Effect of Free-Air CO2 Enrichment (FACE) on Methanogenic Archaeal Communities Inhabiting Rice Roots in a Japanese Rice Field

The effect of free-air CO₂ enrichment (FACE) on the methanogenic archaeal communities inhabiting rice roots was studied in a Japanese rice field by separately collecting rice roots three times (at mid-tillering, panicle initiation, and heading stages) according to their nodal number, extracting DNA from the roots and subjecting it to polymerase-chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) and sequence analyses. Appearance of roots indicated that aging and senescence occurred faster under the FACE conditions than under the ambient conditions. The number of DGGE bands of methanogenic archaeal communities tended to increase with the growth stages. Cluster analysis showed that the succession of methanogenic archaeal communities in the ambient plot preceded that in the FACE plot, while the trend of the appearance of rice roots was opposite. All the closest relatives associated with the DGGE bands belonged to Methanomicrobiales and Rice cluster I, and FACE did not affect the phylogenetic position of the closest relatives associated with the characteristic DGGE bands. Faster succession of methanogenic archaeal communities in the ambient plot and similar phylogenetic members between the plots were observed in rice roots in years with both warmer (1999) and cooler (2003) weather during the rice cultivation period than in average years.     

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.     

Coal fly ash–based synthetic aggregates as potential alternative container substrates for ornamentals

This research was carried out to study the characteristics and the potential utilization of coal fly ash–based synthetic aggregates (CSA) with oil palm waste as an alternative container substrate for ornamental‐plant production. CSA only, oil palm waste only, and two mixing ratios of CSA with oil palm waste at the ratio of 1:5 and 1:10 (V/V) were utilized under this study. Zeolite was utilized as a standard substrate to compare characteristics of other substrates. The physical and chemical properties of all substrates were characterized. Scanning electron microscopy (SEM) of coal fly ash and CSA were conducted in order to study the structural configuration of the CSA. Developed CSA gave an alkaline pH (9.82), high electrical conductivity (96.1 mS m^–1), high cation concentrations, high water‐holding capacity, and low bulk density (0.56 g cm^–3) compared to zeolite. Mixing of CSA with oil palm waste at the ratio of 1:10 gave enhanced physical and chemical properties such as bulk density (0.25 g cm^–3), particle density (1.76 g cm^–3), air space (20.6%), total pore space (85.8%), total water‐holding capacity (652 mL L^–1), pH (6.18), and electrical conductivity (42.4 mS m^–1), which were in the established ideal substrate range. Moreover, SEM study revealed that CSA is a dual‐composite material, which had well enmeshed coal–fly ash particles in the fibrous paper‐waste matrix creating porous spaces within the aggregate. The growth of French marigold (Tagetes patula), which is a popular ornamental plant in Japan, was assessed using these newly developed substrates. The mixing ratio of CSA and oil palm wastes at 1:10 reported the best maximum growth and yield parameters of French marigold, with increase in shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, plant height, and number of flowers per plant by 51%, 93%, 54%, 150%, 19%, and 61%, respectively, compared to the zeolite. It is revealed that a mixture of CSA and oil palm waste at the ratio of 1:10 can be successfully utilized as an alternative container substrate for French marigold production.     

Decontamination of Chlorate in Longan Plantation Soils by Bio-Stimulation with Molasses Amendment

Potassium chlorate is widely used as an active substance for flower induction in longan plantation fields for off-season production of longan fruits in northern Thailand. Contamination of groundwater with residual chlorate in soil is a cause for concern because of its toxicity to human health. Based on our previous finding that the addition of glucose or sucrose to soil was effective for accelerating the disappearance of residual chlorate in soil, the effect of the addition of molasses, which contains a high concentration of sucrose, as a substitute for glucose or sucrose was examined in laboratory and pot experiments. Under laboratory conditions, the addition of molasses to soil at the concentrations of 100 to 200 g kg⁻¹ soil strikingly enhanced the rate of disappearance of chlorate applied at 341 mg kg⁻¹ soil. Addition of diluted molasses was also effective for the accelerated disappearance of chlorate in soil when 33 g kg⁻¹ soil of molasses was added repeatedly. The effect of repeated addition of diluted molasses to soil on the decontamination of residual chlorate in soil was also confirmed in an outdoor pot experiment. These results may lead to the development of a practical method of cleaning-up chlorate-polluted soil in longan plantation fields.     

Novel capsid genes (g23) of T4-type bacteriophages in a Japanese paddy field

Viruses exist everywhere on the planet. Recent development in viral genomics confirmed that genomic information is preserved among viral subsets and can be used for phylogenetic classification of viruses and for evaluation of viral diversity in the environment. The capsid gene of T4-type bacteriophages, g23, is the most widely applied gene for evaluating the diversity of the T4-type bacteriophage family. In this study, we applied denaturing gradient gel electrophoresis to PCR products of DNA with g23-specific primers that were extracted from a Japanese paddy field under long-term fertilizer trial and obtained 39 different g23 clones at the DNA level. They showed identities of 27–99% with the clones within the NCBI database at the amino acid level. They were quite distinctive from those obtained in marine environments and most of them formed six phylogenetically novel groups in the T4-type bacteriophage family with the clones obtained from another paddy field. The existence of six novel groups was confirmed from molecular analysis of all the amino acid sequences between the primers, of the amino acid sequences excluding hypervariable region, and of those of conserved regions. These findings indicate that T4-type bacteriophage communities in paddy fields consist of previously uncharacterized members phylogenetically distant from those in marine environments. The type of fertilizers and the stage during rice cultivation were not the major factors in determining T4-type bacteriophage communities in the paddy field.     

Spontaneous hemangiosarcoma in the spleen and liver of a young rat

Spontaneous hemangiosarcoma in young rats is rare. In this report, we describe a case of a spontaneous hemangiosarcoma in the spleen and liver of young rats. At necropsy, multiple pale red masses were observed in the spleen. Histopathologically, solid growth and haphazardly arranged neoplastic cells were observed, although no characteristic growth pattern was observed. In contrast, irregularly sized small slit-shaped spaces containing erythrocytes were found among the neoplastic cells. Reticular fibers incompletely surrounding the neoplastic cells were observed by silver staining. Immunohistochemistry revealed that the neoplastic cells were positive for vWF and CD34. Electron microscopic examination revealed that the neoplastic cells had erythrocytes in the lumen and Weibel-Palade bodies in the cytoplasm and were arranged along a discontinuous basal lamina. These features indicate that the tumor originated from vascular endothelial cells. Based on these results, the tumor was diagnosed as a hemangiosarcoma in the spleen and liver.     

Effect of Number of Carbons in Added Disulfide on Breadmaking Quality

Breadmaking properties such as bread height and specific volume were improved in bread from wheat flour with added disulfides such as dimethy disulfide (M₂S₂), diethyl disulfide (E₂S₂), dipropyl disulfide (Pro₂S₂), and dibutyl disulfide (B₂S₂). However, the amount of disulfides for maximum breadmaking properties was various and strongly related to the number of carbons (C) in the disulfide. Brabender farinographs of disulfide‐wheat flour showed an interesting profile, and the properties of the modification of the width of the tail. Size‐exclusion high performance liquid chromatography (SE‐HPLC) of the wheat proteins in the control and the disulfide‐added flours showed profiles of low, medium, and high molecular weight peaks. The area of the high molecular weight peak was larger in the disulfide‐added flours than in the control, indicating that this protein was important for the improvement of breadmaking properties.     

Prevalence of honeybee viruses in Apis mellifera in Gifu prefecture of Japan

Viral infection damages honeybee colony health. Viruses can be carried by queen bees and apicultural production materials when imported from foreign countries. We investigated seven honeybee viruses in worker bees (Apis mellifera) from 26 healthy apiaries in Gifu, Japan between 2018 and 2019. Black queen cell virus (BQCV) was detected in 23 (88.5%) of the apiaries, followed by Israeli acute paralysis virus (42.3%), deformed wing virus (DWV) (38.5%), and sacbrood virus (3.8%). In phylogenetic analysis, BQCV and DWV in Gifu were related to those in China and South Korea. Additionally, a high prevalence of BQCV was observed among worker bees in BQCV-positive colonies. Therefore, BQCV horizontal transmission among worker bees may contribute to the high prevalence of BQCV in Gifu.