Unveiling the silent threat: Heavy metal toxicity devastating impact on aquatic organisms and DNA damage.

Heavy metal pollution has significant impacts on aquatic fauna and flora. It accumulates in marine organisms, both plants and animals, which are then consumed by humans. This can lead to various health problems, such as organ damage and the development of cancer. Additionally, this pollution causes biological magnification, where the toxicity concentration gradually increases as aquatic organisms continuously accumulate metals. This process results in apoptotic mechanisms, antioxidant defence, and inflammation, which are reflected at the gene expression level. However, there is limited research on specific heavy metals and their effects on fish organs. The concentration of metal contamination and accumulation in different tropical environments is a concern due to their toxicity to living organisms. Therefore, this review focuses on determining the influences of metals on fish and their effects on specific organs, including DNA alterations.

Review on heavy metal contaminants in freshwater fish in South India: current situation and future perspective.

The primary natural resource we use in our daily lives for a variety of activities is freshwater for drinking and various developmental goals. Furthermore, the pace of human population increase worldwide is rising rapidly and has a great impact on the Earth's natural resources. Natural water quality has diminished owing to various anthropogenic activities. Water is crucial to the life cycle. On the other hand, chemical and agricultural industries pollute heavy metals. Acute and chronic diseases caused by heavy metals, such as slow metabolism and damage to the gills and epithelial layer of fish species, are divided into two categories. Pollutants can also harm liver tissues and result in ulceration as well as diseases such as fin rot, tail rot, and gill disease. The most prevalent heavy metals are As, Cr, Pb, and Hg, which are systemic toxicants that affect human health. These metals are categorized as carcinogens by the US Environmental Protection Agency and the worldwide agency for cancer research because they cause organ damage even at low exposure levels. The focus of the current study is to review various freshwater sources of heavy metal pollution.

Differential coral response to algae contact: Porites tissue loss, praise for Halimeda interaction at southeast coast of India.

Worldwide, reef building corals are being degraded due to increasing anthropogenic pressure, and as a result, macroalgal cover is being increased. Hence, mechanism of coral-algal interaction, differential coral response to algal overgrowth, is critical from every geographical location to predict future coral dynamics. This paper documents the frequency of coral-algal (Halimeda) interactions, differential coral response to algal interaction. We found difference in susceptibility among coral genera to competitive effects. Out of 970 coral colonies surveyed, 36.7% were in contact with Halimeda sp. Most frequent contact was observed in Porites (57%) followed by Favites 28% (n = 60), Acropora 26% (n = 48), Platygyra 5% (n = 5) and Symphyllia 4.2% (n = 3). Frequent discoloration and tissue loss were only observed in Porites. Continuous monitoring revealed that long-term algal physical contact prevents light required for polyp for photosynthesis and stops coral feeding ability. In this study, we also found mutual exclusion between Halimeda and coral recruit. Out of 180 coral colonies (size class between 5 and 15 cm) comprised of Favites (n = 74), Acropora (n = 20), Favia (n = 79) and Porites (n = 7) surveyed, none of them were found in Halimeda-dominated sites. The documented effects of recruitment exclusion and tissue mortality followed by algal interaction on major reef building corals (Porites) could affect replenishing process and health of the remaining healthy corals in the Palk Bay reef if algal proliferation rate is not controlled through proper management strategies.

Extraction, characterization and antioxidant property of chitosan from cuttlebone Sepia kobiensis (Hoyle 1885).

Chitin was extracted from the cuttlebone of Sepia kobiensis and chitosan was prepared through deacetylation. The chitosan was characterized for its structural, physical and thermal (CHN, DDA, FT-IR, NMR, XRD, Viscometric analysis, SEM and DSC) properties. Further, the chitosan exhibited the antioxidant activity of 50.68-74.36% at 1-10 mg ml(-1) and it also showed the reducing power of 0.28% at 1 mg ml(-1). At 10 mg ml(-1), the chitosan exhibited the scavenging ability of 46.17%, on 1,1-diphenyl-2-picrylhydrazyl radicals, 23.38-73.70% on superoxide radicals at 0.05-1.6 mg ml(-1) and 18.34% to 62.39% (0.1-3.2 mg ml(-1)) on hydroxyl radicals; whereas at 1-10 mg ml(-1) the chelating ability on ferrous ions was calculated as 49.74-73.59%. Based on the potential antioxidant activity, scavenging ability on hydroxyl radicals and chelating abilities on ferrous ions, the chitosan from the cuttlebone of S. kobiensis may not only be used as a potent natural antioxidant but also as a possible food quality enhancer ingredient in the pharmaceutical industry.