Displaying publications 81 - 100 of 169 in total

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  1. Fulltext Use of Zebrafish Embryo Assay to Evaluate Toxicity and Safety of Bioreactor-Grown Exopolysaccharides and Endopolysaccharides from European Ganoderma applanatum Mycelium for Future Aquaculture Applications
    Wan-Mohtar WAAQI, Ilham Z, Jamaludin AA, Rowan N
    Int J Mol Sci, 2021 Feb 07;22(4).
    PMID: 33562361 DOI: 10.3390/ijms22041675
    Natural mycelial exopolysaccharide (EPS) and endopolysaccharide (ENS) extracted from bioreactor-cultivated European Ganoderma applanatum mushrooms are of potential high commercial value for both food and adjacent biopharmaceutical industries. In order to evaluate their potential toxicity for aquaculture application, both EPS (0.01-10 mg/mL) and ENS (0.01-10 mg/mL) extracts were tested for Zebrafish Embryo Toxicity (ZFET); early development effects on Zebrafish Embryos (ZE) were also analyzed between 24 and 120 h post-fertilization (HPF). Both EPS and ENS are considered non-toxic with LC50 of 1.41 mg/mL and 0.87 mg/mL respectively. Both EPS and ENS did not delay hatching and teratogenic defect towards ZE with <1.0 mg/mL, respectively. No significant changes in the ZE heart rate were detected following treatment with the two compounds tested (EPS: 0.01-10 mg/mL: 176.44 ± 0.77 beats/min and ENS: 0.01-10 mg/mL: 148.44 ± 17.75 beats/min) compared to normal ZE (120-180 beats/min). These initial findings support future pre-clinical trials in adult fish models with view to safely using EPS and ENS as potential feed supplements for supplements for development of the aquaculture industry.
    Matched MeSH terms: Zebrafish/growth & development*
  2. Fulltext 1H NMR metabolomics insights into comparative diabesity in male and female zebrafish and the antidiabetic activity of DL-limonene
    Benchoula K, Serpell CJ, Mediani A, Albogami A, Misnan NM, Ismail NH, et al.
    Sci Rep, 2024 Feb 15;14(1):3823.
    PMID: 38360784 DOI: 10.1038/s41598-023-45608-z
    Zebrafish have been utilized for many years as a model animal for pharmacological studies on diabetes and obesity. High-fat diet (HFD), streptozotocin and alloxan injection, and glucose immersion have all been used to induce diabetes and obesity in zebrafish. Currently, studies commonly used both male and female zebrafish, which may influence the outcomes since male and female zebrafish are biologically different. This study was designed to investigate the difference between the metabolites of male and female diabetic zebrafish, using limonene - a natural product which has shown several promising results in vitro and in vivo in treating diabetes and obesity-and provide new insights into how endogenous metabolites change following limonene treatment. Using HFD-fed male and female zebrafish, we were able to develop an animal model of T2D and identify several endogenous metabolites that might be used as diagnostic biomarkers for diabetes. The endogenous metabolites in males and females were different, even though both genders had high blood glucose levels and a high BMI. Treatment with limonene prevented high blood glucose levels and improved in diabesity zebrafish by limonene, through reversal of the metabolic changes caused by HFD in both genders. In addition, limonene was able to reverse the elevated expression of AKT during HFD.
    Matched MeSH terms: Zebrafish/metabolism
  3. Fulltext Behavioural, genomics and proteomic approach to examine Alzheimer's disease in zebrafish
    Siddiqui A, Abidin SAZ, Shah ZA, Othman I, Kumari Y
    Comp Biochem Physiol C Toxicol Pharmacol, 2023 Sep;271:109636.
    PMID: 37100105 DOI: 10.1016/j.cbpc.2023.109636
    Globally around 24 million elderly population are dealing with dementia, and this pathological characteristic is commonly seen in people suffering from Alzheimer's disease (AD). Despite having multiple treatment options that can mitigate AD symptoms, there is an imperative call to advance our understanding of the disease pathogenesis to unfold disease-modifying treatments/therapies. To explore the driving mechanisms of AD development, we stretch out further to study time-dependant changes after Okadaic acid (OKA)-induced AD-like conditions in zebrafish. We evaluated the pharmacodynamics of OKA at two-time points, i.e., after 4-days and 10-days exposure to zebrafish. T-Maze was utilized to observe the learning and cognitive behaviour, and inflammatory gene expressions such as 5-Lox, Gfap, Actin, APP, and Mapt were performed in zebrafish brains. To scoop everything out from the brain tissue, protein profiling was performed using LCMS/MS. Both time course OKA-induced AD models have shown significant memory impairment, as evident from T-Maze. Gene expression studies of both groups have reported an overexpression of 5-Lox, GFAP, Actin, APP, and OKA 10D group has shown remarkable upregulation of Mapt in zebrafish brains. In the case of protein expression, the heatmap suggested an important role of some common proteins identified in both groups, which can be explored further to investigate their mechanism in OKA-induced AD pathology. Presently, the preclinical models available to understand AD-like conditions are not completely understood. Hence, utilizing OKA in the zebrafish model can be of great importance in understanding the pathology of AD progression and as a screening tool for drug discovery.
    Matched MeSH terms: Zebrafish/metabolism
  4. The effects of metallothionein in paraquat-induced Parkinson disease model of zebrafish
    Mohamad Najib NH, Yahaya MF, Das S, Teoh SL
    Int J Neurosci, 2023 Dec;133(8):822-833.
    PMID: 34623211 DOI: 10.1080/00207454.2021.1990916
    INTRODUCTION: Parkinson's disease (PD) is the second most common neurodegenerative disease caused by selective degeneration of dopaminergic neurons in the substantia nigra. Metallothionein has been shown to act as a neuroprotectant in various brain injury. Thus, this study aims to identify the effects of full-length human metallothionein 2 peptide (hMT2) in paraquat-induced brain injury in the zebrafish.

    METHODOLOGY: A total of 80 adult zebrafish were divided into 4 groups namely control, paraquat-treated, pre-hMT2-treated, and post-hMT2-treated groups. Fish were treated with paraquat intraperitoneally every 3 days for 15 days. hMT2 were injected intracranially on day 0 (pre-treated group) and day 16 (post-treated group). Fish were sacrificed on day 22 and the brains were collected for qPCR, ELISA and immunohistochemistry analysis.

    RESULTS: qPCR analysis showed that paraquat treatment down-regulated the expression of genes related to dopamine activity and biosynthesis (dat and th1) and neuroprotective agent (bdnf). Paraquat treatment also up-regulated the expression of the mt2, smtb and proinflammatory genes (il-1α, il-1β, tnf-α and cox-2). hMT2 treatment was able to reverse the effects of paraquat. Lipid peroxidation decreased in the paraquat and pre-hMT2-treated groups. However, lipid peroxidation increased in the post-hMT2-treated group. Paraquat treatment also led to a reduction of dopaminergic neurons while their numbers showed an increase following hMT2 treatment.

    CONCLUSION: Paraquat has been identified as one of the pesticides that can cause the death of dopaminergic neurons and affect dopamine biosynthesis. Treatment with exogenous hMT2 could reverse the effects of paraquat in the zebrafish brain.

    Matched MeSH terms: Zebrafish/metabolism
  5. 1H NMR-metabolomics studies on acute toxicity effect of lead in adult zebrafish (Danio rerio) model
    Chong SG, Ismail IS, Chong CM, Mad Nasir N, Saleh Hodin NA
    Drug Chem Toxicol, 2024 Sep;47(5):573-586.
    PMID: 38726945 DOI: 10.1080/01480545.2024.2346751
    Zebrafish (Danio rerio) is ideal for studying the effects of toxins like lead or plumbum (Pb) which persist in the environment and harm body systems when absorbed. Increasing Pb concentration could result in a higher mortality rate and alteration of behavior and metabolism. The present study evaluates the acute toxicity effect of Pb on metabolome and behavior in adult zebrafish. The zebrafish were exposed to various Pb concentrations ranging from 0 to 30 mg/L for different periods (24, 48, and 72 h) before the fish samples were subjected to Nuclear Magnetic Resonance (NMR)-multivariate data analysis (MVDA) with additional support from behavioral assessment. The behavior of zebrafish was significantly altered after Pb inducement and the differential metabolites increased in low (5 mg/L) while decreased in high (10 mg/L) Pb concentrations. An ideal Pb induction could be achieved by 5 mg/L concentration in 24 h, which induced significant metabolite changes without irreversible damage. Continuing research on the effects of lead toxicity is crucial to develop effective prevention and treatment strategies.
    Matched MeSH terms: Zebrafish*
  6. Fulltext Beyond drug discovery: Exploring the physiological and methodological dimensions of zebrafish in diabetes research
    Roohi TF, Faizan S, Shaikh MF, Krishna KL, Mehdi S, Kinattingal N, et al.
    Exp Physiol, 2024 Jun;109(6):847-872.
    PMID: 38279951 DOI: 10.1113/EP091587
    Diabetes mellitus is a chronic disease that is now considered a global epidemic. Chronic diabetes conditions include type 1 and type 2 diabetes, both of which are normally irreversible. As a result of long-term uncontrolled high levels of glucose, diabetes can progress to hyperglycaemic pathologies, such as cardiovascular diseases, retinopathy, nephropathy and neuropathy, among many other complications. The complete mechanism underlying diabetes remains unclear due to its complexity. In this scenario, zebrafish (Danio rerio) have arisen as a versatile and promising animal model due to their good reproducibility, simplicity, and time- and cost-effectiveness. The Zebrafish model allows us to make progress in the investigation and comprehension of the root cause of diabetes, which in turn would aid in the development of pharmacological and surgical approaches for its management. The current review provides valuable reference information on zebrafish models, from the first zebrafish diabetes models using genetic, disease induction and chemical approaches, to the newest ones that further allow for drug screening and testing. This review aims to update our knowledge related to diabetes mellitus by gathering the most authoritative studies on zebrafish as a chemical, dietary and insulin induction, and genetic model for diabetes research.
    Matched MeSH terms: Zebrafish*
  7. Fulltext Aromatic compounds and organic acids identified from Ganoderma formosanum exhibit synergistic anti-melanogenic effects
    Hsieh CC, Hou CY, Lei HY, Khumsupan D, Chai HJ, Lim PK, et al.
    J Food Drug Anal, 2024 Dec 15;32(4):532-543.
    PMID: 39752867 DOI: 10.38212/2224-6614.3509
    This study reveals the anti-tyrosinase activity of Ganoderma formosanum extracts, pinpointing compounds including gluconic acid, mesalamine, L-pyroglutamic acid, esculetin, 5-hydroxyindole, and salicylic acid, as effective melanin production inhibitors in melanoma cells and zebrafish embryos. Furthermore, multiple molecular docking simulations provided insights into interactions between the identified compounds and tyrosinase, increasing binding affinity up to -16.36 kcal/mol. The enhanced binding of identified compounds to tyrosinase facilitated synergistic inhibitory effects on melanin production. This study highlights the potential of GFE-EA as a source of natural tyrosinase inhibitors and contributes to understanding the role of active compounds extracted from G. formosanum.
    Matched MeSH terms: Zebrafish*
  8. Features of the rare pathogen Meyerozyma guilliermondii strain SO and comprehensive in silico analyses of its adherence-contributing virulence factor agglutinin-like sequences
    Lim SJ, Muhd Noor ND, Sabri S, Mohamad Ali MS, Salleh AB, Oslan SN
    J Biomol Struct Dyn, 2025 Apr;43(7):3728-3748.
    PMID: 38189364 DOI: 10.1080/07391102.2023.2300757
    Meyerozyma guilliermondii is a rare yeast pathogen contributing to the deadly invasive candidiasis. M. guilliermondii strain SO, as a promising protein expression host, showed 99% proteome similarity with the clinically isolated ATCC 6260 (type strain) in a recent comparative genomic analysis. However, their in vitro virulence features and in vivo pathogenicity were uncharacterized. This study aimed to characterize the in vitro and in vivo pathogenicity of M. guilliermondii strain SO and analyze its Als proteins (MgAls) via comprehensive bioinformatics approaches. M. guilliermondii strain SO showed lower and higher sensitivity towards β-mercaptoethanol and lithium, respectively than the avirulent S. cerevisiae but exhibited the same tolerance towards cell wall-perturbing Congo Red with C. albicans. With 7.5× higher biofilm mass, M. guilliermondii strain SO also demonstrated 75% higher mortality rate in the zebrafish embryos with a thicker biofilm layer on the chorion compared to the avirulent S. cerevisiae. Being one of the most important Candida adhesins, sequence and structural analyses of four statistically identified MgAls showed that MgAls1056 was predicted to exhibit the most conserved amyloid-forming regions, tandem repeat domain and peptide binding cavity (PBC) compared to C. albicans Als3. Favoured from the predicted largest ligand binding site and druggable pockets, it showed the highest affinity towards hepta-threonine. Non-PBC druggable pockets in the most potent virulence contributing MgAls1056 provide new insights into developing antifungal drugs targeting non-albicans Candida spp. Virtual screening of available synthetic or natural bioactive compounds and MgAls1056 deletion from the fungal genome should be further performed and validated experimentally.
    Matched MeSH terms: Zebrafish*
  9. Fulltext FAT1 mutations cause a glomerulotubular nephropathy
    Gee HY, Sadowski CE, Aggarwal PK, Porath JD, Yakulov TA, Schueler M, et al.
    Nat Commun, 2016 Feb 24;7:10822.
    PMID: 26905694 DOI: 10.1038/ncomms10822
    Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease (CKD). Here we show that recessive mutations in FAT1 cause a distinct renal disease entity in four families with a combination of SRNS, tubular ectasia, haematuria and facultative neurological involvement. Loss of FAT1 results in decreased cell adhesion and migration in fibroblasts and podocytes and the decreased migration is partially reversed by a RAC1/CDC42 activator. Podocyte-specific deletion of Fat1 in mice induces abnormal glomerular filtration barrier development, leading to podocyte foot process effacement. Knockdown of Fat1 in renal tubular cells reduces migration, decreases active RAC1 and CDC42, and induces defects in lumen formation. Knockdown of fat1 in zebrafish causes pronephric cysts, which is partially rescued by RAC1/CDC42 activators, confirming a role of the two small GTPases in the pathogenesis. These findings provide new insights into the pathogenesis of SRNS and tubulopathy, linking FAT1 and RAC1/CDC42 to podocyte and tubular cell function.
    Matched MeSH terms: Zebrafish; Zebrafish Proteins/genetics*
  10. Fulltext Sexual Dimorphic Distribution of Hypothalamic Tachykinin1 Cells and Their Innervations to GnRH Neurons in the Zebrafish
    Ogawa S, Ramadasan PN, Anthonysamy R, Parhar IS
    Front Endocrinol (Lausanne), 2020;11:534343.
    PMID: 33763023 DOI: 10.3389/fendo.2020.534343
    Substance P (SP) and neurokinin A (NKA), encoded by TAC1/Tac1 gene are members of the tachykinin family, which exert their neuromodulatory roles in vertebrate reproduction. In mammals, SP and NKA have been shown to regulate gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion via kisspeptin neurons. On the other hand, the role of SP/NKA in the regulation of reproduction in non-mammalian vertebrates is not well known. In the present study, we first localized expression of tac1 mRNA in the brain of male and female zebrafish, Danio rerio. Next, using an antibody against zebrafish tachykinin1 (Tac1), we examined the neural association of SP/NKA neural processes with GnRH3 neurons, and with kisspeptin (kiss2) neurons, in the brains of male and female zebrafish. In situ hybridization showed an apparent male-dominant tac1 expression in the ventral telencephalic area, the anterior and posterior parts of the parvocellular preoptic nucleus, and the suprachiasmatic nucleus. On the other hand, there was female-dominant tac1 expression in the ventral periventricular hypothalamus. Confocal images of double-labeled zebrafish Tac1 and GnRH3 showed associations between Tac1-immunoreactive processes and GnRH3 neurons in the ventral telencephalic area. In contrast, there was no apparent proximity of Tac1 processes to kiss2 mRNA-expressing neurons in the hypothalamus. Lastly, to elucidate possible direct action of SP/NKA on GnRH3 or Kiss2 neurons, expression of SP/NKA receptor, tacr1a mRNA was examined in regions containing GnRH3 or Kiss2 neurons by in situ hybridization. Expression of tacr1a mRNA was seen in several brain regions including the olfactory bulb, preoptic area and hypothalamus, where GnRH3 and Kiss2 cells are present. These results suggest that unlike in mammals, Tac1 may be involved in male reproductive functions via direct action on GnRH3 neurons but independent of kisspeptin in the zebrafish.
    Matched MeSH terms: Zebrafish; Zebrafish Proteins/metabolism
  11. Fulltext Deep Brain Photoreceptor (val-opsin) Gene Knockout Using CRISPR/Cas Affects Chorion Formation and Embryonic Hatching in the Zebrafish
    Hang CY, Moriya S, Ogawa S, Parhar IS
    PLoS One, 2016;11(10):e0165535.
    PMID: 27792783 DOI: 10.1371/journal.pone.0165535
    Non-rod non-cone photopigments in the eyes and the brain can directly mediate non-visual functions of light in non-mammals. This was supported by our recent findings on vertebrate ancient long (VAL)-opsin photopigments encoded by the val-opsinA (valopa) and val-opsinB (valopb) genes in zebrafish. However, the physiological functions of valop isoforms remain unknown. Here, we generated valop-mutant zebrafish using CRISPR/Cas genome editing, and examined the phenotypes of loss-of-function mutants. F0 mosaic mutations and germline transmission were confirmed via targeted insertions and/or deletions in the valopa or valopb gene in F1 mutants. Based on in silico analysis, frameshift mutations converted VAL-opsin proteins to non-functional truncated forms with pre-mature stop codons. Most F1 eggs or embryos from F0 female valopa/b mutants showed either no or only partial chorion elevation, and the eggs or embryos died within 26 hour-post-fertilization. However, most F1 embryos from F0 male valopa mutant developed but hatched late compared to wild-type embryos, which hatched at 4 day-post-fertilization. Late-hatched F1 offspring included wild-type and mutants, indicating the parental effects of valop knockout. This study shows valop gene knockout affects chorion formation and embryonic hatching in the zebrafish.
    Matched MeSH terms: Zebrafish/embryology*; Zebrafish/genetics*
  12. Diurnal Rhythm of trek2a Expression is Associated with Diurnal Rhythm of gnrh3 Expression in Zebrafish
    Loganathan K, Moriya S, Parhar IS
    Zoolog Sci, 2019 04 01;36(2):167-171.
    PMID: 31120653 DOI: 10.2108/zs180111
    The two-pore domain potassium ion (K + ) channel-related K + (TREK) channel and melatonin receptors play roles in the regulation of reproduction in zebrafish. Since reproduction is regulated by diurnal rhythms, the TREK family and melatonin receptors may exhibit diurnal rhythms in expression. In this study, we aimed to investigate diurnal variations of the gene expressions of TREK family and melatonin receptors and their associations with kisspeptin and gonadotrophin-releasing hormone (GnRH). Diurnal variations of trek1b, trek2a, trek2b, mt1, mt2, mel1a, kiss2 and gnrh3 expressions were examined by real-time PCR. For reproduction-related genes, kiss2 and gnrh3 exhibited diurnal rhythms. trek2a revealed a diurnal rhythm in the TREK family. mt2 and mel1c exhibited diurnal rhythms in the melatonin receptors. Since Trek2a regulates gnrh3 expression, the diurnal rhythm of gnrh3 expression suggests to be regulated by the diurnal rhythm of trek2a expression.
    Matched MeSH terms: Zebrafish/genetics; Zebrafish/metabolism*
  13. Fulltext In Vivo Toxicity Evaluation of Sugar Adulterated Heterotrigona itama Honey Using Zebrafish Model
    Fakhlaei R, Selamat J, Razis AFA, Sukor R, Ahmad S, Amani Babadi A, et al.
    Molecules, 2021 Oct 15;26(20).
    PMID: 34684803 DOI: 10.3390/molecules26206222
    Honey is prone to be adulterated through mixing with sugars, cheap and low-quality honey, and other adulterants. Consumption of adulterated honey may cause several health issues such as weight gain, diabetes, and liver and kidney dysfunction. Therefore, studying the impact of consumption of adulterated honey on consumers is critical since there is a lack of study in this field. Hence, the aims of this paper were: (1) to determine the lethal concentration (LC50) of adulterated honey using zebrafish embryo, (2) to elucidate toxicology of selected adulterated honey based on lethal dose (LD50) using adult zebrafish, (3) to determine the effects of adulterated honey on histological changes of zebrafish, and (4) to screen the metabolites profile of adulterated honey by using zebrafish blood serum. The LC50 of Heterotrigona itama honey (acacia honey) and its sugar adulterants (light corn sugar, cane sugar, inverted sugar, and palm sugar in the proportion of 1-3% (w/w) from the total volume) was determined by the toxicological assessment of honey samples on zebrafish embryos (different exposure concentrations in 24, 48, 72, and 96 h postfertilization (hpf)). Pure H. itama honey represents the LC50 of 34.40 ± 1.84 (mg/mL) at 96 hpf, while the inverted sugar represents the lowest LC50 (5.03 ± 0.92 mg/mL) among sugar adulterants. The highest concentration (3%) of sugar adulterants were used to study the toxicology of adulterated honey using adult zebrafish in terms of acute, prolong-acute, and sub-acute tests. The results of the LD50 from the sub-acute toxicity test of pure H. itama honey was 2.33 ± 0.24 (mg/mL). The histological studies of internal organs showed a lesion in the liver, kidney, and spleen of adulterated treated-honey groups compared to the control group. Furthermore, the LC-MS/MS results revealed three endogenous metabolites in both the pure and adulterated honey treated groups, as follows: (1) S-Cysteinosuccinic acid, (2) 2,3-Diphosphoglyceric acid, and (3) Cysteinyl-Tyrosine. The results of this study demonstrated that adulterated honey caused mortality, which contributes to higher toxicity, and also suggested that the zebrafish toxicity test could be a standard method for assessing the potential toxicity of other hazardous food additives. The information gained from this research will permit an evaluation of the potential risk associated with the consumption of adulterated compared to pure honey.
    Matched MeSH terms: Zebrafish/blood; Zebrafish/embryology
  14. Fulltext RAC1 Missense Mutations in Developmental Disorders with Diverse Phenotypes
    Reijnders MRF, Ansor NM, Kousi M, Yue WW, Tan PL, Clarkson K, et al.
    Am J Hum Genet, 2017 Sep 07;101(3):466-477.
    PMID: 28886345 DOI: 10.1016/j.ajhg.2017.08.007
    RAC1 is a widely studied Rho GTPase, a class of molecules that modulate numerous cellular functions essential for normal development. RAC1 is highly conserved across species and is under strict mutational constraint. We report seven individuals with distinct de novo missense RAC1 mutations and varying degrees of developmental delay, brain malformations, and additional phenotypes. Four individuals, each harboring one of c.53G>A (p.Cys18Tyr), c.116A>G (p.Asn39Ser), c.218C>T (p.Pro73Leu), and c.470G>A (p.Cys157Tyr) variants, were microcephalic, with head circumferences between -2.5 to -5 SD. In contrast, two individuals with c.151G>A (p.Val51Met) and c.151G>C (p.Val51Leu) alleles were macrocephalic with head circumferences of +4.16 and +4.5 SD. One individual harboring a c.190T>G (p.Tyr64Asp) allele had head circumference in the normal range. Collectively, we observed an extraordinary spread of ∼10 SD of head circumferences orchestrated by distinct mutations in the same gene. In silico modeling, mouse fibroblasts spreading assays, and in vivo overexpression assays using zebrafish as a surrogate model demonstrated that the p.Cys18Tyr and p.Asn39Ser RAC1 variants function as dominant-negative alleles and result in microcephaly, reduced neuronal proliferation, and cerebellar abnormalities in vivo. Conversely, the p.Tyr64Asp substitution is constitutively active. The remaining mutations are probably weakly dominant negative or their effects are context dependent. These findings highlight the importance of RAC1 in neuronal development. Along with TRIO and HACE1, a sub-category of rare developmental disorders is emerging with RAC1 as the central player. We show that ultra-rare disorders caused by private, non-recurrent missense mutations that result in varying phenotypes are challenging to dissect, but can be delineated through focused international collaboration.
    Matched MeSH terms: Zebrafish/genetics; Zebrafish/growth & development
  15. Fulltext Transcriptional activation of zebrafish fads2 promoter and its transient transgene expression in yolk syncytial layer of zebrafish embryos
    Tay SS, Kuah MK, Shu-Chien AC
    Sci Rep, 2018 03 01;8(1):3874.
    PMID: 29497119 DOI: 10.1038/s41598-018-22157-4
    The front-end desaturases (Fads) are rate-limiting enzymes responsible for production of long-chain polyunsaturated fatty acids (LC-PUFA). The full spectrum of the transcriptional regulation of fads is still incomplete, as cloning of fads promoter is limited to a few species. Here, we described the cloning and characterisation of the zebrafish fads2 promoter. Using 5'-deletion and mutation analysis on this promoter, we identified a specific region containing the sterol regulatory element (SRE) which is responsible for the activation of the fads2 promoter. In tandem, two conserved CCAAT boxes were also present adjacent to the SRE and mutation of either of these binding sites attenuates the transcriptional activation of the fads2 promoter. An in vivo analysis employing GFP reporter gene in transiently transfected zebrafish embryos showed that this 1754 bp upstream region of the fads2 gene specifically directs GFP expression in the yolk syncytial layer (YSL) region. This indicates a role for LC-PUFA in the transport of yolk lipids through this tissue layer. In conclusion, besides identifying novel core elements for transcriptional activation in zebrafish fads2 promoter, we also reveal a potential role for fads2 or LC-PUFA in YSL during development.
    Matched MeSH terms: Zebrafish/embryology*; Zebrafish/genetics*
  16. Trek2a regulates gnrh3 expression under control of melatonin receptor Mt1 and α2-adrenoceptor
    Loganathan K, Moriya S, Parhar IS
    Biochem Biophys Res Commun, 2018 02 12;496(3):927-933.
    PMID: 29395088 DOI: 10.1016/j.bbrc.2018.01.117
    Gonadotrophin-releasing hormone (GnRH) expression is associated with the two-pore domain potassium ion (K+) channel-related K+ (TREK) channel trek2a expression and melatonin levels. We aimed to investigate correlation of trek2a expression with gnrh3 expression, and regulatory mechanisms of trek2a expression by the melatonin receptor Mt1 and α2-adrenoceptor which are regulated by melatonin. trek2a specific siRNA, Mt1 antagonist luzindole and α2-adrenoceptor antagonist prazosin were administered into the adult zebrafish brain and gene expressions were examined by real-time PCR. trek2a specific siRNA administration significantly reduced expression levels of trek2a, gnrh3 and mt1. Luzindole administration suppressed trek2a and gnrh3 expressions. Prazosin administration reduced trek2a and gnrh3 expressions. It is suggested that Trek2a regulates gnrh3 expression under the control of Mt1 and α2-adrenoceptor.
    Matched MeSH terms: Zebrafish; Zebrafish Proteins/metabolism*
  17. Fulltext Reproductive Neuroendocrine Pathways of Social Behavior
    Parhar IS, Ogawa S, Ubuka T
    Front Endocrinol (Lausanne), 2016;7:28.
    PMID: 27065948 DOI: 10.3389/fendo.2016.00028
    Social behaviors are key components of reproduction, because they are essential for successful fertilization. Social behaviors, such as courtship, mating, and aggression, are strongly associated with sex steroids, such as testosterone, estradiol, and progesterone. Secretion of sex steroids from the gonads is regulated by the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Gonadotropin-releasing hormone (GnRH) is a pivotal hypothalamic neuropeptide that stimulates gonadotropin release from the pituitary. In recent years, the role of neuropeptides containing the C-terminal Arg-Phe-NH2 (RFamide peptides) has been emphasized in vertebrate reproduction. In particular, two key RFamide peptides, kisspeptin and gonadotropin-inhibitory hormone (GnIH), emerged as critical accelerator and suppressor of gonadotropin secretion. Kisspeptin stimulates GnRH release by directly acting on GnRH neurons, whereas GnIH inhibits gonadotropin release by inhibiting kisspeptin, GnRH neurons, or pituitary gonadotropes. These neuropeptides can regulate social behavior by regulating the HPG axis. However, distribution of neuronal fibers of GnRH, kisspeptin, and GnIH neurons is not limited within the hypothalamus, and the existence of extrahypothalamic neuronal fibers suggests direct control of social behavior within the brain. It has traditionally been shown that central administration of GnRH can stimulate female sexual behavior in rats. Recently, it was shown that Kiss1, one of the paralogs of kisspeptin peptide family, regulates fear responses in zebrafish and GnIH inhibits sociosexual behavior in birds. Here, we highlight recent findings regarding the role of GnRH, kisspeptin, and GnIH in the regulation of social behaviors in fish, birds, and mammals and discuss their importance in future biological and biomedical research.
    Matched MeSH terms: Zebrafish
  18. Fulltext Effects of Pegagan (Centella asiatica L.) Ethanolic Extract SNEDDS (Self-nanoemulsifying Drug Delivery Systems) on the Development of Zebrafish (Danio rerio) Embryos
    Hayati F, Chabib L, Fauzi IS, Awaluddin R, Sumayya, Faizah WS, et al.
    J Pharm Bioallied Sci, 2020 10 08;12(4):457-461.
    PMID: 33679093 DOI: 10.4103/jpbs.JPBS_297_19
    Introduction: Pegagan is a traditional medicinal plant with three major bioactive properties, triterpenoid, steroids, and saponin. It has the properties of antioxidant, antistress, and wound healing. Pegagan extract is prepared in self-nanoemulsifying drug delivery systems (SNEDDS) to overcome the problem of low water-solubility level.

    Objectives: This study aimed to observe the effect of pegagan ethanolic extract SNEDDS on the development of zebrafish embryos.

    Materials and Methods: This study used 12 sets of zebrafish embryos presented in five sets of extract SNEDDS with different concentrations, that is, 20, 10, 5, 2.5, and 1.25 μg, five sets of SNEDDS without extract with different concentrations, that is, 20, 10, 5, 2.5, and 1.25 μg, a set of positive control (3.4-DCA 4 mg/L) with one control set (diluted with water), and a negative control (SNEDDS without extract). The procedure was conducted for 96 h with observations every 24 h. The parameters observed were embryonic coagulation, formation of somites, detachment of tail bud from the yolk, and abnormality of embryo.

    Results: The results showed that in 96 h the 20ppm concentration caused 100% mortality. Embryo abnormality appeared as coagulation of embryo, somite malformation, and abnormal tail.

    Discussion: There is a correlation between the concentration of SNEDDS and the incidence of embryo coagulation. The malformation in the group of pegagan extract SNEDDS is characterized by cardiac edema, somite malformation, and abnormal tail.

    Conclusion: Pegagan ethanolic extract SNEDDS of 20ppm can inhibit the development of zebrafish embryos.

    Matched MeSH terms: Zebrafish
  19. Fulltext Toxicity assessment of gallic acid loaded graphene oxide (GAGO) nano-formulation in zebrafish (Danio Rerio) embryos
    Ahmad Ashraful Hadi Abdul Ghafor, Nurhuda Elias, Suhaili Shams, Faizah Md Yasin, Sarchio, Seri Narti Edayu
    Pertanika Journal of Science & Technology, 2020;28(1):311-326.
    MyJurnal
    Gallic acid (GA) is a phenolic compound found in almost all plants and has been reported to possess powerful health benefits such as anti-oxidant, anti-inflammatory, anti-cancer, and anti-diabetic properties. However, GA suffers a short half-life when administered in vivo. Recent studies have employed graphene oxide (GO), a biocompatible and cost-effective graphene derivative, as a nanocarrier for GA. However, the toxicity effect of this formulated nano-compound has not been fully studied. Thus, the present study aims to evaluate the toxicity and teratogenicity of GA loaded GO (GAGO) against zebrafish embryogenesis to further advance the development of GA as a therapeutic agent. GAGO was exposed to zebrafish embryos (n ≥ 10; 24hr post fertilization (hpf)) at different concentrations (0-500 μg/ml). The development of zebrafish was observed and recorded twice daily for four days. The toxicity of pure GO and GA was also observed at similar concentrations. Distilled water was used as control throughout the experiment. A significantly high mortality rate, delayed hatching rate and low heartbeat were recorded in embryos exposed to GO at concentrations of ≥ 150 μg/ml at 48 hr (p
    Matched MeSH terms: Zebrafish
  20. Fulltext Orthosiphon stamineus Proteins Alleviate Pentylenetetrazol-Induced Seizures in Zebrafish
    Chung YS, Choo BKM, Ahmed PK, Othman I, Shaikh MF
    Biomedicines, 2020 Jul 02;8(7).
    PMID: 32630817 DOI: 10.3390/biomedicines8070191
    The anticonvulsive potential of proteins extracted from Orthosiphon stamineus leaves (OSLP) has never been elucidated in zebrafish (Danio rerio). This study thus aims to elucidate the anticonvulsive potential of OSLP in pentylenetetrazol (PTZ)-induced seizure model. Physical changes (seizure score and seizure onset time, behavior, locomotor) and neurotransmitter analysis were elucidated to assess the pharmacological activity. The protective mechanism of OSLP on brain was also studied using mass spectrometry-based label-free proteomic quantification (LFQ) and bioinformatics. OSLP was found to be safe up to 800 µg/kg and pre-treatment with OSLP (800 µg/kg, i.p., 30 min) decreased the frequency of convulsive activities (lower seizure score and prolonged seizure onset time), improved locomotor behaviors (reduced erratic swimming movements and bottom-dwelling habit), and lowered the excitatory neurotransmitter (glutamate). Pre-treatment with OSLP increased protein Complexin 2 (Cplx 2) expression in the zebrafish brain. Cplx2 is an important regulator in the trans-SNARE complex which is required during the vesicle priming phase in the calcium-dependent synaptic vesicle exocytosis. Findings in this study collectively suggests that OSLP could be regulating the release of neurotransmitters via calcium-dependent synaptic vesicle exocytosis mediated by the "Synaptic Vesicle Cycle" pathway. OSLP's anticonvulsive actions could be acting differently from diazepam (DZP) and with that, it might not produce the similar cognitive insults such as DZP.
    Matched MeSH terms: Zebrafish
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