Variegated translocation mosaicism in human skin fibroblast cultures.

The term "variegated translocation mosaicism" is used to describe the repeated occurrence, within cultures of human skin fibroblasts, of a multiplicity of chromosomal rearrangements. With respect to the frequencies of such cytogenetically aberrant clones we found that they (1) were not detectable in routine diagnostic skin fibroblast cultures from 29 subjects with a wide variety of indications for biopsy; (2) were not detectable during in vitro aging of diploid strains with four normal individuals; (3) could be detected after rescue from bacterial contamination of a culture from an otherwise normal diploid male; (4) occurred with high frequencies in independent cultures from another apparently normal subject; (5) occurred with high frequencies in multiple biopsies obtained at autopsy from a patient with Werner's syndrome who died of sepsis; (6) were of pseudodiploid nature; and (7) involved a different spectrum of chromosomes in different individuals. A consistent association with mycoplasma contamination could not be made.     

Conversion of covalently mercurated nucleic acids to tritiated and halogenated derivatives.

Mercurated nucleic acids are converted to the corresponding tritiated, brominated, and iodinated derivatives by treatment with sodium borotritiide, N-bromosuccinimide, and elemental iodine, respectively. All three reactions occur under mild conditions in neutral aqueous solutions. Mercury-halogen conversions are essentially quantitative at both the mono- and polynucleotide levels. Tritiation reactions also proceed efficiently with mononucleotides, although polymers undergo incomplete demercuration. In spite of the latter limitation , these reactions provide novel and efficient synthetic routes to radiolabeled nucleic acid derivatives.     

Angular sensitivity of light and dark adapted locust retinula cells

Summary Angular sensitivity functions for light and dark-adapted locust retinula cells have been measured. The angular sensitivity for light-adapted cells follows a Gaussian function but in the dark-adapted condition the measured function is broader than Gaussian at its base. Acceptance angles for light-adapted cells are 1.5°±0.2° (horizontal), 1.4°±0.1° (vertical) and for dark-adapted cells, 2.4°±0.5° (horizontal) and 2.5°±0.4° (vertical). These values are significantly smaller than those previously reported and show the locust eye to be closer to its theoretical limit of resolution than was previously indicated.The angular sensitivity of light-adapted cells agress well with the minimum resolvable stripe period reported by those authors refuting anomalous resolution.     

Pericarditis,pleural effusion,and pneumonitis with transient mitochondrial antibodies.

Four women with fever, arthromyalgias, pericarditis, pleural effusion, high erythrocyte sedimentation rates, and lymphopenia had mitochondrial antibodies in the serum in the absence of antinuclear antibody. Their illness lasted 5-12 weeks and the antibody test results became negative on remission. Absence of specific bacteriological findings, normal antistreptolysin O titres, resistance to antibiotics, and good response to steroids suggested that these cases represented a milder and less persistent form of the syndrome resembling systemic lupus erythematosus described by German authors.     

Diversity,migration routes,and worldwide population genetic structure of Lecanosticta acicola,the causal agent of brown spot needle blight

Lecanosticta acicola is a pine needle pathogen causing brown spot needle blight that results in premature needle shedding with considerable damage described in North America, Europe, and Asia. Microsatellite and mating type markers were used to study the population genetics, migration history, and reproduction mode of the pathogen, based on a collection of 650 isolates from 27 countries and 26 hosts across the range of L. acicola. The presence of L. acicola in Georgia was confirmed in this study. Migration analyses indicate there have been several introduction events from North America into Europe. However, some of the source populations still appear to remain unknown. The populations in Croatia and western Asia appear to originate from genetically similar populations in North America. Intercontinental movement of the pathogen was reflected in an identical haplotype occurring on two continents, in North America (Canada) and Europe (Germany). Several shared haplotypes between European populations further suggests more local pathogen movement between countries. Moreover, migration analyses indicate that the populations in northern Europe originate from more established populations in central Europe. Overall, the highest genetic diversity was observed in south‐eastern USA. In Europe, the highest diversity was observed in France, where the presence of both known pathogen lineages was recorded. Less than half of the observed populations contained mating types in equal proportions. Although there is evidence of some sexual reproduction taking place, the pathogen spreads predominantly asexually and through anthropogenic activity.