Community structure of the microbiota in the floodwater of a Japanese paddy field estimated by restriction fragment length polymorphism and denaturing gradient gel electrophoresis pattern analyses

The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-denaturing gradient gel electrophoresis (DGGE) patterns of 16S rDNA were studied to elucidate the effects of the type of fertilization and the growth stage of rice plants on the community structure of the microbiota in the floodwater of a Japanese paddy field under a long-term fertilizer trial. From the mid tillering stage, a higher pH and temperature were observed in the plot without fertilization (NoF plot) than in the plots supplied with chemical fertilizers (CF plot) and with compost (CM plot). DNA fragments specific to the respective plots and common to every plot were detected after the digestion of PCR products by restriction enzymes. Cluster analysis separated the RFLP and DGGE patterns of the microbiota in the floodwater into four clusters; the microbiota in (1) the NoF plot, (2) the CF plot, (3) the CM plot, and (4) the CF and CM plots in the early growing stage. The effect of fertilizer application on the community structure was more conspicuous than that of seasonal variation.     

Identification of irradiated prawn (Penaeus monodon ) using thermoluminescence and 2-alkylcyclobutanone analyses

Thermoluminescence (TL) and 2-alkylcyclobutanone (2-ACB) analyses were performed to identify irradiated prawns ( Penaeus monodon ). With the TL method, minerals were extracted from prawns using acid hydrolysis. The experimental results satisfied the evaluation criteria of European Norm (EN) 1788, even after low-dose irradiation (0.5 kGy) and a 60 day storage at -20 °C. With the 2-ACB method, 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) were successfully extracted from prawns by direct solvent extraction with purification using a conventional silica column and a sulfoxide column, which was used for 2-ACB for the first time. Both 2-ACB derivatives were absent from the non-irradiated samples but were identified in all irradiated samples by gas chromatography-mass spectrometry. Moreover, 2-DCB and 2-TCB production correlated with the applied dose (2.5-10 kGy), and the correlation did not diminish after 60 days of storage at -20 °C for any dose. Therefore, these two techniques provide rapid, simple, and promising methods for routine investigation of frozen prawns.     

Isolated and companion young brown dwarfs in the taurus and chamaeleon molecular clouds

Infrared imaging observations have detected a dozen faint young stellar objects (YSOs) in the Taurus and Chamaeleon molecular clouds whose near-infrared colors are similar to those of classical T Tauri stars (TTS). They are around four magnitudes fainter than low-luminosity YSOs in Taurus detected in earlier surveys and as much as eight magnitudes fainter than typical TTS. The extreme faintness of the objects and their lower luminosity relative to previously identified brown dwarfs in the Pleiades indicate that these faint YSOs are very young brown dwarfs on the order of 1 million years old.     

Studies on BHC isomers and related compounds V. Some physicochemical properties of BHC isomers (1)

Physicochemical properties of biological interest were measured for hexachlorocyclohexane (benzene hexachloride) isomers, including solubility in water and in aqueous protein solutions, partition coefficients between organic solvents and water, and some “adsorption equilibrium” constants between the macromolecules and water. Some of the properties show a correlation with the free energy-related hydrophobic parameter “π”.     

Indirect hemagglutination test in equine infectious anemia.

An indirect hemagglutination was developed for the diagnosis of equine infectious anemia using sheep red blood cells coated with group specific virus antigen which had been highly purified by affinity chromatography. The presence of indirect hemagglutination antibodies was demonstrated in horses with equine infectious anemia since the cells were specifically agglutinated by all the serum samples obtained from experimentally infected horses. Antibodies appeared within 35 days after inoculation, and development of which coincided well with that of precipitating and complement fixing antibodies. Titer of indirect hemagglutination antibodies were ten to 320 times greater than those of precipitating antibodies. Test results could be read more clearly by the indirect hemagglutination test especially in weakly positive cases. Ninety-six samples from suspected field cases collected from every region of Japan which were positive on the immunodiffusion test were also positive on indirect hemagglutination test. Serum samples from 420 horses in one race track were examined by both the indirect hemagglutination and immunodiffusion tests to determine the reliability of the indirect hemagglutination test for diagnosis of equine infectious anemia. The same result was obtained on both tests. Based on this evidence, the indirect hemagglutination test can be employed as a very sensitive serological test for the diagnosis of equine infectious anemia.     

Studies on BHC isomers and related compounds: VIII. Urinary metabolites produced from γ- and β-BHC in the mouse: Chlorophenol conjugates

Metabolites produced from γ-BHC and β-BHC in the mouse urine were purified and characterized. Most metabolites from the both isomers were not extractable by organic solvents, and were conjugates such as sulfates and glucuronides. After hydrolysis with an appropriate enzyme, the conjugates gave chlorophenols, among which 2,4,6-trichlorophenol existed most abundantly—about 25% in the total urine metabolites. 2,4-Dichlorophenol constituted also a significant portion.     

Catabolism of tryptamine by cockroach head enzyme preparation

An enzyme preparation from the homogenate of American cockroach heads [Periplaneta americana (L.)] converted tryptamine hydrochloride to a toluene-extractable material. Optimum conditions for the reaction were obtained with 0.3 M sodium phosphate buffer, pH 6.6, at 30°C. The enzyme was very unstable. Its activity was scarcely inhibited by such typical monoamine oxidase inhibitors as iproniazid phosphate and tranylcypromine hydrochloride. Enzyme activity was not affected by the addition of NADPH₂, but was accelerated by acetyl coenzyme A or coenzyme A. A main product of the enzymic reaction was isolated and identified as N-acetyltryptamine by chromatography and spectroscopic analyses, which suggests that the enzyme is a kind of N-acetyltransferase.     

The role of primary germ tubes (PGT) in the life cycle of Blumeria graminis: The stopping of PGT elongation is necessary for the triggering of appressorial germ tube (AGT) emergence

The conidia of Blumeria graminis f. sp. hordei (Bgh), following contact with a host surface, first form a short germ tube, called the primary germ tube (PGT), and then an elongating germ tube emerges. It differentiates into an appressorial germ tube (AGT), and then the AGT elongates and swells. It forms a hooked, appressorial lobe that penetrates the epidermal cell wall of the host. In a series of infections, the positive role of PGT in the morphogenesis of the fungus is unclear except for the possibility reported by Carver and Ingerson that the growth of a long germ tube, with the potential to differentiate into an appressorium, seems to be dependent on the perception of a suitable host surface through contact with the PGT. Therefore, the aim of the present study is to further clarify the role of PGT in the morphogenesis of the fungus. When the conidia of Bgh were inoculated onto the coleoptile surface whose cuticle was removed with cellulose acetate, the emergence of the AGT was delayed. This delay was related to the length of the PGT. That is, on the cuticleless coleoptile surface the PGT tended to continue elongating without stopping. If there were gaps on the coleoptile surface such as a cell border on the more hydrophilic substratum like cuticleless coleoptile surface, the PGT stopped elongating there and after that the AGT emerged. Moreover, the length of PGT in the beginning of AGT emergence was same as that of the PGT after appressorium formation. This means that PGT elongation had stopped when AGT began to emerge. Therefore, it is necessary to stop the PGT elongation for the triggering of AGT emergence.     

A new preparation protocol for measurement of testicular sperm production

In studies of male reproductive toxicity, measuring daily sperm production is a quite important criterion. However, the accuracy of the values measured by the basic protocol is still controversial. In order to enhance the homogeneity of countable testicular sperm/spermatid heads, this report introduces a new enzymatic method with a subsequent detergent treatment. The testis of rat was firstly homogenized in phosphate-buffered saline. The homogenate (buffer mix) was then treated with collagenase and trypsin, and then sodium dodecyl sulfate (SDS) was added to produce detergent-resistant sperm/spermatid heads (detergent mix). After examination by hemocytometer, the coefficient of variation (CV) of the number of sperm/spermatid heads was compared with that obtained from the buffer mix. In addition, a MicroCell chamber was applied to the examination, and the CV was compared with other cases. In both examinations, homogeneity was improved by the detergent mix preparation. Counting with the hemocytometer showed an increased number of sperm/spermatid heads compared with that of the buffer mix (P<0.001), and the CV was decreased (P<0.05). In addition, when the MicroCell chamber was applied, the numbers increased about 3-hold compared with that of the buffer mix (P<0.001). The CV of the detergent mix was 23.7%, while that of the buffer mix was 38.9%. These results clearly demonstrate that the new preparation protocol generated in this study can provide more actual and accurate values when measuring daily sperm production.