Screening of microalgae with the potential as anti quorum sensing and anti-vibrio agent in shrimp culture.

Vibriosis, caused by Vibrio parahaemolyticus, is a major bacterial disease in shrimp aquaculture, often managed with antibiotics that contribute to antimicrobial resistance and environmental concerns. This study investigated the antimicrobial properties of Kiam wood (Cotylelobium lanceotatum) extract and its potential as a dietary supplement to enhance the disease resistance of Pacific white shrimp, Penaeus vannamei. Kiam wood extracts were prepared using ethanol-water mixture at different ratios, and their antimicrobial activity was evaluated against V. parahaemolyticus. The water extract (KWE) exhibited the strongest anti-Vibrio activity as indicated by the widest clearance zone (15.65 mm), with a minimum inhibitory concentration (MIC) of 256 µg/mL and a minimum bactericidal concentration (MBC) of 512 µg/mL. Further assays demonstrated that KWE effectively inhibited biofilm formation and restricted bacterial motility at 512 µg/mL (MBC). Scanning electron microscopic images revealed significant cell-wall damages in treated bacteria as shown by membrane disruption and pore formations. Liquid chromatography-mass spectrometry (LC-MS) analysis identified Amuresins D (C42H30O9), Pauciflorol A (C24H32O9), Vaticasides A (C48H42O14), Vaticanols B (C56H42O12), and Cotylelophenol B (C24H30O10) as key bioactive compounds. For the in vivo trials, P. vannamei was firstly infected by feeding them a V. parahaemolyticus-impregnated diet (1.5 × 10⁴ CFU/g) for two days, followed by a 15-day feeding period with KWE-supplemented diets at 2MBC (1 mg/g). Shrimp-fed KWE diets showed a significant reduction in intestinal Vibrio loads, enhanced immune responses (total hemocyte count, semi-granulocyte, and granulocyte levels), and improved survival rates. Notably, the KWE diet achieved the highest survival rate (85%), compared to 52% in the control group. These findings highlight KWE as a promising natural antimicrobial agent with immunostimulatory properties, offering a sustainable alternative to synthetic antibiotics for managing vibriosis in shrimp aquaculture. Further studies should explore its mode of action and long-term effects on shrimp health and aquaculture environments.

Genomic identification and characterization of co-occurring Harveyi clade species following a vibriosis outbreak in Pacific white shrimp, Penaeus (litopenaeus) vannamei

Antimicrobial resistance is among the world’s most urgent public health problems. Diminishing of the virulence of bacteria is a promising approach to decrease the development of bacterial resistance. Quorum sensing (QS) systems orchestrate the bacterial virulence in inducer–receptors manner. Bacteria can spy on the cells of the host by sensing adrenergic hormones and other neurotransmitters, and in turn, these neurotransmitters can induce bacterial pathogenesis. In this direction, α-adrenergic blockers were proposed as an anti-virulence agents through inhibiting the bacterial espionage. The current study aimed to explore the α-blockers’ anti-QS activities. Within comprehensive in silico investigation, the binding affinities of seven α-adrenoreceptor blockers were evaluated towards structurally different QS receptors. From the best docked α-blockers into QS receptors, terazosin was nominated to be subjected for further in vivo and in vitro anti-QS and anti-virulence activities against Chromobacterium violaceum and Pseudomonas aeruginosa. Terazosin showed a significant ability to diminish the QS-controlled pigment production in C. violaceum. Moreover, Terazosin decreased the P. aeruginosa biofilm formation and down-regulated its QS-encoding genes. Terazosin protected mice from the P. aeruginosa pathogenesis. In conclusion, α-adrenergic blockers are proposed as promising anti-virulence agents as they hinder QS receptors and inhibit bacterial espionage.

In Indonesia, vibriosis is the main disease in shrimp. This disease is caused by Vibrio sp that may decrease the productivity of shrimp cultivation. Thus, exploration for new bioactive compounds as vibriosis biocontrol agent is necessary. Marine sponge-associated bacteria is one of many sources for bioactive compounds. The aim of this study was to screen marine sponge-associated bacteria producing anti-Vibrio sp’s bioactive compounds. Total 12 bacterial isolates (15%) of 80 isolates was isolated from marine sponges Hyrtios sp, Verongula sp. and Smenospongia sp. had anti-Vibrio sp activity in different spectra. The hemolytic assay showed that these 12 bacteria were not pathogen. Interestingly, 3 out of 4 potential isolates with the best anti-Vibrio activity have been confirmed to have genes involved in the synthesis of bioactive compounds, mainly Polyketide Synthase (PKS) and Non-Ribosomal Peptide Synthetase (NRPS) based on the occurrence of Ketosynthase (KS) and Adenilase (A) domain, respectively. Based on 16S rRNA gene, those four isolates were highly homolog to the Bacillus sp in different species and strains. Isolate coded as P2.24 was the only bacterium that had the widest spectrum of anti-Vibrio bioactive compounds against three Vibrio sp used i.e., Vibrio harveyi, V. parahaemolyticus, V. vulnificus. Consistently, an anti- Vibrio sp. activity of the P2.24 was also shown by antagonism assay using culture, supernatant and crude extract of the isolate. Our study indicates this bacterial isolate potentially to be further exploited for controlling vibriosis biologically and important for elucidation of bioactive compounds synthesized by this bacterium.

Bacillus pumilus of Palk Bay origin inhibits quorum-sensing-mediated virulence factors in Gram-negative bacteria

Antibacterial and anti-quorum sensing activities of a substituted thiazole derivative against methicillin-resistant Staphylococcus aureus and other multidrug-resistant bacteria

In face of the shortage of, and competition with, land and water, the sustainability of aquaculture will have to depend on vertical development, through improving production environments, increasing productivity and enhancing aquaculture technologies. Biofloc technology (BFT) has emerged as new alternative for sustainable aquaculture, which could contribute to FAO Sustainable Development Goals (SDGs) related to food security. Extensive research has been carried out on the development and application of BFT in aquaculture since early 1990s, with emphasis on shrimp culture. Over 40% of BFT publications in aquaculture were directed to shrimp farming. Therefore, I strongly believe that the accumulated knowledge on the applications of BFT in shrimp farming and the experience gained, especially during the last 10 years (2010–2020), are now more than worthy of critical review and analysis. This review summarizes the most update knowledge on the use of BFT in different marine shrimp and freshwater prawn aquaculture. Emphasis has been on factors affecting shrimp production in BFT systems, integration of biofloc‐based shrimp farming with other aquatic farmed species, nutritional value of bioflocs as a natural food or feed ingredient for farmed shrimp and prawn, the application of BFT in different rearing phases, the use of biofloc as a natural probiotics and their effects on shrimp health and physiological functions, economic considerations and commercial applications of BFT‐based shrimp aquaculture, and the major challenges facing shrimp farming in biofloc systems.

The marine symbiont Pseudovibrio denitrificans, is effective to control pathogenic Vibrio spp. in shrimp aquaculture

Ethnopharmacological relevanceThirty-five herbal formulations used in this current work are utilized as anti-cariogenic agents in Thai traditional medicine. Acidogenic properties play a crucial role in the initiation of dental caries caused by Streptococcus mutans, and a quorum sensing (QS) system is an associated virulence factor in dental caries. Aim of the studyThe current work aimed to determine the anti-acidogenic effect of these polyherbal formulas against S. mutans and explore their anti-QS activity using Chromobacterium violaceum as a biosensor. Materials and methodsEthanol and water extracts from the formulas were evaluated for their anti-acidogenic effects using glycolytic pH drop assays. Qualification and quantification of anti-QS activity indicated by the level of violacein production in C. violaceum were performed using paper disc-diffusion and flask incubation assays, respectively. ResultsAmong the extracts tested, THF-DC 02 and THF-DC 04 significantly inhibited the acidogenesis of S. mutans in a dose-dependent manner without affecting the cell viability. THF-DC 20 and THF-DC 29 sharply reduced the violacein production of C. violaceum, indicating the promising anti-QS activity of these extracts. ConclusionThe findings of the present study, preliminarily propose that the polyherbal formulas THF-DC 02, THF-DC 04, THF-DC 20, and THF-DC 29 produce promising anti-acidogenic or anti-QS activities. The anti-acidogenic effect of THF-DC 04 may possibly act by interrupting streptococcal membrane enzymes via its herbal components: Alpinia galanga (L.) Willd., Albizia myriophylla Benth., Avicennia marina subsp. eucalyptifolia (Valeton) J.Everett and Ocimum tenuiflorum L. The anti-QS activity of THF-DC 20 and THF-DC 29 could be due to their herbal ingredients, including Piper betle L., Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz., and Syzygium aromaticum (L.) Merr. & L.M.Perry.

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 8:147-155 (2016) - DOI: https://doi.org/10.3354/aei00169 Protective effects of sea cucumber surface-associated bacteria against Vibrio harveyi in brown-marbled grouper fingerlings Norfarrah Mohamed Alipiah1,*, Nur Hasli Syahidda Ramli1, Chen-Fei Low1, Mariana Nor Shamsudin1,2, Fatimah Md. Yusoff1,3 1Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 2Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 3Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia *Corresponding author: norfarrah_80@yahoo.com ABSTRACT: Brown-marbled grouper Epinephelus fuscoguttatus (Forsskål) fingerlings are more vulnerable to diseases than the adult grouper because the fingerlings’ adaptive immune system is still in the development stage. The mortality rates are approximately 20 to 70% during outbreaks of vibriosis in aquacultures of grouper fingerlings. Studies were conducted to identify alternative treatments with low impacts on humans, animals and the environment as well as treatments that minimize the use of antibiotics in aquaculture. In this study, we report the first use of surface-associated bacteria isolated from marine invertebrates to increase fingerlings’ resistance against infections. Twenty-two surface-associated bacteria were isolated from the sea cucumber Stichopus badionotus and were identified with 16S rRNA gene sequencing. Three of the surface-associated bacteria had inhibitory activities against pathogenic Vibrio harveyi and V. parahaemolyticus. The fingerlings treated with the surface-associated bacteria Exiguobacterium acetylicum for 12 d prior to the challenge experiment with pathogenic V. harveyi showed significantly higher survival rates and increases in antibody titres compared to the control group. This study illustrats a symbiotic interaction between E. acetylicum and grouper fingerlings. E. acetylicum colonized the scales of grouper fingerlings and enhanced the fish’s immune response against the pathogen V. harveyi. KEY WORDS: Epinephelus fuscoguttatus · Surface-associated bacteria · Surface colonizer · Symbiotic relation · Bacterial attachment · Bio-control · Marine bacteria · Immune response Full text in pdf format Supplementary material PreviousNextCite this article as: Mohamed Alipiah N, Ramli NHS, Low CF, Shamsudin MN, Yusoff FM (2016) Protective effects of sea cucumber surface-associated bacteria against Vibrio harveyi in brown-marbled grouper fingerlings. Aquacult Environ Interact 8:147-155. https://doi.org/10.3354/aei00169 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 8. Online publication date: February 25, 2016 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2016 Inter-Research.

Quorum sensing-disrupting compounds protect larvae of the giant freshwater prawn Macrobrachium rosenbergii from Vibrio harveyi infection

Construction of suspended bagasse bioflocs and evaluation of their effectiveness in shrimp (Penaeus vannamei) aquaculture systems

Succession of phytoplankton community during intensive shrimp (Litopenaeus vannamei) cultivation and its effects on cultivation systems

To study the anti-quorum sensing (anti-QS) activity of AgCl-TiO2 nanoparticles (ATNPs) and its mechanism. Anti-QS activity of ATNPs was evaluated using the bacterial model Chromobacterium violaceum. Silver present in ATNPs significantly reduced violacein production in a concentration-dependent manner, indicating inhibition of QS. Anti-QS activity was confirmed by the absence of signalling molecule, oxo-octanoyl homoserine lactone during growth in the presence of ATNPs. TiO2 acted as a good supporting matrix facilitating controlled release of silver with prolonged residual activity. ATNPs are proposed as QS inhibitors with potential for use as an antipathogenic but nontoxic bioactive material. Although silver is well known for its bioactive potential of antibacterial, antifungal and antiviral properties, this study adds further note on its anti-QS activity and its potential use in food packaging industry. Food spoilage is a major socio-economic problem, and the potential role of QS in food spoilage and food safety has been indicated. Anti-QS materials such as ATNPs are proposed as efficient models for controlling food spoilage. ATNPs incorporated in food packaging materials could play an important role in food preservation and ensure safety of food by prolonging their shelf life.

This study explored the development of inhibitors from marine algae against luminescence disease causing Vibrio harveyi. Organic solvents such as ethyl acetate (EA) and methanol:chloroform (CM) were treated to extract compounds from marine algae such as Skeletonema costatum, Ulva fasciata and Kappaphycus alvarezii. Antagonistic effect of algae extracts was determined against marine V. harveyi. EA extract of S. costatum and U. fasciata at 300 µg showed maximum zone of inhibition (12.6 and 12.3 mm) against V. harveyi. Similarly, CM extract of S. costatum also showed maximum zone of inhibition (8.3 mm). When crude EA extract of S. costatumat 300 µg/ml was used for V. harveyi, the level of luciferase was reduced to three to seven counts per second (CPS) as compared to the control for 4 days as read by luminometer. 300 mg/ml of CM extract of U. fasciata, reduced the luciferase to 3 to 6 CPS. When EA extract of S. costatum at (300 µg/ml) was treated against V. harveyi, the luminescence was reduced 10 to 15 CPS. The CM extract from U. fasciatashowed reduction in the luminescence production (7 to 13 CPS). Considering the cumulative effect of anti-luminescence and anti-Vibrio activities, 300 mg of crude extract prepared from S. costatum in both solvents were confirmed as inhibitory to V. harveyi. Significant difference (p<0.05) was observed among the levels of luciferase and luminescence in all the extracts but S. costatum showed less. This study confirms that marine algae extracts can be used to control luminescent disease causing V. harveyi among the shrimp grow-out system and larviculture. Key words: Algae extracts, antagonism, Vibrio harveyi, anti-luciferase, anti-luminescence.