Further studies on complementation between mutants of Clostridium perfringens

1. Mutants devoid of lambda- and kappa-toxin and hemagglutinin (HA), respectively, were isolated from Cl. perfringens PB6K. The lambda- and HA- mutants could be classified into a and b groups by complementation but the kappa- mutants were all of the a group. 2. All b group mutants isolated, irrespective of the marker used for isolation, were pleiotropically negative or leaky with respect to theta-, lambda- and kappa-toxin and HA production. 3. Lambda-toxin produced by complementation was proved to be a rennet-like protease. 4. The activities of 12 extracellular enzymes, including sialidase, of several b group strains and the parent PB6K were compared, but no definite differences were observed. From this finding, the productions of these enzymes were concluded not to be regulated by the same mechanism as theta-, lambda- and kappa-toxin and HA. 5. Cl. perfringens CN3870 was also studied. Findings were similar to those on PB6K except for very low activity of HA.

Optimum conditions in the attenuated total reflection technique

In this paper the optimum condition for using the attenuated total reflection (ATR) technique is studied. In optimum conditions, the energy of an incident plane wave can be totally absorbed. The optimum condition can be realized by fabricating a localized thickness variation in the gap between a prism and a sample substrate with a point contact pressure. In the ATR technique, for example, the complex refractive index and the foil thickness of a thin metal foil, and the gap thickness are unknown parameters. To determine these unknown parameters, we prepared three prism coupling systems with different refractive indices. By this technique, we measured the complex refractive indices and the foil thicknesses of thin gold foils sputtered onto glass substrates, and the refractive index and the film thickness of a silica film sputtered onto a metal substrate.

Thickness measurement of ultrathin films on metal substrates using ATR

By modifying the surface plasma mode on a bare metal surface with an ultrathin film deposited on the metal, we measured the film thickness by attenuated total reflection (ATR). Various factors causing measurement errors are estimated with numerical examples. As a result, for example, it is shown that for some thicknesses, the errors due to the real part of the complex refractive index of a metal substrate become extremely small. Thicknesses of SiO(2) films sputtered onto Au foil and A1(2)O(3) films produced on Al foil by oxidation are measured.

Effect of age on C1q and C3 levels in human serum and their presence in colostrum

The initiating complement component (C1q) in the classical pathway of 730 subjects and the first essential component (C3) in the alternative pathway of 461 subjects in Japan were examined. The study population consisted of normal healthy newborns, infants, children, adults and the old (from birth up to 75 years of age). In cord sera, both C1q and C3 were about 60% to the total mean level. At 3 days of age, C1q markedly increased to the mean level which remained relatively invariable up to 40 years of age. And above 40 years, the C1q level increased steadily with age up to about 75 years of age. C3 reached the mean level at about 1 month of age, and was highest during infancy. This level declined at about puberty and then continued to increase steadily with age up to around 55 years. In normal healthy subjects, a moderate positive rank correlation was found between C1q and C3 amounts. No significant differences of C1q and C3 levels were evident between male and female. No C1q was demonstrable in the colostrum from which lipids were previously removed, but after concentration by precipitation in a chelating agent with a low ionic strength, C1q, measured immunochemically, was detectable at concentrations of 300 ng/ml of colostrum. C3 was also detected at concentrations of about 200 microgram/ml of colostrum.