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), iso-C15 : 0, iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine, an unidentified aminolipid and an unidentified phospholipid. The respiratory quinone of strain R18H21T was menaquinone-6. The DNA G+C content was 40.0 mol%. Based on phylogenetic, physiological and chemotaxonomic features, strain R18H21T has been classified as a novel species in the genus Arenibacter, for which the name Arenibacterantarcticus sp. nov. is proposed. The type strain of the novel species is R18H21T (=GDMCC 1.1159T=KCTC 52924T).