| 1. |
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| 2. |
- Baruah, Kartik
(författare)
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Acute hepatopancreatic necrosis disease (AHPND) toxin degradation by Bacillus subtilis DSM33018
- 2021
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 540
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Tidskriftsartikel (refereegranskat)abstract
- Early mortality syndrome (EMS) or acute hepatopancreatic necrosis disease (AHPND), results in significant mortality in penaeid shrimp aquaculture. AHPND is caused by toxins secreted by pathogenic strains of Vibrio parahaemolyticus, that have acquired a unique 63-70 kb AHPND-associated plasmid (pVA1). This plasmid encodes the binary PirA/BVP toxins that consist of two subunits PirAVP and PirBVP. Consequently, the degradation of these toxins might be a valid strategy to control or mitigate AHPND. There is literature-based evidence that the application of Bacillus improves shrimp survival upon challenge with pathogenic V. parahaemolyticus. In this study, Bacillus subtilis DSM33018 strain was shown to degrade AHPND toxins in vitro, as detected by Western blots. Further, an in vivo challenge test, using gnotobiotically cultured brine shrimp Artemia franciscana exposed to PirA/BVP toxins, the DSM33018 Bacillus strain could completely alleviate toxicity. This finding indicates that mitigation of AHPND might include Bacillus-based degradation of PirVP toxins.
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| 3. |
- Baruah, Kartik
(författare)
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Bamboo powder protects gnotobiotically-grown brine shrimp against AHPND-causing Vibrio parahaemolyticus strains by cessation of PirAB(VP) toxin secretion
- 2021
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 539
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Tidskriftsartikel (refereegranskat)abstract
- Acute hepatopancreatic necrosis disease (AHPND), caused by virulent Vibrio parahaemolyticus strains, is causing havoc in the shrimp industry. However, the culture conditions markedly influence the phenotypic status of V. parahaemolyticus. For instance, under low shaking conditions, the free-living planktonic virulent form of AHPND-causing V. parahaemolyticus switches into a non-virulent biofilm phenotype. Hence, strategies that could stimulate phenotype switching can be a novel way to control AHPND in shrimp. In this study, we evaluated the role of bamboo powder, a natural biofilm carrier, on the phenotypic switch in AHPND-causing and non-AHPND V. parahaemolyticus strains under both in vitro and in vivo conditions. The results showed that bamboo powder addition (50?100 mg/l) significantly enhanced the survival of brine shrimp larvae upon challenge with AHPND M0904 and RY strains. Furthermore, addition of bamboo powder also has profound effects on the phenotypic responses of AHPND-causing V. parahaemolyticus strains. The V. parahaemolyticus AHPND strains (M0904 and RY) grown with bamboo powder developed cellular aggregates or floccules in the culture medium and switch in the pattern of protein production and secrete alkaline phosphatase PhoX instead of PirAVP and PirBVP toxins. Based on the overall results, it can be suggested that bamboo powder induces phenotype switching, which might contribute in part to the protection of the brine shrimp larvae against AHPND-causing V. parahaemolyticus.
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| 4. |
- Baruah, Kartik
(författare)
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Beta-glucan's varying structure characteristics modulate survival and immune-related genes expression from Vibrio harveyi-infected Artemia franciscana in gnotobiotic conditions
- 2020
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Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 102, s. 307-315
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Tidskriftsartikel (refereegranskat)abstract
- beta-Glucans have long been used as an immunostimulant in aquaculture. However, the relationship of its structure to its immunomodulatory properties are poorly understood. In this study, the particle size and chemical structure of beta-glucans extracted from wild-type strain of baker's yeast (Saccharomyces cerevisiae) and its null-mutant yeasts Gas1 were characterised. Using Sigma beta-glucan as a reference, the immunomodulatory properties of these polysaccharides in the germ-free Anemia franciscana model system in the presence of Vibrio harveyi bacterial challenge were investigated. The survival of the A. franciscana nauplii, upon challenge with V. harveyi, was significantly higher in all three glucan-treated groups compared to the control. The glucan Gas1 with a lower degree of branching and shorter side chain length had the most prominent V. harveyi-protective effects. The particle size did not affect the nauplii survival when challenged with V. harveyi. Results also showed that the salutary effect of the tested glucans was associated with the upregulation of innate immune genes such as lipopolysaccharide and beta-1,3-glucan-binding protein (lgbp), high mobility group box protein (hmgb), and prophenoloxidase (proPO). Interestingly, the up-regulation of superoxidase dismutase (sod) and glutathione-stransferase (gst) was only observed in Gas1 treated group, indicating that Gas1 could function to induce higher reactive oxygen species and stronger immunomodulatory function in A. franciscana, and therefore higher survival rate. The expression of heat shock protein 70 (hsp70), peroxinectin (pm), and down syndrome cell adhesion molecule (dscam) remain unaltered in response to glucan treatment. Taken together, this study provides insights into the structure-function relationship of beta-glucan and the results confirmed that beta-glucan can be an effective immunostimulant in aquaculture, especially the Gas1 glucan.
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| 5. |
- Baruah, Kartik
(författare)
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Differential expression of immune-related biomarkers in primary cultures from Atlantic salmon ( Salmo salar ) exposed to processed Paecilomyces variotii with or without inactivated Moritella viscosa
- 2024
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Ingår i: Fish and Shellfish Immunology. - 1050-4648 .- 1095-9947. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- Paecilomyces variotii (a filamentous fungus), is a promising novel protein source in fish feeds due to its high nutritional value. Also, P. variotii has Microbial-Associated Molecular Patterns (MAMPs) such as glucans and nucleic acids that could modulate the host's immune response. To understand the potential bioactive properties of this fungus in Atlantic salmon (Salmo salar), our study was conducted to evaluate the gene expression of immune-related biomarkers (e.g., cytokines, effector molecules and receptors) on primary cultures from salmon head kidney (HKLs) and spleen leukocytes (SLs) exposed to either UV inactivated or fractions from P. variotii with or without inactivated Moritella viscosa (a skin pathogen in salmonids). Moreover, the effect of the fermentation conditions and down-stream processing on the physical ultrastructure and cell wall glucan content of P. variotii was characterized. The results showed that drying had a significant effect on the cell wall ultrastructure of the fungi and the choice of fermentation has a significant effect on the quantity of beta-glucans in P. variotii. Furthermore, stimulating Atlantic salmon HKLs and SLs with P. variotii and its fractions induced gene expression related to pro-inflammatory (tnf alpha, il1 beta) and antimicrobial response (cath2) in HKLs, while response in SLs was related to both pro-inflammatory and regulatory response (tnf alpha, il6 and il10). Similarly, the stimulation with inactivated M. viscosa alone led to an up-regulation of genes related to pro-inflammatory (tnf alpha, il1 beta, il6) antimicrobial response (cath2), intra-cellular signalling and recognition of M. viscosa (sclra, sclrb) and a suppression of regulatory response (il10) in both HKLs and SLs. Interestingly, the co-stimulation of cells with P. variotii and M. viscosa induced immune homeostasis (il6, tgf beta) and antimicrobial response (cath2) in SLs at 48h. Thus, P. variotii induces immune activation and cellular communication in Atlantic salmon HKLs and SLs and modulates M. viscosa induced pro-inflammatory responses in SLs. Taken together, the results from physical and chemical characterization of the fungi, along with the differential gene expression of key immune biomarkers, provides a theoretical basis for designing feeding trials and optimize diets with P. variotii as a functional novel feed ingredient for Atlantic salmon.
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| 6. |
- Baruah, Kartik
(författare)
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Differential modulation of oxidative stress, antioxidant defense, histomorphology, ion-regulation and growth marker gene expression in goldfish (Carassius auratus) following exposure to different dose of virgin microplastics
- 2020
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Ingår i: Comparative Biochemistry and Physiology - Part C: Toxicology and Pharmacology. - : Elsevier BV. - 1532-0456. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Goldfish (Carassius auratus) juveniles were exposed to virgin polyvinyl chloride microplastics (PVC-MPs) in triplicate at 0, 0.1 or 0.5 mg/L for four days. Afterwards, the histopathology of the gills, liver and intestines were examined, along with various antioxidant enzymes and indicators of oxidative damage (malondialdehyde (MDA) and hydrogen peroxide (H2O2)), in the brain, liver and gills. In addition, we also studied the expression of hepatic insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 1 (IGFBP-1) and growth hormone (GH) receptor, while cortisol receptor (CR) and cytochrome P450 1A (CYP1A) gene expression were assayed in both the liver and gills. Histological analysis revealed PVC-MPs in the intestines at 0.1 and 0.5 mg/L, along with substantially shorter villi. The gills appeared undamaged by PVC-MPs exposure and had limited or no effect to antioxidant activity, Na+/K+-ATPase and II tATPase activity or plasma ion levels, but there was a prominent upsurge of the detoxification enzymes glutatione S-transferase (GST) activity and CYP1A expression. Livers showed inflammation and some occurrences of hemorrhaging and necrosis at 0.5 mg/L. While the brain showed some evidence of oxidative damage, the liver was the most susceptible to oxidative damage, based on increased MDA, H2O2 and various antioxidant enzymes. Hepatic expression of IGFBP-1 and GH receptor were significantly downregulated at 0.5 mg/L while CR was upregulated. Results indicate that exposure to environmentally relevant PVC-MP can cause oxidative damage in the brain and liver, adverse histomorphological changes to the intestine and liver and alter the gene expression in goldfish.
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| 7. |
- Baruah, Kartik
(författare)
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Effects of heat shock protein 70 knockdown on the tolerance of the brine shrimp Artemia franciscana to aquaculture-related stressors: Implications for aquatic animal health and production
- 2022
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 550
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Tidskriftsartikel (refereegranskat)abstract
- Temperature, pH, salinity and ammonia stress adversely affect the performance and well-being of aquatic organisms, especially those used in aquaculture, a major food production sector. Management strategy to mitigate stress caused by abiotic factors in farmed aquatic organisms is scarce but is highly warranted considering the negative impact of these factors on the welfare and economic production of the farmed animals. The induction of heat shock proteins, mainly 70 kDa Hsp (Hsp70), in farmed fish and shellfish, including the live feed brine shrimp Artemia franciscana, by exposure to a non-lethal heat shock (NLHS) of 37 ?C for 30 min followed by 6 h recovery period caused a significant improvement in the tolerance of the animals towards subsequent challenge with an abiotic stress. Although the protective effect of NLHS was associated with enhanced Hsp70 accumulation in these species, the induction of other members of Hsp and their collective involvement in the stress tolerance could not be ignored. This triggered an argument as to whether only Hsp70 or its combination with other Hsps was responsible for inducing stress tolerance phenotype in these species. In this study, we employed RNAi technology in the biological model organism Artemia to gain insight into the functional role of Hsp70 in stress tolerance. The results showed that upon exposure to a NLHS, the wild-type Artemia nauplii capable of producing Hsp70 exhibited significantly higher survival than the unexposed control in all the abiotic stress tolerance tests performed in this study. However, the Hsp70-deficient mutant nauplii did not exhibit increased stress-tolerant phenotypes as the survival percentage of the nauplii decreased by 29, 19, and 15%, respectively, upon challenge with a median lethal concentration of salinity, pH, and ammonia. These results suggest that Hsp70 was involved in inducing tolerance against stress caused by the abiotic factors, and hence can be a potential target for developing strategies to protect economically important aquaculture species from environmental disturbances.Superscript/Subscript Available
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| 8. |
- Baruah, Kartik, et al.
(författare)
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Heat Shock Proteins in Fish Health and Diseases: A Pharmacological Perspective
- 2017
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Ingår i: Heat Shock Proteins in Veterinary Medicine and Sciences. - Cham : Springer International Publishing. - 9783319733760 ; 12:12, s. 197-213
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Bokkapitel (refereegranskat)abstract
- Disease outbreaks are considered one of the largest constraints for the sustainable development of the aquaculture sector. Though applications of antibiotics manage to control and prevent infectious microbial diseases, however, its extensive uses have also unavoidably resulted in the emergence of `superbugs' that resist conventional antibiotics. This calls for the development of new approaches for combating infections. Recently, heat shock proteins have been suggested to mediate the generation of strong innate and adaptive immune responses against many diseases in plants and terrestrial animals, leading to the formulation of strategies to fight infections. In this review, the potential of a new treatment, heat shock protein based therapy, for overcoming the menace of diseases in farmed aquatic animals of commercial importance are discussed.
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| 9. |
- Baruah, Kartik
(författare)
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High doses of sodium ascorbate act as a prooxidant and protect gnotobiotic brine shrimp larvae (Artemia franciscana) against Vibrio harveyi infection coinciding with heat shock protein 70 activation
- 2019
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Ingår i: Developmental and Comparative Immunology. - : Elsevier BV. - 0145-305X .- 1879-0089. ; 92, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- Ascorbate is an essential nutrient commonly regarded as an antioxidant. In this study, using axenic brine shrimp and pathogenic strain Vibrio harveyi as the host-pathogen model, we confirmed that pretreatment of sodium ascorbate (NaAs), at an optimum concentration, was a prooxidant by generation of hydrogen peroxide, inducing protective effects in the brine shrimp against V. harveyi infection. Such a protective effect could be neutralized by the addition of an antioxidant enzyme catalase. We further showed that generation of oxygen radicals is linked to the induction of heat shock protein 70 (Hsp70), which is involved in eliciting the antioxidant protection system including superoxidase dismutase (SOD) and possibly many other immune responses. Furthermore, using RNA interference technique, we found that the pretreatment of sodium ascorbate increased the survival significantly in the control knockdown groups (using green fluorescent protein, GFP) but not in Hsp70 knockdown groups and the result directly suggested that the up-regulated Hsp70 induced by sodium ascorbate pretreatment induced the protective effect. These results provide a mechanistic rationale for exploring the further use of ascorbate for antimicrobial therapy in aquaculture.
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| 10. |
- Baruah, Kartik
(författare)
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In vitro Selection of Synbiotics and in vivo Investigation of Growth Indices, Reproduction Performance, Survival, and Ovarian Cyp19 alpha Gene Expression in Zebrafish Danio rerio
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we tested the compatibility of two extracts from the plant Jerusalem artichokes and button mushrooms with two different Lactobacillus probiotics (Lactobacillus acidophilus; La and Lactobacillus delbrueckii subsp. Bulgaricus; Lb) to develop a synbiotic formulation to improve the growth, survival, and reproductive performances of farmed fishes. Initially, we employed in vitro approach to monitor the growth of the probiotic lactobacilli in the presence of the different doses of the plant-based prebiotics, with the aim of selecting interesting combination(s) for further verification under in vivo conditions using zebrafish as a model. Results from the in vitro screening assay in the broth showed that both the probiotic species showed a preference for 50% mushroom extract as a source of prebiotic. A synbiotic formulation, developed with the selected combination of L. acidophilus, L. bulgaricus, and 50% mushroom extract, showed a positive influence on the growth and reproductive performances of the zebrafish. Our findings also imply that the improvement in the reproductive indices was associated with the upregulation of a cyp19a gene. Overall results suggest that a combination of L. acidophilus, L. bulgaricus, and mushroom extract can be considered as a potential synbiotic for the successful production of aquaculture species.
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