Search

Biological control agents (BCAs) from different microbial taxa are increasingly used to control bacterial wilt caused by Ralstonia solanacearum. However, a quantitative research synthesis has not been conducted on the role of BCAs in disease suppression. Therefore, the present study aimed to meta-analyze the impacts of BCAs on both Ralstonia wilt disease suppression and plant (host) growth promotion. The analysis showed that the extent of disease suppression by BCAs varied widely among studies, with effect size (log response ratio) ranging from −2.84 to 2.13. The disease incidence and severity were significantly decreased on average by 53.7% and 49.3%, respectively. BCAs inoculation also significantly increased fresh and dry weight by 34.4% and 36.1%, respectively on average. Also, BCAs inoculation significantly increased plant yield by 66%. Mean effect sizes for genus Pseudomonas sp. as BCAs were higher than for genus Bacillus spp. Among antagonists tested, P. fluorescens, P. putida, B. cereus, B. subtilis and B. amyloliquefaciens were found to be more effective in general for disease reduction. Across studies, highest disease control was found for P. fluorescens, annual plants, co-inoculation with more than one BCA, soil drench and greenhouse condition were found to be essential in understanding plant responses to R. solanacearum. Our results suggest that more efforts should be devoted to harnessing the potential beneficial effects of these antagonists, not just for plant growth promoting traits but also in mode of applications, BCAs formulations and their field studies should be considered in the future for R. solanacearum wilt disease suppression.

ABSTRACT Present study aim to evaluate the antimicrobial, antioxidant and cytotoxic potential of crude extract of Marine Streptomyces carpaticus MK-01 isolated from seawater collected from Daejeong-cost of Jeju Island. About 24 actinomycetes strains were isolated and subjected to morphological and molecular analysis that confirmed the isolate as S. carpaticus MK-01. Crude ethyl acetate extract of MK-01 strain showed extensive antibacterial activity against Gram-positive fish pathogenic bacteria namely Streptococcus iniae and S. parauberis with a maximum zone of inhibition (0.92±0.03mm) was recorded against S. parauberis at the minimum extract concentration (3.12µg/ml). The MK-01 ethyl acetate extract shows dose dependant significant increase in antioxidant activity. The 50% cytotoxic concentration (CC50) of MK-01 ethyl acetate extract was attained at 53.71 μg/ml and the effective concentration 50 (EC50) against virus-infected Epithelioma papulosum cyprini cell lines was 8.72 μg/ml of S. carpaticus MK-01 crude ethyl acetate extract.

Kudoa septempunctata (Myxozoa: Multivalvulida) myxospores infect the trunk muscles of olive flounder (Paralichthys olivaceus). In this study, two popular commercially formulated anti-coccidial drugs (amprolium hydrochloride and toltrazuril) were serially diluted and incubated with purified mature Kudoa septempunctata myxospores. The viability of K. septempunctata spores was determined after a 2-day incubation followed by Hoechst 33342 and propidium iodide staining, and scanning electron microscopy. Amprolium hydrochloride significantly decreased spore viability (18% of control) at a concentration of 920 μg/mL, whereas toltrazuril showed almost no effect (83% of control). Viability of the control (untreated spores) was 90%. In vivo studies are required to confirm the efficacy of amprolium hydrochloride in fish infected with K. septempunctata myxospores on their growth and immune system performance.

Vibrio anguillarum is the aetiological agent of vibriosis, a disease affecting many marine fish species. The occurrence of vibriosis in starry flounder, Platichthys stellatus, grown in an aquaculture farm has demonstrated the urgent need for information on pathogenic infection and immune response for efficient disease management. This is the first study to report Vibrio anguillarum isolation and infection in starry flounder. We evaluated immune responses, serum biochemical parameters, and cumulative mortality of the fish by experimentally challenging healthy fish. The expression levels of five immune genes (TNF, TNFR, IL-6, MHCII, and CXC) were measured by real-time quantitative PCR. The transcriptional levels of the genes encoding tumor necrosis factor (TNF), TNF receptor (TNFR), interleukin-6 (IL-6), the major histocompatibility complex (MHC-II), and a chemokine (CXC) in the head-kidney of V. anguillarum infected fish were significantly upregulated compared with control fish and biochemical indices including the alanine aminotransferase, total serum protein, and glucose levels of infected fish differed significantly from those of control. Additionally, Starry flounder infected with V. anguillarum at 1.67 × 106 and 1.67 × 108CFU/mL showed 53%, and 100% mortality, respectively. This study furthers our understanding of the immune and serum biochemical alterations, and mortality induced by bacterial infections, depending on pathogen concentration. This may advance strategies for control of V. anguillarum in cultured starry flounder. [ABSTRACT FROM AUTHOR]

In the present study we evaluated the dietary effect of Hallabong peel oil (HPO) on growth, disease resistance, and immune gene expression of rock bream, Oplegnathus fasciatus challenged with Edwardsiella tarda after a 4 week feeding trial with 5 treatments: control-C, probiotic-P, HPO (0.1%), HPO (0.5%), and P+HPO, diets. All fish groups were assessed for growth performance, innate immune parameters, serum biochemical profile, and immune gene expression in head kidney on 2nd, and 4th week, and 1st, 3rd and 7th day post infection with Edwardsiella tarda. Fish fed the HPO enriched diets showed increased growth performance with significantly decreased (P>0.05) mortality compared with the control and probiotic diet groups. The positive effects of HPO enriched diet were also found in all assessed innate immune and biochemical parameters which included increased respiratory burst and lysozyme activity, with significantly increased erythrocyte and leukocytes counts, increased serum protein, decreased glucose, triglycerides, cholesterol level in serum compared with control diet fed fish. Moreover, the probiotic bacterial count in the intestine of fish was enhanced with the HPO diet and the P+HPO diet compared to fish fed the probiotic diet. The head kidney of HPO enriched diet fed fish showed up-regulated expression of inflammatory cytokines genes such as TNFα, IL-1β, and FST, after 4th week of feeding trial which was increased ~2 to 3 times on 1dpi and 3 dpi. These results indicate that limonene rich (91.26%), HPO enriched diets enhance growth and immunity and enhance disease resistance of Oplegnathus fasciatus challenged against E. tarda. [ABSTRACT FROM AUTHOR]

Copyright of Parasite (1252607X) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article documents the addition of 268 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Alburnoides bipunctatus, Chamaerops humilis, Chlidonias hybrida, Cyperus papyrus, Fusarium graminearum, Loxigilla barbadensis, Macrobrachium rosenbergii, Odontesthes bonariensis, Pelteobagrus vachelli, Posidonia oceanica, Potamotrygon motoro, Rhamdia quelen, Sarotherodon melanotheron heudelotii, Sibiraea angustata, Takifugu rubripes, Tarentola mauritanica, Trimmatostroma sp. and Wallago attu. These loci were cross-tested on the following species: Alburnoides fasciatus, Alburnoides kubanicus, Alburnoides maculatus, Alburnoides ohridanus, Alburnoides prespensis, Alburnoides rossicus, Alburnoides strymonicus, Alburnoides thessalicus, Alburnoides tzanevi, Carassius carassius, Fusarium asiaticum, Leucaspius delineatus, Loxigilla noctis dominica, Pelecus cultratus, Phoenix canariensis, Potamotrygon falkneri, Trachycarpus fortune and Vimba vimba. [ABSTRACT FROM AUTHOR]

The antioxidant and antimicrobial potential of an ethanolic extract of Rubus coreanus Bokbunja (RcEE) was analyzed. The 70% ethanolic extract is rich in phenolic compound (48.36±0.39 mg gallic acid equivalent/g) and has a wide range of antibacterial activity against gram-negative (Edwardsiella tarda, Vibrio ichthyoenteri, V. furnissii, V. fluvialis, V. anguillarum) and grampositive (Streptococcus iniae, S. parauberis) fish pathogenic bacteria; its highest zone of inhibition (12±0.14 mm) was against E. tarda. The extract had a significant dose dependant increase in antioxidant activity. The 50% cytotoxic effect of the extract was obtained with 63.52 μg/ml RcEE and the effective concentration 50 against virus-infected Epithelioma papulosum cyprini cell lines was 7.34 μg/ml RcEE. [ABSTRACT FROM AUTHOR]

The antibacterial activity of individual and mixed medicinal plant compounds, azadirachtin (Az), camphor (Ca) and curcumin (Cu), was tested at 100, 200, 300, 400, 500, 600 and 700 ppm (mg L−1) against fungal fish pathogen, Aphanomyces invadans, in vitro. At the lower concentrations between 100 and 300 ppm, the mixture of the tri-herbal (Az+Ca+Cu) compound yielded a higher ( P>0.05) zone of inhibition (ZI) of 7 mm than the positive control; the maximum ZI values (8–15 mm) were realized between 400 and 700 ppm ( P<0.05). At the lowest minimum inhibitory concentration (MIC) the tri-herbal compound (100 ppm) yielded 13 colony-forming units; hence, this dose can be effectively used at the lowest concentration of 100 mg L−1 to ward off the growth of A. invadans in vitro. In Cirrhina mrigala, intramuscular administration (100 μL) of the selected doses of 100, 400 and 700 ppm (mg L−1) significantly enhanced ( P<0.05) the serum lysozyme activity (Ly), production of reactive oxygen species and reactive nitrogen species (RNS or NO) by peripheral blood leucocytes on the 10th, 20th and 30th day. A priori administration of the compound in the fish (100 ppm on 30th day) decreased the percentage mortality when challenged with the pathogen while in the untreated group the mortality increased ( P<0.05). This study indicates that intramuscular administration of the tri-herbal compound Az+Ca+Cu at a concentration of 100 ppm could augment the immune response in C. mrigala against A. invadans. [ABSTRACT FROM AUTHOR]