T P Sajeevan

Bio: T P Sajeevan is an academic researcher from Cochin University of Science and Technology. The author has contributed to research in topics: Glucan & Shrimp. The author has an hindex of 11, co-authored 19 publications receiving 372 citations. Previous affiliations of T P Sajeevan include University of California, San Diego & University of Texas Southwestern Medical Center.

Comparative efficacy of MS-222 and benzocaine as anaesthetics under simulated transport conditions of a tropical ornamental fish Puntius filamentosus (Valenciennes)

Abstract: There is a growing commercial interest in the fish, Puntius filamentosus, in the ornamental fish trade in India and elsewhere. The trade is, however, hampered by severe mortalities during transport of the fish owing to insufficient data available on the use of anaesthetics. To resolve this problem, we evaluated the efficacy of two anaesthetics, MS-222 and benzocaine, in sedating P. filamentosus in simulated transportation experiments and used stress response parameters such as cortisol and blood glucose levels to perform assessments. We observed that MS-222 at 40 mg L−1 and benzocaine at 20 mg L−1 were sufficient to induce sedation for 48 h. Above these concentrations, both the anaesthetics adversely affected the fish and resulted in mortalities. Both anaesthetics significantly lowered the blood cortisol and glucose levels compared with the unsedated controls. Importantly, the anaesthetics treatment significantly lowered the post-transport mortality in the fish. The results of the study show that MS-222 and benzocaine could be used as sedatives to alleviate transport-related stress in P. filamentosus to improve their post-transport survival and hence reduce economic loss.

A Systematic Review of Recently Reported Marine Derived Natural Product Kinase Inhibitors.

Abstract: Protein kinases are validated drug targets for a number of therapeutic areas, as kinase deregulation is known to play an essential role in many disease states. Many investigated protein kinase inhibitors are natural product small molecules or their derivatives. Many marine-derived natural products from various marine sources, such as bacteria and cyanobacteria, fungi, animals, algae, soft corals, sponges, etc. have been found to have potent kinase inhibitory activity, or desirable pharmacophores for further development. This review covers the new compounds reported from the beginning of 2014 through the middle of 2019 as having been isolated from marine organisms and having potential therapeutic applications due to kinase inhibitory and associated bioactivities. Moreover, some existing clinical drugs based on marine-derived natural product scaffolds are also discussed.

Marine yeast glucans confer better protection than that of Baker's yeast in Penaeus monodon against white spot syndrome virus infection.

Abstract: The immunostimulatory property of glucan isolates from three marine yeasts (Debaryomyces hansenii S8, Debaryomyces hansenii S169 and Candida tropicalis S186) and one Baker's yeast (Saccharomyces cerevisiae S36) as examined for potential application as immunostimulants in Penaeus monodon postlarvae against White Spot Syndrome Virus (WSSV) infection. Structural characterization of the glucan component in the isolates by proton nuclear magnetic resonance (NMR) indicated similar structures containing (1-3)-linked anhydroglucose repeat units (AGRUs) in the backbone with (1-6)-linked AGRUs in side chains that are (1-6)-linked to the backbone AGRUs. Glucan from C. tropicalis (S186) with the highest molecular weight and the lowest level of branching supported maximum survival (69%) followed by the other two marine yeast (S169 and S8) glucans of 27% and 23% respectively while glucan from Baker's yeast, S. cerevisiae S36 with the lowest molecular weight and the highest level of branching exhibited poor survival (4%) in P. monodon post challenge WSSV. The present study showed that the glucan isolate from marine yeast with a higher molecular weight and a lower degree of branching acts as better immunostimulants in P. monodon postlarvae than did the glucan isolate from S. cerevisiae.

Beta-glucan: an ideal immunostimulant in aquaculture (a review).

Abstract: The major hindrance in the development and sustainability of aquaculture industry is the occurrence of various diseases in the farming systems. Today, preventive and management measures are central concern to overcome such outbreak of diseases. Immunostimulants are considered as an effective tool for enhancing immune status of cultured organisms. Among different immunostimulants used in aquaculture practices, β-glucan is one of the promising immunostimulant, which is a homopolysaccharide of glucose molecule linked by the glycoside bond. It forms the major constituents of cell wall of some plants, fungi, bacteria, mushroom, yeast, and seaweeds. Major attention on β-glucan was captivated with the gain in knowledge on its receptors and the mechanism of action. The receptor present inside the animal body recognizes and binds to β-glucan, which in turn renders the animal with high resistance and enhanced immune response. This review highlights β-glucan as an immunostimulant, its effective dosages, and route of administration and furthermore provides an outline on role of β-glucan in enhancing growth, survival, and protection against infectious pathogens pertaining to fishes and shellfishes. Study also summarizes the effect of β-glucan on its receptors, recognition of proteins, immune-related enzymes, immune-related gene expression and their mechanisms of action.

Tricaine methane-sulfonate (MS-222) application in fish anaesthesia

Abstract: Summary Tricaine methane-sulfonate (MS-222) is one of the most widely used anaesthetics for poikilotherms worldwide. This paper outlines its anaesthetic efficacy and dosage in fish and legislation for its use, fish stress responses to MS-222 anaesthesia and its effect on fish physiology and blood properties, pharmacokinetics, genotoxicity, immune response, potential interference with fish hepatic cytochrome P450 spectra, and its impact on nerve sensitivity. Key questions arising from the available data are analysed, such as regulatory constraints on its use, the need for the standardization of buffering protocols, and interdependencies of the factors impacting the specific applicative efficacy of MS-222. Current research has provided an abundance of data on MS-222 use in fish, although the applications within these studies are often impractical at the farming level. Specific emphasis is therefore placed on highlighting application strategies on a practical basis, presenting potential future research on topics that require in-depth analysis (preparation and storage of anaesthetic solutions, pre-anaesthetic sedation and stress reduction, cortisol response in aquarium fish, toxicity of MS-222 metabolites, and possible immunodepressive properties). Additionally, both from a scientific and practical perspective, it is necessary to have a better understanding of safety margins, induction, immersion and recovery times for many (marine and freshwater, farmed and ornamental) fish species in order to achieve optimal utilization.

Use of immunostimulants and nucleotides in aquaculture: a review

Abstract: Currently there are numerous gaps in existing knowledge about exogenous nucleotide application to fish including various aspects of digestion, absorption, metabolism, and influences on various physiological responses, especially expression of immunogenes and modulation of immunoglobulin production. Additional information is also needed in regard to age/size-related responses and appropriate doses and timing of administration. Thus further research in these areas should be pursued. Immunostimulants Abstract It is well established that proper nutrition is essential for maintenance of normal growth and health of all animals including various aquatic species. During the last two decades increased attention has focus on immunostimulants and nucleotides to reduce susceptibility to various stressors and diseases, as well as enhance the overall health of fish. The immune response can be modulated by β-glucans and high-M-alginate. β-glucans are glucose polymers that are major structural components of the cell wall of yeast, fungi, and bacteria, but also of cereals like oat and barley. There is much structural variation in the β-glucans from these different sources, which may influence their physiological functions. Alginate is a polysaccharide composed of β-1,4-D-mannuronic acid (M) and α-L-glucuronic acid (G). In vitro as well as in vivo studies in fish show that especially β-glucans derived from fungi and yeast and alginate have immune modulating properties. Most frequently evaluated are effects on macrophage activation and on lysozyme, respiratory burst and leukocyte activity, which have been suggested to contribute to the increased resistance against infections, after immunostimulant exposure. Although more fish studies are needed, it is tempting to suggest that dietary β-glucans and alginate may be useful tools to prime the host immune system and increase resistance against invading pathogens. As no knowledge is available regarding short versus long-term effects and efficiency, more knowledge is needed on this topic.

Beta-glucans as immunostimulant in vertebrates and invertebrates.

Abstract: Beta-glucans have been studied in animal species, from earthworms to humans. They are a heterogeneous group of glucose polymers found in fungi, plants, some bacteria, and sea weeds. The recognition of conserved microbial structures is a key aspect of metazoan immunity, and β-glucans are emerging as major target for the recognition of fungal pathogens. However, the receptors and mechanisms by which this is achieved differ significantly between vertebrates and invertebrates. In this review, we will highlight the known receptors for β-glucans and will discuss the various immune responses they can initiate, with some applications of these products, in both vertebrates and invertebrates.