Characterization of ammonia-assimilating bacteria in a lagoon for wastewater from a paddock of dairy cattle

We investigated microorganisms that assimilated ammonia in lagoon treatment processes. Ammonia‐assimilating microorganisms were detected by nitrogen‐limited medium that contained ammonia as the sole nitrogen source. Numbers of ammonia‐assimilating aerobes (log CFU/g) were 3.4, 4.8, 5.0, 4.8 and 5.0 (log CFU/mL) on the culture plate incubated at 4°C, 10°C, 15°C, 20°C and 25°C, respectively. Many isolates used ammonia in high rates when they were purely cultivated in nitrogen‐limited medium added to sterilized lagoon extract. Many of them used ammonia even when they were cultivated in media containing viable microbial flora of the lagoon. Among them, enterobacteriaceae and Pseudomonas sp. were identified by analysis of 16S ribosomal DNA.     

Biosynthesis of estradiol-17β in the ovarian follicles of the red seabream Pagrus major during vitellogenesis

ABSTRACT: The red seabream Pagrus major is a useful experimental fish for studying the endocrine control of oogenesis in teleosts. This study investigated the steroidogenic pathway for estradiol-17β (E2) biosynthesis in the ovarian follicles of red seabream. Intact follicles were isolated during vitellogenesis and incubated in vitro with different radiolabeled steroid precursors. When 17-hydroxyprogesterone (17-P), dehydroepiandrosterone (DHEA), or androstenedione (AD) were used as precursors, both testosterone (T) and estrone (E1) were synthesized by follicles, leading to estradiol-17β (E2) production. Serum steroid levels measured by enzyme-linked immunosorbent assay showed that T, E1, and E2 were present in the circulation at levels ranging from 1 ng/mL to 2 ng/mL throughout the day during the spawning season. In vitro conversion of E1 into E2, however, was 15.8-fold greater than T conversion into E2, suggesting that E2 is synthesized mainly via E1 rather than T. The results showed that E2 was synthesized from pregnenolone via 17-hydroxypregnenolone, DHEA, AD, and E1. Thus, the study demonstrated the complete steroidogenic E2 synthesis pathway in the ovarian follicles of red seabream, and revealed that E1 is the major precursor of E2.     

Functional Analysis of Lysosomes During Mouse Preimplantation Embryo Development

Lysosomes are acidic and highly dynamic organelles that are essential for macromolecule degradation and many other cellular functions. However, little is known about lysosomal function during early embryogenesis. Here, we found that the number of lysosomes increased after fertilization. Lysosomes were abundant during mouse preimplantation development until the morula stage, but their numbers decreased slightly in blastocysts. Consistently, the protein expression level of mature cathepsins B and D was high from the one-cell to morula stages but low in the blastocyst stage. One-cell embryos injected with siRNAs targeted to both lysosome-associated membrane protein 1 and 2 (LAMP1 and LAMP2) were developmentally arrested at the two-cell stage. Pharmacological inhibition of lysosomes also caused developmental retardation, resulting in accumulation of lipofuscin. Our findings highlight the functional changes in lysosomes in mouse preimplantation embryos.     

Tomatidine, a tomato sapogenol, ameliorates hyperlipidemia and atherosclerosis in apoE-deficient mice by inhibiting acyl-CoA:cholesterol acyl-transferase (ACAT)

It was previously revealed that esculeoside A, a new glycoalkaloid, and esculeogenin A, a new aglycon of esculeoside A, contained in ripe tomato ameliorate atherosclerosis in apoE-deficent mice. This study examined whether tomatidine, the aglycone of tomatine, which is a major tomato glycoalkaloid, also shows similar inhibitory effects on cholesterol ester (CE) accumulation in human monocyte-derived macrophages (HMDM) and atherogenesis in apoE-deficient mice. Tomatidine significantly inhibited the CE accumulation induced by acetylated LDL in HMDM in a dose-dependent manner. Tomatidine also inhibited CE formation in Chinese hamster ovary cells overexpressing acyl-CoA:cholesterol acyl-transferase (ACAT)-1 or ACAT-2, suggesting that tomatidine suppresses both ACAT-1 and ACAT-2 activities. Furthermore, the oral administration of tomatidine to apoE-deficient mice significantly reduced levels of serum cholesterol, LDL-cholesterol, and areas of atherosclerotic lesions. The study provides the first evidence that tomatidine significantly suppresses the activity of ACAT and leads to reduction of atherogenesis.     

Development of an on-site plum pox virus detection kit based on immunochromatography

Sharka disease, caused by plum pox virus (PPV), is the most serious viral disease of stone fruit trees. Among the eight known strains of the virus, PPV-D is the most important due to its recent global spread. Although enzyme-linked immunosorbent assay (ELISA) is the most common approach for diagnosing sharka, it involves time-consuming steps and requires expensive equipment and trained technicians. In this study, an on-site PPV detection kit based on immunochromatography was developed using polyclonal antibodies against the coat protein (CP) of a PPV-D isolate. The immunochromatographic (IC) assay kit was as sensitive as a commercial ELISA system for detecting Japanese PPV-D isolates. Moreover, it was easy to use (a one-step procedure), and results could be obtained on-site within 15 min without special laboratory equipment. The IC assay kit detected the virus from every aerial part of symptomatic Japanese apricot trees. In a detailed study of viral localization in leaves, the most suitable plant parts for use in the IC assay were symptomatic mesophyll tissues and the region from the petiole to the main vein. A positive reaction was also observed using the CP of other major (PPV-M and PPV-Rec) and minor (PPV-EA, PPV-W, and PPV-T) strains.     

Biomass allocation and nitrogen limitation in a Cryptomeria japonica plantation chronosequence

We investigated soil net nitrogen mineralization rate, above- and belowground biomass allocation, and nitrogen use in a Cryptomeria japonica plantation chronosequence. Total biomass accumulation showed an asymptotic accretion pattern, and the peak total biomass accumulation rate occurred approximately 30 years after afforestation. Soil net nitrogen mineralization rate was lowest 30 years after afforestation. Between years 30 and 88, net nitrogen mineralization increased again. These results indicate that an imbalance in soil nitrogen supply and plant nitrogen demand occurred approximately 30 years after afforestation. Furthermore, leaf nitrogen concentration, which was used as an index of plant nitrogen status, was lower in mature forest than in young forest, suggesting that mature stands did not take up nitrogen as successfully. If soil resources such as nitrogen limit plant growth, plants may increase biomass allocation to fine root structure; however, fine root biomass was not higher in 30- and 88-year-old stands than in younger stands, suggesting that changes in biomass allocation may not be effective against nitrogen deficiency in a C. japonica plantation chronosequence.     

Algal growth in an irrigation canal and its effect on flow function

Paddy and Water Environment - In the A irrigation district in Yamagata Prefecture, Japan, a rehabilitation project is being implemented due to the aging of the irrigation facilities;...