Mutated intramolecular chaperones generate high-activity isomers of mature enzymes.

The propeptide of carboxypeptidase Y precursor (proCPY) acts as an intramolecular chaperone that ensures the correct folding of the mature CPY (mCPY). Here, to further characterize the folding mechanism mediated by the propeptide, folding analysis was performed using a yeast molecular display system. CPYs with mutated propeptides were successfully displayed on yeast cell surface, and the mature enzymes were purified by the selective cleavage of mutated propeptides.

Purification of inactive precursor of carboxypeptidase Y using selective cleavage method coupled with molecular display.

A novel purification system for inactive precursor proteins without conventional time-consuming purification steps was established. We purified an inactive precursor protein, procarboxypeptidase Y (proCPY), which was displayed on the cell surface of yeast, due to difficulty of purifying it by a system in which it is produced in cells.

Analysis of a processing system for proteases using yeast cell surface engineering: conversion of precursor of proteinase A to active proteinase A.

The display of a protease, carboxypeptidase Y (CPY) or procarboxypeptidase Y (proCPY), which is the vacuolar protease, on the yeast-cell surface was successfully performed using yeast-cell-surface engineering for the first time. Through that we could confirm the processing of vacuolar proteases containing proteinase A (PrA) and proteinase B (PrB) which are related to the maturation of proCPY, using a novel cell-surface engineering technique. Various protease-knockout strains of Saccharomyces cerevisiae with the CPY-displaying system were constructed to evaluate the operation of the activation process of CPY.

Thrombocytosis at an early stage of respiratory tract viral infection.

Aim: To determine whether thrombocytosis, a platelet count of more than 500 x 10(9)/l, occurs at an early stage of respiratory tract viral infection.

Methods: The medical records of 345 patients with respiratory syncytial virus (RSV), influenza, measles, adenovirus or human herpes virus 6 infections were retrospectively reviewed.

Results: The mean platelet count was significantly higher in RSV patients than in patients with other respiratory infections.

Construction of a selective cleavage system for a protein displayed on the cell surface of yeast.

We constructed a novel protein-purification system in which Saccharomyces cerevisiae with a protein displayed on the cell surface is harvested and the displayed protein is then cleaved from the cell surface. GFPuv was used as a model protein in this cell surface engineering experiment. In this system, the C-terminal 320 amino acids of alpha-agglutinin were bound to the C-terminal of GFPuv for display on the cell surface.

Indiscriminate glycosylation of procarboxypeptidase Y expressed in Pichia pastoris.

To obtain large amounts of deglycosylated procarboxypeptidase Y (proCPY), in which all of the N-glycosylation sites were replaced by alanine residue by the point mutation method, an expression system was constructed using Pichia pastoris. The secreted enzyme was characterized by SDS-PAGE, native PAGE, MALDI-TOF mass spectrometry, and dynamic light scattering, and the results indicated heterogeneity. The recombinant proCPY contained 29 mol of glucose per mole of protein in average, according to the carbohydrate analysis by the phenol-sulfuric acid method.

Leigh syndrome associated with West syndrome.

Leigh syndrome (LS) (sub-acute necrotizing encephalomyelopathy) is characterized by symmetric brain lesions occurring mainly in the basal ganglia and associated with variable clinical manifestations such as hypotonia, psychomotor retardation, and feeding difficulties. Patients with LS may develop seizures. Only three patients with LS have been identified in the literature as having West syndrome (WS).

Cerebral hemorrhage associated with vitamin K deficiency in congenital tuberculosis treated with isoniazid and rifampin.

We report a male infant with congenital tuberculosis who developed cerebral hemorrhage associated with vitamin K deficiency during treatment with isoniazid and rifampin. Despite an absence of risk factors for vitamin K deficiency, the severe hemorrhagic disorder occurred at 4 months of age. We speculate that vitamin K deficiency in the present case may have resulted from a synergic effect of antituberculosis agents and immaturity of vitamin K metabolism and/or its absorption.

[Streptococcus salivarius meningitis after oral trauma by a skewer: a case report].

Although Streptococcus salivarius is one of the normal flora in the oral cavity and gastrointestinal tract, the agent may cause bacteremia, meningitis, endocarditis and sinusitis under certain circumstances. We report a 3-year-old female with meningitis after oral trauma by a skewer due to penicillin resistant S. salivarius.