Coccus-shaped Bacillus subtilis cells are inhibited at stage 0 of sporulation

RodA and rodB mutations cause rod-shaped Bacillus subtilis cells to become coccus-shaped when the growth temperature is increased from 30 to 45 degrees C. At 30 degrees C four rod strains sporulated as well as the genetically closely related rod+ strains. In contrast, at 45 degrees C the sporulation frequencies of rod strains decreased approximately 10(2)- to 10(4)-fold, while those of rod+ strains remained either unchanged or decreased only slightly. Temperature shift experiments and ultrastructural data indicated that coccus-shaped cells were unable to form prespore septa and were, therefore, inhibited at stage 0 of sporulation.     

Naloxone reversal of ischemic arrhythmia is stereospecific and suggests role of endogenous opioid peptides in ischemic heart disease.

The effects of the stereoisomers of naloxone during myocardial ischemia were studied. (-)-Naloxone (but not the (+)-isomer naloxone) attenuated the ischemia-induced cardiac arrhythmias, hypotension, and bradycardia that result from coronary artery occlusion in anesthetized rats. From these findings, it may be inferred that endogenous opioid peptides may play a role in the pathophysiology of myocardial ischemia. It is also suggested that naloxone may have therapeutic value in the prevention and treatment of ischemic heart disease.     

Oleanolic Acid: A Novel Cardioprotective Agent That Blunts Hyperglycemia-Induced Contractile Dysfunction

Diabetes constitutes a major health challenge. Since cardiovascular complications are common in diabetic patients this will further increase the overall burden of disease. Furthermore, stress-induced hyperglycemia in non-diabetic patients with acute myocardial infarction is associated with higher in-hospital mortality. Previous studies implicate oxidative stress, excessive flux through the hexosamine biosynthetic pathway (HBP) and a dysfunctional ubiquitin-proteasome system (UPS) as potential mediators of this process. Since oleanolic acid (OA; a clove extract) possesses antioxidant properties, we hypothesized that it attenuates acute and chronic hyperglycemia-mediated pathophysiologic molecular events (oxidative stress, apoptosis, HBP, UPS) and thereby improves contractile function in response to ischemia-reperfusion. We employed several experimental systems: 1) H9c2 cardiac myoblasts were exposed to 33 mM glucose for 48 hr vs. controls (5 mM glucose); and subsequently treated with two OA doses (20 and 50 µM) for 6 and 24 hr, respectively; 2) Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mM glucose vs. controls (11 mM glucose) for 60 min, followed by 20 min global ischemia and 60 min reperfusion ± OA treatment; 3) In vivo coronary ligations were performed on streptozotocin treated rats ± OA administration during reperfusion; and 4) Effects of long-term OA treatment (2 weeks) on heart function was assessed in streptozotocin-treated rats. Our data demonstrate that OA treatment blunted high glucose-induced oxidative stress and apoptosis in heart cells. OA therapy also resulted in cardioprotection, i.e. for ex vivo and in vivo rat hearts exposed to ischemia-reperfusion under hyperglycemic conditions. In parallel, we found decreased oxidative stress, apoptosis, HBP flux and proteasomal activity following ischemia-reperfusion. Long-term OA treatment also improved heart function in streptozotocin-diabetic rats. These findings are promising since it may eventually result in novel therapeutic interventions to treat acute hyperglycemia (in non-diabetic patients) and diabetic patients with associated cardiovascular complications.