Isolation of three collagenous components of probable basement membrane origin from several tissues

Fractionation of pepsin-solubilized collagens from several human tissues has shown that substantial quantities of collagen-like protein remain in solution under conditions leading to the precipitation of Type I, II, and III collagens. Characterization of the more soluble collagens has led to the isolation of three unique collagenous components each of which exhibit compositional features indicative of their origin from basement membranes. One of these has an apparent molecular weight of 55,000 daltons and appears to originate in endothelial basement membranes. The other two components (A chain and B chain) are somewhat larger than collagen α chains and appear to be derived from the collagen of epithelial and smooth muscle basement membranes, respectively.     

Aberrant metabolism of matrix components in neonatal fibular cartilage of brachypod (bpH) mice.

Collagen and the acid mucopolysaccharides (AMPS) were studied in the fibular cartilage of brachypod ($\text{bp}{}^{\mathrm{<mtext>H</mtext>}}\text{bp}{}^{\mathrm{<mtext>H</mtext>}}$) and normal (+/+) newborn mice. At this age the mutant fibulae are still cartilaginous and are comprised of closely packed chondrocytes, homogenous in size and shape.Brachypod fibular chondrocytes synthesized a normal cartilage-type collagen molecule but at half the normal rate. Incorporation of tryptophan indicated this was related to a depression of general protein synthesis rather than being specific for collagen. Pulse-chase experiments showed that collagen degradation over a 3-day culture period was 15% slower than normal thus accounting for the higher collagen content in mutant fibulae.AMPS synthesis in normals and brachypods was nearly equal; however, in pulse-chase experiments radioactivity could not be chased out of the mutant tissue. The failure of AMPS degradation also accounted for greater than normal quantity of AMPS in the mutant cartilage. Characterization of the AMPS led to the discovery of a small population of unsulfated chondroitin molecules in normal, but not brachypod cartilage. The importance of a coordinated metabolism of matrix products during limb development is discussed.     

Toxicity of zinc to schistosoma Mansoni Cercariae in a Chemically Defined Water Medium

Time-until-death studies were run on cercariae of Schistosoma mansoni in 15 concentrations of zinc (from zinc sulfate) ranging from 57.6 ppm to 1 ppb. A chemically defined water medium was used for the dilution and control medium, and a partially enclosed slide chamber was perfected for the detailed observation of test cercariae. In concentrations of less than 57.6 ppm, zinc was found to have little lethal effect on cercariae during that period in which these larvae were most likely to be infective (0–6 hours) after emergence. Zinc concentration of 1 ppb killed all test cercariae within 46 hours at 21–22°C.At the highest concentration tested, 57.6 ppm zinc immobilized all test organisms within 6 hours at 21–2°C. The average time for 100 percent mortality for the control was 49 hours. The cercaricidal effects of zinc were shown to be insignificant in concentrations that would not be detrimental to other aquatic organisms.     

The effects of dogfish MSH''s and of corticotrophin-like intermediate lobe peptides (CLIP''s) on avoidance behavior in rats

Recently purified melanocyte-stimulating hormones (MSH's) from dogfish pituitary tissue were tested on extinction of a conditioned avoidance response (CAR). Corticotrophin like intermediate lobe peptides (CLIP's) from dogfish and porcine origin were tested for an effect on avoidance extinction as well. All peptides appeared to delay extinction of the CAR.The results suggest that the pituitary contains various peptides which influence adaptive behavior. The observation that MSH is more potent in delaying extinction of the CAR then CLIP leads to the conclusion that the behavioral active sequence of the ACTH molecules is located in the N terminal part rather than in the C terminal part of the polypetide.     

The properties of cinnamic acid 4-hydroxylase of aged swede root disks

The cinnamic acid 4-hydroxylase of swede root disks is a microsomal enzyme with a specific requirement for NADPH and cinnamic acid. The enzyme is inhib     

Componental analysis of the ocellar electroretinogram of the locust, Schistocerca gregaria

Ruck's componental analysis of the ocellar electroretinogram (ERG) has been reappraised using techniques of signal averaging and waveform subtraction. Components (1), (3), and (4) can readily be isolated in the locust ocellus but component (2) as recorded in the locust ocellus is probably an artefact. Component (1), produced by the receptor cells, only contributes significantly to the total ERG at higher light intensities and it is this contribution which changes most with the degree of light and dark adaptation employed in these experiments. Component (3), the response of the second-order neurones, indicates that the majority of second-order neurones hyperpolarize on illumination of the ocellus. Component (4), the afferent activity of the second-order cells, indicates that more than one afferent axon is involved in the production of off spikes in the locust ocellus.