Search

Strain A2 with algicidal activity against Microcystis aeruginosa was isolated and identified with the genus Acinetobacter on the basis of phenotypic tests and 16S rRNA gene analysis. It was identified with the species Acinetobactor guillouiae by partial rpoB sequence analysis. When 10% ( v / v ) of the bacterial culture was co-incubated with M . aeruginosa culture, algicidal efficiency reached 91.6% after 7 days. Supernatant of A2 culture showed similar algicidal activity, while the cell pellet had little activity, suggesting that Acinetobacter guillouiae A2 indirectly attacked M. aeruginosa cells by secreting an extracellular algicidal compound, which was characterized as heat-stable. A significant decrease in the microcystin (microcystin-LR) concentration was observed after 10% ( v / v ) addition of A2 culture. Transcription of three microcystin-related genes ( mcy A, mcy D and mcy H) was also found to be inhibited. The algicidal compound 4-hydroxyphenethylamine was obtained by further isolation and purification using various chromatographic techniques. The EC 50, 3d and EC 50, 7d values of 4-hydroxyphenethylamine against M. aeruginosa were 22.5 and 10.3 mgL −1 , respectively. These results indicate that A . guillouiae strain A2 inhibits growth of M. aeruginosa and degrades microcystin production. The identified compound, 4-hydroxyphenethylamine, has potential for development as a new algicidal formulation or product. [ABSTRACT FROM AUTHOR]

With the aim of finding natural anthelmintic agents against Dactylogyrus intermedius (Monogenea) in goldfish ( Carassius auratus), 26 plants were screened for antiparasitic properties using in vivo anthelmintic efficacy assay. The results showed that Caesalpinia sappan, Lysima chiachristinae, Cuscuta chinensis, Artemisia argyi, and Eupatorium fortunei were found to have 100 % anthelmintic efficacy at 125, 150, 225, 300, and 500 mg L −1 after 48 h of exposure. Crude extract of the five plants were further partitioned with petroleum ether, chloroform, ethyl acetate, methanol, and water to obtain anthelmintically active fractions with various polarity. Among these fractions tested, the ethyl acetate extract of L. chiachristinae was found to be the most effective with a 50 % effective concentration (EC 50) value of 5.1 mg/L after 48 h of exposure. This was followed by ethyl acetate extract of C. chinensis (48 h-EC 50 = 8.5 mg L −1), chloroform extracts of C. sappan (48 h-EC 50 = 15.6 mg L −1), methanol extract of C. chinensis (48 h-EC 50 = 15.9 mg L −1), and chloroform and petroleum ether extract of L. chiachristinae (EC 50 values of 17.2 and 21.1 mg/L, respectively), suggesting that these plants, as well as the active fractions, provide potential sources of botanic drugs for the control of D. intermedius in aquaculture. [ABSTRACT FROM AUTHOR]

Highlights: [•] New methods for the controlling harmful cyanobacterial blooms are urgent. [•] A new algicidal compound from Salvia miltiorrhiza Bung was isolated and identified. [•] Neo-przewaquinone A destroyed the M. aeruginosa cell structure. [•] Neo-przewaquinone A induced oxidative damage of M. aeruginosa. [•] Neo-przewaquinone A reduced expression of the photosynthesis-related genes. [Copyright &y& Elsevier]

Four alkaloids (Sanguinarine, 6-Methoxyl-dihydro-chelerythrine, Cryptopine and β-Allocryptopine) were isolated from aerial parts of Macleaya microcarpa (Maxim) Fedde using bioassay-guided isolation method, and the inhibitory activity of ethanolic extract, various fractions and these four alkaloids against four fish pathogenic bacteria ( Aeromonas hydrophila, Aeromonas salmonicida, Vibrio anguillarum and Vibrio harveyi) was assessed in vitro using the agar dilution method and the microdilution assay method respectively. A. hydrophila was the most sensitive strain to all the tested compounds. Minimum inhibitory concentration ( MIC) values were lower for sanguinarine against all tested Gram-negative strains than other three alkaloids, with MIC values of 12.5 mg L−1 for A. hydrophila and 50 mg L−1 to other pathogenic bacteria. Followed by 6-methoxyl-dihydro-chelerythrine, which showed considerable antibacterial activity with MIC values of 80 mg L−1 for A. hydrophila, 100 mg L−1 for V. harveyi, and 125 mg L−1 for both V. anguillarum and A. salmonicida. Cryptopine and β-allocryptopine revealed similar inhibitory activity with MIC values of 100 mg L−1 for A. hydrophila and 200 mg L−1 for other three bacterial species. These finding provided evidence that extract, as well as isolated compounds from M. microcarpa might be potential sources novel antibacterial agents for the treatment of fish infectious diseases. [ABSTRACT FROM AUTHOR]

Ichthyophthiriasis is a widespread disease in aquaculture and causes mass mortalities of fish. The development of new antiprotozoal agents for the treatment of Ichthyophthirius multifiliis infections is of increasing interest. The aim of the present study was to investigate the efficacy of 30 medicinal plants against I. multifiliis. The results showed that the methanol extracts of Magnolia officinalis and Sophora alopecuroides displayed the highest antiprotozoal activity against theronts, with 4-h LC values estimated to be 2.45 and 3.43 mg L, respectively. Concentrations of 2.5, 5.0, 10.0, and 20.0 mg L of M. officinalis extracts resulted in tomont mortality of 9.7, 43.7, 91.3, and 100 % at 20 h, respectively. From 40 to 320 mg L of S. alopecuroides extracts, tomont mortality increased from 29.7 to 100 %. Antiprotozoal efficacy against settled tomonts (2 and 10 h) was also applied; the results indicated that encysted I. multifiliis tomonts were less susceptible to these plant extract treatments. In vivo experiments demonstrated that high concentrations of M. officinalis and S. alopecuroides extracts could kill tomonts, and M. officinalis significantly reduced its reproduction ( P < 0.05). These results suggested that the methanol extracts of M. officinalis and S. alopecuroides have the potential to be used as an eco-friendly approach for the control of I. multifiliis. [ABSTRACT FROM AUTHOR]

In search of a botanical algicide, 40 traditional medicinal plants were screened for antialgal activity against the bloom-forming cyanobacterium Microcystis aeruginosa using coexistence culture system assay. The results of the coexistence assay showed that significant inhibition of the algae at 800 mg L were observed for methanolic extracts of the root of Salvia miltiorrhiza (Radix Salviae Miltiorrhizae), rhizome of Acorus tatarinowii (Rhizoma Acori), rhizome of Polygonum cuspidatum (Rhizoma Polygoni), cortex of Phellodendron amurense (Cortex Phellodendri), and fruits of Crataegus pinnatifida (Fructus Crataegi). Methanol extract of these plants were further partitioned with petroleum ether, chloroform, ethyl acetate, and acetone to obtain allelopathically active fractions with various polarity. Among these fractions tested, the ethyl acetate extract of S. miltiorrhiza was observed to be more efficient than the other plant extracts with the inhibitory rate (IR) of 91.3% at 800 mg L and 50% effective concentrations (EC) values 98.9 mg L after 7 days, followed by chloroform extracts of A. tatarinowii, S. miltiorrhiza, and P. cuspidatum, and the petroleum ether extracts of A. tatarinowii with EC 102.5, 111.5, 122.9, and 130.0 mg L, respectively. [ABSTRACT FROM AUTHOR]

The article introduces "Huayi 7," a new cultivar of collectible Wenwan Walnut with deep Chinese cultural significance, highlighting its historical roots dating back to the Silk Road era. Topics include the cultural, health, and economic values of Wenwan walnuts, emphasizing their role in traditional Chinese culture, therapeutic applications, and substantial market potential, with the recently released cultivar 'Huayi 7' characterized by distinct nut traits and health benefits.

Natural plant agents are considered promising sources to control harmful algal blooms. The primary purpose of this study was to isolate the algicidal compounds from Ginkgo biloba exocarp against the toxic cyanobacterium Microcystis aeruginosa and determine the potential inhibition mechanisms. Bioassay-guided fractionation of petroleum ether extract yielded ginkgolic acids, which were identified by spectral analysis (infrared and reversed-phase high-performance liquid chromatography/electrospray mass spectrometry). Bioassays showed ginkgolic acids inhibited M. aeruginosa growth effectively with the 3- and 7-day median effective concentration (EC, EC) of 3.26 and 2.03 mg L, respectively. For the potential inhibition mechanisms, cellular morphology, physiological changes, and genes expression during 12-96 h of exposure were investigated. Ginkgolic acids caused morphologic damage or lysis of cells. They induced oxidative damage by increasing malondialdehyde content and decreasing total antioxidant and superoxide dismutase activities. Transcription of three photosynthetic genes ( psaB, psbD, and rbcL) and two nutrient uptake related genes ( ntcA and phoU) were also found to be inhibited. Additionally, ginkgolic acids also affected the microcystin contents and the transcription of microcystin-related genes. The results suggested that ginkgolic acids isolated from G. biloba exocarp have the potential to inhibit M. aeruginosa growth effectively by causing pleiotropic effects on several physiological and biochemical reactions. [ABSTRACT FROM AUTHOR]