Purification and physiological properties of two lipolytic enzymes of Solanum tuberosum

Two lipolytic enzymes have been separated and partially purified from potato tubers. One enzyme of higher isoelectric value, possessed acyl hydrolase activity toward a number of p-nitrophenyl fatty acyl derivatives, the relative activity depending on the fatty acyl chain length. There was also some activity towards phosphatidyl choline. The other enzyme possessed phospholipase and galactolipase activity, but showed a low acyl hydrolase activity towards p-nitrophenyl fatty acyl derivatives. When applied to plant tissues, the enzyme with the greater acyl hydrolase activity caused rapid ion efflux from discs of potato tuber and beetroot, foflowed by reabsorption of ions by the tissues. The purified phospholipase did not produce this effect but induced acid phosphatase leakage from lysosome-enriched fractions of potato sprout tissue. No maceration of tissue or protoplast disruption was observed when either of the two enzymes were incubated with a variety of plant preparations.     

Effect of flow and surface area on angiotensin-converting enzyme activity in rabbit lungs

Pulmonary angtiotensin-converting enzyme (ACE) is located on the luminal surface of pulmonary microvasculature. Multiple indicator-dilution techniques have been used to measure pulmonary ACE activity in vivo and in isolated lungs. These studies suggest that ACE activity is depressed in several forms of acute lung injury. Depression of ACE activity may reflect impaired substrate delivery to enzyme sites because of flow-related reduction of perfused surface area. To assess the role of altered microvascular flow and surface area in the measurement of ACE activity, we utilized similar techniques to estimate the apparent Km and Vmax of pulmonary ACE in isolated, Krebs-perfused rabbit lungs. Km is an estimate of the affinity of a synthetic ACE substrate, [3H]benzoyl-phenyl-alanyl-alanyl-proline ([3H]BPAP), for ACE and should not be influenced by the rate of substrate delivery to luminal enzyme sites. Conversely, Vmax is an index of the number of ACE sites and should be influenced by perfusion changes that alter the number of perfused sites (recruitment or derecruitment). When isolated lungs were subjected to physiological maneuvers designed to increase or decrease perfused surface area, apparent Vmax increased or decreased respectively. Apparent Km was not altered by these maneuvers. Km and Vmax were independent of changes in perfusion rate when surface area was held constant. Thus these parameters should be useful in evaluating perfusion changes in normal and injured lungs.     

Streptokinase Therapy in Acute Major Pulmonary Embolism: Effectiveness and Problems

Eighteen patients with major pulmonary embolism were treated with streptokinase infused by a catheter or given intravenously. Fourteen showed clinical improvement and 12 out of 16 patients investigated showed definite angiographic improvement after 24 to 48 hours of treatment with streptokinase. The angiographic improvement following streptokinase contrasted with the lack of this in three patients after 24 hours of heparin treatment.Resolution following streptokinase therapy was most noticeable in patients treated shortly after a single embolic episode, and was least marked in those with recurrent embolism complicated by associated cardiac or pulmonary disease. Of the four patients who failed to improve, two died and two had pulmonary embolectomy and survived.The results suggest that streptokinase therapy is practicable provided that adequate laboratory control is available, and that it hastens early resolution in acute major pulmonary embolism.     

Newborn Screening

Early detection of many disorders, mainly inherited, is feasible with population-wide analysis of newborn dried blood spot samples. Phenylketonuria was the prototype disorder for newborn screening (NBS) and early dietary treatment has resulted in vastly improved outcomes for this disorder. Testing for primary hypothyroidism and cystic fibrosis (CF) was later added to NBS programs following the development of robust immunoassays and molecular testing. Current CF testing usually relies on a combined immunoreactive trypsin/mutation detection strategy. Multiplex testing for approximately 25 inborn errors of metabolism using tandem mass spectrometry is a relatively recent addition to NBS. The simultaneous introduction of many disorders has caused some re-evaluation of the traditional guidelines for NBS, because very rare disorders or disorders without good treatments can be included with minimal effort. NBS tests for many other disorders have been developed, but these are less uniformly applied or are currently considered developmental. This review focuses on Australasian NBS practices.     

Shorter,warmer winters may inhibit production of ephyrae in a population of the moon jellyfish Aurelia aurita

Hydrobiologia - Scyphozoan jellyfish blooms display high interannual variability in terms of timing of appearance and size of the bloom. To understand the causes of this variability, the conditions...     

Serological relationships of the O antigens of Klebsiella pneumoniae O5, Escherichia coli O8 and a new O serotype of Serratia marcescens

Klebsiella pneumoniae O5, Escherichia coli O8 and Serratia marcescens 3255 were shown to cross-react in both ELISA and immunoblotting. The cross-reaction appeared to be due to the O antigen of their lipopolysaccharide (LPS). In addition, there was evidence that the reactions of these strains with their homologous antisera were due, in part, to determinants other than O polysaccharide.     

Morphoanalysis of Bacterially Precipitated Subaqueous Calcium Carbonate from Weebubbie Cave,Australia

In this article, we present a previously unreported morphology of bacterially precipitated calcite (determined using XRD, FTIR, and SAED) occurring subaqueously in Weebubbie Cave. Observations using FESEM and TEM revealed spindle-shaped crystals with curved [hk.0] faces lying parallel to the c-axis. Calcite precipitated under conditions designed to mimic the inorganic solution chemistry of the cave revealed a different morphology. These differences between the crystals suggest that the formation of the cave crystals is a consequence of biologically activity.