Induction of superovulation using inhibin antiserum and competence of embryo development in wild large Japanese field mice (Apodemus speciosus)

Seasonally, bred wild mice provide a unique bioresource, with high genetic diversity that differs from wild‐derived mice and laboratory mice. This study aimed to establish an alternative superovulation method using wild large Japanese field mice (Apodemus speciosus) as the model species. Specifically, we investigated how the application of inhibin antiserum and equine chorionic gonadotropin (IASe) during both the reproductive and non‐reproductive seasons impact the ovulation rate and competence of embryo development after in vitro fertilization (IVF) with fresh and cryopreserved sperm. When the wild mice were superovulated by injecting eCG followed by human chorionic gonadotropin (hCG), few oocytes were collected during the reproductive and non‐reproductive seasons. In comparison, the number of ovulated oocytes was dramatically enhanced by the administration of IASe, followed by isolation of ovulated oocytes 24 hr after 30 IU hCG administration. The IVF oocytes that were in vitro cultured (IVC) with medium containing serum further developed to the 2‐ and/or 4‐cell stage using both fresh and frozen‐thawed sperm. In conclusion, we successfully established an alternative protocol for collecting ovulated oocytes from wild large Japanese field mice by administering IASe and hCG during both the reproductive and non‐reproductive seasons. This study is the first to develop IVF–IVC wild large Japanese field mice beyond the 2‐ and/or 4‐cell stage in vitro using fresh and cryopreserved sperm. This approach could be used in other species of wild or endangered mice to reduce the number of animals used for experiments, or in maintaining stocks of germ cells or embryos.     

Biochar amendment to coarse sandy subsoil improves root growth and increases water retention

Crop yields and yield potentials on Danish coarse sandy soils are strongly limited due to restricted root growth and poor water and nutrient retention. We investigated if biochar amendment to subsoil can improve root development in barley and significantly increase soil water retention. Spring barley (Hordeum vulgare cv. Anakin) was grown in soil columns (diameter: 30 cm) prepared with 25 cm topsoil, 75 cm biochar‐amended subsoil, and 30 cm un‐amended subsoil lowermost placed on an impervious surface. Low‐temperature gasification straw‐biochar (at 0, 0.50, 1.0, 2.0, and 4.0 wt%) and slow pyrolysis hardwood‐biochar (at 2 wt%) were investigated. One wt% can be scaled up to 10² Mg/ha of char. After full irrigation and drainage, the in‐situ moisture content at 30‐80 cm depth increased linearly (R² = 0.99) with straw‐biochar content at a rate corresponding to 0.029 m³/m³/%. The lab determined wilting point also increased linearly with char content (R² = 0.99) but at a much lower rate (0.003 m³/m³/%). Biochar at concentrations up to 2% significantly increased the density of roots in the 40–80 cm depth interval. Addition of 1% straw‐biochar had the most positive effect on root penetration resulting in the highest average root density (54% coverage compared to 33% without biochar). This treatment also resulted in the greatest spring barley grain yield increase (22%). Improving the quality of sandy subsoils has global potentials, and incorporation of the right amount of correctly treated residues from bioenergy technologies such as straw‐biochar is a promising option.     

Effects of Fruit Numbers and Plant Status on Fruit Size in the Strawberry

Abstract

Based on yield and fruit size data from a number of experiments implying effects of nitrogen nutrition, drip-irrigation, plant material and planting times, and including cultivars “Dania”, “Elsanta”, “Bogota” and “Pandora”, distinct negative relationships between fruit size and fruit number per plant or fruit/leaf ratio, were established. Apart from that, fruit size may be affected by plant material and cropping year, the latter probably related to weather conditions. Achene spacing was influenced by year, and increased by irrigation under drought conditions. Relevance of factors influencing fruit size is discussed. It is concluded that an increase in the number of flower meristems (or a more vigorous vegetative growth) might aggravate internal competition, which in turn impairs flower development, resulting in a reduced flower quality and consequently smaller fruits.     

Two-Dimensional Gel Electrophoresis of Proteins in Healthy Roots and Clubroots of Brassica oleracea

Abstract

Seedlings of Brassica oleracea were infected by the pathogenic fungus Plasmodiophora brassicae. causing clubroot formation. Proteins from healthy roots and clubroots were extracted by two different methods and analysed by two-dimensional gel electrophoresis. Host-proteins induced during clubroot infection were not analysed, since the fungus was always present in the infected roots. This work showed that several proteins present in non-infected roots were lost or strongly reduced in the infected roots.     

Cultivar and year-to-year variation of phytosterol content in rye (Secale cereale L.)

Intake of phytosterols (and -stanols) has been shown to decrease the level of low-density lipoprotein cholesterol and thus protect against development of cardiovascular diseases. Therefore, studies on the cultivar and year-to-year variation in phytosterol content in rye grains have been performed. The phytosterol content and composition of different rye cultivars, grown under identical conditions on the same field in three consecutive years, were analyzed. Both cultivar and year-to-year variation in sterol content were statistically significant (p < 0.0001). The total sterol content varied from 1007 +/- 21 mg/kg in the highest yielding cultivar, Tsulpan 3, to 761 +/- 10 mg/kg in the lowest yielding cultivar (Amando in the 1999 harvest). Because the meteorological conditions varied substantially between the different years, it was possible to deduce the impact of varying weather conditions on phytosterol content in the different cultivars. The studied cultivars had all the lowest phytosterol contents in the dry and warm harvest season of 1999. Although there were statistically significant cultivar and year-to-year variations in the sterol composition (p < 0.0001), these were only between 2 and 4% of the total sterol content.     

Inhibitory effects of (-)-epigallocatechin gallate on the mutation,DNA strand cleavage,and DNA adduct formation by heterocyclic amines

Green tea is known to be a potential chemopreventive agent against cancer. In this study, we investigated the inhibitory activities of tea extracts, and in particular the polyphenolic component (-)-epigallocatechin gallate (EGCG), against heterocyclic amine-induced genotoxicity. The tea extracts displayed inhibition of 2-hydroxyamino-6-methyldipyrido[1,2-a,3',2'-d]imidazole (Glu-P-1(NHOH))-induced mutagenicity. This inhibition can be accounted for by the presence of EGCG in the extracts. The mutagenic effect of Glu-P-1(NHOH), which induces single-strand cleavage in supercoiled circular DNA under neutral conditions, was inhibited by EGCG. Using the Drosophila repair test, a test for gross DNA damage, and DNA adduct detection by (32)P-postlabeling, we showed that EGCG prevented 2-amino-3,8-dimethylimidazo[4,5-f]quinoline-induced DNA damage and adduct formation in insect DNA. EGCG was found to accelerate the degradation of Glu-P-1(NHOH) in vitro. This observation suggested that the inhibition by EGCG is associated with an accelerated degradation of metabolically activated heterocyclic amines.