A Highly Sensitive Enzyme Immunoassay for Mouse β Nerve Growth Factor

Abstract: A sensitive two-site enzyme immunoassay system for mouse β nerve growth factor (NGF) was developed, based on the sandwiching of the antigen between anti-mouse β NGF antibody IgG coated to a polystyrene tube and anti-mouse β NGF antibody Fab'-linked β- d -galactosidase (β- d -galactoside hydrolase, EC 3.2.1.23). This method has the following advantages: (a) the procedures are simple and rapid compared to bioassay or two-site radioimmunoassay; (b) antibody Fab'-β- d -galactosidase complex is more stable than ¹²⁵I-labeled antibody; (c) purified β NGF is detectable at a concentration as low as 10 pg/ml. Our enzyme immunoassay was used to examine the levels of NGF in some tissues of mice. The submaxillary gland contained a high concentration of NGF. However, other tissues, such as the heart, brain, and skeletal muscle, and serum did not contain detectable NGF. These results support recent findings by other investigators that NGF was not found in the organs/tissues other than the submaxillary gland of mice.     

Staining air dried protoplasts for study of plant chromosomes

The air drying technique used in mammalian cytology was applied to isolated plant protoplasts for study of chromosomes. For cultured celery cells, this technique resulted in good spreads of metaphase chromosomes with high resolution. Mitotic chromosomes of Brassica species are relatively small, poor stained by common stains, and difficult to spread by the squash technique. In this study, however, the chromosomes of B. carinata in callus culture were spread well and stained clearly with Giemsa staining solution. The chromosome preparations by the present techniques should also be amenable to chromosome banding studies in plants.     

Quantitative Analysis of the Inactivation of Photosynthetic Oxygen Evolution and the Release of Polypeptides and Manganese in the Photosystem II Particles of Spinach Chloroplasts

Photosynthetic oxygen evolution by photosystem II particleswas inactivated by treatment with NaCl, NH₂OH or high pH. Whenthe degree of inactivation was compared with the degree of releasefrom the particles of Mn and three polypeptides having molecularmasses of 33, 24 and 18kdaltons, two types of inactivation werefound: one, brought about with 960 mM NaCl, was related to therelease of the 24 kdalton polypeptide, and the other, broughtabout with 1.5 mM NH₂OH or high pH, seemed to be related tothe release of Mn. ¹Present address: Department of Chemistry, Faculty of Science,Toho University, Miyama 2-2-1, Funabashi 274, Japan. (Received January 31, 1983; Accepted March 28, 1983)     

Effects of ingested phytoecdysteroids on the growth and development of two Lepidopterous larvae

The effects of ingested or injected 20-hydroxyecdysone on silkworm larvae (Bombyx mori) including death without moulting, death following completion of promoted moulting, death during promoted moulting (ecdysis inhibition) and inhibition in growth with and without effects on moulting, are dependent upon the concentration of exogenous hormone, the precise developmental stage of the treated larvae, and the duration of exposure to the exogenous ecdysteroid. Comparisons of 20-hydroxyecdysone with other phytoecdysteroids in the silkworm and pink bollworm, Pectinophora gossypiella, show a similar but more potent effect induced by ponasterone A, while cyasterone causes an ‘antiecdysone’ effect.     

Role of microstructure of nerve impulse train in relation to transmission of neuronal activity and coding mechanism of neural information

Input-output relation were of giant neurons of a marine mollusc, Onchidium verruculatum, and a computer-simulated neuron investigated in terms of microstructure of nerve impulse train. The microstructure of input impulse train, the size of a unitary EPSP, and the extent of spontaneous firing activity of a single neuron had an important influence upon the effective summation of arriving synaptic inputs, the elicitation of output spikes, and intervals between succeeding output spikes. The neuron responded differently to respective input trains with different time structures, i.e. it discriminated input time pattern to various degrees. The manner in discrimination of input time pattern was dependent on the size of the unitary EPSP and the extent of the spontaneous firing activity, if it had. Some discussions were made with regard to possible coding systems of neural signal, assuming a frequency code and/or a pattern code.     

Physiological and Biochemical Studies of Chilling Injury in Bananas

The physiological changes in green bananas (cv. Sin-zun), which are very sensitive to chilling injury, were studied during and after exposure to low temperatures (4±1°C, 6±0.5°C) for various periods. While the fruits injured by chilling did not fail to produce CO₂ and ethylene, the pattern of both CO_2- and ethylene production in these chilled fruits (9 and 15 days at 6°C) after transfer to 20°C was not normal. The contents of acetaldehyde and ethanol in chilled fruits, both in peels and pulps, increased with the advance of chilling, injury. There was an accumulation of α-keto acids in the peels of chilled fruits. Only half the conversion of ¹⁴C (fed as succinic acid-1, 4-¹⁴C) to citric acid and isocitric acid was observed in chilled tissues as compared with healthy ones; the activity of citrate synthase in banana peels appears therefore to be inhibited by chilling injury. A histological study of the tissues showed that the browning substances (polyphenols) present in chilled fruits accumulate around the vascular tissues.