Hydroxylysine-deficient skin collagen in a patient with a form of the Ehlers-Danlos syndrome.

Two sibs with the Ehlers-Danlos syndrome, one of whom was shown to have hydroxylysine-deficient collagen, are described. In addition to the usual features of the Ehlers-Danlos syndrome (loose-jointedness and excessively stretchable, fragile, and bruisable skin), these patients had severe scoliosis and fragility of ocular tissues leading to rupture of the globe or retinal detachment. This combination of symptoms was tentatively classified as Ehlers-Danlos syndrome, Type VI.

A sex-linked defect in the cross-linking of collagen and elastin associated with the mottled locus in mice.

A genetic abnormality in collagen and elastin cross-linking resembling experimental lathyrism has been identified in mice. The defect is an X-linked trait, attributed to the mottled locus which also influences coat color. The affected mice have aneurysms of the aorta and its branches, weak skin, and bone deformities in a spectrum of severity varying with the alleles at the mottled locus.

Deficiency of the second component of complement associated with anaphylactoid purpura and presence of mycoplasma in the serum.

A patient, with deficiency of the second component of complement (C2), who has had anaphylactoid purpura for 12 years is described. Other classical complement components were present normally and the very markedly low total haemolytic complement activity was restored by the addition of functionally purified C2. Glycine-rich β-glycoprotein (GBG), measured antigenically, was reduced to about 50% of normal but the alternate pathway to complement activation was normal as judged by the platelet factor three activation test.

A 5'-Adenosine Monophosphate-Dependent Adenylate Cyclase and an Adenosine 3':5'-Cyclic Monophosphate-Dependent Adenosine Triphosphate Pyrophosphohydrolase in Dictyostelium discoideum.

Cell aggregation in Dictyostelium discoideum appears to involve the production and detection of 3':5'-cyclic AMP. Two pertinent catalytic activities have been studied in concentrates from D. discoideum purified 50- to 100-fold.

Parasexual recombination in Dictyostelium discoideum: selection of stable diploid heterozygotes and stable haploid segregants (clones-temperature sensitive-ploidy-fruiting bodies-spore-slime mold).

Haploid strains of Dictyostelium discoideum bearing temperature-sensitive mutations have been used to select stable diploid, heterozygotic clones, which arise at low frequency (about 10(-5)). Segregants arise from such diploids at low frequency (about 10(-3)). The diploids were heterozygous for resistance to cycloheximide and were phenotypically sensitive to the drug.