Quantitative serum proteomics analyses reveal shrimp responses against WSSV infection

For the past decades, quantitative serum proteomics in mammals have been widely applied in biomarker screening. Various serum protein removal methods have been developed to effectively sequester serum abundant proteins. However, few methods have been found for the removal of arthropod serum abundant proteins. Here, gel filtration chromatography and ultracentrifugation methods were applied to remove hemocyanin from Litopeaneus vannamei serum. When shrimps were challenged with white spot syndrome virus (WSSV), a total of 486 serum proteins were identified using mass spectrometry, and 18 upregulated WSSV responsive proteins were identified with isobaric tags for relative and absolute quantification (iTRAQ). These results provide an effective method to remove hemocyanin from shrimp serum. With this method some previously unidentified WSSV responsive serum proteins were revealed, which would give us a better insight into the response of crustaceans to WSSV infection.

Effect of Low Temperature on Globin Expression, Respiratory Metabolic Enzyme Activities, and Gill Structure of Litopenaeus vannamei

Low temperature frequently influences growth, development, and even survival of aquatic animals. In the present study, physiological and molecular responses to low temperature in Litopenaeus vannamei were investigated. The cDNA sequences of two oxygen-carrying proteins, cytoglobin (Cygb) and neuroglobin (Ngb), were isolated. Protein structure analysis revealed that both proteins share a globin superfamily domain. Real-time PCR analysis indicated that Cygb and Ngb mRNA levels gradually increased during decrease in temperatures from 25 to 15°C and then decreased at 10°C in muscle, brain, stomach, and heart, except for a continuing increase in gills, whereas they showed a different expression trend in the hepatopancreas. Hemocyanin concentration gradually reduced as the temperature decreased. Moreover, the activities of respiratory metabolic enzymes including lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) were measured, and it was found that LDH activity gradually increased while SDH activity decreased after low-temperature treatment. Finally, damage to gill structure at low temperature was also observed, and this intensified with further decrease in temperature. Taken together, these results show that low temperature has an adverse influence in L. vannamei, which contributes to systematic understanding of the adaptation mechanisms of shrimp at low temperature.

Sublethal behavioral and physiological effects of the biomedical bleeding process on the American horseshoe crab, Limulus polyphemus

The hemolymph of the American horseshoe crab, Limulus polyphemus, is harvested from over 500,000 animals annually to produce Limulus amebocyte lysate (LAL), a medically important product used to detect pathogenic bacteria. Declining abundance of spawning Limulus females in heavily harvested regions suggests deleterious effects of this activity, and while mortality rates of the harvest process are known to be 10%-30%, sublethal behavioral and physiological effects are not known. In this study, we determined the impact of the harvest process on locomotion and hemocyanin levels of 28 female horseshoe crabs. While mortality rates after bleeding (18%) were similar to previous studies, we found significant decreases in the linear and angular velocity of freely moving animals, as well as changes in their activity levels and expression of circatidal behavioral rhythms. Further, we found reductions in hemocyanin levels, which may alter immune function and cuticle integrity. These previously unrecognized behavioral and physiological deficits suggest that the harvest of LAL may decrease female fitness, and thus may contribute to the current population decline.

Determination of a new antibacterial peptide S-thanatin in rat plasma by an indirected-ELISA

In this study, antimicrobial peptide S-thanatin (Ts) was chemically synthesized and linked to keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) by carbodiimide reagent. Rabbits were immunized with Ts-KLH and polyclonal antibody against Ts was purified by fractional precipitation of ammonium sulfate, coupled with anion-exchange chromatography. The purified antibody specifically binding to Ts residues but not BSA molecules was observed by Western-Blot analysis. Ts-BSA was selected as immobilized antigen and reacted with the residual antibody after the excess of anti-Ts antibody was combined with Ts in the sample. The binding antibody was recognized by HRP-conjugated secondary antibody. Finally, the horseradish peroxidase in the complex could catalyze the TMB substrate, resulting in color development. The method was evaluated by analysis of linearity, precision and accuracy and successfully applied in determination of Ts in rat plasma. The data of the pharmacokinetic parameters were also obtained. The proposed ELISA has a great value in routine analysis of Ts for its therapeutic monitoring and pharmacokinetic studies.

Comparative proteomic analysis of hemocyanins in Dinocras cephalotes and Perla marginata (Plecoptera)

Hemocyanins are large oligomeric respiratory proteins found in many arthropods and mollusks. The overall expression of hemocyanin mRNA, revealed by studies on Plecoptera hemocyanin sequencing, has raised the question of whether the protein is expressed or not. In fact, the presence of expressed hemocyanin has only been reported in the literature for one species, Perla marginata (Panzer, 1799). In this paper, we report the presence of hemocyanin and hexamerin proteins in Dinocras cephalotes (Curtis, 1827), a species closely related to P. marginata. To assess the presence of hemocyanin, we used a reproducible and highly sensitive method based on liquid chromatography tandem mass spectrometry. We conclude that regardless of its putative function (respiratory, immune defense, storage protein), the hemocyanin is actually expressed in species in which its mRNA is present.

The effects of diclofenac on the physiology of the green shore crab Carcinus maenas

In recent years there has been increasing concern regarding the influx of pharmaceuticals into aquatic environments. One group of pharmaceuticals that has been identified as being of particular concern are the non-steroidal anti-inflammatory drugs (NSAIDs). This study examined the effects of one of the most commonly reported NSAID contaminants, diclofenac, on the physiology of Carcinus maenas. Two environmentally realistic concentrations were examined in this study (10 ng/l and 100 ng/l) at two salinities (35 and 17.5 psu). Female and male crabs were exposed to these two concentrations for 7 days. Following exposure, haemolymph samples were taken from the animals. Measurements were taken for oxyhaemocyanin and lactate concentrations. The effects of this compound on osmoregulatory capacity (OC) in C. maenas were also measured. Exposure to diclofenac had no significant effect on haemolymph lactate and oxyhaemocyanin concentrations suggesting that exposure to this compound does not elicit a stress response in this species. However, exposure to this pharmaceutical did have significant effects on both the OC and the haemolymph osmolality in C. maenas. At both salinities the data suggests that the osmoregulatory ability of C. maenas is impaired when exposed to diclofenac.

Heterosis of haemolymph analytes of two geographic populations in Chinese shrimp Fenneropenaeus chinensis

Fenneropenaeus chinensis is distributed along the coasts of the northern seacoast of China and the Korean Peninsula. According to their migration routes, spawning and overwintering places, F. chinensis is divided mainly into three geographic variety populations. These populations represent potentially different genetic resources important to hybridisation breeding programs. To evaluate heterosis of the total protein concentration (PC), haemocyanin concentration (HC), penoloxidase (PO) activity, acid phosphatase (ACP) activity, alkaline phosphatase (ALP) activity and antimicrobial activity (Ua) mating was produced between and within Yellow and Bo sea (YB) population and southern seacoast of Korean Peninsula (SK) population, and the offspring of 49 families was reared to 7.64 g in the controlled environment. The results showed that the content of all haemolymph analytes of SK population was higher than that of YB population, and the immunocompetence in all hybridisations were higher than that in YB male x YB female except of HC in YB male x SK female. Nine of 12 hybridisations had manifested positive heterosis in six haemolymph analytes. Heterosis of SK x YB was all-positive, and this hybridisation was better than YB x SK in HC, PO, ALP activity and Ua. The results suggested that the haemolymph analytes of YB and SK populations had many genetic differences, and hybridisation was an important tool to increase immune reaction and adverse resistance.

The discriminative bilateral filter: An enhanced denoising filter for electron microscopy data

Advances in three-dimensional (3D) electron microscopy (EM) and image processing are providing considerable improvements in the resolution of subcellular volumes, macromolecular assemblies and individual proteins. However, the recovery of high-frequency information from biological samples is hindered by specimen sensitivity to beam damage. Low dose electron cryo-microscopy conditions afford reduced beam damage but typically yield images with reduced contrast and low signal-to-noise ratios (SNRs). Here, we describe the properties of a new discriminative bilateral (DBL) filter that is based upon the bilateral filter implementation of Jiang et al. (Jiang, W., Baker, M.L., Wu, Q., Bajaj, C., Chiu, W., 2003. Applications of a bilateral denoising filter in biological electron microscopy. J. Struc. Biol. 128, 82-97.). In contrast to the latter, the DBL filter can distinguish between object edges and high-frequency noise pixels through the use of an additional photometric exclusion function. As a result, high frequency noise pixels are smoothed, yet object edge detail is preserved. In the present study, we show that the DBL filter effectively reduces noise in low SNR single particle data as well as cellular tomograms of stained plastic sections. The properties of the DBL filter are discussed in terms of its usefulness for single particle analysis and for pre-processing cellular tomograms ahead of image segmentation.

Relation between reproductive, physiological, and immunological condition of Litopenaeus setiferus pre-adult males fed different dietary protein levels (Crustacea; Penaeidae)

The present study was designed to evaluate the effect of amount of dietary protein levels on blood indicators of protein metabolism and immune condition (blood protein, hemocyanin, osmotic pressure, and hemocytes concentrations), and reproductive capacity of pre-adult Litopenaeus setiferus males (F0). Assessments were made of the relationship between amount of dietary protein, immune condition, and reproductive condition of the shrimp during the maturation process. Three different diets, with different amounts of protein (DP; 35, 45, and 55%), were evaluated over 55 days and compared with shrimp that were from a baseline group before treatments were administrated. Osmotic pressure, hemocyanin, blood protein, and hemocytes were greater in shrimp from control ponds than those obtained of shrimp fed 35 and 45% DP and similar to that obtained in shrimp fed 55% DP, demonstrating that food in the control pond had a nutritional value to that obtained by feeding amounts of dietary protein beyond 45%. Osmotic pressure, hemocyanin (Hc), blood protein (BP), and hemocytes were influenced by amount of DP with the physiology and immune system of shrimp being influenced by diet. At the same time, a maximum reproductive condition (measured as a proportion of normal cells of the total sperm cells) of shrimp males was observed in shrimp fed 45% DPL with lesser normal cells being present in shrimp fed 35 and 55% DPL. These results indicate that an immune reaction can occur in response to dietary protein with excess DP affecting several physiological functions included the sperm synthesis and sperm quality. Influence on hemocytes concentration in shrimp fed protein in excess could activate an attack on sperm cells in the vas deferens provoking lose of sperm quality in such conditions. Results indicate an optimal DP of 45 for maintaining the broodstock bank of L. setiferus.

Conformational states of the Rapana thomasiana hemocyanin and its substructures studied by dynamic light scattering and time-resolved fluorescence spectroscopy

Hemocyanins are dioxygen-transporting proteins freely dissolved in the hemolymph of mollusks and arthropods. Dynamic light scattering and time-resolved fluorescence measurements show that the oxygenated and apo-forms of the Rapana thomasiana hemocyanin, its structural subunits RtH1 and RtH2, and those of the functional unit RtH2e, exist in different conformations. The oxygenated respiratory proteins are less compact and more asymmetric than the respective apo-forms. Different conformational states were also observed for the R. thomasiana hemocyanin in the absence and presence of an allosteric regulator. The results are in agreement with a molecular mechanism for cooperative dioxygen binding in molluscan hemocyanins including transfer of conformational changes from one functional unit to another.

Evaluation of tests based on the antibody response to keyhole limpet haemocyanin and soluble egg antigen to differentiate acute and chronic human schistosomiasis mansoni

Specific IgG and IgM responses to soluble egg antigen (SEA) and keyhole limpet haemocyanin (KLH) were measured by ELISA in patients with acute and chronic schistosomiasis. The tests based upon IgM and IgG antibodies responses to KLH presented the best diagnostic discrimination, and can be used in conjunction with clinical and epidemiological data to the differential diagnosis of acute schistosomiasis.

Automatic particle detection through efficient Hough transforms

Manual selection of single particles in images acquired using cryo-electron microscopy (cryoEM) will become a significant bottleneck when a very large number of images are required to achieve three-dimensional reconstructions at near atomic resolution. Investigation of fast, accurate approaches for automatic particle detection has become one of the current challenges in the cryoEM community. At the same time, the investigation is hampered by the fact that few benchmark particles or image datasets exist in the community. The unavailability of such data makes it difficult to evaluate newly developed algorithms and to leverage expertise from other disciplines. The paper presents our recent contribution to this effort. It also describes our newly developed computational framework for particle detection, through the application of edge detection and a sequence of ordered Hough transforms. Experimental results using keyhole limpet hemocyanin (KLH) as a model particle are very promising. In addition, it introduces a newly established web site, designed to support the investigation of automatic particle detection by providing an annotated image dataset of KLH available to the general scientific community.

Fruit flesh betacyanin pigments in hylocereus cacti

Determination of profiles and total contents of betacyanins in cactus fruits of Hylocereus species using chromatographic and spectrophotometric method is described. The investigated species were H. polyrhizus, H. purpusii, H. costaricensis, H. sp. 487 (all red-flesh species and hybrids made among them), and the white- or red-flesh species H. undatus. Hybrids included hybrid 1 (H. undatus white-flesh clone and H. sp. 487), hybrid 35 (H. sp. 487 and H. polyrhizus), and the reciprocal hybrid hybrid 95 (H. polyrhizus and H. sp. 487). Fruits of H. polyrhizus exhibited the highest relative concentration (expressed as percentage of the total HPLC peak area) of hylocerenin, a recently discovered pigment, and a high relative concentration of phyllocactin. Hylocerenin and isohylocerenin, present in fruits at relative concentrations of 11.7 and 5.8%, respectively, are probably responsible for the fluorescent color of the fruit pulp. H. costaricensis fruits have a much higher content of phyllocactin (63.9%), which is almost 4 times higher than the betanin content. These differences in pigment concentrations might explain the differences in red hues of the flesh of these fruits.

A study of Cu turnover in proteins of the visceral complex of Littorina littorea by stable isotopic analysis using coupled HPLC-ICP-MS

A two-dimensional HPLC system, tandemly coupled to an ICP-MS, has been used to study copper accumulation and turnover in the visceral complex cytosol of the gastropod, Littorina littorea. Animals were exposed for 8 weeks to NTA-buffered seawater containing stable isotopic 65Cu and then transferred to media containing stable isotopic 63Cu. The free ion activity of each isotope was maintained at 10(-11) M. Size exclusion (SE) HPLC showed Cu associated with haemocyanin (HC) and metallothionein-like (MT) proteins in two ligand pools with apparent molecular weights of >300 kDa and approximately 17 kDa, respectively. The MT pool was inducible by Cu, could assimilate the metal from both intrinsic and extrinsic sources and showed a higher rate of Cu accumulation and turnover than the HC pool. The induction of this pool also caused the sequestration and cytosolic redistribution of Zn, Cd, Pb, Mn and Co. Further fractionation of the MT pool by ion-exchange (IE) HPLC revealed that the Cu was associated with a single, major isoform of the protein that was Cu inducible and also bound trace quantities of Zn and Pb. A number of additional metal containing proteins were also resolved by IE. the most prominent of which also bound Pb, Mn and minor quantities of Zn. The significance of these findings in metal homeostasis and detoxification is discussed.

Effects of molting and environmental factors on trace metal body-burdens and hemocyanin concentrations in the American lobster, Homarus americanus

Hemocyanin concentrations in the hemolymph of marine crustacea are dependent on the molt cycle and on environmental conditions. Studies in our laboratories have found that hemocyanin levels in blue crabs are reduced after ecdysis and under conditions of environmental stress (Engel, Brouwer, & McKenna, 1993. Hemocyanin concentrations in marine crustaceans as a function of environmental conditions. Marine Ecology Progress Series, 93, 233-244). We have extended those studies to include the American lobster, Homarus americanus. Hemolymph and digestive gland tissues from Long Island Sound lobsters were analyzed for hemocyanin, copper, and zinc during different stages of the molt cycle. Hemocyanin, copper and zinc in the hemolymph were highest in premolt stages (D1-D4), and lowest in the postecdysal papershell stages (B1-B2). Concomitantly, copper in digestive glands decreased significantly following ecdysis, but no significant changes in the metals bound to metallothionein (MT) were observed. Copper-MT was the predominant form throughout the molt cycle, presumably because lobsters were obtained from copper-contaminated areas. To examine the effects of environmental factors, intermolt lobsters were collected from locations of different environmental quality along the Atlantic coast, and were analyzed for hemocyanin and trace metals. In general, animals from areas with a history of contamination showed the highest hemocyanin concentrations.

Connection between the inner ear and the lymphatic system

OBJECTIVE

The aim of this study was to identify the lymphatic drainage of the inner ear in guinea pigs.

STUDY DESIGN

Prospective study.

METHODS

The prospective study was performed in guinea pigs by injection of keyhole limpet hemocyanin (KLH) into either the right-side scala tympani or the middle ear cavity. The left side was not injected and served as a control. Fifteen minutes after injection, the animals were killed by intracardiac perfusion with paraformaldehyde and tissue specimens (right and left temporal bones, cervical lymph nodes, and the spleen) were collected. The presence of KLH in each specimen was determined by immunohistochemical assay of frozen sections using polyclonal mouse anti-KLH antibodies.

RESULTS

After injection into the middle ear, labeled cells were identified in the parotid, superficial ventral, mandibular, and deep cranial cervical lymph nodes. However, after inner ear injections KLH was present in only the parotid and superficial ventral cervical nodes. The spleen contained KLH-positive cells following injection into either the middle or inner ear, but not all animals contained labeled spleen cells.

CONCLUSIONS

The inner ear has a connection to the lymphatic drainage system. Because fewer lymph nodes contained labeled cells after inner ear injection than after middle ear injection, it is concluded that the inner ear does not simply drain to the middle ear and subsequently to the lymph nodes but seems likely to have its own connections.

Subunit compositions of crustacean haemocyanins are species-specific: evidence from non-decapod species

Electrophoretic examination of dissociated haemocyanin subunits from a number of amphipod, decapod and isopod crustaceans supports the hypothesis that subunit composition is species-specific, despite marked within-species variation in many species. General patterns of heterogeneity on native PAGE gels were also evident between groupings within the Amphipoda. Gammarid amphipods could be split into two groups; one characterised by a high degree of heterogeneity and the other by a low degree of heterogeneity. The talitrid amphipods generally displayed a low degree of heterogeneity similar to, although still distinct from, the second gammarid category. Haemocyanin from the Hyalidae, a family allied to the talitrids was highly heterogeneous, similar to the first gammarid group and unlike the talitrids. Isopod haemocyanin banding patterns were more similar to one another than to any of the amphipod or decapod species examined. In general, the molecular weights of the amphipod Hcs tended to be greater than those of the isopods, with the decapods being lowest of all. It is suggested that Hc subunit heterogeneity may be a useful tool for investigating speciation and speciation events, and for reliably separating very closely-related species (e.g. Gammarus spp.), purely on the basis of their Hc subunit compositions.

Hemocyanin re-uptake in the renal and branchial heart appendages of the coleoid cephalopod Sepia officinalis

The renal and branchial heart appendages of Sepia officinalis L. were investigated in order to elucidate a possible involvement of their excretory epithelia in hemocyanin metabolism. Immunocytochemical findings and tracer experiments indicate that after passing the barrier of ultrafiltration the hemocyanin molecules are taken up by the epithelial cells of the renal and branchial heart appendages and are subsequently carried back to the circulatory system, suggesting a mechanism of hemocyanin recycling. Apart from a function in maintaining constant hemocyanin levels, the present study indicates that the renal and branchial heart appendages are also sites of temporary hemocyanin storage.

Oxygen transport proteins: III. Structural studies of the scorpion (Buthus sindicus) hemocyanin, partial primary structure of its subunit Bsin1

The hemocyanin (Hc) from Buthus sindicus, studied in the native state, demonstrated to be an aggregate of eight different types of subunits arranged in four cubic hexamers. Both, the 'top' and the 'side' views of the native molecule have been identified from the negatively stained specimens using transmission electron microscopy. Out of these, eight different polypeptide chains, the partial primary structure (68%) of a subunit Bsin1 (Mr = 72422.7 Da) was established using a combination of automated Edman degradation and mass spectrometry. A multiple sequence alignment with other closely related cheliceratan Hc subunits revealed average identities of ca. 60%. Most of the structurally important residues, i.e. copper and calcium-binding ligands, as well as the residues involved in the presumed oxygen entrance pathway, proved to be strictly conserved in Bsin1. Sequence variations have been observed around the functionally important chloride-binding site, not only for the B. sindicus subunit Bsin1, but also for the subunit Aaus-6 of the scorpion A. australis and the subunit Ecal-a from the spider Eurypelma californicum Hcs. Deviation in the primary structure related to the chloride-binding site suggest that the effect of chloride ions may vary in different hemocyanins. Furthermore, the secondary structural contents of the Hc subunit Bsin1 were determined by circular dichroism revealing ca. 33% alpha-helix, 18%, beta-sheet, 19% beta-turn, and 30% random coil composition. These values are in good agreement with the crystal structure of the closely related Hc subunit Lpol-II from horseshoe crab L. polyphemus. Electron microscopic studies of the purified Hc subunit under native conditions revealed that Bsin1 has self aggregation properties. Results of these studies are discussed.

Mass spectrometric characterization of Limulus polyphemus hemocyanin

Electrospray ionization-mass spectrometry of ion-exchange and reverse-phase purified hemocyanin from Limulus polyphemus revealed six predominant isoforms with molecular weights ranging from 71,730 to 72,695 Da. The heaviest of these agreed closely with the molecular weight calculated for the previously determined Edman sequence with substitution of isoleucine for valine at position 9 and inclusion of three internal disulfide bonds and one copper atom. Proposed structures for the other isoforms were made on the basis of the molecular weight measurements. Reverse-phase chromatography can be used in addition to the traditional ion-exchange step to produce hemocyanin preparations of greater purity that might be valuable for further detailed investigations of the physicochemical properties of these important proteins. The results reflect yet again the value of mass spectrometry for recognizing molecular microheterogeneity in biological macromolecules and for following protein purification.

Influence of the antibody purification method on immunoassay performance: hapten-antibody binding in accordance with the structure of the affinity column ligand

The effects of ligands for immunoaffinity chromatography on the immunoassay were investigated with three goat anti-methamphetamine (anti-MA) antibodies (Abs). An N-4-aminobutyl derivative of methamphetamine (4-ABMA) was conjugated with proteins and used as immunogens. All the antisera produced were purified by affinity chromatography with various ligands of 4-ABMA-proteins and of haptens as well as protein G: 4-ABMA-bovine serum albumin (4-ABMA-BSA), 4-ABMA-keyhole limpet hemocyanine (4-ABMA-KLH), 4-ABMA-ovalbumin (4-ABMA-OVA), MA, 4-ABMA, and amphetamine were used as ligands. Enzyme-linked immunosorbent assay (ELISA) was conducted to examine characteristics of the purified Abs with the 4-ABMA-OVA competitor coated. The results obtained revealed that characters of the purified Abs were closely related with chemical structures of ligands used. The Abs from the MA and the amphetamine columns showed better sensitivities than those from the others in each antiserum. Particularly, the Ab from the amphetamine column gave the best results in terms of sensitivity and specificity. The recognition or the affinity of the Ab selected was considered to be affected by the structure of the ligand concerned. These results suggest that the Ab purification method should be considered as an important parameter which has great influence on the performance of immunoassays with polyclonal Abs.

Intercellular adhesion molecule-1 expression in the inner ear of rats following secondary immune reaction in the endolymphatic sac

An immunological aetiology for inner ear diseases has long been proposed. The endolymphatic sac (ES) is the only immunoprivileged site in the inner ear with a resident population of immunocompetent cells. By keyhole limpet hemocyanin (KLH) challenge into the ES of systemically pre-immunized guinea pigs, we previously demonstrated an infiltration of inflammatory cells into the perilymphatic space of the cochlea. In order to understand the mechanisms involved in the recruitment of immunocompetent cells into the inner ear, and their relation to the development of endolymphatic hydrops (EH), we investigated the expression and time-kinetics of intercellular adhesion molecule 1 (ICAM-1) in the inner ear of systemically pre-immunized rats after antigen (KLH) challenge into the ES, its relation to cell infiltration in the cochlea and subsequent development of EH. By immunohistochemistry, strong ICAM-1 expression was detected in the spiral ligament, suprastrial region, spiral prominence, spiral modiolar veins, spiral collecting venules, surface membrane of the perilymphatic compartment, perilymphatic space and ES of immunized rats, but not of control rats. ICAM-1 expression was detected at 5-6 h, peaked at 10-15 h, and gradually reduced by 2 weeks. Cell infiltration into the cochlea started at 6-12 h and peaked at day one. By 6 h, 50% of challenged rats developed EH. This figure rose to 70% at 12 h, and then gradually reduced. However, immunoreactivity for KLH (antigen) was only detected in the ES. These results emphasize that the sac is the central immunological organ of the inner ear, and suggest that ICAM-1 may play a pivotal role in the aetiology of immune-mediated inner ear diseases through the recruitment of immunocompetent cells into the inner ear and subsequent development of EH.

Production and characterization of a bivalent single chain Fv/alkaline phosphatase conjugate specific for the hemocyanin of the scorpion Androctonus australis

A102 is a monoclonal antibody raised against the hemocyanin of the Tunisian scorpion Androctonus australis. It is directed against the subunit Aa6 and does not cross-react when tested against a variety of similar scorpion hemocyanins. Here, we report the construction of a plasmid encoding a recombinant enzyme-linked antigen-binding protein with the antigen-binding specificity of antibody A102. The DNA fragments encoding the variable domains of A102 were inserted into a prokaryotic expression vector so as to produce a single chain antibody variable fragment (scFv) fused to the bacterial alkaline phosphatase. The fusion protein preserved the IgG binding and alkaline phosphatase activities. Immunoelectron microscopic analysis showed that the recombinant protein bound antigen bivalently as is the case for natural antibodies. Crude preparations containing the conjugate were used in a rapid visual immunoassay for the specific detection of A. australis hemocyanin, using a droplet of hemolymph removed from live animals by puncture. The simplicity of the test made it suitable for the direct identification of animals belonging to this species. It could be useful in areas where A. australis, the most dangerous African scorpion, is found with other species from which it is not easy to distinguish using morphological criteria.

Cytobiological studies on hemocyanin metabolism in the branchial heart complex of the common cuttlefish Sepia officinalis (Cephalopoda, Dibranchiata)

The present study confirms previous investigations that demonstrated a high copper content in the branchial heart and its appendage, and that gave the first indication that this organ complex might be involved in hemocyanin metabolism in Sepia officinalis L. Immunocytochemical localization of hemocyanin molecules within the endocytotic lysosomal system of the ovoid cells and tracer experiments with 125I-labeled Sepia hemocyanin suggest its endocytotic uptake. Energy-dispersive X-ray microanalysis and histochemical methods reveal a high copper content within the ovoid cells of the branchial heart. In view of the turnover of the respiratory pigment in the branchial heart of Sepia officinalis L., we believe that the ovoid cells are a site of hemocyanin catabolism.

Changes in immunostaining of inner ears after antigen challenge into the scala tympani

To study the mechanisms of immune responses and immune injuries in inner ears, labyrinthitis was induced by inoculation of keyhole limpet hemocyanin (KLH) into the scala tympani of systemically sensitized guinea pigs. Inner ears were then immunostained for KLH, immunoglobulin G (IgG), albumin, connexin26 (Cx26), and sodium-potassium adenosine triphosphate (Na,K-ATPase). Inflammatory cells containing KLH were observed in the scala tympani and in the collecting venule of the spiral modiolar vein (SMV). Spiral ligament, spiral limbus, and blood vessels including the SMV were diffusely positive for IgG and albumin. Immunoreactivity for Cx26 and Na,K-ATPase was decreased compared with the normal ears in the fibrocytes of the spiral ligament. These results suggest that inflammatory cells and blood constituents could extravasate into the cochlea from blood vessels and that fibrocyte damage in the spiral ligament could cause cochlear dysfunction.

Detection of oxidized phospholipid-protein adducts using anti-15-hydroperoxyeicosatetraenoic acid-modified protein antibody: contribution of esterified fatty acid-protein adduct to oxidative modification of LDL

The reaction of lipid hydroperoxide with protein was investigated using an antibody, which was prepared using 15-hydroperoxyeicosatetraenoic acid (15-HPETE)-modified keyhole limpet hemocyanin as an immunogen. The obtained antibody recognized not only 15-HPETE-modified bovine serum albumin (BSA) but also 13-hydroperoxyoctadecadienoic acid (13-HPODE)-modified BSA. Glutaroyl-BSA adduct, which was prepared by the reaction of glutaric anhydride with protein, was also recognized by the antibody. The results revealed that the carboxyl terminus of lipid moiety in adducts was required for an appearance of the antigenicity. The cross-reactivity of phosphatidylcholine hydroperoxide-modified BSA (PCAOOH-BSA) with the antibody was examined. The antibody could not recognize the intact PCAOOH-BSA, whereas alkaline-treated modified BSA revealed the antigenicity. Furthermore, stearic acid at the 1 position in the phospholipid was liberated from the PCAOOH-BSA following treatment with 0.25 N NaOH. The result showed that the phospholipid moiety could be covalently bound to the protein molecule. The formation of esterified fatty acid-protein adduct during oxidation was confirmed using low-density lipoprotein (LDL). During oxidation of LDL by copper ion or 2,2'-azo-bis(2-amidinopropane)dihydrochloride, the formation of antigenic materials was observed in a time- or dose-dependent fashion. The antigenicity was significantly enhanced by the alkaline treatment on the oxidized LDL, suggesting that considerable amounts of oxidized esterified fatty acids can covalently react with apoprotein B-100 in oxidatively modified LDL.

Immunocytochemical reaction of a haemocyanin antibody in the midgut gland of Nautilus (Cephalopoda, Tetrabranchiata)

The branchial gland of the dibranchiate cephalopods is described as the site of haemocyanin synthesis. Because there is no equivalent to this organ in tetrabranchiate cephalopods the localization of haemocyanin synthesis remained unknown for a long time. In this study we could confirm the conclusions from preliminary investigations concerning the copper content of the midgut gland of Nautilus, which gave the first indications for a possible localization of haemocyanin synthesis in this organ. We developed a polyclonal antibody against Nautilus haemocyanin, tested its specificity, and used it on ultra-thin sections of the tissue of the midgut gland. It could be shown that there is a clear immunogold precipitation only on the triangular basal cells in the terminal alveoli. All the other types of cell in this organ were free of any immunoreactivity. It can be supposed that the triangular basal cells in the terminal alveoli of the midgut gland are the sites of haemocyanin synthesis in Nautilus.

Identification of the major lipoproteins in crayfish hemolymph as proteins involved in immune recognition and clotting

Lipid-containing hemolymph proteins from males of the crayfish Pacifastacus leniusculus were isolated by density gradient ultracentrifugation. Two major lipoproteins, one high density lipoprotein (HDL) and one very high density lipoprotein (VHDL), were characterized. The HDL and the VHDL were found to be identical to two proteins previously studied for their roles in immune recognition and hemolymph clotting, namely the beta-1,3-glucan binding protein and the clotting protein. These results imply that crayfish lipoproteins have dual functions, and that they are involved in immunity, hemolymph clotting, and lipid transport in these animals. Also, the oxygen-transporting protein hemocyanin was found to have a small lipid content.

Characterization of N-linked carbohydrate chains of the crayfish, Astacus leptodactylus hemocyanin

The primary structure of the carbohydrate chains of hemocyanin from the crayfish Astacus leptodactylus were investigated. The carbohydrate content is 0.2% (w/w) as referred to total hemocyanin content, resp. 1.8% as referred only to the one subunit which is glycosylated. Mannose and N-acetylglucosamine are present in a molar ratio of 6:2. The carbohydrate chains are N-glycosidically linked as revealed by dot blot analysis using various lectins and enzymatic deglycosylation. Furthermore, they are part of only one hemocyanin subunit of A. leptodactylus. After enzymatic deglycosylation with PNGase F, the oligosaccharide pool was separated by FPLC on Mono Q and subsequent HPLC on Lichrosorb-NH2, the subfractions were characterized by 1H NMR spectroscopy. A total of six oligosaccharides, ranging from Man4GlcNAc2 to Man9GlcNAc2 is present, Man6GlcNAc2 representing the most abundant one with 57% of all oligosaccharides.

Electron microscopy of a double helical tubular filament in keyhole limpet (Megathura crenulata) hemolymph

A approximately 25 nm hollow double helical filament has been detected ultrastructurally in the cell-free supernatant from hemolymph of the keyhole limpet Megathura crenulata (Gastropoda: Prosobranchia: Fissurellidae). Subsequently, much higher concentrations of this material were found in the cell pellet from hemolymph. Both negative staining and thin sectioning have been performed in an attempt to obtain a preliminary structural characterization of this new filament. It is proposed that the filaments are released or secreted from blood hemocytes in response to bleeding, but it has not been possible to define absolutely an intracellular organelle containing this material. It is shown that the hollow filaments, which have fine fibrillar surface extensions, are readily distinguishable from collagen fibrils and from tubular (multi-decameric) keyhole limpet hemocyanin (KLH).

Differential scanning calorimetry of lobster haemocyanin

Differential scanning calorimetry has been performed with Palinurus vulgaris haemocyanin monomers and hexamers. The denaturation of the protein is irreversible. Both the temperature of the transition maximum and the enthalpy are lower for the monomer than for the hexamer. A scan rate dependence of the temperature of the maxima is found for both the monomer and the hexamer; for the hexamer at least, this can be explained in terms of a two-state kinetic model. Some comments are made as to the use of equilibrium thermodynamics in the analysis of irreversible scanning calorimetric traces.

Spectroscopic investigations of Panulirus interruptus hemocyanin in the crystalline state

Single-crystal ultraviolet spectroscopy, X-ray absorption spectroscopy and EPR measurements have been used to examine the oxidation and oxygenation state of the dinuclear copper site of several types of hemocyanin crystals. The crystals contain Panulirus interruptus hemocyanin which forms hexameric molecules with a molecular mass of approximately 470 kDa. Three types of crystals have been investigated. Type-I monoclinic crystals, which have been used for the X-ray structure determination, contain virtually only deoxyhemocyanin. Type-II monoclinic crystals, which are less well ordered than the type-I crystals, contain a mixture of deoxy, oxy and met forms. Older crystals contain relatively more methemocyanin. A third, hexagonal, crystal form is also partially oxygenated, and, like the type-II monoclinic form, subject to gradual conversion to methemocyanin.

Partial amino acid sequence of a hemocyanin subunit from Palinurus vulgaris

1. Hemocyanin from the spiny lobster Palinurus vulgaris was separated into two fractions, which were designated as subunits a and b. 2. 55% of the amino acid sequence of subunit b has been determined. A comparison with Panulirus interruptus hemocyanins shows 78% sequence identity with subunit a and 56% with subunit c. It has carbohydrate attached to domain one. Two half-cystines have been substituted, indicating that it probably possesses only one disulfide bridge. Heterogeneity has been observed in seven out of 380 positions determined so far. 3. Subunit a is almost identical with subunit b. In contrast to Panulirus interruptus and Panulirus japonicus, Palinurus vulgaris hemocyanin contains no c-type subunit. 4. A position in the tentative evolutionary tree of arthropod hemocyanins based on sequence differences has been assigned to Palinurus vulgaris subunit b.

Subunit structure and higher order assembly of the hemocyanins of the Melongenidae family: Melongena corona (Gmelin), Busycon canaliculatum (Linné), B. carica (Gmelin), B. contrarium (Conrad), and B. spiratum (Lamarck)

1. The hemocyanins of the Melongenidae family of marine gastropods: Melongena corona, Busycon canaliculatum, B. carica, B. contrarium, and B. spiratum exist in solution as multi-decameric aggregates characterized by sedimentation coefficients of approximately 105 S, 130 S, 150 S, 170 S, and higher values, corresponding to di-, tri-, tetra-, penta-, and larger multi-decameric particles. 2. The hemocyanins of B. contrarium and B. carica seem to form the largest decameric aggregates with the tri- to penta-decamers respresenting the major constitutents. Scanning transmission electron microscopy (STEM), both of unstained, freeze-dried and negatively-stained specimens, shows the presence of discrete aggregates consisting of up to ten decameric units. 3. The particle masses as determined by STEM mass measurements for individual molecules gave integral multiples of from 4.2 x 10(6) to 4.4 x 10(6) daltons ranging from about 8.2 x 10(6) daltons for the typical di-decamer of B. canaliculatum hemocyanin to as high as about 39 x 10(6) and 43 x 10(6) for the nano-and deca-decamers of B. contrarium hemocyanin. 4. The appearance of the higher multi-decamers in both negatively-stained and freeze-dried specimens suggest that they are formed by the addition of decameric units to a single di-decameric unit "tail-wise" in both directions. The higher aggregates formed seem to terminate with a closed head or collar at both ends of the assembly.

Structure and function of the carboxyl-terminal oxygen-binding domain from the subunit of Octopus dofleini hemocyanin

The C-terminal domain, Od-1, of the 7-domain subunit of Octopus dofleini hemocyanin has been prepared by partial trypsinolysis followed by ion-exchange chromatography. It binds oxygen reversibly and is homogeneous in molecular weight. Its physical properties have been compared with those of the subunit. The domain molecular weight is found by sedimentation equilibrium to be 4.7 X 10(4), in excellent agreement with the result recently obtained in our laboratory from cDNA sequencing of this domain [Lang, W. H. (1988) Biochemistry (preceding paper in this issue)]. It has a sedimentation coefficient of 3.8 S. Both the molecular weight and sedimentation coefficient are consistent with the domain constituting approximately one-seventh of the Mr 3.5 X 10(5) subunit. Its amino acid composition and carbohydrate content differ significantly from that of the whole subunit, confirming the heterogeneity in domains previously established on an immunological basis. Circular dichroism predicts similar secondary structure for the domain and subunit. The domain does not self-associate in the presence of Mg2+ but does bind to the whole molecule in a ratio of approximately 1 domain/subunit. The oxygen affinity of this domain is quite low. It shows intrinsic magnesium and Bohr effects similar to those of the whole molecule but of greatly reduced magnitude.

Chromatographic and radioimmunological methods for the determination of 5'-deoxy-5'-methylthioadenosine in biological fluids

Two specific methods for the determination of 5'-deoxy-5'-methylthioadenosine (MTA) in biological samples have been developed. The chromatographic procedure requires a preliminary step on a phenylboronate column to remove non-cis-diol compounds. The sample is then analysed using a high-performance liquid chromatography system equipped with a reversed-phase column. 5'-Deoxy-5'-methyl-thio[2-3H]adenosine with high specific activity was synthesized and employed as an internal standard. An alternative radioimmunoassay (RIA) procedure has also been developed. The RIA method is based on competition between the unlabelled thio-ether and 3H-labelled MTA for the binding to a specific antiserum. Anti-MTA antibodies were obtained from rabbits immunized with the nucleoside covalently linked to carrier proteins. Both the chromatographic and RIA procedures gave identical results when employed to determine MTA in human urine.

Subunits of Panulirus japonicus hemocyanin. 1. Isolation and properties

Structural and functional diversities of the subunits of Panulirus japonicus (spiny lobster) hemocyanin were investigated. The hemocyanin mostly exists as a hexamer in the native state. It was found that the hemocyanin is composed of three major subunits (Ib, II and III) and one minor subunit (Ia), which differ in N-terminal sequence. In the dissociated state, the major subunits (Ib, II and III) showed no or very small Bohr effects. The O2 affinity of the subunit III was about three times as high as those of the other two. The subunits could be reassociated into homogeneous and heterogeneous hexamers, which exhibited the cooperativity in O2 binding. The homohexamers were similar to each other in O2 affinity and the Bohr effect, though some differences were observed in the magnitude of the cooperativity. In particular, the subunit II homohexamer exhibited a high cooperativity, which was comparable to that of the native protein. The heterohexamers showed slightly higher O2 affinities and slightly lower cooperativity, as compared with the parent homohexamers. It was concluded that there is no essential difference among the three major subunits of P. japonicus hemocyanin in the O2 binding and assembly properties.

Subunits of Panulirus japonicus hemocyanin. 2. Cooperativity of the homogeneous hexamers

Hexameric hemocyanin from a spiny lobster, Panulirus japonicus, comprises three major subunits (Ib, II and III) and one minor subunit (Ia), as reported in the preceding paper in this journal. It has previously been shown that the O2 equilibria of Panulirus hemocyanin can be described by a concerted model extended to three affinity states [Makino, N. (1986) Eur. J. Biochem. 154, 49-55]. In this study the equilibrium binding of O2 to the reassociated subunits (Ib, II and III) was examined at various pH in the presence or absence of Ca2+ in order to test the applicability of the three-state model to the homogeneous hexamers. The hexameric structure of the reassembled subunits was less stable than that of the native protein under the conditions examined. The model could be fitted to the O2-binding isotherms of the homohexamers composed of the subunits II or III, if the molecular dissociation of the protein was taken into account. It was postulated that the monomeric hemocyanin has the same ligand affinity as that of the hexamer in the intermediate-affinity state (S). The fitting of the model to the O2 binding of the subunit I was unsuccessful mainly because of the low cooperativity of the assembled subunits.

Active-site heterogeneity in Limulus hemocyanin as revealed by reaction with peroxides

Previously reported differences in the reactivities toward active-site ligands such as hydrogen peroxide indicate that the active-site geometries of the arthropod and mollusc hemocyanins are significantly different. Results are presented which demonstrate that the purified subunits composing the native hemocyanin of an arthropod show comparable active-site heterogeneity. Neither whole nor stripped samples of Limulus oxyhemocyanin are completely oxidized by reaction with hydrogen peroxide. Moreover, the addition of hydrogen peroxide to deoxy or completely oxidized samples causes partial regeneration to the oxy form. This behavior is most pronounced for one of the five major chromatographic fractions, Zone III, which retains greater than 60% of its copper-oxygen absorbance band when treated with hydrogen peroxide. Zone III is composed of three subunits (IIIA, IIIB, and IIIB'). With excess hydrogen peroxide, the deoxy and oxidized forms of Subunit IIIA can be completely regenerated to a fully functional oxy state, while Subunits IIIB and IIIB' are less than 30% regenerated. Upon long-term storage, Subunit IIIA slowly loses 340 nm absorbance, an aging process that can be reversed by hydrogen peroxide. These features of Subunit IIIA, that set it apart from other subunits of the 48-member ensemble of intact Limulus hemocyanin, are typically exhibited by mollusc hemocyanins rather than arthropod hemocyanins. These findings clearly illustrate that significantly different active-site geometries can occur within a single type of metalloprotein and suggest that comparisons between the various Limulus subunits and Subunit IIIA may prove valuable in unraveling the structural basis for the disparity in the chemical reactivity exhibited by hemocyanins of different species.

Bivalve hemocyanins--a comparison with other molluscan hemocyanins

1. The hemocyanins of the protobranch bivalves Yoldia thraciaeformis, Yoldia limatula and Acila castrensis have absorption spectra similar to other hemocyanins. 2. Hemocyanins from all three bivalves appear as six-tiered cylinders in the electron microscope (30-32 nm in diameter by 34-38 nm in height). Yoldia thraciaeformis and A. castrensis hemocyanins tend to dissociate to three-tiered half molecules with polar images and also to associate into long tubular polymers. 3. Yoldia thraciaeformis and A. castrensis hemocyanins chromatograph on Sepharose 4B gel close to gastropod hemocyanin (Mr = 9 x 10(6] rather than chiton hemocyanin (Mr = 4 x 10(6]. 4. Hemocyanins from all three vivalves have subunits with electrophoretic mobilities similar to gastropod and polyplacophoran hemocyanin subunits and slower than octopodan hemocyanin subunits. 5. These similarities between bivalve and gastropod hemocyanins are consistent with the hypothesis that bivalves and gastropods have shared a common ancestor.

Complete amino-acid sequence of a functional unit from a molluscan hemocyanin (Helix pomatia)

From the beta c-hemocyanin (beta c-Hc) of the vineyard snail, Helix pomatia, the functional unit d (Mr approximately equal to 50,000-55,000) was isolated by limited proteolysis and gel chromatography. A small quantity of functional unit d was obtained intact, but the major part in the form of two peptides (Mr approximately equal to 43,000 and 10,000, respectively) connected by a disulfide bridge. After reduction and carboxymethylation, these were separated from each other and cleaved by conventional methods. The peptides were isolated by gel chromatography and HPLC, and sequenced manually or automatically. The complete sequence of Helix beta c-Hc d comprises 410 residues plus 3 residues at the N-terminus seemingly resulting from incomplete cleavage. There is apparently only one carbohydrate side-chain. Comparison of this gastropodan hemocyanin sequence to the partial sequence of a cephalopodan Hc C-terminal unit revealed sufficient identities to state that the functional units of molluscan hemocyanins have arisen by a series of gene duplications. On the other hand, there is practically no homology with arthropodan hemocyanins except for one section of 42 residues which is clearly homologous. This section corresponds to the "Copper B" site of Panulirus interruptus hemocyanin. It is also found in tyrosinases from Neurospora crassa, Streptomyces glaucescens, and mouse. In the N-terminal half of Helix beta c-Hc d there are other sections clearly homologous to the tyrosinases, but overall homology is limited. The second copper-binding site was not identified but must be completely distinct from the "Copper A" binding site of arthropodan hemocyanins. It is suggested that molluscan and arthropodan hemocyanins have evolved independently from a common ancestral mononuclear copper protein.

High and low molecular weight tracers for the electron microscopical detection of sialoglycoconjugates

Hydrazide-derivative tracers of different molecular weights have been synthesized for use in the electron microscopical detection of sodium periodate-oxidized sialyl residues of glycoconjugates in various tissues and cells. Haemundecapeptide hydrazide, horseradish peroxidase hydrazide, and Limulus polyphemus haemocyanin hydrazide were obtained by coupling adipic acid dihydrazide to the tracers with the aid of water-soluble carbodiimide. The enzymatic tracers thus prepared retained their peroxidatic activity. On conversion to the hydrazide derivative, the haemocyanin molecule dissociated into its hexameric subunits. In order to test by transmission electron microscopy the ability of the conjugates to bind to the sialoglycoconjugates of endothelial cell surfaces, each tracer was perfused in situ into rat pancreatic vasculature previously oxidized with 1 mM sodium periodate. The three tracers characteristically labelled the various microdomains of the luminal cell coat of the capillary endothelial cell. The electron opacity of the haemocyanin subunits allowed their easy detection when bound to the cell surface or to components of the extracellular matrix. The bound markers were not displaced by a high ionic strength buffer, and did not label desialylated cell surfaces. These results indicate that the three hydrazide-derivative tracers may be useful tools for the electron microscopical detection of cellular and extracellular sialoglycoconjugates.

Studies on the detrimental effects of bivalent binding in a microtitration plate ELISA and possible remedies

During the development of a microtitration plate enzyme-linked immunosorbent assay (ELISA) for 3-acetyldeoxynivalenol, using an immobilised hapten:protein conjugate, problems were encountered in obtaining an inhibition curve with hapten. Investigations into this phenomenon were conducted. Univalent Fab fragments were prepared and their binding compared with untreated antiserum on plates coated with different immobilised coating concentrations and with conjugate of a lower hapten:protein ratio. The studies showed that standard curves obtained with Fab fragments using the coating conjugate of high hapten ratio were more sensitive and showed a greater degree of inhibition. However with the conjugate of lower hapten ratio the untreated antiserum gave the more sensitive curve although inhibition was incomplete. From these results it is concluded that the antiserum probably contains two populations of antibodies, one of which binds bivalently to the plates at all concentrations of immobilised hapten.

Primary structure of the neutral carbohydrate chains of hemocyanin from Panulirus interruptus

The N-glycosidic carbohydrate chains of Panulirus interruptus hemocyanin, consisting of only mannose and N-acetylglucosamine residues, were liberated by hydrazinolysis of a pronase digest of the purified glycoprotein. The carbohydrate chains were fractionated by high-voltage paper electrophoresis, yielding mainly neutral oligosaccharide-alditols. These were further separated by high-performance liquid chromatography and characterized by 500-MHz 1H-NMR spectroscopy as (formula; see text).

Antigen detection in immune complexes by a modified staphylococci binding assay and Western blot analysis

The combination of a modified Staphylococci binding assay for immune complexes and Western blot analysis is described for the isolation and detection of antigen in immune complexes from human sera. The strategy of the procedure is to preclear immune complexes from other serum components by sequential polyethylene glycol precipitation and incubation with insoluble protein A under conditions in which immune complexes are preferentially bound. Immune complexes are eluted from protein A in sodium dodecyl sulfate buffer and dissociated by acrylamide electrophoresis. Resolved proteins are then transblotted to nitrocellulose, and antigen is detected with specific antibody. Immune complexes were prepared in vitro with an antigen (keyhole limpet hemocyanin) that focuses well on electrophoresis and for which a potent immunologic probe (antibody) was available. In this system, antigen could be detected when immune complexes were present in sera in concentrations as low as 20 micrograms aggregated-IgG eq/ml, regardless of antigen-antibody ratio. We demonstrate the detection of horse globulin in immune complexes from a patient with acute serum sickness and hepatitis B virus antigen in complexes from a patient with vasculitis.

Primary structure of the low-molecular-weight carbohydrate chains of Helix pomatia alpha-hemocyanin. Xylose as a constituent of N-linked oligosaccharides in an animal glycoprotein

alpha-Hemocyanin of Helix pomatia is a copper-containing glycoprotein which serves as an oxygen carrier in the hemolymph. Its carbohydrate moiety has as constituents fucose, xylose, 3-O-methylgalactose, mannose, galactose, N-acetylgalactosamine, and N-acetyl-glucosamine residues. Alkaline borhydride did not split off any carbohydrate material, suggesting the absence of O-glycosidic chains. The N-glycosidic carbohydrate chains of this glycoprotein were liberated by hydrazinolysis of a Pronase digest then fractionated as alditols on Bio-Gel P-4. The fractions containing the low-molecular-weight glycans were investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar and methylation analysis. The largest, and most abundant, compound was established to be: (Formula: see text). Another compound was characterized as the afuco analogue of this structure. H. pomatia alpha-hemocyanin is the first example of an animal glycoprotein having xylose as a constituent of N-glycosidic carbohydrate chains.

Centipedal hemocyanin: its structure and its implications for arthropod phylogeny

The oxygen carrier hemocyanin occurs in the blood of Scutigera coleoptrata, a uniramous arthropod, as well as the crustaceans and chelicerates. The native polymer appears to be composed of substructures having the same size and electron-dense image as those of other arthropod hemocyanins but assembled into a unique multiple and arranged in a unique configuration. The simplest explanation of these findings is that the arthropod hemocyanins have a common origin, exemplifying a derived (as opposed to primitive) character shared by each of the three living groups.

Immunological correspondence between arthropod hemocyanin subunits. II. Xiphosuran (Limulus) and spider (Eurypelma, Cupiennius) hemocyanin

The hemocyanins of the horseshoe crab Limulus polyphemus (48-mer), the tarantula Eurypelma californicum (24-mer), and the lycosid spider Cupiennius salei (dodecamer, hexamer) were dissociated into subunits, the subunits isolated and studied by two-dimensional immunoelectrophoresis for interspecific cross-reactivities. Among the subunits a to g of Eurypelma on the one side, and I to VI of Limulus on the other, a number of cross-reactions were obtained which agree with the topologic subunit positions in the published models of quaternary structure: a = II, b-c = V-VI, d = IV, e = I, f = IIIb, g = IIIa (IIa). However, cross-reactivity was only strong in the following combinations: a/II, d/IV, b-c/V-VI (the monomers of the two heterodimers could not be correlated individually). A rather weak cross-reaction was obtained in the case of e/I and g/IIIa (IIa); a cross-reaction between f and IIIb was almost undetectable. On the other hand, f/IV clearly cross-reacted, and so did e/IIIa (IIa), which apparently is not in agreement with the two models of quaternary structure. These unexpected relationships, however, indicate the possible phylogeny of the subunits. Antiserum against Cupiennius hemocyanin precipitated subunit f of Eurypelma and subunit IV of Limulus and, moreover, revealed common antigen determinants present on these subunits. Denaturation of hemocyanin subunits of the three species with 8M urea yielded a completely different immunological behavior in that in all intra- and interspecific combinations the reaction of immunological identity was obtained. The published models of quaternary structure and a possible subunit phylogeny of cheliceratan hemocyanins is discussed in view of the present results and the results of the preceding paper. [Markl, J. et al. (1984) Hoppe-Seyler's Z. Physiol. Chem. 365, 619-631.]

Immunological correspondence between arthropod hemocyanin subunits. I. Scorpion (Leiurus, Androctonus) and spider (Eurypelma, Cupiennius) hemocyanin

The hemocyanins of the scorpions Leiurus quinquestriatus and Androctonus australis, the tarantula Eurypelma californicum (all 24-mers), and the lycosid spider Cupiennius salei (dodecamer) were dissociated into subunits, the subunits isolated and studied by two-dimensional immunoelectrophoresis for interspecific cross-reactivities. Androctonus hemocyanin yielded a pattern of 8 subunit types in agreement with data from Lamy et al. (1979, Arch. Biochem. Biophys. 193, 140-149). Leiurus hemocyanin is also composed of 8 immunologically distinct subunits which could be assigned to the pattern of Androctonus in a subunit-to-subunit correlation. The subunit designations 1 to 6 of Lamy et al. could be adopted for both scorpion hemocyanins; however, in the present communication, Lamy's subunits 3A/3B are designated as 3'/3", because we could not unequivocally decide if 3' = 3A and 3" = 3B or vice versa. The 7 subunit types a to g of Eurypelma hemocyanin could be correlated with the scorpion hemocyanin subunits as follows: a = 3', b = 5B, c = 3C, d = 5A, e = 6, f = 2, g = 4. Additional cross-reactivities were detected between e/4, and f/5A, respectively. No subunit of Eurypelma hemocyanin is homologous to scorpion 3", which could not be precipitated by anti-Eurypelma antiserum. Antiserum against Cupiennius hemocyanin precipitated subunit f of Eurypelma and subunits 2 and 5A of scorpion hemocyanin. The published models of quaternary structure and a possible subunit phylogeny of arachnidan hemocyanins are discussed in view of the present results.