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Toshiaki Itami

Bio: Toshiaki Itami is an academic researcher from University of Miyazaki. The author has contributed to research in topics: Shrimp & White spot syndrome. The author has an hindex of 29, co-authored 120 publications receiving 3054 citations.


Papers
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Journal ArticleDOI
TL;DR: Results indicate that the oral administration of PG to kuruma shrimp enhances the phagocytic activity of the granulocytes and increases the disease resistance of shrimps.

283 citations

Journal ArticleDOI
TL;DR: The bacilliform virus is considered to be the causative agent of the disease and found by electron microscopy in the lymphoid organ of both naturally and experimentally infected shrimps.
Abstract: Beginning in the spring of 1993, a serious mortality among cultured kuruma shrimp, Penaeus japonicus occurred in Japan. The typical sign of this disease was white spots on the inside surface of the carapace. Challenge tests demonstrated that the causative agent was highly virulent. This was demonstrated by injection of a filtrered homogenate of the lymphoid organ obtained from diseased shrimp. A non-occluded bacilliform virus was found by electron microscopy in the lymphoid organ of both naturally and experimentally infected shrimps. The virion was bacilliform and surrounded by a virion envelope (a lipid bilayer membrane). The dimension of the virion was 83 nm in diameter and 275 nm in length. From these results, the bacilliform virus is considered to be the causative agent of the disease.

252 citations

Journal ArticleDOI
TL;DR: Gene expression in haemocytes of the kuruma prawn (Penaeus japonicus) was investigated using an expressed sequence tag (EST) approach and one hundred fifty-two deduced proteins were newly identified.

211 citations

Journal ArticleDOI
TL;DR: Standardized LAMP procedure was used to detect the presence of WSSV in the heart, stomach and lymphoid organ from infected shrimp, and the detection limit was up to 1 fg, when compared to 10 fg by nested polymerase chain reaction (PCR).

165 citations


Cited by
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Journal ArticleDOI
TL;DR: The current understanding of different types of lysozyme and their expression and its role in fish innate immune system is reviewed.
Abstract: The innate immune system of fish is considered to be the first line of defence against a broad spectrum of pathogens and is more important for fish as compared with mammals. Lysozyme level or activity is an important index of innate immunity of fish and is ubiquitous in its distribution among living organisms. It is well documented that fish lysozyme possess lytic activity against both Gram-positive bacteria and Gram-negative bacteria. It is also known to be opsonic in nature and activates the complement system and phagocytes. It is present in mucus, lymphoid tissue, plasma and other body fluids of freshwater and marine fish. It is also expressed in a wide variety of tissues. Lysozyme activity has been shown to vary depending on the sex, age and size, season, water temperature, pH, toxicants, infections and degree of stressors. Here, we review our current understanding of different types of lysozyme and their expression and its role in fish innate immune system.

1,251 citations

Journal ArticleDOI
TL;DR: The Effects of Harmful Algal Blooms on Aquatic Organisms: Vol. 10, No. 2, pp. 113-390 as mentioned in this paper was the first publication of this article.
Abstract: (2002). The Effects of Harmful Algal Blooms on Aquatic Organisms. Reviews in Fisheries Science: Vol. 10, No. 2, pp. 113-390.

1,242 citations

Journal ArticleDOI
TL;DR: Innate defenses provide a pre-existing and fast-acting system of protection which is non-specific and relatively temperature-independent and thus has several advantages over the slow-acting and temperature-dependent specific immune responses.
Abstract: The integumental defenses provide a physical and chemical barrier to the attachment and penetration of microbes. Besides the entrapping and sloughing of microbes in the mucus, the latter contains many antibacterial substances including anti-bacterial peptides, lysozyme, lectins and proteases. The gastro-intestinal tract is a hostile environment of acids, bile salts and enzymes able to inactivate and digest many viruses and bacteria. In most cases the integumental defenses are sufficient to protect against even quite virulent organisms which often only produce disease when the integument has been physically damaged. If a microbe gains access to the tissues of the fish, it is met with an array of soluble and cellular defenses. The complement system, present in the blood plasma, plays a central role in recognising bacteria and its activated products may lyse the bacterial cells, initiate inflammation, induce the influx of phagocytes and enhance their phagocytic activity. Complement can be activated directly by bacterial products and constituents and also indirectly by other factors, principally C-reactive protein and lectins, which can also bind to the bacterial surface. Plasma also contains a number of factors which inhibit bacterial growth(e.g. transferrin and anti-proteases) or which are bactericidal e.g. lysozyme. Following the infection of fish with virus pathogens, infected cells produce interferon. This induces antiviral defenses in neighbouring cells which are then protected from becoming infected. Anti-viral cytotoxic cells are able to lyse virally infected cells and thus reduce the rate of multiplication of virus within them. Innate defenses thus provide a pre-existing and fast-acting system of protection which is non-specific and relatively temperature-independent and thus has several advantages over the slow-acting and temperature-dependent specific immune responses.

1,115 citations

Journal ArticleDOI
TL;DR: This review summarizes the commercial applications of Bacillus probiotics and makes a case that many Bacillus species should not be considered allochthonous microorganisms but, instead, ones that have a bimodal life cycle of growth and sporulation in the environment as well as within the GIT.
Abstract: The field of probiosis has emerged as a new science with applications in farming and aqaculture as alternatives to antibiotics as well as prophylactics in humans. Probiotics are being developed commercially for both human use, primarily as novel foods or dietary supplements, and in animal feeds for the prevention of gastrointestinal infections, with extensive use in the poultry and aquaculture industries. The impending ban of antibiotics in animal feed, the current concern over the spread of antibiotic resistance genes, the failure to identify new antibiotics and the inherent problems with developing new vaccines make a compelling case for developing alternative prophylactics. Among the large number of probiotic products in use today are bacterial spore formers, mostly of the genus Bacillus. Used primarily in their spore form, these products have been shown to prevent gastrointestinal disorders and the diversity of species used and their applications are astonishing. Understanding the nature of this probiotic effect is complicated, not only because of the complexities of understanding the microbial interactions that occur within the gastrointestinal tract (GIT), but also because Bacillus species are considered allochthonous microorganisms. This review summarizes the commercial applications of Bacillus probiotics. A case will be made that many Bacillus species should not be considered allochthonous microorganisms but, instead, ones that have a bimodal life cycle of growth and sporulation in the environment as well as within the GIT. Specific mechanisms for how Bacillus species can inhibit gastrointestinal infections will be covered, including immunomodulation and the synthesis of antimicrobials. Finally, the safety and licensing issues that affect the use of Bacillus species for commercial development will be summarized, together with evidence showing the growing need to evaluate the safety of individual Bacillus strains as well as species on a case by case by basis.

928 citations

Journal ArticleDOI
TL;DR: This review provides a comprehensive summary of probiotics in aquaculture with special reference to mollusc culture.

756 citations