The antibacterial action of chitosan hydroglutamate (CH), chitosan lactate (CL) and chitosan derived from fungal mycelia was examined against both gram‐negative and gram‐positive bacteria. Plate counts indicated inactivation rates of one‐ to five‐log‐cycles within one hour. Fungal chitosan had significantly less antibiotic effect than CH and CL. The antibacterial action of CH and CL was very similar and shown to be concentration dependent with 0.1 mg/mL more effective than 2.0 and 5.0 mg/mL. When CH (or CL) and polygalacturonate were added to cell suspensions, death was prevented, possibly indicating that chitosan complexed with polygalacturonate could not penetrate the cell or disrupt the membrane. Leakage of intracellular components caused by chitosan was determined by exposing lactose‐induced Escherichia coli to chitosan with assay for s‐galactosidase activity indicating that cell permeabilization occurred more extensively at the low chitosan concentrations. Microscopic examination showed that...

Antibacterial action of chitosan

Background:Hemorrhage remains a leading cause of death in both civilian and military trauma patients. The HemCon chitosan-based hemostatic dressing is approved by the US Food and Drug Administration (FDA) for hemorrhage control. Animal data have shown the HemCon dressing to reduce hemorrhage and imp

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A special report on the chitosan-based hemostatic dressing: experience in current combat operations.

Immunity enhancement in black tiger shrimp (Penaeus monodon) by a probiont bacterium (Bacillus S11)

Approximately 500 mya two types of recombinatorial adaptive immune systems appeared in vertebrates. Jawed vertebrates generate a diverse repertoire of B and T cell antigen receptors through the rearrangement of immunoglobulin V, D, and J gene fragments, whereas jawless fish assemble their variable lymphocyte receptors through recombinatorial usage of leucine-rich repeat (LRR) modular units. Invariant germ line-encoded, LRR-containing proteins are pivotal mediators of microbial recognition throughout the plant and animal kingdoms. Whereas the genomes of plants and deuterostome and chordate invertebrates harbor large arsenals of recognition receptors primarily encoding LRR-containing proteins, relatively few innate pattern recognition receptors suffice for survival of pathogen-infected nematodes, insects, and vertebrates. The appearance of a lymphocyte-based recombinatorial system of anticipatory immunity in the vertebrates may have been driven by a need to facilitate developmental and morphological plasticity in addition to the advantage conferred by the ability to recognize a larger portion of the antigenic world.

The evolution of adaptive immunity.

Chitin and its deacetylated derivative chitosan are natural polymers composed of randomly distributed β-(1-4)-linked d-glucosamine (deacetylated unit) and N-acetyl-d-glucosamine (acetylated unit). Biopolymers like chitin and chitosan exhibit diverse properties that open up a wide-ranging of applications in various sectors especially in biomedical science. The latest advances in the biomedical research are important emerging trends that hold a great promise in wound-healing management products. Chitin and chitosan are considered as useful biocompatible materials to be used in a medical device to treat, augment or replace any tissue, organ, or function of the body. A body of recent studies suggests that chitosan and its derivatives are promising candidates for supporting materials in tissue engineering applications. This review article is mainly focused on the contemporary research on chitin and chitosan towards their applications in numerous biomedical fields namely tissue engineering, artificial kidney, skin, bone, cartilage, liver, nerve, tendon, wound-healing, burn treatment and some other useful purposes.

Chitin and Chitosan: Structure, Properties and Applications in Biomedical Engineering

SummarySpiny lobsters, P. argus, immunized with living or killed bacteria, have been shown to synthesize a nondialyzable bactericidin. This substance was present in the hemolymph and was usually detectable within 12 hours. In the primary response, it reached a peak within 24-48 hours. The most effective antigen was a gram-negative bacillus, EMB-1, isolated from the normal intestinal flora of healthy P. argus. Varying results were obtained when specificity was tested with heterologous bacteria, but the bactericidin was less specific than mammalian antibody. Heating at 65°C for 20 min was required for complete inactivation. EDTA, dialysis, carrageenin, and freezing failed to inactivate this substance. It could be adsorbed by homologous and heterologous bacteria.

An induced bactericidin in the spiny lobster, Panulirus argus.

Approaches to the fundamental problems of antibody synthesis have been quite varied, but until recently, investigations of the cellular and molecular events in this form of immune responsiveness have been limited to the higher vertebrate groups, and even here to comparatively few species. Current interest of several research groups in the evolution of the immune response is now leading to rapid progress in our knowledge of comparative immunology, and in this paper I would like to describe some recent experiments on antibody synthesis and immunological memory of representative poikilothermic vertebrates. Historically, antibody formation in the lower vertebrate classes was first studied by Metchnikoff' and by Widal and Sicard,' who noted the important effect of environmental temperature on the process. A number of subsequent reports have also dealt with the role of Among authors to present good evidence fo r the effect of ambient temperature on the rate of antibody synthesis was Cushing,\"' who compared the ra te of formation of sperm agglutinins by carp at 15\" to 28°C. Hildemann and associates\"'-'!' have also described the role of temperature in their extensive investigations of homograft reactions in poikilotherms. Recently, a number of investigations'5,'!'-2'' have given renewed emphasis and direction to the study of immune responses in the more primitive animals. These studies have brought the realization tha t this general area represents a relatively unexplored region of immunology, and have offered the hope of new approaches and different perspectives on old problems as well as a potential source of fundamentally new information.

Antibody synthesis in poikilothermic vertebrates.

Since relatively few quantitative immunological studies had been conducted with invertebrates, this study was designed to learn more about the immune potential of the oyster, a molluscan representative Experiments measured the primary and secondary clearance rates of T2 coliphage in the oyster The fate of phage injected intracardially or intramuscularly was traced by measuring serum and tissue fluid plaque-forming unit levels at various times postinjection Phage-neutralizing activity was also measured Although circulating T2-neutralizing antibody was not induced in the oyster, secondary injections of T2 were cleared more rapidly than primary injections The difference in clearance rates between primary and secondary groups was not as pronounced in the oyster as in the lemon shark, an animal capable of producing high levels of serum antibody to T2

Bacteriophage Clearance in the Oyster (Crassostrea virginica)

SummaryEncapsulated nodes of lymphoid tissue have been demonstrated in the upper thorax, neck and axilla of the amphibian, Bujo marinus. The nodes phagocytize India ink and form antibody to bovine serum albumin. The anatomical and functional characteristics of these lymph nodes indicate that they are comparable to lymph nodes of mammals.

Comparative immunology. lymph nodes in the amphibian, bufo marinus.

THERE is increasing evidence that inducible immunity may be demonstrated in several invertebrate species using appropriate methods. The bactericidal system1,2 seems to occupy an important position in the phylogenetic emergence of inducible immunity. Such responses and others have been reviewed recently2,3.

E. Edward Evans

Papers

An induced bactericidin in the spiny lobster, Panulirus argus.

Antibody synthesis in poikilothermic vertebrates.

Bacteriophage Clearance in the Oyster (Crassostrea virginica)

Comparative immunology. lymph nodes in the amphibian, bufo marinus.

Induced bactericidal response in a sipunculid worm.