HYBRIDIZATION OF PANUS TIGRINUS AND LENTODIUM SQUAMULOSUM

Crosses between monokaryotic isolates of two strains of Lentodium squamulosum and one strain of Panus tigrinus showed complete intercompatibility. Hybrid fruits from crosses between monokaryotic isolates of L. squamulosum and P. tigrinus were uniformly like the P. tigrinus parent. Though both isolates of L. squamulosum showed considerable variability in form, merging toward P. tigrinus, L. squamulosum could always be distinguished from P. tigrinus from hand sections of the hymenophore. The significance of these results as they bear on the problem of inter-relationships between hymenomycetes and gasteromycetes is discussed. L. squamulosum is recognized as variety squamulosus of P. tigrinus.     

Unaltered metabolism of taurolithocholic acid with changes in composition of rat intestinal microflora

Changes in composition of both total aerobes and anaerobes of rat intestinal microflora do not appear to affect the metabolism of taurolithocholic acid.     

Flow distribution and cryoprotectant concentration in rabbit kidneys perfused with glycerol solutions

Rabbit kidneys were perfused at 10 °C with a solution containing gelatin polypeptides (Haemaccel), and glycerol was introduced, and then removed, using a technique that has previously been shown to result in viable kidneys. This involved increasing the concentration of glycerol in the perfusate from zero to a maximum of 3 , holding it at this level for 30 min, and then decreasing it at the same rate to < 0.1 . Measurements were made of the concentration of glycerol in cortex, cortico-medullary zone, and medulla at various stages of perfusion. During the experiments it was observed that vascular resistance increased dramatically toward the end of deglycerolization, and changes in regional perfusate flow were measured by the diffusable indicator method. It was found that renal tissue is effectively permeated by glycerol using this technique. The perfusate flow throughout all regions of the kidney was reduced during deglycerolization but the greatest effect was on cortico-medullary flow, which was found to be abnormally high during the initial stages of hypothermic perfusion, but was severely impaired when the glycerol was removed. The cryoprotectant was almost completely removed by the washout procedure adopted.     

The “specific” binding of insulin to polyethene and other materials

It is known that insulin is adsorbed onto glass but it has been assumed that it is not adsorbed onto plastic. We find that tritium-labelled insulin is adsorbed onto all materials tried. The adsorption is reduced in the presence of other proteins and can be prevented altogether by coating the vessels with cetyl alcohol.     

Cleavage of proteoglycan aggregate by leucocyte elastase.

The partial degradation of proteoglycan aggregate by human leucocyte elastase yielded products that banded with Mr 190,000, 140,000, 88,000, and 71,000 when analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide electrophoresis. Analysis of these bands revealed that the 190,000- and 140,000-Da bands contained chondroitin and keratan sulfate stubs and had N-terminal amino acid sequences corresponding to a sequence starting at residue 398 of the core protein of rat or human aggrecan. With increased time of digestion, the staining intensities of the 190,000-, 140,000-, and 88,000-Da bands decreased relative to the 71,000-Da band. Analysis of the 88,000- and 71,000-Da bands showed that they contained peptides substituted only with keratan sulfate stubs and that each band contained two peptides with different N-terminal sequences. One of these corresponded to a sequence that started at residue 398 of rat or human aggrecan and the other to the N-terminal sequence of bovine aggrecan. Under conditions of complete digestion, bands of 71,000 and 56,000 Da which contained only keratan sulfate stubs were observed on SDS-polyacrylamide electrophoresis. The 71,000-Da band was shown to have a single sequence similar to that starting at residue 398 of human and rat aggrecan and thus represents the globular domain 2 (G2) of the core protein of aggrecan. The 56,000-Da band was shown to have a sequence similar to that of the N-terminal sequence of bovine aggrecan indicating that this peptide corresponds to the globular domain 1 (G1) of the molecule. These results suggest that leucocyte elastase cleaves the core protein of aggrecan between valine 397 and isoleucine 398, which are located in the interglobular domain linking the G1 and G2 domains of the core protein of aggrecan. Further digestion of the proteoglycan aggregate with elastase resulted in the cleavage of the core protein within the chondroitin sulfate attachment domains.