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Biomedical subjects

C H Bigger

Publications and source records attributed to C H Bigger.

12 recordsLinked to original sources
PubMed2000

Phagocytic activities of the gorgonian coral Swiftia exserta.

The cellular response component of body defense in gorgonians and other cnidarians is thought to be carried out by cells with phagocytic capabilities. To test for the phagocytic character of cells, the introduction of foreign particles was employed and observed in both living cells and histological preparations of the gorgonian coral Swiftia exserta. Observations of untreated tissues revealed normal cells and tissue morphologies. A microscopic observation of living cells following the introduction of particles in a cut revealed that only a mixed population of colorless cells phagocytized the particles. Also particles or clumps of particles were seen on the surface of the colorless cells. Subsequent histological observations allowed identity of colorless cells to be inferred as granular amoebocytes, ectodermal cells, and gastrodermal cells. Cells stained for localization of peroxidase (indicative of phagocytic activity) demonstrated the presence of peroxidase-positive cells. Histological preparations revealed that major phagocytosis of particles was associated with tissue trauma. When particles were introduced by means of a cut or inserted thread, phagocytic activity was detected within 2 h. However, it was confined to the granular amoebocytes in the immediate site of trauma. After 24 h, extensive phagocytosis spread throughout a relatively large area surrounding the wound. At that later time, phagocytic cell types included granular amoebocytes, epidermal cells, sclerocytes, mesogleal cells, and gastrodermal cells of the solenia. Observations suggest that trauma induces phagocytosis in cells not normally phagocytic in S. exserta. No localization of phagocytic cells and no mitotic cells were observed at either 2 or 24 h after particle introduction.

Animals↗
PubMed1994

Aspects of histocompatibility and regeneration in the solitary reef coral Fungia scutaria.

Discoid coralla of the solitary free-living reef coral Fungia scutaria were cut with a rock saw and rejoined in various paired combinations and orientations of autogeneic sections (self to self), isogeneic sections (clone-mate to clone-mate), and allogeneic sections (two different genotypes). Results of these experiments provide the first evidence of histocompatibility in a solitary coral. Autogeneic or isogeneic sections of coralla with one section containing a mouth were joined along cut edges. In all cases, fusion of tissues occurred within weeks, followed by skeletal fusion within months. However, autogeneic or isogeneic sections rejoined along the uncut edges did not fuse. Isogeneic pairings between two sections with mouths produced neither tissue/skeletal fusion nor cytotoxicity at the interface. Individual cut sections were allowed to regenerate. Sections containing the parent mouth did not develop new mouths. However, cut sections lacking a mouth always regenerated multiple mouths along the cut edge, but not along the uncut edge. Sections without mouths cut along a second line parallel to the first cut always regenerated mouths along the cut edge located closest to what had been the mouth area of the original corallum. The new mouths eventually developed into individual polyps.

Animals↗
PubMed1983

Cytotoxic transplantation immunity in the sponge Toxadocia violacea.

The Hawaiian sponge, Toxadocia violacea, exhibited discriminating transplantation immunity in an extensive series of allogeneic and xenogeneic parabioses. Cytotoxic alloincompatibility occurred without exception, but with differing degrees of severity. The allorejection reactions developed more rapidly than has been observed in any other animal species. An intense tissue-bridging reaction in allogeneic contact zones preceded acute soft tissue destruction; the cytotoxic reactivity was usually restricted to the immediate zone of direct contact. The median reaction times were closely temperature-dependent and much accelerated at higher temperature. Specific, short-term alloimmune memory was revealed by second-set and third-party graftings. Extensive allogeneic polymorphism was evident from the invariable rejection observed among more than 140 different pairings. Xenograft reactions between Toxadocia violacea and Callyspongia diffusa were characterized by acute cytotoxicity, immune memory, and a qualitative change in secondary versus primary responses.

Animals↗
PubMed1982

Characterization of alloimmune memory in a sponge.

Alloimmune memory, revealed by consistently accelerated second-set graft rejection in contrast to unrelated third-party reactions, has been reported in four species of marine sponge. Allogeneic tissue of the marine sponge, Callyspongia diffusa was grafted/parabiosed to examine critically the essential features of alloimmune memory in this member of the least complex major metazoan phylum. Although sponges lack an organized circulatory system, the immunologic memory spreads rapidly through body tissues. Heightened reactivity persisted for only 3 yo 4 wk after primary sensitization. This appears to constitute a major difference from the long-term alloimmune memory found among vertebrates. This limited duration of memory, however, is apparently sufficient for the individual sponge to cope with repeated challenges to its integrity.

Animals↗
PubMed1981

Afferent sensitization and efferent cytotoxicity in allogeneic tissue responses of the marine sponge Callyspongia diffusa.

Allogeneic branches of the marine sponge Callyspongia diffusa were paired either in parabiosis or as allografts. To examine the specificity of the allogeneic rejection process, naive second sets and third parties were substituted in the midst of primary allogeneic tissue responses. Other experiments were conducted with 0.2-, 0.8-, 3.0-, and 5.0-micron pore size membrane barriers separating various combinations of naive and presensitized allogeneic paired sponges. The results of these experiments demonstrate that both the afferent and efferent phases of allograft rejection in Callyspongia diffusa depend on direct allogeneic cell contact. Cytotoxic reactivity does not involve a readily diffusible cytotoxic molecule. Moreover, the specificity of allogeneic sponge graft rejections resides in the early recognition or afferent phase; once the effector response is generated or turned on, subsequent allogeneic cytotoxicity is nonspecific.

Animals↗
PubMed1980

Allogeneic polymorphism and alloimmune memory in the coral, Montipora verrucosa.

Populations of the coral Montipora verrucosa exhibited very extensive allogeneic polymorphism revealed by parabiotic incompatibility amont 890 different pairings of colonies (clones) without exception. More than 1,400 reciprocal histoincompatibilities were actually recorded because bilateral cytotoxicity was observed among most of the the alloparabionts tested. This "uniqueness of the individual" in terms of cell surface histocompatibility (H) markers is manifest in the whole spectrum of possible incompatibilities from strong to moderate to weak. The directionality, severity, and rate of rejection were mainly determined by the genetic constitutions of the interclonal parabionts. Allograft reaction times were closely temperature dependent and inversely related to the strength of the H barrier. Heightened alloimmunity or early memory was demonstrable after only 2 days of presensitization and became maximal after 4 to 8 days. After prolonged primary immunization, potent alloimmune memory persisted for 4 weeks, but disappeared after 8 to 16 weeks. Immunological primitiveness in corals may therefore be reflected in the lack of long-lived memory as found among vertebrates.

Animals↗
PubMed1980

Characteristics of transplantation immunity in the sponge, Callyspongia diffusa.

Very extensive polymorphism of histocompatibility (H) molecules in the sponge Callyspongia diffusa was revealed by the incompatibility found among 480 different allogeneic pairings without exception. This represents some 960 individual clones utilized as alloparabionts or sources of fitted allografts. Consistent cytotoxic reactivity provoked by allogeneic cell surface contact in Callyspongia is manifest in a continuum of strong to weak histoincompatibilities; however, strong reactions are most frequent at normal temperatures of 23 to 27 C. The directionality, vigor, and timing of alloparabiotic rejection in this species all depend mainly on the genetic constitutions of the interacting clones. Replicate interclonal combinations yield essentially identical rejection reactions, and differences in graft dosage had no effect on either the direction or intensity of allocytotoxicity. Alloreaction times are inversely proportional to the strength of the H barrier. Maximal allosensitization indicated by accelerated second-set reactivity was gradually achieved, as a function of the interclonal combination, after 2 to 8 days of primary contact. Heightened transplantation immunity or memory persists for at least 2 to 3 weeks after contact sensitization.

Animals↗
PubMed1976

The form and function of cnidarian spirocysts. 1. Ultrastructure of the capsule exterior and relationship to the tentacle sensory surface.

The commonest intracellular organelle characteristic of the Phylum Cnidaria or Coelenterata (Subclass Zoantharia) is the spirocyst. Based on scanning and transmission electron microscopy of the tentacles of sea anemones and corals, it appears that the tip of the spirocyst is either exposed to the environment or covered by a thin plasma membrane and often has a pebbled or knobby appearance. Surrounding the spirocyst tip is a ring-like structure which seems to be formed by the junction of the enclosing cell (the spirocyte) and the tip of the spirocyst. The spirocyst thread is continuous with the capsule wall and emerges from within the apical ring during discharge. No ciliary structures appear to be associated with spirocysts. Instead, two different types of microvilli have been found: short microvilli on the spirocyte itself and long microvilli furnished by the cell or cells surrounding the spirocyte. The significance of these findings is discussed in relation to the reception of stimuli for spirocyst discharge.

Animals↗
PubMed1975

Neurospora crassa invertase. A study of amino acids at the active center.

1. The effects on Neurospora crassa invertase (beta-D-fructofuranoside fructohydrolase, EC 3.2.1.26) of a variety of group specific reagnets and other potential inhibitors were determined during a search for an irreversible inhibitor of the enzyme. Aniline, pyridoxal, enzyme substrate and products did not inactivate invertase under reducing conditions. Bromoacetic acid, iodoacetic acid, iodoacetamide, p-chloromercuribenzoate, hydroxylamine and 2-hydroxy-5-nitrobenzyl bromide were also ineffective. Iodine was the only reagent which irreversibly inhibited invertase. 2. Invertase was rapidly inactivated by low concentrations of iodine, indicating specific inhibition. However, the enzyme could not be protected from this inactivation by substrate. It was not reactivated by mercaptoethanol or cysteine. 3. Experiments on the uptake of radioactive iodine demonstrated that invertase is not iodinated under the conditions of iodine inactivation. 4. The sedimentation (S20,w) value of invertase was not altered by iodine inactivation. One-dimensional electrophoresis and finger-printing of tryptic digests revealed no differences between iodine treated and untreated invertase. There was no loss of carbohydrate from this glycoprotein during iodine inactivation. 5. Standard amino acid analyses of iodine-inactivated invertase showed some loss of tyrosine and a trace amount of methionine sulfone. Attempts to demonstrate oxidation of methionine to the sulfone, through modification of the procedure for preparation of samples for analysis, were unsuccessful. However, oxidation of half-cystine was indicated and further loss of tyrosine noted. A hypothesis is advanced that half-cystine is oxidized by iodine to a normally unstable oxidation state which is maintained and protected by its protein invironment and that loss of tyrosine may be an artifact caused by the presence of this residue during acid hydrolysis.

Amino Acids↗