A note on the effect of storage on the chemical resistance of spores of Bacillus subtilis SA22 and Bacillus subtilis globigii B17

Spores of Bacillus subtilis SA22, harvested from nutrient agar after 9 d at 30°C and stored in distilled water at 4°C, were unaltered in their resistance to 17.7% hydrogen peroxide or 0.04% peracetic acid after storage for up to 134 weeks. Three spore crops of B. subtilis globigii were unaffected by storage for up to 134 weeks with respect to 17.7% hydrogen peroxide resistance but were significantly more resistant to 0.04% peracetic acid following storage.     

“Unblocking” Serum Activity <Emphasis Type="Italic">in vitro</Emphasis> in the Polyoma System may Correlate with Antitumour Effects of Antiserum <Emphasis Type="Italic">in vivo</Emphasis>

In a variety of tumour systems, individuals carrying progressively growing neoplasms have lymphoid cells with a specific cytotoxic effect on cultured tumour cells from the same individual^1–4. Since the sera of tumour-bearing individuals have been shown to prevent tumour cell destruction by immune lymphocytes in vitro^2,5–8 and since this serum blocking activity appears early in primary and transplant tumour development^5,7, it has been suggested that the appearance of this serum blocking activity might be responsible for the progressive growth of tumours in individuals having cytotoxic lymphocytes. Counteraction of this blocking activity would thus be of primary importance in facilitating the function of an already existing or bolstered cell-mediated immunity. The serum blocking activity might be inhibited in various ways, by preventing the formation of blocking antibody or by interfering with its action (“unblocking”), as demonstrated in Moloney sarcoma regressor sera⁹. This type of serum also has a therapeutic effect on Moloney sarcomas in vivo^10,11, which has been tentatively attributed to its unblocking activity^8,9 or, possibly, to a complement-dependent cytotoxicity¹⁰. Tumour growth in the Moloney sarcoma system, however, might be due in part to continuous recruitment of neoplastic cells by virus-induced transformation and so the therapeutic effect could be due to a virus-neutralizing serum activity^9,10.     

The role of polypyrrole as charge transfer mediator and immobilization matrix for d-fructose dehydrogenase in a fructose sensor

A fructose dehydrogenase (FDH) modified electrode is produced by the electroadsorption of a layer of FDH on a platinum electrode followed by the electropolymerization of a polypyrrole (PPy) film around and over the enzyme. This immobilizes and stabilizes the enzyme as well as providing an electron transfer pathway to the electrode. The amperometric response to fructose and the enzymatic activity are measured as a function of PPy film thickness. The electrode is shown to have a maximum response at a PPy thickness of approximately the thickness of the enzyme layer. A measure of the electrode efficiency is also obtained, this is the amperometric response to fructose as a percentage of that expected on the basis of the enzyme activity. The functioning of the electrode is also dependent on the counter-ion used for PPy polymerization. This is shown to be mainly related to the nucleation and growth of the PPy film in the interfacial region.     

Effects of exercise on collateral development in myocardial ischemia in pigs

To study the effects of exercise on collateral development in myocardial ischemia, we induced coronary arterial stenosis of the left circumflex coronary artery (LCCA) in 18 of 30 pigs. During that surgery, we identified the coronary bed at risk. Nine of these pigs were then subjected to 5 mo of exercise training on a treadmill. After exercise training, we determined regional collateral and myocardial blood flow using radiolabeled microspheres. At autopsy, all animals had complete occlusion of the LCCA. Infarct size in the exercise-trained pigs was significantly less than in the sedentary pigs (5.9 +/- 1.0 vs. 11.7 +/- 1.0% of the left ventricle). The exercise-trained animals had a greater increase in collateral flow, 35.1 +/- 3.0 vs. 28.7 +/- 4.1 ml X min-1 X 100 g-1, in the noninfarcted jeopardized zone of the LCCA bed. The major findings of the study were the following: 1) chronic coronary artery stenosis progressing to occlusion stimulated development of the collateral circulation and salvaged tissue in the jeopardized myocardium of an animal model with sparse collaterals; 2) development of the collateral circulation and tissue salvage is increased by exercise training; 3) collaterals develop primarily in or near the ischemic zone; and 4) all collateral beds develop a circumferential flow gradient following occlusion.     

On the mechanism of ATP-induced shape changes in the human erythrocyte membranes: the role of ATP

In the preceding paper (Sheetz, M. and S.J. Singer. 1977. J Cell Biol. 73:638-646) it was shown that erythrocyte ghosts undergo pronounced shape changes in the presence of mg-ATP. The biochemical effects of the action of ATP are herein examined. The biochemical effects of the action of ATP are herein examined. Phosphorylation by ATP of spectrin component 2 of the erythrocyte membrane is known to occur. We have shown that it is only membrane protein that is significantly phosphorylated under the conditions where the shape changes are produced. The extent of this phosphorylation rises with increasing ATP concentration, reaching nearly 1 mol phosphoryle group per mole of component 2 at 8mM ATP. Most of this phosphorylation appears to occur at a single site on the protein molecule, according to cyanogen bromide peptide cleavage experiments. The degree of phosphorylation of component 2 is apparently also regulated by a membrane-bound protein phosphatase. This activity can be demonstrated in erythrocyte ghosts prepared from intact cells prelabeled with [(32)P]phosphate. In addition to the phosphorylation of component 2, some phosphorylation of lipids, mainly of phosphatidylinositol, is also known to occur. The ghost shape changes are, however, shown to be correlated with the degree of phosphorylation of component 2. In such experiment, the incorporation of exogenous phosphatases into ghosts reversed the shape changes produced by ATP, or by the membrane-intercalating drug chlorpromazine. The results obtained in this and the preceding paper are consistent with the proposal that the erythrocyte membrane possesses kinase and phosphates activities which produce phosphorylation and dephosphorylation of a specific site on spectrin component 2 molecules; the steady-state level of this phosphorylation regulates the structural state of the spectrin complex on the cytoplasmic surface of the membrane, which in turn exerts an important control on the shape of the cell.     

Effect of acute exercise stress in cardiac hypertrophy: I. correlation of regional blood flow and qualitative ultrastructural changes.

Ultrastructural myocardial cell changes were determined in eight miniswine after the development of pressure-overload hypertrophy induced by supra-valvular aortic constriction. Four miniswine served as control animals. Regional myocardial blood flows were measured at rest and during exercise stress with radioactive microspheres after two days and one month of aortic constriction. Exercise stress, causing the heart rate to increase to 85 percent of its maximum, was imposed twice weekly for 7 minutes on four pressure-overloaded animals and the four control animals to elicit differences between the control and experimental groups that might not occur at rest. After one month of pressure overload the swine were killed and myocardial samples were processed for electron microscopy. Ultrastructural changes similar to those in hypertrophied hearts were present throughout the left ventricular walls of the pressure-overloaded animals. Other changes consistent with ischemic injury were present in the subendocardial regions of pressure-overloaded animals subjected to exercise stress. These changes included disorganization of myofibrils, disintegration and broadening of Z-bands, swelling and aggregation of mitochondria, electron-dense deposits in mitochondria, decreased cristal density and vacuolization of mitochondria, intracellular edema, margination and clumping of nuclear chromatin, and a decrease of glycogen granules. Regional ischemia in the subendocardium of these animals was confirmed by functional studies which showed decreased regional myocardial blood flow to the subendocardium during exercise and S-T segment elevation for the first 2-10 days after inducing pressure overload. The ischemia, as shown by flow studies, during exercise stress persisted in the compensatory stage of hypertrophy although S-T segments returned to normal. Thus, the combined effect of pressure overload and exercise stress can produce focal subendocardial ischemia in the compensated, hypertrophied heart.     

Kinetics of subcellular distribution in rat intestine of 1,25-dihydroxycholecalciferol administered in vivo. Evidence for concentration within 5 min into purified nuclei.

To better understand the initial steps in the induction of intestinal Ca2+ transport by 1,25-dihydroxycholecalciferol [1,25(OH)2D3], we studied the early subcellular localization of 1,25(OH)2D3 in rat intestine. Vitamin D-deficient rats received 300 pmol of 1,25(OH)2[3H]D3 intravenously at 5 min to 4h before being killed. Cells homogenized in buffer of I = 90 mmol/litre were fractionated by centrifugation into a crude nuclear pellet, purified nuclei, Golgi and basal-lateral membranes, cytosol and a post-nuclear pellet. Nuclear purification was established by biochemical and morphological criteria and gave a yield of 32 +/- 2% (mean +/- S.E.M.; n = 21). Although re-establishment of Ca2+ uptake by Golgi is one of the earliest reported intestinal responses to 1,25(OH)2D3, no direct localization of 1,25(OH)2D3 to Golgi was detected. Purified nuclei had the highest specific radioactivity at all times studied, with nuclear localization detectable at 5 min and peak nuclear uptake at 1 h. Relative specific radioactivity of nuclei to cytosol increased from 5 min to 30 min, at which time equilibrium between cytosol and nucleus appeared to be attained. Nuclear uptake occurred in all cells from villus to crypt. Of total nuclear binding 10% was resistant to high ionic strength buffer (I = 365 mmol/litre); peak nuclear uptake was observed at 30 min in this buffer. This tight binding may represent the active fraction of 1,25(OH)2D3. These results indicate that localization of 1,25(OH)2D3 to rat intestinal nuclei precedes the observed Golgi-membrane effects and suggest the existence of high-affinity nuclear 1,25(OH)2D3-binding sites.     

Release of leukotrienes from guinea pig lung stimulated by C5ades Arg anaphylatoxin

The complement anaphylatoxins C5a and C5Ades Arg contract guinea pig peripheral airway preparations and trachea by a mechanism largely independent of histamine release. In trachea the contractions are inhibited by FPL 55712, a relatively specific inhibitor of slow-reacting substance of anaphylaxis (SRS-A). SRS-A is now known to be a mixture of leukotrienes C4, D4, and E4 (LTC4, LTD4, LTE4). These data suggest that C5-derived anaphylatoxins stimulate production and release of leukotrienes in pulmonary tissues. To define these observations more precisely, fragments of guinea pig lung were incubated with porcine C5ades Arg, and the supernatant fluids were analyzed for leukotrienes by using both pharmacologic and chemical methods. In addition to histamine, a smooth muscle contracting activity characteristic of SRS-A was released from C5a-treated lung preparations. The contractile substance was identified as a leukotriene based on: 1) the characteristic contraction of guinea pig ileum, 2) inhibition of the contractile activity by FPL 55712, 3) enhanced release of activity in the presence of indomethacin or L-cysteine, 4) chromatographic behavior of ethanol-extracted active material on Amberlite XAD-7 resin, and 5) cochromatography of the active material on reverse-phase, high performance liquid chromatography with standard LTD4. We therefore concluded the humoral factor C5ades Arg induces a leukotriene release reaction in guinea pig lung tissue. This particular response of pulmonary tissue to anaphylatoxin has not been appreciated previously as an immediate effect of complement activation on the pathophysiology of the lung.