Some aspects on the nature of humic acid

For the extraction of humic acid from soils, solutions of sodium hydroxide or neutral sodium salts of inorganic and organic acids such as sodium fluoride, sodium oxalate and sodium pyrophosphate have been used most generally.     

Nitrogen-Fixing Microorganisms in Paddy Soils: VIII

In the previous paper (1), we reported that the ability of the nitrogen fixation in the mixed culture of Rhodopseudomonas capsulatus either with non-nitrogen-fixing bacteria Propionibacterium, or with nitrogen-fixing bacteria Azotobacter vinelandii, was superior to that in the separate culture of each. Because of reason dedused from past experiments, we have proposed a hypothesis on substrate cycle. In this research, we performed the study of the following two directions: firstly, on the nitrogen fixation in the mixed culture of R. capsulatus with anaerobic nitrogen-fixing bacteria Clostridium butyricum and secondly, on the consumption of glucose used as the substrate and on the production of volatile acids in the mixed culture of R. capsulatus either with Az. vinelandii, or with Cl. butyricum.     

Anesthesia,fasting tolerance,and nutrient requirement of juvenile northern bluefin tuna

ABSTRACT:   The present study aimed to investigate a suitable anesthesia protocol for nutritional studies, fasting tolerance, and nutrient requirements for maintenance in juvenile northern bluefin tuna Thunnus orientalis weighing 0.8–0.9 g. The fish grew in a mass seedling production under completely controlled aquaculture. The solution of 0.2 mL 2-phenoxyethanol/L prepared by filtered seawater has been notably estimated as a anesthesia protocol for the juvenile, due to a shorter mean time necessary for anesthesia and recovery and higher survival rate at 24 h after recovery. All other anesthetics, 0.1 and 0.3 mL 2-phenoxyethanol/L, 0.05, 0.1 and 0.2 mL 4-allyl-2-methoxyphenol/L, and cool water temperature shocks at 16.8, 12.6 and 10.4°C, were inferior. In a 5-day tolerance test, the juvenile was fed sand lance Ammodytes personatus through the rearing period or fasted for 2, 3, 4 and 5 consecutive days. Survival rates were about 80 or 60, 50, 10 and 0%, respectively. From the relationships between days fasting and energetic and nutritional retentions, juvenile tuna require about 142.7 kJ, 5.46 g protein and 0.44 g fat/kg body weight a day for maintenance, indicating remarkably higher requirements than other aquaculture fish.     

Food sources for the bivalve Corbicula japonica in the foremost fishing lakes estimated from stable isotope analysis

ABSTRACT:   Carbon and nitrogen stable isotope ratios in tissue of the bivalve corbicula Corbicula japonica and particulate organic matter (POM) were measured in Lake Jusan, Lake Ogawara and Lake Shinji, which are the foremost fishing grounds for the corbicula in Japan, to determine their food sources. The bivalves in Lake Ogawara and Lake Shinji showed enriched isotope composition, while those in Lake Jusan were depleted. In addition, the difference in the isotope ratios between the sampling sites was remarkable in Lake Jusan. Chlorophyll concentrations were significantly higher in Lake Ogawara and Lake Shinji than those in the inflow rivers, although that in Lake Jusan was equivalent to that in the river. Residence time of river water was estimated at 1 day, 455 days and 88 days in Lake Jusan, Lake Ogawara and Lake Shinji, respectively. These values indicate that the bivalves in Lake Ogawara and Lake Shinji assimilate autochthonous phytoplankton, while those in Lake Jusan assimilate terrestrial matter in the upper reaches and marine phytoplankton in the lower reaches because of low production in the lake.     

Different effects of ionic and non-ionic compounds on the freeze denaturation of myofibrils and myosin subfragment-1

The effects of non-ionic (sorbitol, maltose, trehalose) and ionic compounds (Na-glutamate, Na-acetate, Na-sulfate, ammonium sulfate) on freeze denaturation of myosin subfragment-1 (S-1) and of myofibrils were compared. Sugars, Na-glutamate and Na-acetate well suppressed the freeze denaturation of myofibrils as well as S-1 in a concentration dependent manner. Although sulfate suppressed freeze denaturation of S-1 irregularly, it accelerated myofibril denaturation. It was concluded that sulfate salts were useless as cryoprotectant for myofibrils. Stabilization extent by F-actin in frozen storage was much less than that in heating.     

Histological study of the hypertrophic placentas and open eyelids observed in cloned fetuses

Mice cloned from somatic or ES cells showed signs of phenotypically various abnormalities. These abnormalities are now considered to result from aberrant gene expressions by epigenetic reprogramming errors but it is still unclear when these abnormalities occur and what histological changes occur during the gestation period. To address these issues, we histologically examined the hypertrophic placentas and open eyelids at 12.5, 17.5 and 19.5 days of the gestation period in ES-derived cloned mice that we have previously reported. In the placentas, the histology revealed that the hypertrophy had already occurred at 12.5 dpc and that the main change was the proliferation of trophoblast cells in the labyrinth layer. In the fetuses and placentas at 17.5 and 19.5 dpc, extensive proliferation of spongiotrophoblast and glycogen cells in the spongiotrophoblast layer and enlarged trophoblast giant cells were observed. Open eyelids in cloned mice were observed from 17.5 dpc, whereas the eyelids of the control mice had already been closed. The histology showed the malformation of eyelids where the formation of the stratum corneum and stratum granulosum in the epidermis was insufficient. Based on the histology described here, further comparative studies of the gene expression and histology of abnormalities seen in cloned mice and in gene-targeted and spontaneously mutated mice with similar phenotypic abnormalities could help illuminate these abnormalities and could contribute to the development of somatic cloning technology.     

Infection frequency of mature apple fruit with Erwinia amylovora deposited on pedicels and its survival in the fruit stored at low temperature

The infection frequency of mature apple fruit by Erwinia amylovora and the survival of E. amylovora in the fruit stored at low temperature were investigated. The fruit stems (pedicels) of 460 mature apple fruit were inoculated with 10⁵ or 10⁴ cfu of bioluminescent E. amylovora, tagged with lux genes. Nine days after inoculation, 43% and 27% of the fruit inoculated with 10⁵ and 10⁴ cfu, respectively, were infected. All infected fruit looked healthy. After 6 months of storage at 5°C, almost all of the 142 infected fruit had viable E. amylovora. Of the fruit containing E. amylovora internally, 19.5% had latent infections and the rest had blight symptoms. E. amylovora was not uniformly distributed in the fruit flesh, and internal brown lesions were observed where E. amylovora was densely distributed. These findings showed that mature apple fruit may be infected with E. amylovora, especially as latent infections, and act as a source for long-range dissemination.