Progression of the transformed phenotype in clonal lines of Abelson virus-infected lymphocytes.

Some molecular changes which correlate with the tumorigenic progression of neoplastic cells can best be studied with in vitro cell lines that represent each stage in the progression. Lymphoid cells infected by Abelson murine leukemia virus exhibit a wide range of growth potential in vitro and in vivo. Uncloned populations that are poorly oncogenic early after infection become progressively more oncogenic with successive passages of the cells in culture. In such mass cultures, it is difficult to evaluate whether a rare subpopulation of highly oncogenic cells becomes dominant in the culture or whether the individual cells progress in oncogenic phenotype. To examine this latter possibility, Abelson virus-infected lymphoid cells were cloned by limiting-dilution culture 10 days postinfection. We isolated two clones that grew poorly in agar, required feeder layers of adherent bone marrow cells for growth in liquid culture, and were extremely slow to form tumors in syngeneic animals. Both clones, after passage in the presence of adherent feeder layers for 3 months, grew well in liquid and agar-containing cultures in the absence of feeder layers and formed tumors in animals at a rapid rate. The progression of these clonal cell lines to a more malignant growth phenotype occurred in the absence of detectable changes in the concentration, half-life, phosphorylation, in vitro kinase activity, or cell localization of the Abelson virus-encoded transforming protein. No change in the concentration or arrangement of integrated Abelson viral DNA sequences was detected in either clone. Thus, perhaps changes in the expression of cellular genes would appear to alter the growth properties of lymphoid cells after their initial transformation by Abelson virus. Such cellular changes could complement the activity of the Abelson virus transforming protein in producing the fully malignant growth phenotype.     

Immunological studies in tropical splenomegaly syndrome in Uganda

An immunological evaluation carried out in eight patients with the tropical splenomegaly syndrome showed no evidence of impairment in cellular or humoral immunity, though raised levels of macroglobulins were noted in four patients. Hence gross immunological deficiency cannot be associated with the intense lymphoreticular proliferation observed in this disorder.     

Micro Radiometric Method for Study of Acid-insoluble Materials in Monolayer Cell Cultures

A simple radiometric procedure for study of acid-insoluble products synthesized in monolayer cell cultures is described. Cell cultures were produced directly on the bottom surface of scintillation vials or on glass cover slips (8 X 30 mm). The cells were labeled and extracted; the radioactivity was determined while the cells remained affixed to the glass surface upon which they were grown. This procedure enabled rapid investigations of certain biosynthetic processes to be carried out by using many individual cell cultures. The method was applied to an investigation of (3)H-thymidine incorporation induced by vaccinia virus in a 5-bromodeoxyuridine-resistant cell line. (14)C-labeling was evaluated as an alternate procedure for cell quantitation.     

Mechanism of Antifungal Action of 2,4,5,6-Tetrachloroisophthalonitrile

Studies of the toxicity of 2,4,5,6-tetrachloroisophthalonitrile (TCIN) to cells of Saccharomyces pastorianus and Neurospora crassa showed that 2 to 4 μg/ml of the toxicant were required to inhibit growth. Several thiol compounds reversed toxicity to growth. Glucose oxidation was severely impaired in treated cells of both test organisms. The toxicant at 2 or 4 μg/ml markedly reduced soluble thiol content of these cells. Bound thiol content was less affected in S. pastorianus cells than soluble thiol content. Uptake of toxicant by yeast cells was accompanied by formation of derivatives, some of which resembled those formed by reaction of glutathione with TCIN in vitro. Coenzyme A, glutathione, and 2-mercaptoethanol readily formed derivatives with TCIN in vitro. The nature of these derivatives was studied using 2-mercaptoethanol products as model substituents. Four derivatives were formed with 2-mercaptoethanol each with similar functional groups but showing dissimilar degrees of mobility during silica gel chromatography. Evidence indicated that these are derivatives of TCIN in which 1 to 4 of the halogens has been substituted by 2-mercaptoethanol. The mechanism of fungicidal action of TCIN is attributed to thiol inactivation.     

Uraninschwellen des Protoplasmas der BraunalgeStypocaulon scoparium

Ohne Zusammenfassung     

A physical map including a new class I gene (cda12) of the human major histocompatibility complex (A2/B13 haplotype) derived from a monosomy 6 mutant cell line

To avoid interpretative problems due to restriction fragment length polymorphisms, the monosomy 6 mutant cell line BM19.7 was employed to establish a molecular map of the human major histocompatibility (HLA) complex in the A2,B13,Bw4,DRw6,DRw52,DQw1,DPw2 haplotype. Results were obtained mainly by field-inversion gel electrophoresis and Southern blotting techniques. The map extends to 4800 kb and includes the HLA complex with a length of 4200 kb. Five HTF islands could be positioned on the map. The class I region has a size of about 2000 kb and includes nonclassical HLA class I genes, some of which must be localized within 200 kb telomeric of HLA-A. A new class I gene, cda12, distinct from HLA-A, HLA-B, or HLA-C, has been localized within 50 kb from HLA-A. The class I region contains a gap of about 500 kb, just telomeric of HLA-C, in which further class I genes could not be detected. The class II region has a size of 1000 kb, which is separated from the class I region by about 1200 kb. The 5' end of the HLA-B gene is situated centromeric, giving an orientation opposite to that of the TNFA and TNFB loci. The estimated length of the HLA complex correlates well with its size determined cytogenetically using mutant cell lines with interstitial deletions.     

Chromosomal localization of ARSB,the gene for human N-acetylgalactosamine-4-sulphatase

Summary A deficiency of N-acetylgalactosamine-4-sulphatase (G4S, gene symbol ARSB), results in the accumulation of undegraded substrate and the lysosomal storage disorder, Maroteaux-Lamy syndrome (mucopolysaccharidosis type VI). In situ hybridization using an ³H-labelled human G4S genomic DNA fragment to human metaphase chromosomes localized ARSB to chromosome 5q13–5q14. This location is consistent with, an refines, previous chromosomal assignments based on the expression of human G4S in somatic cell hybrids.     

Ocean current variability and the spawning season of Hawaiian reef fishes

Synopsis The spawning patterns of four Hawaiian reef fishes with similar reproductive habits, but different biogeographic distributions were studied from September 1980 to October 1981. Two species are Hawaiian endemics [Centropyge potteri (Pomacanthidae) and Chaetodon multicinctus (Chaetodontidae)] and the other two have pan-tropical Pacific distributions [Ctenochaetus strigosus and Zebrasoma flavescens (Acanthuridae)]. All showed increased spawning activity from January to July, the prevalent pattern among a majority of coastal marine fishes in Hawaii. Environmental correlatives to the period of peak reproduction include cycles of (a) daylight length and temperature which probably function as proximate cues and (b) seasonal variations in ocean current patterns which may ultimately affect survival of larvae and dispersal. Peak reproduction takes place during months when (1) mesoscale eddies most likely occur, and (2) the probability is greatest of drifting objects remaining near the islands.