[Effects of light quality on growth and internal quality of Whitmania pigra].

In this study, four light color treatments (red blue, white, natural light) were tested to determine effects of light spectrum on the growth of larval Whitmania pigra (30 days old) at the same intensity. The experiment lasted for 50 days. The specific growth rate (SGR) under blue light condition was significantly higher during 30 days to 40 days. At the end of the experiment, specific growth rate (SGR) and weight gain rate under red light condition were higher (P<0.05) than those under other groups. Meanwhile, the enzymes activities of digestive enzymes (protease, amylase and lipase) were higher under red light condition. However, the enzymes activities of antioxidant enzymes (SOD, CAT, ALP) were lower under white light condition compared with the other treatments（P＜0.05）. In addition, no significant changes were observed for water content, total ash, acid insoluble ash, pH and antithrombin activity in the all treatments. After 50 days, the digestive enzymes and growth rate were higher under red light condition but antioxidant enzymes were lower under white light condition. Furthermore, light spectrum has no significant effect on the internal quality of Wh. pigra.

Effects of millimeter wave irradiation and equivalent thermal heating on the activity of individual neurons in the leech ganglion.

Many of today's radiofrequency-emitting devices in telecommunication, telemedicine, transportation safety, and security/military applications use the millimeter wave (MMW) band (30-300 GHz). To evaluate the biological safety and possible applications of this radiofrequency band for neuroscience and neurology, we have investigated the physiological effects of low-intensity 60-GHz electromagnetic irradiation on individual neurons in the leech midbody ganglia. We applied incident power densities of 1, 2, and 4 mW/cm(2) to the whole ganglion for a period of 1 min while recording the action potential with a standard sharp electrode electrophysiology setup. For comparison, the recognized U.S. safe exposure limit is 1 mW/cm(2) for 6 min. During the exposure to MMWs and gradual bath heating at a rate of 0.04°C/s (2.4°C/min), the ganglionic neurons exhibited similar dose-dependent hyperpolarization of the plasma membrane and decrease in the action potential amplitude. However, narrowing of the action potential half-width during MMW irradiation at 4 mW/cm(2) was 5 times more pronounced compared with that during equivalent bath heating of 0.6°C. Even more dramatic difference in the effects of MMW irradiation and bath heating was noted in the firing rate, which was suppressed at all applied MMW power densities and increased in a dose-dependent manner during gradual bath heating. The mechanism of enhanced narrowing of action potentials and suppressed firing by MMW irradiation, compared with that by gradual bath heating, is hypothesized to involve specific coupling of MMW energy with the neuronal plasma membrane.

Long-term biological investigations in space.

Missions in space within the next two decades will be of longer duration than those carried out up to the present time, and the effects of such long-term flights on biological organisms are unknown. Results of biological experiments that have been performed to date cannot be extrapolated to results in future flights because of the unknown influence of adaptation over a long period of time. Prior experiments with Axolotl, fishes, and vertebrates by our research team (in part with sounding rockets) showed that these specimens did not appear to be suitable for long-term missions on which minimization of expense, technique, and energy is required. Subsequent investigations have shown the suitability of the leech (Hirudo medicinalis), which consumes blood of mammals up to ten times its own weight (1 g) and can live more than 2 years without further food supply. Emphasis in the experiments with Hirudo medicinalis is placed on metabolic rhythm and motility. Resorption and diffusion in tissue, development, and growth under long-term effects of cosmic proton radiation and zero-gravity are other focal points. The constancy of cellular life in the mature animals is a point in favor of these specimens. We have also taken into account the synergistic effects of the space environment on the problems just mentioned. The life-support system constructed for the leech has been tested successfully in four sounding rocket flights and, on that basis, has been prepared for a long-term mission. Long-term investigations out of the terrestrial biosphere will provide us with information concerning the degree of adaptation of certain physiological and biochemical functions and as to what extent biological readjustment or repair processes can occur under the specific stress conditions of space flight.