Synergistic effects of molasses-based biofloc and sediment integration on growth and survival of sandfish (Holothuria scabra) juveniles

Pulished in:   Aquaculture International

DOI: https://doi.org/10.1007/s10499-025-02362-5

The sandfish Holothuria scabra is one of the most commercially valuable sea cucumber species worldwide due to its high market demand. In Sri Lanka, it supports income generation and the livelihoods of coastal communities; however, the nursery phase is often constrained by suboptimal growth and survival rates. This study evaluated the efficiency of biofloc systems as an improved nursery approach for Hscabra. A 6-week nursery trial was conducted under three treatments: biofloc only (T1), biofloc integrated with marine sediments (sandy-muddy; T2), and marine sediments only (T3; control) with triplicate. Nine fiberglass tanks (1500 L) were stocked with 15 juveniles per tank (mean initial weight 1.48 ± 0.11 g). Fishmeal served as the nitrogen source; molasses was added to maintain a C:N ratio of 15:1. Growth performance, water quality, biofloc volume, and microbial community composition were assessed. Final length, weight, and their gains were significantly (p < 0.05) higher in T2 than in T1 and T3. Specific growth rate (SGR) was significantly (p < 0.05) declined in T1 (0.70 ± 0.55% day−1). Survival was 100% in all treatments. Water quality parameters did not differ (p > 0.05) among the three treatments. Total bacteria density was significantly (p < 0.05) higher in T1 and T2 than in T3. Microbial profiling revealed a higher abundance of Bacillus spp. in T1 and T2, whereas Vibrio spp. dominated in T3. In conclusion, the integration of biofloc–sediment proved to be an economically viable sustainable nursery phase for Hscabra juveniles, ensuring higher growth, no mortality and good microbial profile in zero-water-exchange.

Alkaloids and nitrosamines in betel quid: A biochemical exploration of carcinogenicity

Published in: Chemico-Biological Interactions

DOI: https://doi.org/10.1016/j.cbi.2025.111383

Betel quid contains two major ingredients; Areca catechu and Piper betel, often consumed with slaked lime, tobacco, certain flavouring agents, colouring agents, herbs, and spices according to personal preferences. The areca nut alkaloids (arecoline, arecaidine, guvacine, and guvacoline), and tobacco alkaloids (nicotine, nornicotine) undergo nitrosation during chewing in the oral cavity with the presence of nitrite and thiocyanate and endogenously. Among the nitrosation products generated areca nut-derived nitrosamine (ADNA): 3-(methylnitrosamino) Propionitrile (MNPN) and the two tobacco-specific nitrosamines (TSNAs); N′-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone) (NNK) are considered Group 1 human carcinogens. The slaked lime increases pH, reactive oxygen species (ROS) generation, and inflammation further lead to oral potentially malignant disorders (OPMD). The juice swallowed results in carcinogenicity, mutagenicity, and toxicity in the gastrointestinal tract including hepatocytic carcinoma, stomach, and colon cancer. Areca nut pre-treatments (sun drying, roasting, boiling, and fermentation) increase the quid metabolism, and reduce the arecoline content and associated risks. We review biochemical carcinogenesis of betel quid ingredients and synergic adverse effects and possible mechanism of carcinogenesis of betel quid in the oral cavity and gastrointestinal tract to understand the implication of polyphenols and alkaloids of areca nut and betel quid on carcinogenic nitrosamine formation under oral, gastric, and intestinal conditions.

Molecular Docking and Dynamics Simulations Reveal the Antidiabetic Potential of a Novel Fucoxanthin Derivative from Chnoospora minima

Published in: Marine Drugs

DOI: https://doi.org/10.3390/md23120471

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder requiring safer and more effective therapeutic alternatives. This study investigates a novel fucoxanthin derivative isolated from the marine brown alga Chnoospora minima using a comprehensive in silico approach. Molecular docking revealed that the derivative exhibited higher binding affinities toward α-amylase (–9.4 kcal/mol) and α-glucosidase (–8.0 kcal/mol) compared to the reference drug acarbose (–8.5 and –7.4 kcal/mol, respectively). Pharmacokinetic analysis predicted good intestinal absorption and P-gp inhibition (0.894) and moderate plasma clearance (7.864 mL/min/kg), while toxicity predictions classified it in toxicity class 3, with
no respiratory or ocular toxicity. Drug-likeness evaluation showed only one Lipinski and one Veber rule violation, common for natural products. Molecular dynamics simulations conducted for 100 ns using NAMD 3.0 confirmed stable protein–ligand complexes with average RMSD values of ~1.3 Å and ~1.8 Å for α-amylase and α-glucosidase, respectively, and consistent hydrogen bonding profiles. Structural analysis identified a substitution of the allene bond with an unsaturated ketone at the C8′ position as a key contributor to enhanced enzyme interaction. The findings suggest that this fucoxanthin derivative is a
promising natural candidate for T2DM therapy and warrants further investigation through lab experiments (in vitro and in vivo).

Evaluation of mycoparasitic Trichoderma atroviride and entomopathogenic Aspergillus niger as potential bioinsecticides against the dengue vector, Aedes aegypti

Published in: Frontiers in Cellular and Infection Microbiology

DOI: https://doi.org/10.3389/fcimb.2025.1502579

Introduction: Over the past three decades, dengue disease incidence has significantly increased worldwide, creating serious public health concerns. The principal mosquito vector, Aedes aegypti, exhibits resistance to commonly used insecticides, reducing the efficacy of vector control measures. Thus, the necessity for alternate strategies is critical. Using bioinsecticides such as entomopathogenic fungi (EPF) is one such strategy. This study details the evaluation of mycoparasitic Trichoderma atroviride and entomopathogenic Aspergillus niger against pyrethroid-resistant and pyrethroid-susceptible Ae. aegypti populations.

Materials and methods: Molecular identification of the isolated entomopathogenic fungal strains was done using ITS-rDNA sequence data. Larvicidal and adulticidal assays were performed using different spore concentrations of fungal species. Pupal emergence was assessed from the survived larvae of larvicidal assays.
Results: Larvicidal assays revealed the highest mortality of 60% for T. atroviride after 9 days of exposure when compared with the highest mortality of 52% for A. niger after 6 days of exposure. No significant difference was observed between the pyrethroid-resistant and pyrethroid-susceptible mosquito colonies, suggesting a lack of connection between prior resistance status and EPF pathogenicity. No pupal mortality was observed, although pupal duration was prolonged. Both EPF strains exhibited 100% mortality in adulticidal assays, signifying the potential use of the two fungal species as adulticides.

Conclusion: However, further studies are needed to understand the biology of EPF, its mechanism of action, the mosquito immune pathways activated, and the effect on non-target organisms. The findings have implications for the possible use of A. niger and T. atroviride as potential bioinsecticides against the control of Ae. aegypti.