The influence of environmental salinity on hemocyanin function in the blue crab, Callinectes sapidus

The production and influence of anti-Vibrio parahaemolytics IgY against experimental infection of V. parahaemolyticus in cultured Fenneropenaeus indicus

The increasing number of antibiotic-resistant bacteria emphasizes the need to find alternatives to complement antibiotics. Immunotherapy may also be used as a complementary treatment against pathogens that are difficult to treat with traditional antibiotics. Eggs are normal dietary components and there is practically no risk of toxic side effects of IgY given orally. In the present study, pathogenic Vibrio parahaemolyticus was isolated from infected shrimp and studied their virulence factors including LD₅₀ (by challenging with Fenneropenaeus indicus), proteolytic and hemolytic activities. The edible antibody IgY was raised by injecting the antigen of Extra Cellular Products (ECP) of V. parahaemolyticus to Gallus gallus domesticus during layoff period with and without the herbal immunoadjuvants, Asparagus racemosus and Glycine max (V.p wo: V. parahaemolyticus ECP without adjuvant; V.p A: V. parahaemolyticus ECP with A. racemosus and V.p G: V. parahaemolyticus ECP with G. max). Eggs were collected after five weeks of immunization and anti- V. parahaemolyticus IgY was extracted and purified. Physicochemical properties of the immunized Chickens' serum and anti- V. parahaemolyticus IgY's cross reactivity, growth inhibition assay, single radial immunodiffusion assay and bacterial agglutination were studied. The results revealed that, the serum protein parameters were significantly (P ≤ 0.001) increased in experimental groups from control group. The antibody raised with immunoadjuvants had significantly (P ≤ 0.001) higher cross reactivity, growth inhibition, single radial immunoassay and bacterial agglutination when compared with and without immunoadjuvant and control groups. Further the control and experimental anti-V. parahaemolytics IgY coated artificial diets were fed to F. indicus for 60 days. After 30 and 60 dpv (days of post vaccination), shrimps from each groups were challenged with virulent V. parahaemolyticus and studied the survival, haematological and immunological parameters. The IgY coated diets (V. p A and V.p G) fed shrimps had decreased cumulative mortality, significantly (P ≤ 0.001) improved coagulase activity, total haemocyte count and oxyhaemocyanin. The immunological parameters such as prophenoloxidase, intracellular anion production, lysozyme production and phagocytosis also improved significantly (P ≤ 0.001) in IgY treated shrimps.

Physicochemical properties of anti Vibrio harveyi egg yolk antibody (IgY) and its immunological influence in Indian white shrimp Fenneropenaeus indicus

Edible antibodies specific to host pathogens is an attractive approach to establish protective immunity, especially against gastrointestinal pathogens both in humans and animals. The edible antibody of anti-Vibrio harveyi IgY (anti-V. h IgY) was produced by antigen mixed with immunoadjuvant Asparagus racemosus and Glycine max. Hens were immunized and eggs were collected five weeks after the immunization. Anti-V. harveyi IgY stability in different digestive enzymes such as trypsin and chymotrypsin were evaluated to determine its ability to withstand in the gastrointestinal tract of F. indicus. Specific binding activity and concentration (average 9.5% of total IgY content) of the anti-V. h IgY were determined by the ELISA using V. harveyi antigen. Further the anti-V. h IgY diets including V.h wo, V.h A, V.h G and control diets were fed to F. indicus for 60 days. After 30 and 60 of feeding, group of shrimps were challenged with virulent V. harveyi. After the respective days of feeding, haematological and immunological changes were studied. The parameters including total haemocyte count (THC), coagulase activity, oxyhaemocyanin level, prophenoloxidase, intracellular superoxide anion production, lysozyme, phagocytosis and bacterial agglutinin had significantly (P ≤ .001) increased in the experimental groups in comparission with the control diet fed shrimps. The anti-V. h IgY coated diets helped to reduce the Vibrio load and boosted the immune system in F. indicus's against V. harveyi challenge. The research work shows the potential applications of egg yolk antibodies as anti-bacterial prophylactic uses for infectious diseases and suggests an edible antibody concept as an alternative to conventional antibiotics.

Structural Basis for Salinity‐Induced Alteration in Oxygen Binding by Haemocyanin from the Estuarine AmphipodChaetogammarus marinus(L.)

In the estuarine amphipod Chaetogammarus marinus, differences in O(2) binding by haemocyanins (Hc) could be related to natural and salinity-related quantitative variation in just one polypeptide subunit (band 2) and not to variations in any of the other seven bands present. Band 2 was always present, irrespective of salinity treatment, and naturally makes up 6%-36% of the total Hc. However, low salinity exposure (S=4 per thousand for 48-49 h, T=15 degrees C) was accompanied by an increase in the prevalence of greater concentrations of band 2 (i.e., range, 20%-36% of total Hc present) and a concomitant increase in Hc-O(2) affinity (half saturation [P(50)] decreased from 1.38 to 1.12 kPa at pH=7.81, T=15 degrees C). A similar salinity-related mechanism (that is, one band altering) has been shown previously for the blue crab Callinectes sapidus, although the functional consequences were different. In contrast with C. marinus, an increase in the proportion of one polypeptide subunit in C. sapidus resulted in a decrease in Hc-O(2) affinity. This study has confirmed that between-individual variation (quantitative rather than qualitative) in just one Hc subunit may have functional consequences, although the significance of such variation is difficult to interpret.

Modulation of haemocyanin oxygen affinity: properties and physiological implications in a changing world

Crustacean haemocyanin oxygen affinity may be modified through changes in concentration of various inorganic and organic allosteric modulators. These may act in both positive and negative directions, increasing or decreasing haemocyanin oxygen affinity, and assist both in oxygen loading at the gills and oxygen release in the tissues. Inorganic ions, except for Mg(2+), do not normally influence cooperativity or the Bohr effect, whereas most of the organic modulators decrease cooperativity without affecting the Bohr coefficient. Several new findings on the influence of sulphide and thiosulphate are reviewed together with evidence for unidentified factors that decrease haemocyanin oxygen affinity. The physiological implications of all these findings are discussed in the context of maintaining a flexible response to a changing environment.

The function of hemocyanin in respiration of the blue crab Callinectes sapidus

Blood PO2 in the blue crab Callinectes sapidus, a very active species of tropical origin, is lower at 22 degrees C than that of larger crabs in colder waters. These low oxygen levels permit its hemocyanin to be highly oxygenated at the gill, and to deliver almost half of its oxygen to the tissues in resting animals. Sustained muscular activity results in conspicuous decreases in blood PO2, pH and hemocyanin oxygenation. Although the venous reserve is fully utilized, hemocyanin oxygenation at the gill decreases so much that there is no change in its total quantitative function. The large Bohr shift becomes functional during activity, but its quantitative importance is not clear.