| 1. |
- Baruah, Kartik
(author)
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Sodium Ascorbate as a Quorum-Sensing Inhibitor Leads to Decreased Virulence in Vibrio campbellii
- 2020
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In: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 11
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Journal article (peer-reviewed)abstract
- Vibrio campbelliiis one of the major bacterial pathogens for animals reared in aquaculture, affecting both vertebrates and invertebrates, and causes significant economic losses. It is now evident that the expressions of virulence factors in this pathogen are regulated by the density of the bacterial population. This type of regulation, termed quorum sensing (QS), is mediated by extracellular signal molecules called autoinducers. In this study, the impact of sodium ascorbate (NaAs) on the virulence ofV. campbelliiwas investigated under bothin vitroandin vivoconditions, to develop a natural anti-infective strategy to containV. campbelliiinfection in aquacultured animals. Results showed that NaAs significantly decreased swimming motility, biofilm production, and the production of virulence enzymes, such as lipase, caseinase, phospholipase, and hemolysin inV. campbellii. Consistent with this, pretreatment ofV. campbelliiwith NaAs before inoculation into the rearing water resulted in significantly increased survival of gnotobiotic brine shrimp larvae, when compared to larvae challenged with untreatedV. campbellii. Furthermore, NaAs could interfere with QS-regulated bioluminescence inV. campbellii, suggesting the QS-inhibitory activity largely determines the protective effect of NaAs toward the brine shrimp. In essence, due to the potent anti-virulence effects observed inin vitrostudies and the clinical brine shrimp-V. campbelliiinfection model, NaAs constitute a promising novel strategy for the control ofV. campbelliiinfections in aquaculture.
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| 2. |
- Erneman, J., et al.
(author)
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Comparison between quantitative metallography and modeling of sigma-phase particle growth in AISI 347 stainless steel
- 2005
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In: Metallurgical and Materials Transactions. A. - : Springer Science and Business Media LLC. - 1073-5623 .- 1543-1940. ; 36A:10, s. 2595-2600
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Journal article (peer-reviewed)abstract
- A comparison was made between two experimental methods to determine the (T-phase volume fraction and three methods to model a-phase growth in a niobium-stabilized stainless steel (AISI 347). The a-phase volume fraction and precipitate size were determined in material statically aged and creep deformed at 700 degrees C with both KOH etched specimens using bright field optical microscopy (OM/BF) (conventional method) and specimens etched with oxalic acid using scanning electron microscopy and backscattered electrons (SEM/BSE) (new method). Both experimental methods used manual thresholding together with digital image analysis. The calculations were made with DICTRA software, using both the TCFE database and the SSOL database with some modification concerning the effect of silicon on the stability of sigma-phase particles. The modeled sigma-phase volume- fractions showed rather good agreement with the measured results from statically aged material using the new method. It was found that the stabilizing effect of silicon on sigma phase should be included in the thermodynamic database used for modeling.
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| 3. |
- Baruah, Kartik, et al.
(author)
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Production performance, fillet quality and cost effectiveness of red Tilapia (Oreochromis sp.) culture in different biofloc systems
- 2023
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In: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 563
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Journal article (peer-reviewed)abstract
- The accumulation of biofloc in a rearing media that may bring about some adverse effects on the cultured fish, can be addressed by using a settlement tank. This study aimed to compare the production performance and flesh quality of red tilapia Oreochromis sp. in biofloc systems with and without a settlement tank. This study comprised of two treatments, i.e. biofloc system with settlement tank (Bioras) and biofloc system without settlement tank (Biofloc), each maintined in triplicates. Fish was reared in outdoor tarpaulin tanks with a diameter of 3 m and a height of 1.2 m, which were filled with about 5 m3 of water. Tilapia with an initial average weight of 100 g was cultured at an initial density of 5 kg m- 3 for 112 days with a partial harvest conducted on day 42. The fish was fed with a commercial diet containing 30.5% crude protein to apparent satiation twice a day. The results showed that the production performance of red tilapia in Bioras (75 kg) was higher than that of the conventional biofloc system (70 kg). Mild deformities and limited parasite infestation were observed in the gills of the fish housed in the Bioras system. The fish quality was similar between the treatments, except for the hardness (8.4 kgf), gumminess (3.4 kgf), and chewiness (1.8 kgf), which was higher in the fish housed in the conventional biofloc system. The increase in fish growth in Bioras system could not compensate the increase in cost for the investment and operation of the settling tank, which was about 17% higher in the Bioras system. In conclusion, the present study confirmed that the addition of a settlement tank can be beneficial in controlling biofloc biomass and could improve the growth performance, but not yet profitable for red tilapia commercial production.
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