Biomedical subjects
Publications and source records attributed to C Vago.
ADNA virus was purified from the salivary gland affected by a large proliferation in the Diptera Merodon equestris. Structure, nucleic acid as well as development and intracellular cycle of the virus have been characterized.
In parenchyme cells of the parasitic Plathelminthe Diplectanum aequans virus-like cytoplasmic particles were observed. Their formation is noted in virogenic areas and they are often gathered in regular geometric arrangements. The infected cells show important lesions.
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Intracellular bacteria (Rickettsia) are found in the Monogenean Euzetrema knoepffleri, vesicular endoparasite of the Amphibian Euproctus montanus (Urodela). In some conditions, they cause cytoplasmic damage in the host tissues, which demonstrates their pathogenicity. These bacteria are present during all the stages of the life-cycle of E. knoepffleri. Their transmission from one generation to the next occurs through the gametes.
Cell cultures of Lymantria dispar (Lepidoptera) have been successfully infected with the Entomopoxvirus of Amsacta Moorei (Lepidoptera). The different steps of viral morphogenesis and pathogenesis have been precisely detailed by light and electron microscopy of infected cells.
The "S" crabe virus recently isolated from Macropipus depurator (Decapoda) has been purified and its nucleic acid has been recognized as a DNA. The visualization of the structure and of several phases of the cycle of the virus permits to situate this virus near the Bunyavirus and Paramyxovirus groups.
Critical analysis of the present status of invertebrate oncology through an appreciation of data relative to the various origins of tumors : spontaneous formations, cell proliferations induced by viruses, so-called hereditary tumors, effects of injuries induced by carcinogenic agents, irradiations or hormones on the formation of neoplasms in invertebrates. Attempts are made to interpret these data as compared with those obtained in medical and veterinary oncology. The possible direction of studies on invertebrates towards comparative oncology is considered, emphasizing the great usefulness for the medical research to study the phylogenetic development of oncogenesis.
In vitro multiplication of a pathogenic intravacuolar mollicute-like procaryote from Melolontha melolontha L. was experimentally obtained in an insect cell line. The elongated and pleomorphic forms observed in the insect-host are reproduced in cell cultures. A third peculiar giant form is missing, showing that it does not play any role in the multiplication of the germ. The intrinsic potentialities of the germ are maintained during the successive passages, as proved by reinfection of the insect and by immunology. The original syndrome including the giant form is reproduced in the insect. The immunserum prepared from the wild germ isolated by density gradient is positive with the in vitro mollicute. The germs are intravacuolar, both in the cultured cells and in the insect host. Clearly the microorganism multiplies within the vacuoles. A cytopathogenic effect is noticed in the cultured cells overcrowed with germs. The germs become extracellular when they are released in the culture medium by disaggregation of the cell membranes. It seems that this work shows the first model of an intravacuolar mollicute-like procaryote experimentally multiplied in cultivated cells.
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Several characteristics of the intracellular cycle of Ricketsiella are elucidated, particularly regarding the envelope and the cytoplasm of dense forms (elementary bodies) as well as the proteinic inclusions of giant bodies. Cleavage faces have been displayed by freeze-etching, both at the level of cell wall and of plasma membrane. Their characteristics approach those of Gram-negative bacteria and are pratically common to all the stages. Appearance and significance of a polysaccharidic cement joining the outer membrane of the cell wall to the inner membrane (plasma membrane) in the dense forms are discussed. The arrangement of ribosomes and the structure of the nucleoid are described. A 6 nm lattice periodical structure is shown in the proteinic inclusion. Significance of these data for a classification of Rickettsiella and chlamydias is discussed.