Ross F. Nigrelli

Antimicrobial substances from sponges.

A marine biologist may look upon the phenomenon of antibiosis, with its broadest implications, as one involved in the limitation or exclusion of certain forms of life by diffusible substances produced by other living species. In the vast capacity of the ocean such materials set up activity gradients, sometimes against each other, and regulate by their presence the entire chain of dependent events (Nigrelli, 1958). This antibiosis may extend its effects to the higher forms, such as many-celled invertebrates and fish, as in the case of some toxic substances, for example, holothurin, elaborated by the sea cucumber (Nigrelli, 1952). Antibiosis becomes of particular interest when materials exhibiting antimicrobial activity originate in the bodies of organisms adapted to live as filter feeders and to act as strainers to myriads of bacteria and microplankton. Long regarded as plantlike in nature, they finally attained their status as an animal phylum in 1835, but retained a rather unique position that sets them apart from other multicellular animals because of their structural and developmental peculiarities. With the exception of one family, sponges are marine, and their natural food consists chiefly of minute organisms and organic detritus. There is also some speculation that they may utilize dissolved nutrients. In the absence of a digestive cavity, digestion is intracellular, and it takes place in the specialized collar cells, the choanocytes, and the amebocytes. Some of the products of digestion are stored as glycogen, fats, glycoproteins, and lipoproteins in amebocytes, and are then known as thesocytes. The excretory products are usually complex nitrogen bases, such as agmatine, a guanidine derivative. In view of their sessile habit and porous structure, sponges are frequently inhabited by a large variety of animals, including fishes, echinoderms, crustaceans, annelids, molluscs, bryozoans, coelenterates, and by other sponges. The interrelationships of these organisms are not known, but many of the associations are no doubt accidental, although commensalism, mutualism, and inquilinism have been established in a few instances (Hyman, 1940). Blue-green algae and cryptomonads in sponges have also been described (Lami, 1941, 1942). In so far as is known, sponges are not generally used as food by fishes and only rarely by other animals, such as nudibranchs (Abeloos and Abeloos, 1932). The reason for this has not been determined, but it may be related to the fact that many sponges contain noxious substances. Sponges are also apparently resistant to the action of the multitude of microorganisms that enter their complex system of canals and cavities (spongocoels) and become part of the diet. Sponges, however, are highly sensitive to the reduction of available oxygen; under such conditions the animals change color and die within a relatively short time, decomposition setting in almost immediately. Gas exchanges have been studied by Hyman (1916, 1925), Houget et al. (1927), and von Ledebur (1939).

VIRUS AND TUMORS IN FISHES

Diseases such as fish pox, lymphocystis and certain papillomatous growths have long been considered to be caused by viruses. The evidence that viruses are the etiological agents in these growths is based primarily on the successive development of the lesions in different individuals of the same species (host specificity), the seasonal appearance and disappearance of the growths, the presence of inclusions in the diseased cells, and on other pathological manifestations. In some instances, experimental transmission to healthy fish has been successfully accomplished, but no definite isolation of the agent by filtration, ultracentrifugation or other recognized means has ever been made. The evidence for including these diseases in the virus category is thus purely circumstantial.

A new method for obtaining barnacle cement in the liquid state for polymerization studies

A new method for collecting barnacle cement in the liquid state is described. This permits studies on the transformation of cement from liquid to solid states not heretofore possible. Preliminary analyses showed that polymerization, i.e., the in vitro change from a clear liquid to an opaque solid mass is not affected by temperatures ranging from-10° to 45°C, by diluting with distilled water up to two-fold, or by treating with selective enzymes; some chemical inhibitors induce the formation of a white precipitate, possibly indicating denaturation of the protein. It is concluded that the liquid cement contains all the necessary components for self-assembly, progressively changing from a clear liquid to an opaque rubbery insoluble mass. The polymerization process is time-dependent and requires no exogenous catalyst. A mechanism that may be involved in the adhesion process of the barnacle is suggested.

Tumors and Other Atypical Cell Growths in Temperate Freshwater Fishes of North America

Abstract This report deals with any abnormal tissue, the growth of which exceeds and is uncoordinated with that of the normal tissue. Included in this category are the neoplasia (benign and cancerous), non-functional hyperplasias, cellular hypertrophy as well as other atypical cell growths. The following topics are discussed with special reference to the temperate freshwater fishes of North America: papillomas, hyperplastic epidermal diseases (including fish pox), parasitic and neoplastic adenomas, carcinomas (incuding thyroid tumors), fibromas, fibro-sarcomas, myxomas, leiomyomas, rhabdomyomas, granulomas, lymphosarcomas, pigment-cell tumors, neurofibromas, neurilemmonas, hamartomas, and teratomas. The role of such factors as physical and chemical irritants, nutrition, endocrine dysfunction, heredity, embryonic disturbances, and such infectious agents as viruses, bacteria, mycotic organisms, and protozoans in the production of these abnormalities is given or suggested. With the exception of certain tumor...

Echinoderm toxins—I. Some biochemical and physiological properties of toxins from several species of Asteroidea

Water soluble toxic fractions were isolated from five species of sea stars, Pycnopodia helianthoides, Asterias forbesi, Patiria miniata, Pisaster ochraceous, and Pisaster brevispinus. Each toxin is a saponin which on hydrolysis yields insoluble aglycones, and four similar sugars as determined by paper chromatography. They give a negative Legal test and a positive sulfate test. In vivo physiological tests, with saponins in solution, caused death in Fundulus heteroclitus (Linnaeus) over a wide concentration range. These compounds, in low concentrations, induced hematological changes in F. heteroclitus. In addition, solutions of the saponins caused hemolysis of human erythrocytes in vitro. While the sugars may be similar or even identical in the different saponins, the aglycone portion of each probably differs. This may be concluded from the graded series of responses seen in the physiological studies. Indications are that the mode of action of the saponins is due to changes in membrane permeability.

SOME PHARMACOLOGIC PROPERTIES OF HOLOTHURIN A, A GLYCOSIDIC MIXTURE FROM THE SEA CUCURMBER

Interest in the toxic principle holothurin, derived from the sea cucumber dctinopyga agassizi Selenka, stems largely from recent observations (Nigrelli, 1952; Nigrelli and Zahl, 1952; Nigrelli et al., 1955; Chanley et al., 1955) employing partially purified preparations that pointed to an antitumorous activity as well as a spectrum of other pharmacological actions. Among the latter, sufficient evidence of action against nerves was found to warrant the present study of the crystalline material on the propagated action potential in desheathed bullfrog sciatic nerve, on single nerve-fiber preparations from the frog, and on the rat nerve-diaphragm preparation.

Some biological characteristics of holothurin.

Summary Holothurin, a thermostable toxic factor derived from the Organ of Cuvier of the Caribbean sea cucumber, acts as a powerful poison to several protozoa grown in pure culture. The same material applied in vitro to cells of mouse Sarcoma 180 markedly reduces their growth potency.

BABESIOSOMA GEN. NOV. AND OTHER BABESIOIDS IN ERYTHROCYTES OF COLD‐BLOODED VERTEBRATES

The history of our knowledge of blood-inhabiting protozoans is intimately connected with their discovery in cold-blooded vertebrates. Numerous important “firsts” have originated from the interest of the early investigators in parasites of fish, amphibians, and aquatic reptiles. Thus, the first observation of a blood parasite was that of Valentin (1841), who saw trypanosomes in trout. Mammalian trypanosomes were not discovered until 25 to 30 years later. Also, the first blood-inhabiting sporozoan in a poikilothermic vertebrate was reported in 1871 by Lankester. This parasite was later designated Dactylosoma ranarum, now recognized as a nonpigmented haemosporidian. This finding, together with the discovery of the malarial parasite by Laveran (1880), is credited with laying the foundation to our knowledge of the Haemosporidia. It apparently excited such interest in the early 20th century that, in the words of Minchin (1903), the study of Sporozoa was to assume in the near future a position of importance scarcely secondary to that held by the science of bacteriology.

Coccomyxa (Myxosporea: Bivalvulida) and Septemcapsula (Myxosporea: Multivalvulida) Infections, the Possible Cause of Death of Coral Catfish Plotosus anguillaris in Captivity

Abstract Coral catfish (eel-catfish) Plotosus anguillaris were found to be infected with two species of myxosporean parasites. The single-capsuled organism Coccomyxa hoffmani, a new species, was found encysted in the cartilage of the gill filaments and arches; the other was a multivalvulid myxosporean parasite, Septemcapsula sp., consisting of heptagonal and hexagonal forms of spores that were free in the endolymph of the utriculus and in pseudocysts in the brain. It is our opinion that a whirling movement and eventual death of the fish were the result of neuronal infection by the multivalvulid myxosporean. The morphologic and morphometric characteristics of the two species of myxosporea are described, with a possible explanation for coexisting heptagonal and hexagonal spores of the Septemcapsula sp. The histopathology associated with the infections is also described.

4-Amino Pteroylglutamic Acid (Aminopterin), Pteroylglutamic (Folic) Acid, and Response of Frogs, Rana clamitans, to Estrogens.

Summary 4-amino pteroylglutamic acid (aminopterin) markedly decreased, whereas, folic acid increased the response of the oviducts of newly metamorphosed female frogs (Rana clamitans) to estradiol. The aminopterin effect could not be reversed by folic acid in ratios as high as 100:1 of folic acid to aminopterin.