Productivity Improvement of Milkfish and Seaweed Polyculture using Vermicomposting Fertilizer from Sources of Waste

Polyculture cultivation depends on the balance of several factors. Seaweed functions as a supplier of oxygen, protection for milkfish from predators, and an absorber of the dissolved CO2 from the respiration of the milkfish. In turn, the milkfish waste was used as nutrients by the seaweed. This research was carried out in Ujungpangkah Pond, Gresik District, East Java. The objective of the study was to increase pond productivity using vermicompost fertilizer from various wastes in a seaweed and milkfish polyculture system. The treatment was using food waste, Alang-Alang (Imperata) waste, banana stems, and a combination of all wastes were used to produce the vermicompost. The polyculture system used milkfish and the seaweed Gracilaria verrucosa and was cultivated for 42 days. It was found that the highest carbon uptake (717.77 ppm/day) by G. Verrucosa was with no added organic waste; the highest nitrogen uptake (16.47 ppm/day) was with combined organic waste, and the highest phosphorus uptake (19.17 ppm/day) was with feed waste. The highest daily specific growth rate (6.21%/day) of the milkfish was with banana stem waste. The feed conversion ratio (FCR) was 1.04–1.26. This small FCR showed that seaweed could be used as an alternative feed source for milkfish within a polyculture system.

Preparation and Properties of Organic Silicon Atomic-Oxygen-Protection Film

Materials used on exterior spacecraft surfaces are subjected to many environmental threats which can cause degradation, atomic oxygen is one of the most threats. We prepared organic silicon atomic-oxygen-protection film using method of polymerization. This paper presented the effects on the film structure and its durability of the preparation processing, and analyzed the polymerization theory, the film structure and composition of the film. At last, we tested the film in our ground based atomic oxygen simulator, and indicated that the film worked well.

Hopanoid lipids inFrankia: identification of squalene-hopene cyclase gene sequences

In Frankia, the microsymbiont in actinorhizal root nodules, nitrogen fixation takes place in specialized structures called vesicles. The lipidic vesicle envelope forms a barrier to oxygen diffusion, an essential part of the nitrogenase oxygen protection system. We have shown previously that the vesicle envelope is composed primarily of two species of hopanoid lipids, sterol-like molecules that are synthesized in a wide range of bacteria, including Frankia, several cyanobacteria, and rhizobia. The levels of hopanoid found in Frankia are among the highest of any organism known to date. Here we report that short (328-bp) DNA sequences from several strains of Frankia spp. have been identified that are homologous to a portion of the coding region of squalene-hopene cyclase (shc) genes. The fragments and corresponding polymerase chain reaction (PCR) primers can be used in phylogenetic comparisons of Frankia, both within Frankiaceae and among bacteria that synthesize hopanoids.Key words: Frankia, squalene-hopene cyclase, shc, hopanoid, phylogeny, actinorhizal.