In vitro isolation of stable rat sarcoma viruses

A Sprague-Dawley (SD-1) rat embryo culture, at low passage level, released an endogenous ecotropic type C virus (SD-RaLV) and after about 20 further passages it underwent spontaneous transformation. The SD-RaLV, released from the transformed cells, did not cause rapid transformation of other rat embryo cells. However, when the transformed cells were repeatedly cocultivated with three different chemically transformed and serially transplanted rat tumor cell lines (sarcoma, carcinoma, and hepatoma), rapidly fibroblast-transforming "sarcoma" viruses (RaSV) were recovered after each attempt. RaSV was not recovered from one of these tumor cell lines before transplantation, nor could focus-forming virus be rescued from these same tumor cells by cocultivation with other cells releasing heterologous type C viruses. Foci were induced on normal rat kidney and several other rat embryo cell strains within 7-15 days and both productive and nonproductive NRK clones were derived. The productive clones were positive for rat specific p30 antigen and the RaSVs released were serially transmitted to other rat embryo cells. RaSV genome was rescued from the nonproductive clones by superinfection with SD-RaLV, wild rat type C virus, and several heterologous type C viruses. These observations appear to represent naturally occurring transformation-specific (src) genes being recovered in vitro in the form of stable "sarcoma" viruses. These viruses differ from the Kirsten and Harvey strains of murine sarcoma virus in that they apparently contain no MuLV sequences and are of purely rat origin.

Establishment of a cell line with associated Epstein-Barr-like virus from a leukemic orangutan

An Epstein-Barr virus like herpesvirus has been isolated from a lymphoid cell line derived from an orangutan with spontaneous myelomonocytic leukemia. Herpesvirus has not previously been isolated from this species of higher ape.

Human bladder carcinoma: characterization of two new tumor cell lines and search for tumor viruses

Two newly established human bladder carcinoma cell lines, designated HT-1197 and HT-1376, were characterized. Cells of both cultures exhibited fine structural microvilli and tonofibrils indicative of their epithelial origin. In addition, desmosomes were also present in HT-1197. Marker chromosomes present in HT-1197 and HT-1376 distinguished these from each other and from other known human tumor cell lines. Both cultures grew in soft agar, induced fibrinolytic activity, and were tumorigenic in mice and hamsters. No type C or other virus expression was detected in these cell lines nor in other human urothelial tumors tested.

Characterization of purely ecotropic and amphotropic naturally occurring wild mouse leukemia viruses

Two new strains of murine leukemia virus, one (strain 4996) purely ecotropic and the other (strain 1313) purely amphotropic, were isolated from spontaneous lymphomas in aged wild mice (Mus musculus). The 4996 virus is the first wild mouse field isolate which consists solely of ecotropic virus without the concomitant presence of amphotropic virus. The 1313 isolate is distinct in host range from seven other previously described wild mouse amphotropic isolates and is also the only murine leukemia virus shown to replicate in chicken cells.

Amphotropic host range of naturally occuring wild mouse leukemia viruses

Seven murine leukemia virus field isolates (uncloned) from wild mice (Musmusculus) of four widely separated areas in southern California show an unusually wide in vitro host range. They replicate well in human, feline, canine, guinea pig, rabbit, rat, and mouse cells, whereas bovine, hamster, and avian cells are resistant. Since this host range includes that of both mouse tropic (ecotropic) and xenotropic murine leukemia viruses, they are designated as "amphotropic". No purely xenotropic virus component is detectable in these field isolates. They may represent the "wild" or ancestral viruses from which the ecotropic and xenotrophic murine leukemia virus strains of laboratory mice have been derived.

Spontaneous release of endogenous ecotropic type C virus from rat embryo cultures

Type C viruses were isolated from embryo cultures of two different rat strains, Sprague-Dawley and Fischer. Both viruses (termed rat leukemia virus, RaLV) were released spontaneously from rat embryo cells, have a density of 1.14 to 1.15 g/cm(3) based on equilibrium sedimentation in sucrose gradients, contain 60-70S RNA, RNA-directed DNA polymerase, and rat type C virus-specific 30,000 molecular-weight-protein determinants. Molecular hybridization studies using the Sprague-Dawley RaLV 60-70S RNA show that the virus-specific nucleotide sequences are present in the DNA of rat embryos. Both Sprague-Dawley and Fischer RaLV can rescue the murine sarcoma virus genome from Kirsten murine sarcoma virus-transformed nonproducer cells and are neutralized by antisera to the RPL strain of RaLV. In contrast to previous RaLV's, these viruses propagate in their own cells of origin as well as in cells of heterologous rat strains.

Acceleration of transformation of rat embryo cells by rat type C virus

Sprague-Dawley and Fischer rat embryo cells became spontaneously transformed about 20 passages after release of endogenous ecotropic type C virus (SD-RaLV and F-RaLV). The virus-producing transformed cells showed loss of contact inhibition, increased growth rate, and tumorigenicity in vivo. Exogenous infection of other Fischer rat embryo cultures in early passage with SD-RaLV and F-RaLV markedly accelerated their rates of transformation.

Morphological transformation of mouse and rat embryo cells in vitro by an agent from S37 ascites tumour

When normal rat and mouse embryo cells were treated with a cell free extract of S37 ascites tumour, morphological transformations occurred in both. The transformed cells readily induced lymphosarcoma-type tumours in the mice inoculated when newborn or young adults (8-12 weeks old), but not so readily in rats.Various tests carried out with these cells strongly indicate the presence of an oncogenic and transmissible agent in S37 ascites tumour. This agent appears to be related to mouse sarcoma virus isolated from animals with Moloney leukaemia but differs in only producing characteristic lymphosarcoma-type tumours.

On some interesting nematode parasites of fish from Pakistan

Two interesting and unusual Spiruroid parasites have been reported from the intestines of marine fish. These are referred to the new genera and species, namely, Bulbocephalus inglisi and Cestocephalus serratus. The former is characterized by a globular head and the muscular oesophagus has two bulbs in its most anterior part. The glandular portion of this oesophagus is 20–25 times as long as the muscular part. The diganosis of Cestocephalus serratus is mainly based on the presence of an oblong head which is covered anteriorly by lobe-like structures in the manner of bothridia in some Cestodes. A new subfamily (family Spiruridae) has been proposed to accommodate Bulbocephalus gen.nov. The family or subfamily diagnosis of Cestocephalus gen.nov. has been restricted at present due to the paucity of material.

The writer wishes to express her gratitude to Professor J. J. C. Buckley for his interest throughout this work.

Some parasitic nematodes from the Cameroons (W. Africa)

1. A new species of Oxysomatium (O. minutum) is described from a frog Rana ptychadena mascareniensis.

2. The crested chameleon (C.? cristatus) and Bufo supercilioris are reported as new species of hosts recorded for Africana africana (Gendre, 1909) Travassos, 1920.

3. Strongyluris brevicandata Müller, 1894 and Thelandros sp. are reported from Agama agama agama.

4. Amplicaecum involutum (Gedoelst, 1916) Yorke and Maplestone, 1926 is redescribed from Chamaeleon (?) cristatus which is regarded as a new host record and A. pesteri n.sp. from Bufo superciloris is described to be the smallest species of this genus.