Specificity of the collagenolytic enzyme from the fungus Entomophthora coronata: comparison with the bacterial collagenase from Achromobacter iophagus.

The specificity of the collagenolytic enzyme from the fungus Entomophthora coronata toward some inhibitors and the B chain of oxidized insulin was investigated and compared to that of the bacterial collagenase from Achromobacter iophagus. The fungal enzyme was completely inhibited by diisopropylfluorophosphate, tosyl-l-lysine chloromethyl ketone, and tosyl-amino-2-phenylethyl chloromethyl ketone but not at all by ethylenediaminetetraacetate. This indicates that it is not a metalloenzyme like the bacterial Achromobacter collagenase. The B chain of insulin was not hydrolysed at all by the bacterial enzyme under conditions where extensive digestion was observed with the Entomophthora enzyme. The fungal enzyme cleaves preferentially the bonds $\text{Leu}\text{15}\text{-}\text{Tyr}\text{16}\text{and}\text{Leu}\text{11}\text{Val}\text{12}$ as determined by automatic sequencing; the secondary cleavages were identified by a systematic analysis of the digestion mixture; thus, the fungal collagenolytic enzyme from Entomophthora coronata differs both structurally and functionally from the bacterial Achromobacter collagenase.     

Effect of antigravity suit inflation on cardiovascular, PRA, and PVP responses in humans

Blood pressure, pulse rate (PR), serum osmolality and electrolytes, as well as plasma vasopressin (PVP) and plasma renin activity (PRA), were measured in five men and two women [mean age 38.6 +/- 3.9 (SE) yr] before, during, and after inflation of an antigravity suit that covered the legs and abdomen. After 24 h of fluid deprivation the subjects stood quietly for 3 h: the 1st h without inflation, the 2nd with inflation to 60 Torr, and the 3rd without inflation. A similar control noninflation experiment was conducted 10 mo after the inflation experiment using five of the seven subjects except that the suit was not inflated during the 3-h period. Mean arterial pressure increased by 14 +/- 4 (SE) Torr (P less than 0.05) with inflation and decreased by 15 +/- 5 Torr (P less than 0.05) after deflation. Pulse pressure (PP) increased by 7 +/- 2 Torr (P less than 0.05) with inflation and PR decreased by 11 +/- 5 beats/min (P less than 0.05); PP and PR returned to preinflation levels after deflation. Plasma volume decreased by 6.1 +/- 1.5% and 5.3 +/- 1.6% (P less than 0.05) during hours 1 and 3, respectively, and returned to base line during inflation. Inflation decreased PVP from 6.8 +/- 1.1 to 5.6 +/- 1.4 pg/ml (P less than 0.05) and abolished the significant rise in PRA during hour 1. Both PVP and PRA increased significantly after deflation: delta = 18.0 +/- 5.1 pg/ml and 4.34 +/- 1.71 ng angiotensin I X ml-1 X h-1, respectively. Serum osmolality and Na+ and K+ concentrations were unchanged during the 3 h of standing.(ABSTRACT TRUNCATED AT 250 WORDS)     

Studies on protein-phosphorylation reactions in isolated chromatin.

The endogenous protein-phosphorylating activity of isolated chromatin was tested. We have found that a group of high-molecular-weight proteins (Mr greater than 50 000) was preferentially phosphorylated when chromatin from mouse ascites cells or from bovine lymphocytes was incubated in the presence of ATP. After disintegration of chromatin by nuclease treatment or by high salt concentration, a larger spectrum of chromatin proteins becomes accessible for phosphorylation by the chromatin-bound protein kinase. Some observations described in this communication may help to partially explain this result. The protein kinase was not found in nucleosomal subunits, indicating a non-random distribution of the enzyme in chromatin. This suggests that enzyme and substrate have to be in close spatial contact for the phosphorylation reaction to occur. Furthermore, we have shown for one protein, histone H1, that phosphorylation sites for the endogenous protein kinase are available on the free but not on the DNA-bound protein, suggesting that phosphate-accepting sites in chromatin proteins may be blocked by protein-DNA or by protein-protein interactions. We also discuss the possibility that chromatin protein kinase occurs in stable complexes with its phosphate-accepting substrates, as has been suggested by the findings of other [Kish, V.M. & Kleinsmith, L.J. (1974) J. Biol. Chem. 249, 750-760].     

CHROMOSOME COUNTS OF COMPOSITAE FROM THE UNITED STATES AND MEXICO

Chromosome counts are reported for 126 taxa representing 122 species and 61 genera of Compositae. First reports include two genera, Stylocline (n = 14) and Chromolepis (n = 19), 17 species, two infraspecific taxa, and one interspecific hybrid. Five additional taxa have chromosome numbers differing from previously published accounts. Carminatia is reinstated to generic status.     

Spinally-mediated antinociception is induced in mice by an adenosine kinase-, but not by an adenosine deaminase-, inhibitor.

Relative involvement of adenosine deaminase and adenosine kinase in antinociception induced by endogenous adenosine was investigated. Antinociception induced by 5'-amino 5'-deoxyadenosine (5'-ADAdo; an adenosine kinase inhibitor) and deoxycoformycin (dCF; an adenosine deaminase inhibitor) administered i.t. was determined using the mouse tail-flick assay. Dose- and time-dependent antinociception was observed following i.t. administration of 5'-ADAdo, but not dCF. Antinociception induced by 5'-ADAdo was reversed by coadministration i.t. of theophylline, an adenosine receptor antagonist, in a dose-dependent manner. These data provide preliminary evidence that adenosine kinase plays a more significant physiological role than adenosine deaminase in the regulation of adenosine involved in spinally-mediated antinociception.