Ronald L. Taylor

Observations on the phenoloxidase system in the haemolymph of the cockroach Leucophaea maderae

Abstract Phenoloxidase in fresh haemolymph of the cockroach Leucophaea maderae showed no significant activity with dopa substrate (2,4-dihydroxy-phenylalanine), whereas that in acetone-powder extracts of the haemolymph did. It was also found that incubation of fresh haemolymph with acetone, certain alcohols, or with trypsin or α-chymotrypsin served to induce enzyme activity. The enzyme catalysed the oxidation of other diphenols besides dopa but not the monophenol tyrosine, even in the presence of a catalytic amount of dopa. Electrophoresis of fresh haemolymph showed three protein bands, while dialysed haemolymph showed only two protein bands and diminished phenoloxidase activity. Other experiments included the histochemical localization of phenoloxidase within the blood cells, analysis of the amino acid composition of the blood of normal and injured cockroaches, determination of the Michaelis constants for dopa, and determination of the effects of temperature and u.v. radiation on the phenoloxidase system. The significance of the results of the above experiments is discussed.

Formation of tumorlike lesions in the cockroach Leucophaea maderae after nerve severance

Abstract Severance of the recurrent nerve in the Madeira cockroach, Leucophaea maderae, induced the formation of lesions in the alimentary canal—lesions which were similar to those obtained by earlier investigators using the same technique on the same animal. Whereas these have been generally considered to be neoplasms, they are interpreted here to be inflammatory lesions. Recurrent nerve severance prevents passage of food from the crop to the midgut and, since feeding apparently is not inhibited, results in an abnormally engorged foregut. The hypothesis is made that the resultant stagnation throughout the alimentary canal provided ideal circumstances for the proliferation of certain microorganisms—microorganisms which infected the gut epithelium, which was stressed and possibly injured by the overdistension and/or accumulated secretions. Regardless of the involvement of micro-organisms (which were involved in many but apparently not all lesions), blood cells infiltrated the injured areas and established inflammatory foci. The presence of blood cells in the lesions was established both by light and electron microscopy. Additional observations are made on the histology and fine structure of the lesions and on other possible mechanisms by which denervation may induce tumorlike lesions.

Haplosporidium tumefacientis sp. n., the etiologic agent of a disease of the California sea mussel, Mytilus californianus Conrad☆

Abstract Examination of large numbers of two species of marine mussels—the California sea mussel, Mytilus californianus Conrad, and the Bay mussel, Mytilus edulis Linnaeus—revealed the presence of tumefactions (swellings) in the digestive gland (“liver”) and kidney of the California mussel. Microscopic examination demonstrated that a haplosporidian parasite was responsible for the diseased condition. The parasite was found to be an undescribed species of Haplosporidium and was therefore described and named Haplosporidium tumefacientis sp. n. It is the first member of the genus (as recently redefined) reported from a mollusk. Certain histochemical reactions of the parasite are described as well as the negative results from culture and infection experiments.

A fibrous banded structure in a crop lesion of the cockroach, Leucophaea maderae.

Fibrous banded structures of uncertain significance were observed intracellularly in crop cells of the cockroach Leucophaea maderae Fabricius. They were seen exclusively in abnormal muscle cells after severance of the recurrent nerve. In sections, the structures were generally fusiform in shape and varied in length from 0.6 to 2.2 μ and in width (widest point) from 0.2 to 0.5 μ . They consisted of alternating light and dark bands with a major periodicity of 1200–1450 A; the light bands were usually two to four times thicker than the dark bands. The fibrous banded structures found in the cockroach were compared with structures of similar morphology and with roughly comparable periodicites which have been described from a variety of tissues by others. The possible collagenous nature of these fibers was discussed.

Tissue damage induced by an oxyuroid nematode, Leidynema sp., in the hindgut of the Madeira cockroach, Leucophaea maderae☆

Abstract An oxyuroid nematode ( Leidynema ) was found to be causally related to a hindgut lesion in the Maderia cockroach, Leucophaea maderae . As oxyuroids are generally believed to live commensally within the hindgut of their hosts and not to cause intestinal damage, the lesion is described in some detail. The lesion apparently resulted from the damaged tissue eliciting a blood cell response and was not a defense reaction directed against the nematode. Additional observations are made and discussed concerning (1) the hemocytic nature of the lesion, (2) the lack of involvement of the epithelial cells, (3) the apparent health of the animal in spite of the continuity between gut lumen and hemolymph, and (4) the formation of “melanin” by blood cells in response to diverse stimuli.

The formation of tumorlike lesions in the cockroach Leucophaea maderae after anal blockage

Abstract Sealing the anus of the Madeira cockroach, Leucophaea maderae , prevented the elimination of wastes and resulted in an abnormally engorged gut. These stressful conditions induced the formation of inflammatory lessions of the alimentary canal—lesions which were not unlike those resulting from severance of the recurrent nerve. These results support the hypothesis that any treatment—nerve severance, anal blockage, etc.—that causes the accumulation of toxic amounts of secretions or waste products, and/or the tearing of the gut wall due to engorgement, and/or the proliferation of pathogenic organisms may induce the formation of inflammatory lesions of the gut wall.

The inflammatory response of the cockroach Leucophaea maderae to injections of normal and abnormal tissues

Abstract In order to test for the existence of an infectious factor in insect tumorlike lesions, groups of the Madeira cockroach, Leucophaea maderae , were injected intraspecifically with a variety of extracts prepared from animals harboring tumorlike lesions. Such lesions were subsequently found in the injected roaches but not at incidences significantly higher than in control groups. However, lesions classed as “pigmented masses” did occur in large numbers in some of the injected groups at statistically significant incidences. Since these lesions also occurred at a similar incidence in roaches injected with an extract prepared from normal roaches, and since they were essentially encapsulation reactions, there was no evidence to support the existence of an infectious factor. It appears that the lesions resulted simply from the hemocytic encapsulation of proteinaceous particles from the donor tissue, the incidence being related to the quantity of tissue material injected.

Digestive gland and integument lesions associated with malnutrition in a ghost shrimp, Callianassa affinis☆

Abstract A ghost shrimp, Callianassa affinis , maintained alone in an aerated seawater aquarium, refused food for 2 months. During this time it developed grossly visible lesions in the integument, became progressively more listless, and finally died. Histologic study of selected tissues revealed an abnormal accumulation of fat and a marked blood-cell response in the digestive gland (“liver”). The integument lesions consisted primarily of fragmented cuticle underlain by blood cells in various stages of necrosis. Blood cells further from the surface were healthier and were frequently seen in whorls of one or more cell layers around pigmented material. A likely cause of death was digestive gland failure due to a lack of dietary lipotropic factors that, in mammals at least, normally prevent excessive fat accumulation in the liver. The integument lesions may represent pathological changes that are part of a syndrome of malnutrition.

Partial-pupae of the greater wax moth, Galleria mellonella (Linnaeus)☆

Under laboratory culture, individuals of the greater wax moth, Galleria mellonella (Linnaeus), are occasionally observed which only partially complete the larval-pupal transformation and then die. In form they appear as larvae, however, a large portion of the body is hard and dark and thereby appears pupal. Histological sections clearly reveal such individuals to be in a late pharate stage. The last larval cuticle is equally digested over both “larval” and “pupal” areas and appears fully prepared for ecdysis. The new (pupal) cuticle in the hard and dark areas appears normal. The main abnormality is in the light-colored areas where the new cuticle appears to have been partially laid down and then its development arrested. The induction mechanism of G. mellonella partial-pupae is unknown, though it appears to be an injury-induced phenomenon.

The use of the tissue adhesive, methyl-2-cyanoacrylate monomer, in invertebrate surgery☆

Abstract The tissue adhesive, methyl-2-cyanoacrylate monomer, which heretofore has been used exclusively in experimental and clinical studies on higher animals and man, was demonstrated to be of value in sealing surface incisions of cockroaches. In contrast to a beeswax sealant, or no sealant at all, the tissue adhesive provided more favorable conditions for normal repair and wound-healing processes. It would seem to have unexplored possibilities in other research involving invertebrates.