The fine structure of the granular amebocytes of the Pacific oyster, Crassostrea gigas

Oyster granular amebocytes were characterized by electron microscopy to be of two types. Acidophiles contained relatively small, spherical, amorphous, osmiophilic cytoplasmic granules with a maximum dimension of 0.4–0.56 μ. Basophiles contained large, cytoplasmic granules, approximately 0.7–1.2 μ in diameter. The granules resembled hollow, spherical structures in which an outer membrane and a layer of closely associated granular material enclosed an electron-transparent interior.     

Elucidation of the nature and function of the granular oyster amebocytes through histochemical studies of normal and traumatized oyster tissues

Summary A remarkable humoral component of the oyster inflammatory response was elucidated by employing the tools of the determinative histochemist. The humoral component, characterized by the release of copper and a diazotized p-nitroaniline-positive material from an acidophilic granular amebocyte, was associated with the oyster inflammatory reaction. Grossly, this humoral response was associated with the appearance of an avocado or pea green coloration in the traumatized area. A second amebocytic cell type, termed the basophilic granular amebocyte, was observed swelling in traumatized areas and may have released an additional humoral component into injured regions. Copper released in response to trauma was bound to the cells in and around the wound site and appeared to be most avidly bound by the granules of the basophilic granular amebocytes. Once incorporated into the granular matrix of these amebocytes, copper appeared to stabilize and prevent the granule from swelling.A portion of this work was excerpted from a Ph.D. thesis submitted to the Graduate School, University of Washington, Seattle.This work was supported by Public Health Service Contract No. 5 to 1 ES 00038-02. The costs of publication were defrayed in part by HSAA Award No. RR 06138 and Tumor Biology Training Grant, NIH CA 05245.     

In vitro BrdUrd incorporation of colorectal tumour tissue

Abstract. This study describes a novel in vitro method for the incorporation of the thymidine analogue, bromodeoxyuridine (BrdUrd), in fresh colorectal tumour tissue. Disaggregation by pronase, collagenase and DNAse resulted in high cell yields of viable single cell suspensions, representative of the original tumour, which could be infiltrated with BrdUrd. A modified ELISA identified optimal incubation times and BrdUrd concentrations. This technique has been used in preliminary studies to investigate two important areas intrinsic in the analysis of BrdUrd colorectal cell proliferation data: 1 to determine the effects of the individual constituents of the cell culture media, in particular glutamine, on BrdUrd incorporation in suspensions of colorectal cells and 2 to examine the denaturation step. This method will have wide applicability in investigations of cell proliferation status in both normal and diseased tissue.     

A Cytogenetic and Genetic Characterization of a Group of Closely Linked Second Chromosome Mutations That Suppress Position-Effect Variegation in Drosophila Melanogaster

Characterization of a group of dominant second chromosome suppressor of position-effect variegation (PEV) (Su(var)) mutants has revealed a variety of interesting properties, including: maternal-effect suppression of PEV, homozygous lethality or semilethality and male-specific hemizygous lethality, female infecundity, acute sensitivity to the amount of heterochromatin in the cell and sensitivity to sodium butyrate. Deficiency/duplication mapping and complementation tests have revealed that eight of the mutants define at least two genes in section 31 of the left arm of chromosome 2 and they suggest that a ninth corresponds to an additional nonessential Su(var) gene within or near this region. The effects of specific deficiencies and a duplication on PEV indicate that the expression of one or more of the Su(var) genes in this region of the chromosome is dose-dependent, i.e., capable of haplo-abnormal suppression and triplo-abnormal enhancement. Interestingly, the appearance of certain visible phenotypes among a subset of the mutants suggests that they may possess antimorphic properties. Our results are consistent with the hypothesis that two of these Su(var) genes encode structural components of heterochromatin. We also report that two previously isolated mutants located in 31E and 31F-32A act as recessive suppressors of PEV.     

Initiating polymerization of glycol methacrylate with cyclic diketo carbon acids

Several pharmacologically active cyclic diketone carbon acids, including phenylbutazone and 2-phenyl-1,3-indandione, catalyze the polymerization of glycol methacrylate monomers. GMA-cyclic diketone carbon acid monomer mixtures incorporating imidazole polymerize smoothly without obvious exothermicity at temperatures ranging from ambient to -5 C without the use of ultraviolet light. The only equipment required for this embedding technique is a refrigerator with a freezing compartment which can maintain temperatures of -15 C. A recipe consisting of 5 ml glycol methacrylate (2-hydroxyethyl methacrylate), 0.8 ml 1-pentanol, 16 mg imidazole, and 30 mg monophenylbutazone is recommended for general use. The use of dicyclopentyl methacrylate-glycol methacrylate comonomer mixtures incorporating cyclic ketone catalysts is advocated, as blends of these monomers have low basophilia, and tissues embedded in these matrices stain sharply and brilliantly. It is hypothesized that the driving force for the cyclic ketone-mediated polymerization of glycol methacrylate under basic conditions is furnished by the lysis of cyclic ketone carbon acid peroxides.     

The ultrastructure of the oyster brown cell,a cell with a fenestrated plasma membrane

Summary The oyster brown cell, a connective tissue cell of uncertain function and affinity, was characterized in the electron microscope by (1) the presence of large cytoplasmic granules, (2) fenestrations of the plasma membrane, and (3) an extensive tubular network originating in, or emptying into, the plasma membrane fenestrations. The brown cell did not appear to be a cell involved in glycogen storage or in the manufacture of exportable protein. The extensive tubular network and the membrane slits suggested that the brown cell may have been involved in the processing of biological fluids.This work was supported in part by Public Health Service Contract No. 5 To 1 ES00038-02, Health Sciences Advancement Award No. RR06138, and Tumor Biology Training Grant, NIH CA 05245.We wish to thank Miss Grete Nilsen for her expert technical assistance and Mr. Bob Munn for his help in the use of the electron microscope and for proof reading our MS. Our appreciation is also extended to Dr. J. Luft, Dr. A. K. Sparks, Miss P. Phelps, Mr. M. DeVault, and to the personnel of the Johnson Oyster Company, Inverness.