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  1. Acute and chronic effects of the insecticide-endosulfan on freshwater cladoceran, Moina macrocopa straus
    Chuah TS, Loh JY, Hii YS
    Bull Environ Contam Toxicol, 2007 Nov;79(5):557-61.
    PMID: 17639329
    Acute and chronic effects of insecticide-endosulfan on the survival and reproduction performance of Moina macrocopa were determined in a laboratory study. Endosulfan concentrations that cause 50% mortality (LC50) after exposure for 24 and 48 h were 3.34 and 0.16 mg L(-1), respectively. Average longevity, initial age of reproduction and intrinsic rate of natural increase were reduced at 0.002 mg L(-1). Fecundity was greatly reduced by about 70% at 0.0004 mg L(-1) and approximately 97% at 0.002 mg L(-1) as compared to control organisms throughout the whole life span of 15 days. If environmental concentration of endosulfan do not exceed 0.0004 mg L(-1), application of this insecticide is unlikely to induce detrimental effects on these cladoceran populations in agro-ecosystem.
  2. Bioencapsulation and Colonization Characteristics of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana: a Biological Approach for the Control of Edwardsiellosis in Larviculture
    Loh JY, Kay GL, Ting ASY
    Mar Biotechnol (NY), 2018 Jun;20(3):353-362.
    PMID: 29654379 DOI: 10.1007/s10126-018-9813-9
    Predominance of beneficial bacteria helps to establish a healthy microbiota in fish gastrointestinal system and thus to reduce emerging pathogen. In this study, the colonization efficacy of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana and its potential as a probiotic in suppressing Edwardsiella sp. infection were investigated in vivo. The colonization extent of the bioencapsulated L. lactis was established through visualization of gfp gene-transformed L. lactis in A. franciscana. Here, we demonstrate that when A. franciscana is administrated with L. lactis at 108 CFU mL-1 for 8 h, the highest relative percentage of survival (RPS = 50.0) is observed after inoculation with Edwardsiella sp. The total counts of L. lactis entrapped in Artemia were the highest (ranged from 3.2 to 5.1 × 108 CFU mL-1), when 108-109 CFU mL-1 of L. lactis was used as starting inoculum, with the bioencapsulation performed within 8-24 h. Fluorescent microscopy showed gfp-transformed L. lactis colonized the external trunk surfaces, mid-gut and locomotion antennules of the A. franciscana nauplii. These illustrations elucidate the efficiency of colonization of L. lactis in the gastrointestinal tract and on the body surfaces of Artemia. In conclusion, L. lactis subsp. lactis CF4MRS shows a good efficacy of colonization in Artemia and has the potential for biocontrol/probiotic activity against Edwardsiella sp. infection.
  3. Fulltext Gut Immune System and the Implications of Oral-Administered Immunoprophylaxis in Finfish Aquaculture
    Lee PT, Yamamoto FY, Low CF, Loh JY, Chong CM
    Front Immunol, 2021;12:773193.
    PMID: 34975860 DOI: 10.3389/fimmu.2021.773193
    The gastrointestinal immune system plays an important role in immune homeostasis regulation. It regulates the symbiotic host-microbiome interactions by training and developing the host's innate and adaptive immunity. This interaction plays a vital role in host defence mechanisms and at the same time, balancing the endogenous perturbations of the host immune homeostasis. The fish gastrointestinal immune system is armed with intricate diffused gut-associated lymphoid tissues (GALTs) that establish tolerance toward the enormous commensal gut microbiome while preserving immune responses against the intrusion of enteric pathogens. A comprehensive understanding of the intestinal immune system is a prerequisite for developing an oral vaccine and immunostimulants in aquaculture, particularly in cultured fish species. In this review, we outline the remarkable features of gut immunity and the essential components of gut-associated lymphoid tissue. The mechanistic principles underlying the antigen absorption and uptake through the intestinal epithelial, and the subsequent immune activation through a series of molecular events are reviewed. The emphasis is on the significance of gut immunity in oral administration of immunoprophylactics, and the different potential adjuvants that circumvent intestinal immune tolerance. Comprehension of the intestinal immune system is pivotal for developing effective fish vaccines that can be delivered orally, which is less labour-intensive and could improve fish health and facilitate disease management in the aquaculture industry.
  4. Retrospective insights into recent MXene-based catalysts for CO2 electro/photoreduction: how far have we gone?
    Tan XQ, Mo W, Lin X, Loh JY, Mohamed AR, Ong WJ
    Nanoscale, 2023 Apr 06;15(14):6536-6562.
    PMID: 36942445 DOI: 10.1039/d2nr05718b
    The electro/photocatalytic CO2 reduction reaction (CO2RR) is a long-term avenue toward synthesizing renewable fuels and value-added chemicals, as well as addressing the global energy crisis and environmental challenges. As a result, current research studies have focused on investigating new materials and implementing numerous fabrication approaches to increase the catalytic performances of electro/photocatalysts toward the CO2RR. MXenes, also known as 2D transition metal carbides, nitrides, and carbonitrides, are intriguing materials with outstanding traits. Since their discovery in 2011, there has been a flurry of interest in MXenes in electrocatalysis and photocatalysis, owing to their several benefits, including high mechanical strength, tunable structure, surface functionality, high specific surface area, and remarkable electrical conductivity. Herein, this review serves as a milestone for the most recent development of MXene-based catalysts for the electrocatalytic and photocatalytic CO2RR. The overall structure of MXenes is described, followed by a summary of several synthesis pathways classified as top-down and bottom-up approaches, including HF-etching, in situ HF-formation, electrochemical etching, and halogen etching. Additionally, the state-of-the-art development in the field of both the electrocatalytic and photocatalytic CO2RR is systematically reviewed. Surface termination modulation and heterostructure engineering of MXene-based electro/photocatalysts, and insights into the reaction mechanism for the comprehension of the structure-performance relationship from the CO2RR via density functional theory (DFT) have been underlined toward activity enhancement. Finally, imperative issues together with future perspectives associated with MXene-based electro/photocatalysts are proposed.
  5. Calcium lignosulfonate improves proliferation of recalcitrant indica rice callus via modulation of auxin biosynthesis and enhancement of nutrient absorption
    Wan Abdullah WMAN, Tan NP, Low LY, Loh JY, Wee CY, Md Taib AZ, et al.
    Plant Physiol Biochem, 2021 Apr;161:131-142.
    PMID: 33581621 DOI: 10.1016/j.plaphy.2021.01.046
    Lignosulfonate (LS) is a commonly used to promote plant growth. However, the underlying growth promoting responses of LS in plant remain unknown. Therefore, this study was undertaken to elucidate the underlying growth promoting mechanisms of LS, specifically calcium lignosulfonate (CaLS). Addition of 100 mg/L CaLS in phytohormone-free media enhanced recalcitrant indica rice cv. MR219 callus proliferation rate and adventitious root formation. Both, auxin related genes (OsNIT1, OsTAA1 and OsYUC1) and tryptophan biosynthesis proteins were upregulated in CaLS-treated calli which corroborated with increased of endogenous auxin content. Moreover, increment of OsWOX11 gene on CaLS-treated calli implying that the raised of endogenous auxin was utilized as a cue to enhance adventitious root development. Besides, CaLS-treated calli showed higher nutrient ions content with major increment in calcium and potassium ions. Consistently, increased of potassium protein kinases genes (OsAKT1, OsHAK5, OsCBL, OsCIPK23 and OsCamk1) were also recorded. In CaLS treated calli, the significant increase of calcium ion was observed starting from week one while potassium ion only recorded significant increase on week two onwards, suggesting that increment of potassium ion might be dependent on the calcium ion content in the plant cell. Additionally, reduced callus blackening was also coherent with downregulation of ROS scavenging protein and reduced H2O2 content in CaLS-treated calli suggesting the role of CaLS in mediating cellular homeostasis via prevention of oxidative burst in the cell. Taken together, CaLS successfully improved MR219 callus proliferation and root formation by increasing endogenous auxin synthesis, enhancing nutrients uptake and regulating cellular homeostasis.
  6. Fulltext Antibacterial Activity and Mode of Action of β-caryophyllene on Bacillus cereus
    Moo CL, Yang SK, Osman MA, Yuswan MH, Loh JY, Lim WM, et al.
    Pol J Microbiol, 2020;69:1-6.
    PMID: 32162852 DOI: 10.33073/pjm-2020-007
    Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of β-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of β-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of β-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of β-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to -3.98 mV, compared to untreated cells (-5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with β-caryophyllene. Additionally, β-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that β-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.

    Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of β-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of β-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of β-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of β-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to –3.98 mV, compared to untreated cells (–5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with β-caryophyllene. Additionally, β-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that β-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.

  7. Fish-specific TLR18 in Nile tilapia (Oreochromis niloticus) recruits MyD88 and TRIF to induce expression of effectors in NF-κB and IFN pathways in melanomacrophages
    Trung NB, Nan FH, Lee MC, Loh JY, Gong HY, Lu MW, et al.
    Fish Shellfish Immunol, 2021 Dec;119:587-601.
    PMID: 34743023 DOI: 10.1016/j.fsi.2021.11.001
    Toll-like receptors (TLRs) are evolutionarily conserved proteins of pattern recognition receptors (PRRs) and play a crucial role in innate immune systems recognition of conserved pathogen-related molecular samples (PAMPs). We identified and characterized TLR18 from Nile tilapia (Oreochromis niloticus), OnTLR18, to elucidate its role in tissue expression patterns, modulation of gene expression after microbial challenge and TLR ligands, subcellular localization in fish and human cells, and the possible effectors TLR18 induces in a melanomacrophage-like cell line (tilapia head kidney (THK) cells). OnTLR18 expression was detected in all tissues examined, with the highest levels in the intestine and the lowest in the liver. OnTLR18 transcript was up-regulated in immune-related organs after bacterial and polyinosinic-polycytidylic acid (poly I:C) challenges and in the THK cells after lipopolysaccharide (LPS) stimulation. In transfected THK and human embryonic kidney (HEK) 293 cells, OnTLR18 localizes in the intracellular compartment. OnMyD88 and OnTRIF, but not OnTIRAP, were co-immunoprecipitated with OnTLR18, suggesting that the former two molecules are recruited by OnTLR18 as adaptors. The constitutively active form of OnTLR18 induced the production of pro-inflammatory cytokines, type I interferon (IFN), and antimicrobial peptides such as tumor necrosis factor α, interferon (IFN) d2.13, tilapia piscidin (TP)2, TP3, TP4, and hepcidin in THK cells. Our results suggest that OnTLR18 plays an important role in innate immunity through initiating nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and IFN signaling pathways via OnMyD88 and OnTRIF and induces the production of various effectors in melanomacrophages.
  8. Fulltext In-Silico Analysis of Deleterious SNPs of FGF4 Gene and Their Impacts on Protein Structure, Function and Bladder Cancer Prognosis
    Lim EC, Lim SW, Tan KJ, Sathiya M, Cheng WH, Lai KS, et al.
    Life (Basel), 2022 Jul 09;12(7).
    PMID: 35888106 DOI: 10.3390/life12071018
    Dysregulation of fibroblast growth factors is linked to the pathogenesis of bladder cancer. The role of FGF1 and FGF3 is evident in bladder cancer; however, the role of FGF4 is vague. Despite being reported that FGF4 interacts with FGF1 and FGF3 in MAPK pathways, its pathogenesis and mechanism of action are yet to be elucidated. Therefore, this study aimed to elucidate pathogenic nsSNPs and their role in the prognosis of bladder cancer by employing in-silico analysis. The nsSNPs of FGF4 were retrieved from the NCBI database. Different in silico tools, PROVEAN, SIFT, PolyPhen-2, SNPs&GO, and PhD-SNP, were used for predicting the pathogenicity of the nsSNPs. Twenty-seven nsSNPs were identified as “damaging”, and further stability analysis using I-Mutant 2.0 and MUPro indicated 22 nsSNPs to cause decreased stability (DDG scores < −0.5). Conservation analysis predicted that Q97K, G106V, N164S, and N167S were highly conserved and exposed. Biophysical characterisation indicated these nsSNPs were not tolerated, and protein-protein interaction analysis showed their involvement in the GFR-MAPK signalling pathway. Furthermore, Kaplan Meier bioinformatics analyses indicated that the FGF4 gene deregulation affected the overall survival rate of patients with bladder cancer, leading to prognostic significance. Thus, based on these analyses, our study suggests that the reported nsSNPs of FGF4 may serve as potential targets for diagnoses and therapeutic interventions focusing on bladder cancer.
  9. Fulltext Bioactive Compounds from Marine Sponges: Fundamentals and Applications
    Varijakzhan D, Loh JY, Yap WS, Yusoff K, Seboussi R, Lim SE, et al.
    Mar Drugs, 2021 Apr 27;19(5).
    PMID: 33925365 DOI: 10.3390/md19050246
    Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.
  10. Modulation of immune genes in the mucosal-associated lymphoid tissues of cobia by Sarcodia suae extract
    Vakaloloma U, Ho TH, Loh JY, Chong CM, Wangkahart E, Lee MC, et al.
    Vet Res Commun, 2023 Dec;47(4):1973-1990.
    PMID: 37349590 DOI: 10.1007/s11259-023-10152-8
    Rachycentron canadum (cobia) is a marine fish species of high economic value in aquaculture due to its fast growth rate and good feed conversion efficacy. Regrettably, the industry has been affected by significant setbacks from high mortality due to diseases. Consequently, an improved perception of innate immunity correlated to each mucosal-associated lymphoid tissue (MALT) in teleost fish is necessary to understand hosts' response towards infections better. The utilization of polysaccharides in seaweed to stimulate the immune system has gathered unprecedented attention. The present study examined the immunostimulatory effects of Sarcodia suae water extracts (SSWE) on in vivo gill-, gut- and skin-associated lymphoid tissues (GIALT, GALT, and SALT) via immersion and oral ingestions. The GIALT genes (TNF-α, Cox2, IL-1β, IL-6, IL-8, IL-17 A/F1-3, IL-11, IL-12, IL-15, IL-18, MHCIa, IgM, and IgT) except IL-10 recorded positive upregulations in a dose-dependent manner post 24 h immersion in SSWE, indicating the algae extract contained bioactive compounds that could stimulate the immune genes. The upregulation of IL-12, IL-15, and IL-18 in the gills and hindgut post-SSWE immersion indicated that the extract could promote Th1-related responses in the MALTs. The modulation of immune gene expressions in the feeding trial was less potent than in the SSWE immersion. These findings indicated that the SSWE stimulated robust immune responses in both the GIALT and GALT of cobia. This suggests that the SSWE could be further explored as an effective immersive stimulant for fish, enhancing their immune system against pathogens.
  11. High environmental temperature and low pH stress alter the gill phenotypic plasticity of Hoven's carp Leptobarbus hoevenii
    Mohamad S, Liew HJ, Zainuddin RA, Rahmah S, Waiho K, Ghaffar MA, et al.
    J Fish Biol, 2021 Jul;99(1):206-218.
    PMID: 33629400 DOI: 10.1111/jfb.14712
    Climate warming and low pH environment are known to negatively impact all levels of aquatic organism from cellular to organism and population levels. For ammonotelic freshwater species, any abiotic factor fluctuation will cause disturbance to the fish, specifically at the gills which act as a multifunctional organ to support all biological processes. Therefore, this study was designed to investigate the effect of temperature (28 vs. 32°C) and pH (7.0 vs. 5.0) stress on the gill plasticity of Hoven's carp after 20 days of continuous exposure. The results demonstrated that high temperature and low pH caused severe changes on the primary and secondary lamellae as well as the cells within lamellae. An increasing trend of the proportion available for gas exchange was noticed at high temperature in both pH exposures, which resulted from a reduction of the primary lamellae width with elongated and thinner secondary lamellae compared to fishes at ambient temperature. Following exposure to high temperature and acidic pH, Hoven's carp experienced gill modifications including aneurysm, oedema, hypertrophy, curling of secondary lamellae, epithelial lifting, hyperplasia and lamellae fusion. These modifications are indicators of the coping mechanism of Hoven's carp to the changing environment in order to survive.
  12. Fulltext Predicting Deleterious Non-Synonymous Single Nucleotide Polymorphisms (nsSNPs) of HRAS Gene and In Silico Evaluation of Their Structural and Functional Consequences towards Diagnosis and Prognosis of Cancer
    Chai CY, Maran S, Thew HY, Tan YC, Rahman NMANA, Cheng WH, et al.
    Biology (Basel), 2022 Nov 02;11(11).
    PMID: 36358305 DOI: 10.3390/biology11111604
    The Harvey rat sarcoma (HRAS) proto-oncogene belongs to the RAS family and is one of the pathogenic genes that cause cancer. Deleterious nsSNPs might have adverse consequences at the protein level. This study aimed to investigate deleterious nsSNPs in the HRAS gene in predicting structural alterations associated with mutants that disrupt normal protein-protein interactions. Functional and structural analysis was employed in analyzing the HRAS nsSNPs. Putative post-translational modification sites and the changes in protein-protein interactions, which included a variety of signal cascades, were also investigated. Five different bioinformatics tools predicted 33 nsSNPs as "pathogenic" or "harmful". Stability analysis predicted rs1554885139, rs770492627, rs1589792804, rs730880460, rs104894227, rs104894227, and rs121917759 as unstable. Protein-protein interaction analysis revealed that HRAS has a hub connecting three clusters consisting of 11 proteins, and changes in HRAS might cause signal cascades to dissociate. Furthermore, Kaplan-Meier bioinformatics analyses indicated that the HRAS gene deregulation affected the overall survival rate of patients with breast cancer, leading to prognostic significance. Thus, based on these analyses, our study suggests that the reported nsSNPs of HRAS may serve as potential targets for different proteomic studies, diagnoses, and therapeutic interventions focusing on cancer.
  13. Fulltext λ-Carrageenan promotes plant growth in banana via enhancement of cellular metabolism, nutrient uptake, and cellular homeostasis
    Thye KL, Wan Abdullah WMAN, Balia Yusof ZN, Wee CY, Ong-Abdullah J, Loh JY, et al.
    Sci Rep, 2022 Nov 16;12(1):19639.
    PMID: 36385165 DOI: 10.1038/s41598-022-21909-7
    Banana (Musa acuminata) is an important fruit crop and source of income for various countries, including Malaysia. To date, current agrochemical practice has become a disputable issue due to its detrimental effect on the environment. λ-carrageenan, a natural polysaccharide extracted from edible red seaweed, has been claimed to be a potential plant growth stimulator. Hence, the present study investigates the effects of λ-carrageenan on plant growth using Musa acuminata cv. Berangan (AAA). Vegetative growth such as plant height, root length, pseudostem diameter, and fresh weight was improved significantly in λ-carrageenan-treated banana plants at an optimum concentration of 750 ppm. Enhancement of root structure was also observed in optimum λ-carrageenan treatment, facilitating nutrients uptake in banana plants. Further biochemical assays and gene expression analysis revealed that the increment in growth performance was consistent with the increase of chlorophyll content, protein content, and phenolic content, suggesting that λ-carrageenan increases photosynthesis rate, protein biosynthesis, and secondary metabolites biosynthesis which eventually stimulate growth. Besides, λ-carrageenan at optimum concentration also increased catalase and peroxidase activities, which led to a significant reduction in hydrogen peroxide and malondialdehyde, maintaining cellular homeostasis in banana plants. Altogether, λ-carrageenan at optimum concentration improves the growth of banana plants via inducing metabolic processes, enhancing nutrient uptake, and regulation of cell homeostasis. Further investigations are needed to evaluate the effectiveness of λ-carrageenan on banana plants under field conditions.
  14. Fulltext Promoter Cis-Element Analyses Reveal the Function of αVPE in Drought Stress Response of Arabidopsis
    Tang CN, Wan Abdullah WMAN, Wee CY, Balia Yusof ZN, Yap WS, Cheng WH, et al.
    Biology (Basel), 2023 Mar 10;12(3).
    PMID: 36979122 DOI: 10.3390/biology12030430
    Vacuolar processing enzyme (VPE) is a cysteine protease responsible for vacuolar proteins' maturation and regulation of programmed cell death (PCD). Four isoforms of Arabidopsis thaliana VPEs were identified previously, but only the functions of βVPE, γVPE, and δVPE were determined. The specific function of a gene is linked to the cis-acting elements in the promoter region. A promoter analysis found repetitive drought-related cis-elements in αVPE, which highlight its potential involvement in drought regulation in A. thaliana. The further co-expression network portraying genes interacting with αVPE substantiated its drought-regulation-related function. Expression of αVPE was upregulated after drought treatment in A. thaliana. To confirm the role of αVPE, a loss of function study revealed that αVPE knockout mutants remained green compared with WT after drought treatment. The mutants had reduced proline activity, decreased sucrose content, and lower MDA content, but increased photosynthetic pigments, indicating that αVPE negatively regulates drought tolerance in A. thaliana. Taken together, our findings serve as important evidence of the involvement of αVPE in modulating drought tolerance in A. thaliana.
  15. Fulltext Calcium lignosulfonate modulates physiological and biochemical responses to enhance shoot multiplication in Vanilla planifolia Andrews
    Thye KL, Wan Abdullah WMAN, Ong-Abdullah J, Lamasudin DU, Wee CY, Mohd Yusoff MHY, et al.
    Physiol Mol Biol Plants, 2023 Mar;29(3):377-392.
    PMID: 37033764 DOI: 10.1007/s12298-023-01293-w
    Utilisation of calcium lignosulfonate (CaLS) in Vanilla planifolia has been reported to improve shoot multiplication. However, mechanisms responsible for such observation remain unknown. Here, we elucidated the underlying mechanisms of CaLS in promoting shoot multiplication of V. planifolia via comparative proteomics, biochemical assays, and nutrient analysis. The proteome profile of CaLS-treated plants showed enhancement of several important cellular metabolisms such as photosynthesis, protein synthesis, Krebs cycle, glycolysis, gluconeogenesis, and carbohydrate synthesis. Further biochemical analysis recorded that CaLS increased Rubisco activity, hexokinase activity, isocitrate dehydrogenase activity, total carbohydrate content, glutamate synthase activity and total protein content in plant shoot, suggesting the role of CaLS in enhancing shoot growth via upregulation of cellular metabolism. Subsequent nutrient analysis showed that CaLS treatment elevated the contents of several nutrient ions especially calcium and sodium ions. In addition, our study also revealed that CaLS successfully maintained the cellular homeostasis level through the regulation of signalling molecules such as reactive oxygen species and calcium ions. These results demonstrated that the CaLS treatment can enhance shoot multiplication in V. planifolia Andrews by stimulating nutrient uptake, inducing cell metabolism, and regulating cell homeostasis.

    SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-023-01293-w.

  16. Recombinant Lactococcal-based oral vaccine for protection against Streptococcus agalactiae infections in tilapia (Oreochromis niloticus)
    Wong KY, Khair MHMM, Song AA, Masarudin MJ, Loh JY, Chong CM, et al.
    Fish Shellfish Immunol, 2024 Apr 16.
    PMID: 38636739 DOI: 10.1016/j.fsi.2024.109572
    Streptococcosis outbreaks caused by Streptococcus agalactiae infection in tilapia aquaculture have been consistently reported and associated with high mortality and morbidity leading to significant economic losses. Existing vaccine candidates against Streptococcus spp. are designed for intraperitoneal injections that are not practical and labor-intensive which have prompted farmers to protect aquatic animals with antibiotics, thus encouraging the emergence of multidrug resistant bacteria. In this study, a live recombinant L. lactis vaccine expressing a 1403 bp surface immunogenic protein (SIP) and a 1100 bp truncated SIP (tSIP) gene was developed and evaluated against S. agalactiae infection in tilapia. Both SIP and tSIP sequences were cloned and transformed into L. lactis. The recombinant L. lactis vaccine was orally administered to juvenile tilapia for a month. Detection of SIP-specific serum IgM in vaccinated groups compared to control groups indicated that recombinant proteins expressed from L. lactis could elicit immunogenic reactions in tilapia. Fish immunized with the tSIP vaccine also showed the highest level of protection compared to other test groups, and the mortality rate was significantly reduced compared to both control groups. The relative percentage of survival (RPS) against S. agalactiae for both SIP and tSIP-vaccinated groups was 50% and 89%, respectively, at 14 days post-challenge. Significant up-regulation of IgM, IL-1β, IL-10, TNF-α and IFN-γ were observed at day 34 between the vaccinated and control groups. These results indicated that the recombinant lactococcal tSIP vaccine can elicit both cell-mediated and humoral responses and is recommended as a potential oral vaccine against S. agalactiae infection. Future work will include further in vivo challenge assessments of this vaccine candidate fused with adjuvants to boost immunogenicity levels in tilapia.
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