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  1. Impacts of acute hepatopancreatic necrosis disease on commercial shrimp aquaculture
    Tang KFJ, Bondad-Reantaso MG
    Rev. - Off. Int. Epizoot., 2019 Sep;38(2):477-490.
    PMID: 31866681 DOI: 10.20506/rst.38.2.2999
    Acute hepatopancreatic necrosis disease (AHPND) has caused severe losses in farmed populations of marine shrimp Penaeus vannamei and P. monodon. The causative agents are unique strains of the bacteria Vibrio parahaemolyticus and related Vibrio species. The disease emerged in the People's Republic of China (China) and Vietnam in 2010 and spread throughout South-East Asia; it was later reported in countries in both North and South America. The disease has had significant economic impacts on the shrimp aquaculture industry. From 2010 to 2016, combined losses from China, Malaysia, Mexico, Thailand and Vietnam due primarily to outbreaks of AHPND, including losses at the farm gate and those resulting from a drop in feed sales and exports, were estimated at over US$ 44 billion. Other economic losses include those associated with processing facilities, decreased community revenues resulting from increased unemployment, financial investments, and the costs of implementing diagnostic and control measures. The reduced employment opportunities and increases in debt burden and investment risk have had sociological impacts. The responses to the disease have led to a gradual recovery of the shrimp industry in affected countries. These response efforts have included the implementation of changes in farming systems and management, including, among others, enhanced biosecurity and the use of AHPND-free and AHPND-resistant shrimp. This situation of losses and recovery illustrates the importance of having a multi-level response plan in place to prevent, or to reduce the risk of, outbreaks of disease.
    Matched MeSH terms: Penaeidae/microbiology*
  2. High prevalence of Enterocytozoon hepatopenaei in shrimps Penaeus monodon and Litopenaeus vannamei sampled from slow growth ponds in India
    Biju N, Sathiyaraj G, Raj M, Shanmugam V, Baskaran B, Govindan U, et al.
    Dis Aquat Organ, 2016 08 09;120(3):225-30.
    PMID: 27503918 DOI: 10.3354/dao03036
    Hepatopancreatic microsporidiosis in cultivated Litopenaeus vannamei and Penaeus monodon is caused by the newly emerged pathogen Enterocytozoon hepatopenaei (EHP). It has been detected in shrimp cultured in China, Vietnam and Thailand and is suspected to have occurred in Malaysia and Indonesia and to be associated with severely retarded growth. Due to retarded shrimp growth being reported at farms in the major grow-out states of Tamilnadu, Andhra Pradesh and Odisha in India, shrimp were sampled from a total of 235 affected ponds between March 2014 and April 2015 to identify the presence of EHP. PCR and histology detected a high prevalence of EHP in both P. monodon and L. vannamei, and infection was confirmed by in situ hybridization using an EHP-specific DNA probe. Histology revealed basophilic inclusions in hepatopancreas tubule epithelial cells in which EHP was observed at various developmental stages ranging from plasmodia to mature spores. The sequence of a region of the small subunit rDNA gene amplified by PCR was found to be identical to EHP sequences deposited in GenBank. Bioassays confirmed that EHP infection could be transmitted orally to healthy shrimp. Histology also identified bacterial co-infections in EHP-infected shrimp sampled from slow-growth ponds with low-level mortality. The data confirm that hepatopancreatic microsporidiosis caused by EHP is prevalent in shrimp being cultivated in India. EHP infection control measures thus need to be implemented urgently to limit impacts of slowed shrimp growth.
    Matched MeSH terms: Penaeidae/microbiology*
  3. Potential muscle activity disturbance in Penaeus monodon during Acute Hepatopancreatic Necrosis Disease (AHPND) infection: Inference through gene expression, calcium concentration, and MicroRNA
    Soo TCC, See SA, Bhassu S
    J Invertebr Pathol, 2020 11;177:107497.
    PMID: 33130047 DOI: 10.1016/j.jip.2020.107497
    Global shrimp aquaculture farmers have suffered major economic losses due to disease outbreaks. A notable shrimp disease is Acute Hepatopancreatic Necrosis Disease (AHPND), which is caused by a new strain of Vibrio parahaemolyticus bacteria (VpAHPND) that mainly inhabits the shrimp gut and damages the hepatopancreas. Fewer studies have investigated whether this disease will affect shrimp muscle functioning or cause any muscle damage. We challenged Penaeus monodon shrimp with VpAHPND bacteria using an immersion method. Expression of Dystrophin gene, an important regulatory gene for maintenance of muscle integrity, was quantified from muscle samples using qRT-PCR. Additional verification was conducted by determining calcium concentration and bta-miR-4286 and dre-miR-107b miRNAs expression. P. monodon dystrophin gene demonstrated the highest expression level during AHPND infection when muscle calcium concentration was detected at its lowest level at 6 h post-infection (hpi). The highest muscle calcium concentration, determined at 36 hpi, was supported by higher bta-miR-4286 miRNA expression and lower dre-miR-107b miRNA expression in VpAHPND-infected samples compared to uninfected samples at the same time point. We deduced an interactive relationship between dystrophin gene expression, calcium concentration, and miRNA expression in P. monodon muscle tissues triggered by the invading VpAHPND bacterium.
    Matched MeSH terms: Penaeidae/microbiology
  4. The Microbial Composition of Penaeid Shrimps' Hepatopancreas Is Modulated by Hemocyanin
    Zheng Z, Aweya JJ, Bao S, Yao D, Li S, Tran NT, et al.
    J Immunol, 2021 12 01;207(11):2733-2743.
    PMID: 34670821 DOI: 10.4049/jimmunol.2100746
    Aquatic organisms have to produce proteins or factors that help maintain a stable relationship with microbiota and prevent colonization by pathogenic microorganisms. In crustaceans and other aquatic invertebrates, relatively few of these host factors have been characterized. In this study, we show that the respiratory glycoprotein hemocyanin is a crucial host factor that modulates microbial composition and diversity in the hepatopancreas of penaeid shrimp. Diseased penaeid shrimp (Penaeus vannamei), had an empty gastrointestinal tract with atrophied hepatopancreas, expressed low hemocyanin, and high total bacterial abundance, with Vibrio as the dominant bacteria. Similarly, shrimp depleted of hemocyanin had mitochondrial depolarization, increased reactive oxygen species (ROS) levels, and dysregulation of several energy metabolism-related genes. Hemocyanin silencing together with ROS scavenger (N-acetylcysteine) treatment improved microbial diversity and decreased Vibrio dominance in the hepatopancreas. However, fecal microbiota transplantation after hemocyanin knockdown could not restore the microbial composition in the hepatopancreas. Collectively, our data provide, to our knowledge, new insight into the pivotal role of hemocyanin in modulating microbial composition in penaeid shrimp hepatopancreas via its effect on mitochondrial integrity, energy metabolism, and ROS production.
    Matched MeSH terms: Penaeidae/microbiology*
  5. Virulence properties and pathogenicity of multidrug-resistant Vibrio harveyi associated with luminescent vibriosis in Pacific white shrimp, Penaeus vannamei
    Nurhafizah WWI, Lee KL, Laith A AR, Nadirah M, Danish-Daniel M, Zainathan SC, et al.
    J Invertebr Pathol, 2021 11;186:107594.
    PMID: 33878330 DOI: 10.1016/j.jip.2021.107594
    Global high demand for Pacific white shrimp Penaeus vannamei has led to intensified cultivation and a wide range of disease problems, including bacterial diseases due to vibrios. Three presumptive luminescent Vibrio harveyi strains (Vh5, Vh8 and Vh10) were isolated from the hepatopancreas (Vh5) and haemolymph (Vh8 and Vh10) of diseased growout Pacific white shrimp from a farm in Setiu, Terengganu, Malaysia, using Vibrio harveyi agar (VHA) differential medium. All three strains were identified as V. harveyi by biochemical characteristics. 16S rRNA gene-based phylogenetic analyses by neighbour-joining, maximum likelihood and maximum parsimony methods showed all three strains in the V. harveyi cluster. All three strains were β-haemolytic and positive for motility, biofilm formation and extracellular products (caseinase, gelatinase, lipase, DNase, amylase and chitinase). Vh10 was subjected to pathogenicity test in Pacific white shrimp by immersion challenge and determined to have a LC50 of 6.0 × 108 CFU mL-1 after 168 h of exposure. Antibiotic susceptibility tests showed that all strains were resistant to oxytetracycline (OXT30), oleandomycin (OL15), amoxicillin (AML25), ampicillin (AMP10) and colistin sulphate (CT25) but sensitive to doxycycline (DO30), flumequine (UB30), oxolinic acid (OA2), chloramphenicol (C30), florfenicol (FFC30), nitrofurantoin (F5) and fosfomycin (FOS50). Each strain was also resistant to a slightly different combination of eight other antibiotics, with an overall multiple antibiotic resistance (MAR) index of 0.40, suggesting prior history of heavy exposure to the antibiotics. Vh10 infection resulted in pale or discoloured hepatopancreas, empty guts, reddening, necrosis and luminescence of uropods, as well as melanised lesions in tail muscle. Histopathological examination showed necrosis of intertubular connective tissue and tubule, sloughing of epithelial cells in hepatopancreatic tubule, haemocytic infiltration, massive vacuolation and loss of hepatopancreatic tubule structure.
    Matched MeSH terms: Penaeidae/microbiology*
  6. Biodiversity of chloramphenicol-resistant mesophilic heterotrophs from Southeast Asian aquaculture environments
    Huys G, Bartie K, Cnockaert M, Hoang Oanh DT, Phuong NT, Somsiri T, et al.
    Res. Microbiol., 2007 Apr;158(3):228-35.
    PMID: 17350231
    In the present study, samples of pond water, sediment and farmed species were collected at 12 fish and shrimp farms in Malaysia, Thailand and Vietnam to determine the biodiversity and environmental distribution of chloramphenicol-resistant (CmR) mesophilic heterotrophs in Southeast Asian aquaculture sites. Following isolation on Iso-Sensitest agar supplemented with 35mug ml(-1) Cm and dereplication using (GTG)(5)-PCR fingerprinting, 557 genotypically unique CmR strains were subjected to polyphasic identification. The 557 mesophilic heterotrophic CmR isolates represented 18 different genera largely dominated by the genera Escherichia (40.2%), Pseudomonas (11.7%), Acinetobacter (11.1%), Klebsiella (7.5%) and Bacillus (5.9%). A total of 439 CmR isolates were further assigned to 31 described species or species groups, mainly including organisms that have been associated with various human opportunistic infections such as Escherichia coli (n=219), Pseudomonas putida (n=47), Klebsiella pneumoniae (n=38) and Acinetobacter baumannii (n=23). Strains of Escherichia, and most notably, of E. coli, were the only common group of CmR heterotrophs irrespective of country, sample type or farm type. Together with other predominant but less widespread groups such as acinetobacters and pseudomonads, the results of this biodiversity study suggest that E. coli can be regarded as a potential indicator of Cm resistance in Southeast Asian aquaculture environments.
    Matched MeSH terms: Penaeidae/microbiology
  7. Ingestion of food pellets containing Escherichia coli overexpressing the heat-shock protein DnaK protects Penaeus vannamei (Boone) against Vibrio harveyi (Baumann) infection
    Sinnasamy S, Noordin NM, MacRae TH, Bin Abdullah MI, Bossier P, Wahid ME, et al.
    J Fish Dis, 2016 May;39(5):577-84.
    PMID: 26132358 DOI: 10.1111/jfd.12390
    Feeding aquatic animals with bacterial encapsulated heat-shock proteins (Hsps) is potentially a new method to combat vibriosis, an important disease affecting aquatic animals used in aquaculture. Food pellets comprised of shrimp and containing Escherichia coli overexpressing either DnaK-DnaJ-GrpE, the prokaryotic equivalents of Hsp70-Hsp40-Hsp20, or only DnaK were fed to juveniles of the white leg shrimp Penaeus vannamei, and protection against pathogenic Vibrio harveyi was determined. Maintaining pellets at different temperatures for varying lengths of time reduced the number of live adhering E. coli, as did contact with sea water, demonstrating that storage and immersion adversely affected bacterial survival and attachment to pellets. Feeding P. vannamei with E. coli did not compromise their survival, indicating that the bacteria were not pathogenic to shrimp. Feeding P. vannamei with pellets containing bacteria overproducing DnaK (approximately 60 cells g(-1) pellets) boosted P. vannamei survival twofold against V. harveyi, suggesting that DnaK plays a role in Vibrio tolerance. Pellets containing DnaK were effective in providing protection to P. vannamei for up to 2 weeks before loss of viability and that DnaK encapsulated by these bacteria enhanced shrimp resistance against Vibrio infection.
    Matched MeSH terms: Penaeidae/microbiology*
  8. A new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon and its comparison with white spot syndrome (WSS) caused by virus
    Wang YG, Lee KL, Najiah M, Shariff M, Hassan MD
    Dis Aquat Organ, 2000 May 25;41(1):9-18.
    PMID: 10907134
    This paper describes a new bacterial white spot syndrome (BWSS) in cultured tiger shrimp Penaeus monodon. The affected shrimp showed white spots similar to those caused by white spot syndrome virus (WSSV), but the shrimp remained active and grew normally without significant mortalities. The study revealed no evidence of WSSV infection using electron microscopy, histopathology and nested polymerase chain reaction. Electron microscopy indicated bacteria associated with white spot formation, and with degeneration and discoloration of the cuticle as a result of erosion of the epicuticle and underlying cuticular layers. Grossly the white spots in BWSS and WSS look similar but showed different profiles under wet mount microscopy. The bacterial white spots were lichen-like, having perforated centers unlike the melanized dots in WSSV-induced white spots. Bacteriological examination showed that the dominant isolate in the lesions was Bacillus subtilis. The occurrence of BWSS may be associated with the regular use of probiotics containing B. subtilis in shrimp ponds. The externally induced white spot lesions were localized at the integumental tissues, i.e., cuticle and epidermis, and connective tissues. Damage to the deeper tissues was limited. The BWS lesions are non-fatal in the absence of other complications and are usually shed through molting.
    Matched MeSH terms: Penaeidae/microbiology*
  9. Fulltext Phenotypic and genomic characterization of a Vibrio parahaemolyticus strain causing disease in Penaeus vannamei provides insights into its niche adaptation and pathogenic mechanism
    Zhang X, Sun J, Chen F, Qi H, Chen L, Sung YY, et al.
    Microb Genom, 2021 05;7(5).
    PMID: 33952389 DOI: 10.1099/mgen.0.000549
    The virulence of Vibrio parahaemolyticus is variable depending on its virulence determinants. A V. parahaemolyticus strain, in which the virulence is governed by the pirA and pirB genes, can cause acute hepatopancreatic necrosis disease (AHPND) in shrimps. Some V. parahaemolyticus that are non-AHPND strains also cause shrimp diseases and result in huge economic losses, while their pathogenicity and pathogenesis remain unclear. In this study, a non-AHPND V. parahaemolyticus, TJA114, was isolated from diseased Penaeus vannamei associated with a high mortality. To understand its virulence and adaptation to the external environment, whole-genome sequencing of this isolate was conducted, and its phenotypic profiles including pathogenicity, growth characteristics and nutritional requirements were investigated. Shrimps following artificial infection with this isolate presented similar clinical symptoms to the naturally diseased ones and generated obvious pathological lesions. The growth characteristics indicated that the isolate TJA114 could grow well under different salinity (10-55 p.p.t.), temperature (23-37 °C) and pH (6-10) conditions. Phenotype MicroArray results showed that this isolate could utilize a variety of carbon sources, amino acids and a range of substrates to help itself adapt to the high hyperosmotic and alkaline environments. Antimicrobial-susceptibility test showed that it was a multidrug-resistant bacterium. The whole-genomic analysis showed that this V. parahaemolyticus possessed many important functional genes associated with multidrug resistance, stress response, adhesions, haemolysis, putative secreted proteases, dedicated protein secretion systems and a variety of nutritional metabolic mechanisms. These annotated functional genes were confirmed by the phenotypic profiles. The results in this study indicated that this V. parahaemolyticus isolate possesses a high pathogenicity and strong environmental adaptability.
    Matched MeSH terms: Penaeidae/microbiology*
  10. Fulltext Electronic Properties of Synthetic Shrimp Pathogens-derived DNA Schottky Diodes
    Rizan N, Yew CY, Niknam MR, Krishnasamy J, Bhassu S, Hong GZ, et al.
    Sci Rep, 2018 01 17;8(1):896.
    PMID: 29343758 DOI: 10.1038/s41598-017-18825-6
    The exciting discovery of the semiconducting-like properties of deoxyribonucleic acid (DNA) and its potential applications in molecular genetics and diagnostics in recent times has resulted in a paradigm shift in biophysics research. Recent studies in our laboratory provide a platform towards detecting charge transfer mechanism and understanding the electronic properties of DNA based on the sequence-specific electronic response, which can be applied as an alternative to identify or detect DNA. In this study, we demonstrate a novel method for identification of DNA from different shrimp viruses and bacteria using electronic properties of DNA obtained from both negative and positive bias regions in current-voltage (I-V) profiles. Characteristic electronic properties were calculated and used for quantification and further understanding in the identification process. Aquaculture in shrimp industry is a fast-growing food sector throughout the world. However, shrimp culture in many Asian countries faced a huge economic loss due to disease outbreaks. Scientists have been using specific established methods for detecting shrimp infection, but those methods do have their significant drawbacks due to many inherent factors. As such, we believe that this simple, rapid, sensitive and cost-effective tool can be used for detection and identification of DNA from different shrimp viruses and bacteria.
    Matched MeSH terms: Penaeidae/microbiology
  11. Isolation of Potential Bacteria as Inoculum for Biofloc Formation in Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture Ponds
    Kasan NA, Ghazali NA, Ikhwanuddin M, Ibrahim Z
    Pak J Biol Sci, 2017;20(6):306-313.
    PMID: 29023055 DOI: 10.3923/pjbs.2017.306.313
    BACKGROUND AND OBJECTIVE: A new green technology to reduce environmental damages while optimizing production of Pacific Whiteleg shrimp, Litopenaeus vannamei was developed known as "Biofloc technology". Microbial communities in biofloc aggregates are responsible in eliminating water exchange and producing microbial proteins that can be used as supplemented feed for L. vannamei. This study aimed to isolate and identify potential bioflocculant-producing bacteria to be used as inoculum for rapid formation of biofloc.

    MATERIALS AND METHODS: For the purpose of this study, bacterial communities during 0, 30 and 70 days of culture (DOC) of L. vannamei grow-out ponds were isolated and identified through phenotypic and 16S rDNA sequences analysis. Phylogenetic relationships between isolated bacteria were then evaluated through phylogenetic tree analysis. One-way analysis of variance (ANOVA) was used to compare the differences of microbial communities at each DOC.

    RESULTS: Out of 125 bacterial isolates, nine species of bacteria from biofloc were identified successfully. Those bacteria species were identified as Halomonas venusta, H. aquamarina, Vibrio parahaemolyticus, Bacillus infantis, B. cereus, B. safensis, Providencia vermicola, Nitratireductor aquimarinus and Pseudoalteromonas sp., respectively. Through phylogenetic analysis, these isolates belong to Proteobacteria and Firmicutes families under the genera of Halomonas sp., Vibrio sp., Bacillus sp., Providencia sp., Nitratireductor sp. and Pseudoalteromonas sp.

    CONCLUSION: In this study, bioflocculant-producing bacteria were successfully identified which are perfect candidates in forming biofloc to reduce water pollution towards a sustainable aquaculture industry. Presence of Halomonas sp. and Bacillus sp. in all stages of biofloc formation reinforces the need for new development regarding the ability of these species to be used as inoculum in forming biofloc rapidly.

    Matched MeSH terms: Penaeidae/microbiology*
  12. Fulltext Non-lethal heat shock increased Hsp70 and immune protein transcripts but not Vibrio tolerance in the white-leg shrimp
    Loc NH, Macrae TH, Musa N, Bin Abdullah MD, Abdul Wahid ME, Sung YY
    PLoS One, 2013;8(9):e73199.
    PMID: 24039886 DOI: 10.1371/journal.pone.0073199
    Non-lethal heat shock boosts bacterial and viral disease tolerance in shrimp, possibly due to increases in endogenous heat shock protein 70 (Hsp70) and/or immune proteins. To further understand the mechanisms protecting shrimp against infection, Hsp70 and the mRNAs encoding the immune-related proteins prophenoloxidase (proPO), peroxinectin, penaeidin, crustin and hemocyanin were studied in post-larvae of the white-leg shrimp Litopenaeus vannamei, following a non-lethal heat shock. As indicated by RT-qPCR, a 30 min abrupt heat shock increased Hsp70 mRNA in comparison to non-heated animals. Immunoprobing of western blots and quantification by ELISA revealed that Hsp70 production after heat shock was correlated with enhanced Hsp70 mRNA. proPO and hemocyanin mRNA levels were augmented, whereas peroxinectin and crustin mRNA levels were unchanged following non-lethal heat shock. Penaeidin mRNA was decreased by all heat shock treatments. Thirty min abrupt heat shock failed to improve survival of post-larvae in a standardized challenge test with Vibrio harveyi, indicating that under the conditions of this study, L. vannamei tolerance to Vibrio infection was influenced neither by Hsp70 accumulation nor the changes in the immune-related proteins, observations dissimilar to other shrimp species examined.
    Matched MeSH terms: Penaeidae/microbiology*
  13. Lactic acid as a potential decontaminant of selected foodborne pathogenic bacteria in shrimp (Penaeus merguiensis de Man)
    Shirazinejad A, Ismail N, Bhat R
    Foodborne Pathog Dis, 2010 Dec;7(12):1531-6.
    PMID: 21034165 DOI: 10.1089/fpd.2010.0616
    Fresh raw shrimps were dipped for 10, 20, and 30 min at room temperature (25°C ± 1°C) in lactic acid (LA; 1.5%, 3.0%, v/v) to evaluate their antipathogenic effects against Vibrio cholerae, Vibrio parahaemolyticus, Salmonella entreitidis, and Escherichia coli O157:H7 inoculated at a level of 10(5) CFU/g. Significant reductions in the population of all these pathogenic bacteria were recorded after dipping treatments, which were correlated to the corresponding LA concentrations and treatment time. With respect to the microbial quality, 3.0% LA treatment for 10 min was acceptable in reducing the pathogenic bacteria. Additionally, sensory evaluation results revealed a 10-min dip in 3.0% LA to be more acceptable organoleptically compared with 20 and 30 min of treatments. Results of the present study are envisaged to be useful for commercial applications for effective decontamination of shrimp.
    Matched MeSH terms: Penaeidae/microbiology*
  14. Genomic characterization of Vibrio parahaemolyticus from Pacific white shrimp and rearing water in Malaysia reveals novel sequence types and structural variation in genomic regions containing the Photorhabdus insect-related (Pir) toxin-like genes
    Yan CZY, Austin CM, Ayub Q, Rahman S, Gan HM
    FEMS Microbiol Lett, 2019 09 01;366(17).
    PMID: 31589302 DOI: 10.1093/femsle/fnz211
    The Malaysian and global shrimp aquaculture production has been significantly impacted by acute hepatopancreatic necrosis disease (AHPND) typically caused by Vibrio parahaemolyticus harboring the pVA plasmid containing the pirAVp and pirBVp genes, which code for Photorhabdus insect-related (Pir) toxin. The limited genomic resource for V. parahaemolyticus strains from Malaysian aquaculture farms precludes an in-depth understanding of their diversity and evolutionary relationships. In this study, we isolated shrimp-associated and environmental (rearing water) V. parahaemolyticus from three aquaculture farms located in Northern and Central Malaysia followed by whole-genome sequencing of 40 randomly selected isolates on the Illumina MiSeq. Phylogenomic analysis and multilocus sequence typing (MLST) reveal distinct lineages of V. parahaemolyticus that harbor the pirABVp genes. The recovery of pVA plasmid backbone devoid of pirAVp or pirABVp in some V. parahaemolyticus isolates suggests that the toxin genes are prone to deletion. The new insight gained from phylogenomic analysis of Asian V. parahaemolyticus, in addition to the observed genomic instability of pVa plasmid, will have implications for improvements in aquaculture practices to diagnose, treat or limit the impacts of this disease.
    Matched MeSH terms: Penaeidae/microbiology*
  15. Pandanus tectorius fruit extract promotes Hsp70 accumulation, immune-related genes expression and Vibrio parahaemolyticus tolerance in the white-leg shrimp Penaeus vannamei
    Anirudhan A, Okomoda VT, Mimi Iryani MT, Andriani Y, Abd Wahid ME, Tan MP, et al.
    Fish Shellfish Immunol, 2021 Feb;109:97-105.
    PMID: 33352338 DOI: 10.1016/j.fsi.2020.12.011
    Plants and herbal extracts are indispensable for controlling the spread of disease-causing bacteria, including those that infect aquatic organisms used in aquaculture. The use of plant or herbal extract is expected to be safe for aquatic animals and less harmful to the environment, as opposed to conventional therapeutic alternatives such as antibiotics that promote the occurrence of potential antibiotic-resistant bacteria when used improperly. The efficacy of Pandanus tectorius fruit extract in the regulation of Hsp70 expression, pro-phenoloxidase (ProPO), peroxinectin, penaeidin, crustin and transglutaminase, all immune peptides essential for Vibrio tolerance in white leg shrimp, Penaeus vannamei, was investigated in this study, which included the determination of the safety levels of the extract. Tolerance of shrimp against Vibrio parahaemolyticus, a pathogenic bacteria that causes Acute Hepatopancreas Necrosis Disease (AHPND), was assessed on the basis of median lethal dose challenge survival (LD50 = 106 cells/ml). Mortality was not observed 24 h after exposure of 0.5-6 g/L of the fruit extract, indicating that P. tectorius was not toxic to shrimp at these concentrations. A 24-h incubation of 2-6 g/L of the fruit extract increased shrimp tolerance to V. parahaemolyticus, with survival doubled when the maximum dose tested in this study was used. Concomitant with a rise in survival was the increase in immune-related proteins, with Hsp70, ProPO, peroxinectin, penaeidin, crustin and transglutaminase increased 10, 11, 11, 0.4, 8 and 13-fold respectively. Histological examination of the hepatopancreas and muscle tissues of Vibrio-infected shrimp primed with P. tectorius extract revealed reduced signs of histopathological degeneration, possibly due to the accumulation of Hsp70, a molecular chaperone crucial to cellular protein folding, tissue repair and immune response of living organisms, including Penaeid shrimp.
    Matched MeSH terms: Penaeidae/microbiology
  16. Comparative genomic provides insight into the virulence and genetic diversity of Vibrio parahaemolyticus associated with shrimp acute hepatopancreatic necrosis disease
    Yu LH, Teh CSJ, Yap KP, Ung EH, Thong KL
    Infect Genet Evol, 2020 09;83:104347.
    PMID: 32360538 DOI: 10.1016/j.meegid.2020.104347
    Acute hepatopancreatic necrosis disease (AHPND) is an important shrimp disease of economic importance which causes mass mortality of cultivated penaeid shrimps in Southeast Asian countries, Mexico and South America. This disease was originally caused by Vibrio parahaemolyticus (VPAHPND) which is reported to harbour a transferable plasmid carrying the virulent PirAB-like toxin genes (pirABvp). However, little is known about the pathogenicity of VPAHPND. To extend our understanding, comparative genomic analyses was performed in this study to identify the genetic differences and to understand the phylogenetic relationship of VPAHPND strains. Seven Vibrio parahaemolyticus strains (five VPAHPND strains and two non-VPAHPND strains) were sequenced and 31 draft genomes of V. parahaemolyticus were retrieved from NCBI database and incorporated into the genomic comparison to elucidate their genomic diversity. The study showed that the genome sizes of the VPAHPND strains were approximately 5 Mbp. Ten sequence types (STs) were identified among the VPAHPND strains using in silico-Multilocus Sequence Typing analysis (MLST) and ST 970 was the predominant ST. Phylogenetic analysis based on MLST and single nucleotide polymorphisms (SNP) showed that the VPAHPND strains were genetically diverse. Based on the comparative genomic analysis, several functional proteins were identified from diiferent categories associated with virulence-related proteins, secretory proteins, conserved domain proteins, transporter proteins, and phage proteins. The CRISPR analysis showed that VPAHPND strains contained less number of CRISPRs elements than non-VPAHPND strains while six prophages regions were identified in the genomes, suggested the lack of CRISPR might promote prophage insertion. The genomic information in this study provide improved understanding of the virulence of these VPAHPND strains.
    Matched MeSH terms: Penaeidae/microbiology*
  17. Modulation of cell surface hydrophobicity and attachment of bacteria to abiotic surfaces and shrimp by Malaysian herb extracts
    Hui YW, Dykes GA
    J Food Prot, 2012 Aug;75(8):1507-11.
    PMID: 22856578 DOI: 10.4315/0362-028X.JFP-12-062
    The use of simple crude water extracts of common herbs to reduce bacterial attachment may be a cost-effective way to control bacterial foodborne pathogens, particularly in developing countries. The ability of water extracts of three common Malaysian herbs (Andrographis paniculata, Eurycoma longifolia, and Garcinia atroviridis) to modulate hydrophobicity and attachment to surfaces of five food-related bacterial strains (Bacillus cereus ATCC 14576, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Salmonella Enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923) were determined. The bacterial attachment to hydrocarbon assay was used to determine bacterial hydrophobicity. Staining and direct microscopic counts were used to determine attachment of bacteria to glass and stainless steel. Plating on selective media was used to determine attachment of bacteria to shrimp. All extracts were capable of either significantly ( P < 0.05) increasing or decreasing bacterial surface hydrophobicity, depending on the herb extract and bacteria combination. Bacterial attachment to all surfaces was either significantly (P < 0.05) increased or decreased, depending on the herb extract and bacteria combination. Overall, hydrophobicity did not show a significant correlation (P > 0.05) to bacterial attachment. For specific combinations of bacteria, surface material, and plant extract, significant correlations (R > 0.80) between hydrophobicity and attachment were observed. The highest of these was observed for S. aureus attachment to stainless steel and glass after treatment with the E. longifolia extract (R = 0.99, P < 0.01). The crude water herb extracts in this study were shown to have the potential to modulate specific bacterial and surface interactions and may, with further work, be useful for the simple and practical control of foodborne pathogens.
    Matched MeSH terms: Penaeidae/microbiology*
  18. Fulltext Effects of Bacillus subtilis on the growth performance, digestive enzymes, immune gene expression and disease resistance of white shrimp, Litopenaeus vannamei
    Zokaeifar H, Balcázar JL, Saad CR, Kamarudin MS, Sijam K, Arshad A, et al.
    Fish Shellfish Immunol, 2012 Oct;33(4):683-9.
    PMID: 22659618 DOI: 10.1016/j.fsi.2012.05.027
    We studied the effect of two probiotic Bacillus subtilis strains on the growth performance, digestive enzyme activity, immune gene expression and disease resistance of juvenile white shrimp (Litopenaeus vannamei). A mixture of two probiotic strains, L10 and G1 in equal proportions, was administered at two different doses 10(5) (BM5) and 10(8) (BM8) CFU g(-1) feed to shrimp for eight weeks. In comparison to untreated control group, final weight, weight gain and digestive enzyme activity were significantly greater in shrimp fed BM5 and BM8 diets. Significant differences for specific growth rate (SGR) and survival were recorded in shrimp fed BM8 diet as compared with the control; however, no significant differences were recorded for food conversion ratio (FCR) among all the experimental groups. Eight weeks after the start of the feeding period, shrimp were challenged with Vibrio harveyi. Statistical analysis revealed significant differences in shrimp survival between probiotic and control groups. Cumulative mortality of the control group was 63.3%, whereas cumulative mortality of the shrimp that had been given probiotics was 20.0% with BM8 and 33.3% with BM5. Subsequently, real-time PCR was employed to determine the mRNA levels of prophenoloxidase (proPO), peroxinectin (PE), lipopolysaccharide- and β-1,3-glucan-binding protein (LGBP) and serine protein (SP). The expression of all immune-related genes studied was significantly up-regulated (P 
    Matched MeSH terms: Penaeidae/microbiology*
  19. Fulltext Selection and identification of non-pathogenic bacteria isolated from fermented pickles with antagonistic properties against two shrimp pathogens
    Zokaeifar H, Balcázar JL, Kamarudin MS, Sijam K, Arshad A, Saad CR
    J Antibiot (Tokyo), 2012 Jun;65(6):289-94.
    PMID: 22491136 DOI: 10.1038/ja.2012.17
    In this study, potential probiotic strains were isolated from fermented pickles based on antagonistic activity against two shrimp pathogens (Vibrio harveyi and Vibrio parahaemolyticus). Two strains L10 and G1 were identified by biochemical tests, followed by16S ribosomal RNA gene sequence analysis as Bacillus subtilis, and characterized by PCR amplification of repetitive bacterial DNA elements (Rep-PCR). Subsequently, B. subtilis L10 and G1 strains were tested for antibacterial activity under different physical conditions, including culture medium, salinity, pH and temperature using the agar well diffusion assay. Among the different culture media, LB broth was the most suitable medium for antibacterial production. Both strains showed the highest level of antibacterial activity against two pathogens at 30 °C and 1.0% NaCl. Under the pH conditions, strain G1 showed the greatest activity against V. harveyi at pH 7.3-8.0 and against V. parahaemolyticus at pH 6.0-8.0, whereas strain L10 showed the greatest activity against two pathogens at pH 7.3. The cell-free supernatants of both strains were treated with four different enzymes in order to characterize the antibacterial substances against V. harveyi. The result showed considerable reduction of antibacterial activity for both strains, indicating the proteinaceous nature of the antibacterial substances. A wide range of tolerance to NaCl, pH and temperature was also recorded for both strains. In addition, both strains showed no virulence effect in juvenile shrimp Litopenaeus vannamei. On the basis of these results and safety of strains to L. vannamei, they may be considered for future challenge experiments in shrimp as a very promising alternative to the use of antibiotics.
    Matched MeSH terms: Penaeidae/microbiology*
  20. White spot syndrome virus isolates of tiger shrimp Penaeus monodon (Fabricious) in India are similar to exotic isolates as revealed by polymerase chain reaction and electron microscopy
    Mishra SS, Shekhar MS
    Indian J Exp Biol, 2005 Jul;43(7):654-61.
    PMID: 16053274
    Microbiological analysis of samples collected from cases of white spot disease outbreaks in cultured shrimp in different farms located in three regions along East Coast of India viz. Chidambram (Tamil Nadu), Nellore (Andhra Pradesh) and Balasore (Orissa), revealed presence of Vibrio alginolyticus, Vibrio parahaemolyticus, and Aeromonas spp. but experimental infection trials in Penaeus monodon with these isolates did not induce any acute mortality or formation of white spots on carapace. Infection trials using filtered tissue extracts by oral and injection method induced mortality in healthy P. monodon with all samples and 100% mortality was noted by the end of 7 day post-inoculation. Histopathological analysis demonstrated degenerated cells characterized by hypertrophied nuclei in gills, hepatopancreas and lymphoid organ with presence of intranuclear basophilic or eosino-basophilic bodies in tubular cells and intercellular spaces. Analysis of samples using 3 different primer sets as used by other for detection of white spot syndrome virus (WSSV) generated 643, 1447 and 520bp amplified DNA products in all samples except in one instance. Variable size virions with mean size in the range of 110 x 320 +/- 20 nm were observed under electron microscope. It could be concluded that the viral isolates in India involved with white spot syndrome in cultured shrimp are similar to RV-PJ and SEMBV in Japan, WSBV in Taiwan and WSSV in Malaysia, Indonesia, Thailand, China and Japan.
    Matched MeSH terms: Penaeidae/microbiology
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