Expression profile of the fish immune enzyme l-amino acid oxidase (LAAO) after Streptococcus agalactiae infection in zebrafish (Danio rerio)

Huang, Yuxi; Han, Xiao; Peng, Huan; Li, An‐Xing; Li, Ruijun

doi:10.1016/j.dci.2021.104040

Cited by 6 publications

(3 citation statements)

References 33 publications

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“…Additionally, the identified LAO was found to exhibit antibacterial properties, inhibiting the growth of both Gram‐positive and Gram‐negative bacteria, with pronounced effectiveness against V. parahaemolyticus (Huang et al., 2021; Leu et al., 2021). It is a flavoenzyme widely distributed in vertebrates and mammals that can exhibit dual functionality in oxidation and immune response, involving phagocytosis and lymphocyte response (Kasai et al., 2021; Lukasheva et al., 2012).…”

Section: Discussionmentioning

confidence: 99%

Comparative proteome analysis revealed potential biomarkers and the underlying immune mechanisms in Vibrio‐resistant hybrid grouper, Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂

Abu Aziz,

Christianus,

Wan Solahudin

et al. 2024

Journal of Fish Diseases

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Vibrio alginolyticus is the causative agent of vibriosis, a common bacterial infection in grouper aquaculture that is associated with the development of haemorrhagic and non‐haemorrhagic ulcerations on the fish. In the present study, comparative proteome analysis was performed on serum samples from Vibrio‐resistant and Vibrio‐susceptible grouper. Samples were analysed using high‐throughput LC‐MS/MS and identified 2770 unique peptides that corresponded to 344 proteins. Subsequent analysis identified 21 proteins that were significantly up‐regulated in the resistant group compared to the control and the susceptible groups. Those proteins are associated with immunostimulatory effects, signalling and binding cascade, metabolism, and maintaining tissue integrity and physiological condition. Besides, potential protein biomarkers related to the immune system were identified, which could be associated with the disease‐resistant phenotype. These data provide insights into the underlying immune mechanism of hybrid groupers upon Vibrio sp. infection.

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Section: Discussionmentioning

confidence: 99%

Comparative proteome analysis revealed potential biomarkers and the underlying immune mechanisms in Vibrio‐resistant hybrid grouper, Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂

Abu Aziz,

Christianus,

Wan Solahudin

et al. 2024

Journal of Fish Diseases

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“…The fluorescent dye used in the qRT‐PCR was SYBR Green (Monad). Primers were designed against the housekeeping gene, rpl13α , and the LAAO gene (Huang et al, 2021). Next, qRT‐PCR was used to determine the expression levels of the LAAO gene in zebrafish liver, gills and spleen.…”

Section: Methodsmentioning

confidence: 99%

“…The fluorescent dye used in the qRT-PCR was SYBR Green (Monad). Primers were designed against the housekeeping gene, rpl13α, and the LAAO gene (Huang et al, 2021).…”

Section: Expression Analysis Of Laao After Challenge Experimentsmentioning

confidence: 99%

Analysis of inhibition mechanisms of Streptococcus agalactiae by Siganus oramin L‐amino acid oxidase

Huang

Han

Peng

et al. 2022

Aquaculture Research

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In a previous experiment, an L‐amino acid oxidase (LAAO) from the serum of Siganus oramin (SR) had a strong inhibitory effect on Streptococcus agalactiae. But we did not know inhibition mechanisms of SR‐LAAO against S. agalactiae. In this study, after S. agalactiae was treated with SR‐LAAO and hydrogen peroxide (H2O2) at the minimal bactericidal concentration, scanning and transmission electron microscopy showed that there are differences in cell size, degree of surface wrinkle and internal dissolution. These observations suggested that H2O2 can cause more serious damage to S. agalactiae than SR‐LAAO. The metabolites of S. agalactiae that has been treated with SR‐LAAO or H2O2 were analysed and compared. A total of 438 positive ion metabolites were detected and 129 were significantly different between SR‐LAAO and H2O2. We detected 351 negative ion metabolites, of which 104 were significantly different. It should be noted that in the differential amino acid analysis, L‐ergothioneine was the most significantly up‐regulated amino acid in the H2O2 treatment group, which suggested that it may be related to the function of SR‐LAAO. Direct mixing of L‐ergothioneine and SR‐LAAO did not extend the inhibition zone, which suggested that ergothioneine could not react directly with SR‐LAAO, to enhance the antibacterial ability. However, the results of challenge experiments and the qRT‐PCR experiment proved that ergothioneine can up‐regulate the expression of SR‐LAAO and reduce the mortality of S. agalactiae‐challenged zebrafish. This study further revealed the antibacterial mechanism of fish LAAO and provided a foundation for future research.

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Red-spotted grouper Epinephelus akaara blood l-amino acid oxidase utilizes the substrates in plasma

Kitani

2022

Fish Sci

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Abstractl-amino acid oxidases (LAOs) oxidatively deaminate l-amino acids and generate H2O2. Recently, a novel LAO was isolated from the red-spotted grouper Epinephelusakaara serum (EaLAO) and it showed antibacterial activity via H2O2. The enzymatic activity of EaLAO was normally suppressed in blood and was activated by mixing it with seawater. This phenomenon suggested that EaLAO may stand by as an inactive form in the body, and it functions as an antibacterial protein at the bleeding trauma sites. For pathogen protection by EaLAO at the wound site, instant H2O2 production is essential. In this work, the substrate source of EaLAO and the H2O2-generation potential of the grouper plasma were studied. Mixing plasma with seawater or cations generated 0.26–0.48 mM of H2O2 except for the addition of l-amino acid substrates. The amino acid quantification of plasma via fluorescent HPLC showed that the alanine was dominantly consumed after being mixed with seawater. The Vmax, Km, and turnover number of EaLAO with l-alanine at 25 °C in seawater were 1618 μU/reaction, 86.6 mM, and 10.6 s−1, respectively. Furthermore, Vibrioharveyi was 84% killed by the plasma–seawater mixture. These results suggested that l-alanine may be the primary substrate of EaLAO in plasma.

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Expression profile of the fish immune enzyme l-amino acid oxidase (LAAO) after Streptococcus agalactiae infection in zebrafish (Danio rerio)

Cited by 6 publications

References 33 publications

Comparative proteome analysis revealed potential biomarkers and the underlying immune mechanisms in Vibrio‐resistant hybrid grouper, Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂

Comparative proteome analysis revealed potential biomarkers and the underlying immune mechanisms in Vibrio‐resistant hybrid grouper, Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂

Analysis of inhibition mechanisms of Streptococcus agalactiae by Siganus oramin L‐amino acid oxidase

Red-spotted grouper Epinephelus akaara blood l-amino acid oxidase utilizes the substrates in plasma

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