Displaying all 15 publications

  1. Ibrahim MA, Zulkifli SZ, Azmai MNA, Mohamat-Yusuff F, Ismail A
    Toxicol Rep, 2020;7:1039-1045.
    PMID: 32913717 DOI: 10.1016/j.toxrep.2020.08.011
    Early-life exposure to toxic chemicals causes irreversible morphological and physiological abnormalities that may last for a lifetime. The present study aimed to determine the toxicity effect of 3,4-Dichloroaniline (3,4-DCA) on Javanese medaka (Oryzias javanicus) embryos. Healthy embryos were exposed to various 3,4-DCA concentrations for acute toxicity (5, 10, 25, 50, and 100 mg.L-1) and sublethal toxicity (0.10, 0.50, 1.25, 2.50, and 5.00 mg.L-1) for 96 h and 20 days respectively. Acute toxicity test revealed that the median lethal concentration (96h-LC50) was 32.87 mg.L-1 (95 % CI = 27.90-38.74, R2 = 0.95). Sublethal exposure revealed that 1.25 mg.L-1 at 3 days post-exposure (3 dpe) has a significant lower heartrate (120 ± 12.3 beats/min., p 
    Matched MeSH terms: Oryzias
  2. Yusof S, Ismail A, Alias MS
    Mar Pollut Bull, 2014 Aug 30;85(2):494-8.
    PMID: 24731878 DOI: 10.1016/j.marpolbul.2014.03.022
    Glyphosate is globally a widely used herbicide, yet there is little information on their toxicity to marine fishes. Java medaka, a small tropical fish native to coastal areas in several Southeast Asian countries, is viewed as a suitable candidate for toxicity test and thus was used for this study. Java medaka adults were cultured in the laboratory and the fertilized eggs of the F2 generation were exposed to different concentrations of glyphosate-based herbicide (100, 200, 300, 400 and 500 ppm) until they hatched. The survival and hatching rates of the embryos, changes in the heart rate and morphological impairments were recorded. Generally, survival and hatching percentage decreased as glyphosate concentration increased. Absence of pectoral fin(s) and cornea, permanently bent tail, irregular shaped abdomen, and cell disruption in the fin, head and abdomen are among the common teratogenic effects observed. Furthermore, risk factor also increased with the increased in glyphosate concentrations.
    Matched MeSH terms: Oryzias/growth & development; Oryzias/physiology*
  3. Mori IC, Arias-Barreiro CR, Koutsaftis A, Ogo A, Kawano T, Yoshizuka K, et al.
    Chemosphere, 2015 Feb;120:299-304.
    PMID: 25151133 DOI: 10.1016/j.chemosphere.2014.07.011
    The aquatic ecotoxicity of chemicals involved in the manufacturing process of thin film transistor liquid crystal displays was assessed with a battery of four selected acute toxicity bioassays. We focused on tetramethylammonium hydroxide (TMAH, CAS No. 75-59-2), a widely utilized etchant. The toxicity of TMAH was low when tested in the 72 h-algal growth inhibition test (Pseudokirchneriellia subcapitata, EC50=360 mg L(-1)) and the Microtox® test (Vibrio fischeri, IC50=6.4 g L(-1)). In contrast, the 24h-microcrustacean immobilization and the 96 h-fish mortality tests showed relatively higher toxicity (Daphnia magna, EC50=32 mg L(-1) and Oryzias latipes, LC50=154 mg L(-1)). Isobologram and mixture toxicity index analyses revealed apparent synergism of the mixture of TMAH and potassium iodide when examined with the D. magna immobilization test. The synergistic action was unique to iodide over other halide salts i.e. fluoride, chloride and bromide. Quaternary ammonium ions with longer alkyl chains such as tetraethylammonium and tetrabutylammonium were more toxic than TMAH in the D. magna immobilization test.
    Matched MeSH terms: Oryzias/metabolism
  4. Moriya S, Ogawa S, Parhar IS
    Biochem Biophys Res Commun, 2013 Jun 14;435(4):562-6.
    PMID: 23669040 DOI: 10.1016/j.bbrc.2013.05.004
    Most vertebrates possess at least two gonadotropin-releasing hormone (GnRH) neuron types. To understand the physiological significance of the multiple GnRH systems in the brain, we examined three GnRH neuron type-specific transcriptomes using single-cell microarray analyses in the medaka (Oryzias latipes). A microarray profile of the three GnRH neuron types revealed five genes that are uniquely expressed in specific GnRH neuron types. GnRH1 neurons expressed three genes that are homologous to functionally characterised genes, GnRH2 neurons uniquely expressed one unnamed gene, and GnRH3 neurons uniquely expressed one known gene. These genes may be involved in the modulation or maintenance of each GnRH neuron type.
    Matched MeSH terms: Oryzias/metabolism*
  5. Imai S, Koyama J, Fujii K
    Mar Pollut Bull, 2005;51(8-12):708-14.
    PMID: 16291186
    17beta-estradiol (E2) is a female hormone which is known to be one of the strongest estrogenic chemicals in the environment. The present study investigated the effects of E2 on the reproduction of the estuarine fish, Java-medaka (Oryzias javanicus). Starting from the embryonic stages, Java-medaka was exposed for 6 months to 9.5, 16, 68, 159 and 243 ng/l of E2. The fecundity of Java-medaka exposed to E2 levels >16 ng/l was significantly lower than that of the control. The appearance of secondary sexual characteristics seemed to be inhibited by exposure to 159 and 243 ng/l E2. Vitellogenin concentrations in the liver of male fish exposed to 68, 159 and 243 ng/l were significantly higher than that of the control. Thirty-three and sixty percent of male fishes exposed to 159 and 243 ng/l, respectively, had testis-ova. These results suggest that reproduction in the Java-medaka, especially the male fish, could be affected by exposure to E2 concentrations greater than 16 ng/l.
    Matched MeSH terms: Oryzias/physiology*
  6. Kitahashi T, Ogawa S, Parhar IS
    Endocrinology, 2009 Feb;150(2):821-31.
    PMID: 18927220 DOI: 10.1210/en.2008-0940
    Newly discovered kisspeptin (metastin), encoded by the Kiss1/KISS1 gene, is considered as a major gatekeeper of puberty through the regulation of GnRH. In the present study, we cloned a novel kisspeptin gene (kiss2) in the zebrafish Danio rerio and the medaka Oryzias latipes, which encodes a sequence of 125 and 115 amino acids, respectively, and its core sequence (FNLNPFGLRF, F-F form) is different from the previously characterized kiss1 (YNLNSFGLRY, Y-Y form). Our in silico data mining shows kiss1 and kiss2 are highly conserved across nonmammalian vertebrate species, and we have identified two putative kisspeptins in the platypus and three forms in Xenopus. In the brain of zebrafish and medaka, in situ hybridization and laser capture microdissection coupled with real-time PCR showed kiss1 mRNA expression in the ventromedial habenula and the periventricular hypothalamic nucleus. The kiss2 mRNA expression was observed in the posterior tuberal nucleus and the periventricular hypothalamic nucleus. Quantitative real-time PCR analysis during zebrafish development showed a significant increase in zebrafish kiss1, kiss2 (P < 0.002), gnrh2, and gnrh3 (P < 0.001) mRNA levels at the start of the pubertal phase and remained high in adulthood. In sexually mature female zebrafish, Kiss2 but not Kiss1 administration significantly increased FSH-beta (2.7-fold, P < 0.05) and LH-beta (8-fold, P < 0.01) mRNA levels in the pituitary. These results suggest that the habenular Kiss1 and the hypothalamic Kiss2 are potential regulators of reproduction including puberty and that Kiss2 is the predominant regulator of gonadotropin synthesis in fish.
    Matched MeSH terms: Oryzias/genetics*; Oryzias/metabolism
  7. Hassan I, Wan Ibrahim WN, Yusuf FM, Ahmad SA, Ahmad S
    J Toxicol, 2020;2020:8815313.
    PMID: 33029137 DOI: 10.1155/2020/8815313
    Background: Pathophysiological changes leading to the death of nerve cells present in the brain and spinal cord are referred to as neurodegenerative diseases. Presently, treatment of these diseases is not effective and encounters many challenges due to the cost of drug and side effects. Thus, the search for the alternative agents to replace synthetic drugs is in high demand. Therefore, the aim of this study is to evaluate the anticholinesterase properties of Ginkgo biloba seed.

    Methods: The seed was extracted with 80% methanol. Toxicity studies and evaluation of anticholinesterase activities were carried out in adult Javanese medaka (Oryzias javanicus). Phytochemical study to identify the bioactive lead constituents of the crude extract was also carried out using high performance liquid chromatography (HPLC).

    Results: The result shows activities with high significant differences at P < 0.001 between the treated and nontreated groups. A bioactive compound (vitaxin) was identified with the aid of HPLC method.

    Conclusion: The presence of bioactive compound vitaxin is among the major secondary metabolites that contribute to increasing activities of this plant extract. High anticholinesterase activities and low toxicity effect of this plant show its benefit to be used as natural medicine or supplements.

    Matched MeSH terms: Oryzias
  8. Ibrahim MA, Zulkifli SZ, Azmai MNA, Mohamat-Yusuff F, Ismail A
    Animals (Basel), 2021 Mar 12;11(3).
    PMID: 33809309 DOI: 10.3390/ani11030798
    Compound 3,4-dichloroaniline (3,4-DCA) is a metabolite of several urea herbicides and intermediate chemical of several industrial products. Moreover, 3,4-DCA has been frequently detected in aquatic ecosystems around the world. This aniline is more toxic than the parent chemicals, and it affects non-target organisms. This study evaluated a 21-day reproductive response of an emerging aquatic vertebrate model, Javanese medaka (Oryzias javanicus), exposed to 3,4-DCA. Fecundity and gonads histopathology were observed. The spawning rate and fertilisation reduced significantly in the highest exposed-group (250 µg/L). Gonadosomatic index (GSI) was significantly low in females exposed to 250 µg/L. No substantial structural alteration of male gonads. However, oocyte development and ovarian cell structure were disrupted in 250 µg/L exposed females. The gonadal developmental was not affected in the males; however, a significant reduction in the developmental of female gonads was observed at 250 µg/L. These results show that 3,4-DCA interfere with the reproduction of Javanese medaka through fecundity and alteration of gonadal tissues.
    Matched MeSH terms: Oryzias
  9. Amal MNA, Zarif ST, Suhaiba MS, Aidil MRM, Shaqinah NN, Zamri-Saad M, et al.
    Microb Pathog, 2018 01;114:251-254.
    PMID: 29217326 DOI: 10.1016/j.micpath.2017.11.069
    This study describes the susceptibility of different fish gender following acute Streptococcus agalactiae infection by using Javanese medaka Oryzias javanicus as test fish. The fish were grouped into four groups, which were: (1) all-male; (2) all-female; (3) mixed-gender (1 male: 1 female ratio); and (4) control non-infected (1 male: 1 female ratio). The fish in group 1, 2 and 3 were intraperitoneally exposed to 5.4 × 108 CFU/mL of S. agalactiae, while for group 4, the fish were exposed using sterile broth. The main clinical signs and histopathological changes of infected Javanese medaka were commonly observed in S. agalactiae infected fishes. However, no difference on clinical signs and histopathological changes of fish in group 1, 2 and 3 were noticed. The Javanese medaka mortality in group 1, 2 and 3 were observed from 4 h post infection (hpi) to 6 hpi, with the cumulative mortality from 3% to 30%. Then, the mortality increased at 12 hpi, with the range from 53% to 80%. However, 100% of the infected fish dead at 24 hpi. No clinical sign, histopathological change and fish mortality recorded in group 4. Generally, the clinical signs, mortality patterns, cumulative mortality and histopathological changes of Javanese medaka infected by S. agalactiae did not show any difference between the all-male, all-female and mixed-gender groups. This indicates that the susceptibility of fish to S. agalactiae infection is not influenced by their gender.
    Matched MeSH terms: Oryzias/microbiology*
  10. Mohamat-Yusuff F, Sarah-Nabila AG, Zulkifli SZ, Azmai MNA, Ibrahim WNW, Yusof S, et al.
    Mar Pollut Bull, 2018 Feb;127:150-153.
    PMID: 29475647 DOI: 10.1016/j.marpolbul.2017.11.046
    This study was conducted to investigate the median lethal concentration (LC50) of copper pyrithione (CuPT) at 96-hr exposure on adult Javanese medaka (Oryzias javanicus) in revealing toxicological effects of CuPT contamination in the tropical area. Wild stock fishes were acclimatized for 14-days prior analysis. Triplicate of test tanks for seven test concentrations were placed with ten fishes each, this includes two control tanks. The behaviour of the tested fishes was manually observed through a camera. The LC50 of CuPT at 96-h was found to be 16.58mg/L. Tested fishes swam slowly in vertical movement and swam fast towards food during feeding time as the sign of stress behaviour. Meanwhile, fishes in the two control groups swam actively in a horizontal manner and no excitement during feeding time. No mortality in control groups. Results indicate CuPT to be toxic to Javanese medaka at low concentration and caused behavioural stress.
    Matched MeSH terms: Oryzias/physiology*
  11. Amal MNA, Ismail A, Saad MZ, Md Yasin IS, Nasruddin NS, Mastor SS, et al.
    Microb Pathog, 2019 Jun;131:47-52.
    PMID: 30940607 DOI: 10.1016/j.micpath.2019.03.034
    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 104 to 108 CFU/mL, and immersion (IM) route from 103 to 107 CFU/mL. The LD50-240h 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 103 CFU/mL and 104 CFU/mL, respectively. The LD50-240h of S. agalactiae in Javanese medaka was lower following IP injection (4.5 × 102 CFU/mL), compared to IM route (3.5 × 103 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 
    Matched MeSH terms: Oryzias/microbiology*
  12. Moriya S, Chourasia D, Ng KW, Khel NB, Parhar IS
    J. Chem. Neuroanat., 2016 11;77:24-29.
    PMID: 27134039 DOI: 10.1016/j.jchemneu.2016.04.005
    Immediate early response (IER) 2 gene, a member of the IER family, is a gene of unknown function which is affected by external stimuli in the brain. In the present study, the full length sequence and localization of medaka (Oryzias latipes) ier2 was investigated in the brain to understand the functions of Ier2 in the future studies. The full length sequence of medaka ier2 was identified using a 3'-, 5'- rapid amplification of cDNA ends method, and distribution in the brain was identified using in situ hybridization. The identified full length ier2 mRNA consisted of 939 nucleotides spanning along 1 exon. The deduced amino acid sequence consisted of 171 amino acid residues which contains a highly conserved sequence, nuclear localization signal. ier2 mRNA was distributed in the telencephalon, midbrain and the hypothalamus. This highly conserved primary response gene Ier2 can be used to visualize and map functionally activated neuronal circuitry in the brain of medaka.
    Matched MeSH terms: Oryzias/genetics*
  13. Ismail A, Yusof S
    Mar Pollut Bull, 2011;63(5-12):347-9.
    PMID: 21377175 DOI: 10.1016/j.marpolbul.2011.02.014
    Several organisms have been used as indicators, bio-monitoring agents or test organisms in ecotoxicological studies. A close relative of the well established Japanese medaka, the Java medaka (Oryzias javanicus), has the potential to be a test organism. The fish is native to the estuaries of the Malaysian Peninsula, Thailand, Indonesia and Singapore. In this study, newly fertilised eggs were exposed to different concentrations of Cd and Hg. Observations were done on the development of the embryos. Exposure to low levels of Cd and Hg (0.01-0.05 ppm) resulted in several developmental disorders that led to death. Exposure to ≥1.0 ppm Cd resulted in immediate developmental arrest. The embryos of Java medaka showed tolerance to a certain extent when exposed to ≥1.0 ppm Hg compared to Cd. Based on the sensitivity of the embryos, Java medaka is a suitable test organism for ecotoxicology in the tropical region.
    Matched MeSH terms: Oryzias
  14. Nurul Farhana Ramlan, Noraini Abu Bakar, Albert, Emmellie Laura, Syaizwan Zahmir Zulkifli, Syahida Ahmad, Mohammad Noor Amal Azmai, et al.
    An ideal model organism for neurotoxicology research should meet several characteristics, such as low cost and amenable for high throughput testing. Javanese medaka (JM) has been widely used in the ecotoxicological studies related to the marine and freshwater environment, but rarely utilized for biomedical research. Therefore, in this study, the applicability of using JM in the neurotoxicology research was assessed using biochemical comparison with an established model organism, the zebrafish. Identification of biochemical changes due to the neurotoxic effects of ethanol and endosulfan was assessed using Fourier Transform Infrared (FTIR) analysis. Treatment with ethanol affected the level of lipids, proteins, glycogens and nucleic acids in the brain of JM. Meanwhile, treatment with endosulfan showed alteration in the level of lipids and nucleic acids. For the zebrafish, exposure to ethanol affected the level of protein, fatty acid and amino acid, and exposure to endosulfan induced alteration in the fatty acids, amino acids, nucleic acids and protein in the brain of zebrafish. The sensitive response of the JM toward chemicals exposure proved that it was a valuable model for neurotoxicology research. More studies need to be conducted to further develop JM as an ideal model organism for neurotoxicology research.
    Matched MeSH terms: Oryzias
  15. Moriya S, Khel NB, Parhar IS
    Neuroscience, 2015 May 21;294:109-15.
    PMID: 25772790 DOI: 10.1016/j.neuroscience.2015.03.012
    Serotonin (5-HT) is a key regulator of mood and sexual behaviors. 5-HT reuptake inhibitors have been used as antidepressants. Really interesting new gene (RING) finger proteins have been associated with 5-HT regulation but their role remains largely unknown. Some RING finger proteins are involved in the serotonergic system, therefore, we speculate that the gene expression of RING finger protein38 (rnf38) is regulated by the serotonergic system. In the present study, we aimed to identify the full length sequence of medaka (Oryzias latipes) rnf38 mRNA and investigate its association with the serotonergic system using an antidepressant, citalopram (CIT). We identified the full length rnf38 cDNA, which consisted of 2726 nucleotides spanning 12 exons and the deduced protein sequence consisting of 518 amino acid residues including a RING finger domain, a KIT motif and a coiled-coil domain. Medaka exposed to 10(-7)M of CIT showed anxiety-like behavior. The expressions of 5-HT-related genes, pet1, solute carrier family 6, member 4A (slc6a4) and tryptophan hydroxylase (tph2) were significantly low (P<0.05) in the hindbrain. On the other hand, rnf38 gene was significantly high (P<0.05) in the telencephalon and the hypothalamus. This shows that 5-HT synthesis and transport in the hindbrain is suppressed by CIT, which induces rnf38 gene expression in the forebrain where 5-HT neurons project. Thus, the expression of rnf38 is negatively regulated by the serotonergic system.
    Matched MeSH terms: Oryzias
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