The major acid-soluble proteins of Bacillus subtilis spores: partial amino acid sequence and forespore location of their mRNAs.

In Bacillus subtilis the alpha, beta, gamma and delta components comprise 80-90% of the total acid-soluble spore proteins (ASSPs). Sequence analysis demonstrates that alpha and beta share 32 of their first 36 amino acids and are closely related to the A and C ASSPs of Bacillus megaterium spores, confirming the results of analysis of their cloned genes. Despite the difference in apparent size of gamma and delta, they have identical N-terminal sequences (37 residues). Unless gamma and delta derive from very recently duplicated genes, it appears that gamma is derived from delta, either in vivo or during isolation. Although the sequenced regions of gamma and delta have no homology to alpha and beta, outside of the previously recognized pentapeptide recognition sequence for the spore endopeptidase, they share 10 and 15 residue peptides flanking this sequence with ASSP B of B. megaterium, but in reverse order. At least two groups of ASSPs have, therefore, been conserved between B. subtilis and B. megaterium: the multigene AC alpha beta family and the B gamma (delta) group. Sequence conservation in each group implies selection for functions in addition to storage. Both the alpha and beta components of B. subtilis ASSPs and their mRNAs are located in the forespore compartment of cells at t5.5 of sporulation, the time of most rapid ASSP synthesis. The sizes of these transcripts (250-350 bp) and their ability to direct the in vitro synthesis of ASSPs of mature size, indicate that genes for these ASSPs are monocistronic, consistent with dispersed map location. Synthesis of ASSPs is, therefore, coordinately controlled by selective transcription in the forespore.

Intracoronary thrombus in nontransmural myocardial infarction and in unstable angina pectoris.

Although intracoronary thrombus formation plays a major role in acute transmural myocardial infarction (MI), its occurrence in unstable angina (UA) and nontransmural MI has not clearly been established. To determine whether intracoronary thrombus does occur in these syndromes, coronary arteriography was performed before, during, and after intracoronary nitroglycerin and streptokinase infusion in 17 patients. None of the 8 patients with nontransmural MI and 1 of the 9 patients with UA responded to intracoronary nitroglycerin. Seven of 8 patients with nontransmural MI and 4 of 9 patients with UA responded to streptokinase infusion with opening of an occluded vessel, an increase in stenotic diameter, dissolution of an intracoronary filling defect, or a combination of these. Serial opening and closing of ischemia-related vessels occurred spontaneously and in response to streptokinase in some patients in whom thrombolysis was demonstrated. Evidence of thrombolysis was not seen in any patient studied longer than 1 week from the onset of the rest pain syndrome. The finding of thrombolysis in several patients with nontransmural MI and UA suggests that intracoronary thrombus formation plays a pathogenetic role in some patients with these ischemic syndromes.

Immunofluorescent demonstration of myeloperoxidase of phi bodies and rods in leukaemic leucocytes.

Previous studies employing enzyme histocytochemical methods based on the catalysis of the peroxidation of 3,3'-diaminobenzidine (DAB) demonstrated the presence of hydroperoxidase activity in phi bodies and rods of immature leucocytes of patients with active acute myelogenous leukaemia. It could not be determined from these studies whether the DAB oxidation product was demonstrating a single hydroperoxidase, catalase or myeloperoxidase, or both. In the present study, immunofluorescence techniques for the two hydroperoxidases were applied in an attempt to identify this activity specifically. The results obtained indicate that myeloperoxidase is present in the phi bodies and rods, and that this enzyme may be the major or the only hydroperoxidase present. Its activity could account for the peroxidation of DAB under conditions which are more favourable for the demonstration of catalase.

Facilitated light microscopic cytochemical diagnosis of acute myelogenous leukemia.

Hydroperoxidase-positive Phi bodies and rods are much more prominent and prevalent than rods visualized with a Romanovsky-type stain (Auer rods) in immature leukocytes of patients with active acute myelogenous leukemia (AML). They are readily observed with the light microscope in peripheral blood or marrow films of AML patients stained to show their peroxidatic activity. In many of these patients, Auer rods, which apparently constitute only a small subpopulation of the hydroperoxidase-positive Phi bodies and rods, were detected with difficulty, if at all. The hydroperoxidase-positive Phi bodies and rods were observed in 92% of 36 patients with active disease. They were never observed in leukocytes of patients with other hematopoietic disorders or of normal individuals. Thus, they facilitated the distinction of AML from acute lymphocytic leukemia and chronic granulocytic leukemia in blast crisis. They were absent in full clinical remission after chemotherapy and were greatly diminished in partial remission. They were present in disease relapse and reappeared in five patients who had been in full remission. These results suggest that these hydroperoxidase-positive enlarged particles are pathognomonic of AML and that monitoring them with the light microscope may aid in guiding its clinical management.