This study determines the median lethal dose, and describes the clinico-pathological changes and disease development following Streptococcus agalactiae infection in Javanese medaka model. Javanese medakas were infected with S. agalactiae via intraperitoneal (IP) from 10 to 10 CFU/mL, and immersion (IM) route from 10 to 10 CFU/mL. The LD and clinico-pathological changes of the fish was determined until 240 h post infection (hpi). Next, the disease development was determined for 96 hpi in the fish following IP and IM infection at 10 CFU/mL and 10 CFU/mL, respectively. The LD of S. agalactiae in Javanese medaka was lower following IP injection (4.5 × 10 CFU/mL), compared to IM route (3.5 × 10 CFU/mL). The clinical signs included separating from the schooling group, swimming at the surface of water column, lethargy, erratic swimming pattern, corneal opacity and exophthalmia. Histopathological examinations revealed generalized congestion in almost all internal organs, particularly in liver and brain, while the kidney displayed tubular necrosis. Both IP and IM routes showed significant positive correlation (p < 0.05) between the CFU/g of S. agalactiae in the fish tissue and fish deaths. Moreover, the lesions for histopathological scoring in selected organs following IP and IM challenges were also reflecting the CFU/g and fish deaths. This study indicates the capability of Javanese medaka as a model organism in study of streptococcosis development.
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http://dx.doi.org/10.1016/j.micpath.2019.03.034 | DOI Listing |
Toxicol Rep
May 2022
Aquatic Animal Health and Therapeutics Laboratory (Aqua Health), Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
Microplastics (MPs) have become emerging pollutants of public health concern, due to their impact on aqua-terrestrial ecosystems and integration into the food web, with evidence of human exposure and unrevealed health implications. There is a paucity of information regarding the effects of MPs exposure on the gut system using metagenomic and metabolomic approaches. In this study, Javanese medaka fish was exposed to 5 µm beads of polystyrene microplastics (PS-MPs) suspensions, at concentrations of 100 μg/L (MP-LOW), 500 μg/L (MP-MED), and 1000 μg/L (MP-HIGH), for a duration of 21 days, and evaluated for gut microbiome and metabolome responses.
View Article and Find Full Text PDFMar Pollut Bull
May 2022
Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan; Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan. Electronic address:
Cytochrome P450 1a (Cyp1a) is an important enzyme for metabolism of organic pollutants. To understand its reaction to polycyclic aromatic hydrocarbons (PAHs), we knocked out this gene in a marine model fish, Javanese medaka, Oryzias javanicus, using the CRISPR/Cas 9 system. A homozygous mutant (KO) strain with a four-base deletion was established using an environmental DNA (eDNA)-based genotyping technique.
View Article and Find Full Text PDFEcotoxicol Environ Saf
December 2021
Ecological Risk Research Division, Korea Institute of Ocean Science and Technology, Geoje 53201, Republic of Korea; KIOST School, University of Science and Technology, Geoje 53201, Republic of Korea. Electronic address:
Antidepressants are extensively used to treat the symptoms of depression in humans, and the environmentally discharged drugs potentially threaten aquatic organisms. In this study, the acute toxic effects of fluoxetine (FLX) were investigated in two aquatic organisms, the freshwater polyp (Hydra magnipapillata) and Javanese medaka (Oryzias javanicus). The median lethal concentration (LC) of FLX in H.
View Article and Find Full Text PDFInt J Environ Res Public Health
September 2021
Aquatic Animal Health and Therapeutics Laboratory (Aqua Health), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400 UPM, Selangor, Malaysia.
Microplastics (MPs) have become pollutants of concern due to their unknown human health effect and negative impact on terrestrial and aquatic ecosystems. There is increasing number of experimental research on MPs globally with its effects not fully understood; recent animal studies explore its effects on the intestines, yet on other vital organs. Javanese medaka fish was exposed to polystyrene microplastics (PS-MPs) beads for a period of 21 days.
View Article and Find Full Text PDFAnimals (Basel)
July 2021
Department of Biology, Faculty of Science, Universiti Putra Malaysia, UPM Serdang, Selangor 43400, Malaysia.
(1) Background: Zinc oxide nanoparticles (ZnO NPs) are widely applied in various human products. However, they can be extremely toxic for aquatic organisms, particularly fish. This research was conducted to determine the LC of ZnO NPs on the embryos of Javanese medaka () in ultra-pure, deionized, and dechlorinated tap water; (2) Methods: The experiments were conducted in a completely randomized design (CRD) with three replicates for six treatments for acute (0.
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