The two haloacetate dehalogenase genes, dehH1 and dehH2, on the 65-kb plasmid pUO1 from Delftia acidovorans strain B were found to be located on transposable elements. The dehH2 gene was carried on an 8.9-kb class I composite transposon (TnHad1) that was flanked by two directly repeated copies of IS1071, IS1071L and IS1071R. The dehH1 gene was also flanked by IS1071L and a truncated version of IS1071 (IS1071N). TnHad1, dehH1, and IS1071N were located on a 15.6-kb class II transposon (TnHad2) whose terminal inverted repeats and res site showed high homology with those of the Tn21-related transposons. TnHad2 was defective in transposition because of its lacking the transposase and resolvase genes. TnHad2 could transpose when the Tn21-encoded transposase and resolvase were supplied in trans. These results demonstrated that TnHad2 is a defective Tn21-related transposon carrying another class I catabolic transposon.

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In order to reduce the cultivation area re uired for the p w t h of higher plants in space adoption o? algae. which ave a hipher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein.The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself has been conducted. Spirulina was cultivated in the 6-liter medium containing a sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated o x r g e n r was separated using a pol propyrene porous ho low I er membrane module. Througt this experiment, oxygen gas (at a mnccntraiion of more than 46%) a t a rate of 100 -150 ml per minute could be obtained.

Many research activities regarding Controlled Ecological Life Support System ( CELSS ) have been conducted and continued all over the world since the 1960's and the conce t of CELSS is now changing from Science Fiction to Scientific Reality. Development of CELSE technology is inevitable for future long duration stays of human beings in space, for lunar base construction and for manned mars flight programs. CELSS functions can be divided into two categories , Environment Control and Material Recycling.Temperature, humidity, total atmospheric pressure and partial pressure of oxygen and carbon dioxide, necessary for all living things, are to be controlled by the environment control function. This function can be performed by technologies already developed and used as the Environment Control Life Support System ( ECLSS ) of Space Shuttle and Space Station. As for material recycling, matured technologies have not yet been established for fully satisfying the specific metabolic requirements of each living thing including human beings. Therefore, research activities for establishing CELSS technology should be focused on material recycling technolo ies using biological systems such as plants and animals and physico-chemical systems, fx example, a gas recycling system, a water purifying and recycling system and a waste management system. Based on these considerations, Japanese research activities have been conducted and will be continued under the tentative guideline of CELSS research activities as shown in documents f lf,l2f. The status of the over all activities are discussed in this paper.