Activation of lignin and manganese peroxidase excretion in Phanerochaete chrysosporium by fungal extracts

Summary Lignin (LiP) and manganese peroxidase (MnP) excretion by Phanerochaete chrysosporium INA-12 was significantly increased in response to fungal extract supplementation. LiP and MnP production was increased 1.7- and 1.8-fold, respectively, with fungal extracts from agitated pellet cultures of strain INA-12, namely fungal extracts P₆ and P₄. In cultures supplemented with a fungal extract harvested from static cultures of strain INA-12 (fungal extract S₄), LiP and MnP production was increased 1.8- and 1.6-fold, respectively. Succinate dehydrogenase activity, a mitochondrial marker, was significantly enhanced (2.7-fold) in cultures with the addition of fungal extracts. Correspondence to: M. Asther     

Monoclonal antibodies against human low density lipoprotein. Stoichiometric binding studies using Fab fragments

Because of its physical properties, apolipoprotein B (apo B) has remained poorly characterized. In an attempt to elucidate apo B structure, the Fab fragments of 3 different monoclonal anti-human apo B antibodies were tested in a quantitative assay for their binding to human low density lipoprotein (LDL). In each case the assay gave a linear Scatchard plot with a maximum of 1 Fab fragment bound to a single LDL particle. This result favors an LDL model containing a single large Mr apo B protein, which is not composed of multiple, identical, small Mr subunits.     

Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Lipoxygenase activity in apples in relation to storage and physiological disorders

Different methods for the preparation of active lipoxygenase (LOX) extracts from apples were compared. Highest activities were obtained using a 0.25 M phosphate buffer (pH 7) containing 1% Triton X-100 and 10^?2 M metabisulphite as extraction solvent. LOX activity during storage was investigated in the core, flesh, and peel. Activity was always highest in the core and peel. On storage, activity was increased in each part of the fruit but especially in the core and peel. Increase in LOX preceded the browning of the core. LOX may be responsible for the browning and may be concerned in the induction of superficial scald.     

Use of trypsin for rapid and efficient purification of murine sarcoma and leukemia virus

A method is described for purification of MSV-MuLV from culture supernatant of chronically infected 78A₁ rat embryo cell line. This method involves direct polyethylene glycol-NaCl precipitation of the low speed supernatant of culture fluid followed by digestion of the pellet with trypsin. This procedure efficiently disrupts large aggregates which normally entrap most of the virus. Highly purified virus can be obtained in very good yield by a combination of sedimentation velocity and isopycnic centrifugation : yields up to 100 A₂₈₀ units (17 mg of protein) of purified virus per liter of culture fluid can be observed. This procedure appears well suited for large scale isolation of virion associated enzymatic activities.