Renal Tubular Cyst Formation in Newborn Rats Treated with p-Cumylphenol

In this study, we investigated the sequential changes in the development of renal tubular cysts in newborn rats treated with p-cumylphenol (PCP). Fifteen animals per sex were treated orally with 300 mg/kg/day of PCP for up to 18 days from postnatal day (PND) 4 and were sacrificed on PNDs 8, 12, 19 and 22 and after a 7 day recovery period. On PNDs 8 and 12, slight dilatation of the collecting ducts was frequently observed in the medulla and slight papillary necrosis was also noted in some cases. These dilated collecting ducts were lined with slightly hyperplastic epithelial cells. On PNDs 19 and 22, multiple large cystic changes arising from the collecting ducts in the outer medulla were seen. These cystically dilated ducts were also lined with hyperplastic epithelial cells. During the dosing period, the labeling index of proliferating cell nuclear antigen in the collecting duct epithelium was higher in the PCP-treated group than in the control group at all time points. After a 7 day recovery period, the cystic change still remained, although the cell density was decreased and the epithelial cells became flattened. On the other hand, basophilic tubules with peritubular lymphoid cell infiltration were multifocally observed in the cortex. In conclusion, PCP induced multiple renal cysts that developed in the collecting ducts of the outer medulla in neonatal rats, and it is suggested that epithelial cell proliferation may play some roles in the induction of cystic lesions.     

Sequence analysis of VP2 gene of canine parvovirus isolated from domestic dogs in Japan in 1999 and 2000

Seven strains of canine parvovirus (CPV) were isolated from affected dogs in Japan between 1999 and 2000, and their VP2 genes were genetically analyzed. Comparison of the predicted amino acid sequences of VP2 suggested that three field isolates corresponded to CPV type 2a, while the other four to CPV type 2b. The phylogenetic tree constructed from the VP2 genes showed that the newly isolated strains are classified into the cluster consisting of recent Japanese and Taiwanese field isolates, which are distinct from Vietnamese isolates, United States Isolates, or classical CPV type 2. These results suggest that the CPV transmission occurred between Japan and Taiwan in 1990s, and the offspring are still circulating in both countries.     

Gross nitrification rates in four Japanese forest soils: heterotrophic versus autotrophic and the regulation factors for the nitrification

Measurements of gross NH ₄ ⁺ and NO ₃ ^? production in forest soils were conducted using the ¹⁵N pool dilution method. Mineral topsoils (0?C10?cm depth) were collected from four forests from northern to southern Japan with a natural climate gradient to elucidate the mechanisms regulating gross nitrification rates in forest soils. Additionally, we attempted to evaluate the relative importance of heterotrophic nitrification in gross total nitrification using acetylene as a specific inhibitor of autotrophic nitrification. Distinct differences were found among sites in the gross rates of NH ₄ ⁺ production (3.1?C11.4?mg?N?kg^?1?day^?1) and gross total nitrification (0.0?C6.1?mg?N?kg^?1?day^?1). The rates of gross heterotrophic nitrification were low in this study, indicating that heterotrophic nitrification is of minor importance in most forest mineral topsoils in Japan. Significant relations were found between gross autotrophic nitrification and gross NH ₄ ⁺ production, soil N, and soil C concentrations, but none was found between gross autotrophic nitrification and soil pH. We determined the critical value of the gross NH ₄ ⁺ production rates for gross autotrophic nitrification under which no gross autotrophic nitrification occurred, as well as the critical soil C/N ratio above which gross autotrophic nitrification ceased. Results show that tight coupling of production and consumption of NH ₄ ⁺ prevents autotrophic nitrifiers from utilizing NH ₄ ⁺ as long as NH ₄ ⁺ availability is low.     

Comparative analysis of mechanical stretch-induced activation activity of back and leg muscle satellite cells in vitro

It has previously been shown that mechanical stretch induces activation of cultured quiescent satellite cells by rapid release of hepatocyte growth factor (HGF) from its extracellular association with satellite cells and its subsequent presentation to the c‐met receptor. The present study provides evidence that the stretch activation activity varies according to the origin of satellite cells from back and leg skeletal muscles in vitro. Satellite cells were isolated from three muscle groups, back (BK), upper hind limb (UL) and lower hind limb (LL) muscles, of adult male rats and stretch activation activities were compared. In response to stretch, lower hind limb satellite cells showed significantly greater response than upper hind limb and back muscles (LL > UL > BK). Immunoblots of stretched culture media revealed a higher HGF‐releasing capacity of lower hind limb satellite cells than back muscle satellite cells. In addition, lower hind limb satellite cells exhibited a greater activation activity in response to exogenous HGF added to culture media than compared to satellite cells from back and upper hind limb (LL > UL > BK). The increased ability to release HGF and the increased cellular responsiveness might account for higher stretch activation activities of lower hind limb satellite cells. Electrophoretic analysis of myosin heavy chain isoforms verified a higher content of slow muscle fibers in lower limb muscles (LL > UL > BK), suggesting a difference in stretch‐induced activation activity between satellite cells associated with fast and slow muscle fibers.     

Cryopreservation of canine ovaries by vitrification

The cryopreservation of ovarian tissues is a technology with significant potential for the preservation of the genetic resource materials of working dogs, including guide dogs for the blind. However, no attempt has been reported on cryopreservation of the canine ovary. Thus, we evaluated a vitrification method for cryopreservation of canine ovaries and determined the potential functionality of vitrified-warmed canine ovaries by means of transplantation into non-obese diabetic-severe combined immunodeficiency (NOD-SCID) mice. All ovarian tissues cryopreserved by vitrification were morphologically normal in terms of histology. Cryopreserved ovaries were transplanted into the ovarian bursa of the NOD-SCID mice, and the xenografts were recovered from 23 of 23 mice (100%) 4 weeks after the operation. The transplanted canine tissue was tightly adhered to the mouse ovary. Although antral follicle formation did not occur after grafting, proliferating cell nuclear antigen immunoreactivity was detectable in many of the granulosa cells in the primary follicles of the grafts. These results indicate that cryopreservation of the canine ovary by vitrification appears to have the potential to restore endocrine function and ovulation potential.     

Effect of farm household income levels and rice-based diet or water hyacinth (Eichhornia crassipes) supplementation on growth/cost performances and meat indexes of growing and finishing pigs in the Mekong Delta of Vietnam

An on‐farm trial was carried out to improve the current low‐income farmers’ diet and to assess farm conditions that could accept the new ingredients using locally available feed resources in the Mekong Delta region. A total of 42 local Large White‐type pigs, comprising 20 barrows and 22 gilts with initial‐to‐final mean live weight of 34.2–93.0 kg, were used. The trial was designed as a 3 × 3 factorial with three agricultural gross income levels of seven farm households and three dietary treatments. The annual income levels were high income (HI; $US2355 on average), medium income (MI; $US1439) and low income (LI; $US1116). The three types of diets were farmers’ common diet (FCD), rice‐based diet (RBD) and water‐hyacinth (Eichhornia crassipes)‐supplemented diet (WHD). A total of 12 pigs, consisting of two barrow–gilt couples in each diet treatment, were slaughtered at the end of the trial. The daily weight gain (DG) was higher and the feed conversion ratio (FCR) was lower in the MI and LI pigs than in the HI pigs over the entire fattening period (P < 0.01). No significant effect of the diet treatments was observed on the aforementioned two parameters, but the backfat thickness was least in WHD (16.8 mm) and next least in RBD (17.1 mm), compared with that of FCD pigs (19.4 mm; P < 0.05). The iodine values of RBD and WHD backfat were lower (P < 0.001) than those of FCD backfat. The cost performance, defined as feed cost per kg weight gain, was lowest for MI, intermediate for LI and highest for HI levels (P < 0.05). Therefore, the benefit was highest at the MI level and lowest at the HI level (P < 0.05). In contrast, cost performance of the diet treatments tended to be higher in FCD, and lower in RBD and WHD (P < 0.1). Then, the benefit tended to be higher in RBD and WHD than in the FCD diet (P < 0.1). Overall, these results suggest that the RBD and WHD diets be recommended especially to households with medium and low agricultural incomes.     

Two New Lyngbyatoxin Derivatives from the Cyanobacterium,Moorea producens

The toxin-producing cyanobacterium, Moorea producens, is a known causative organism of food poisoning and seaweed dermatitis (also known as “swimmer’s itch”). Two new toxic compounds were isolated and structurally elucidated from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies, as well as optical rotations and CD spectra indicated two new lyngbyatoxin derivatives, 2-oxo-3(R)-hydroxy-lyngbyatoxin A (1) and 2-oxo-3(R)-hydroxy-13-N-desmethyl-lyngbyatoxin A (2). The cytotoxicity and lethal activities of 1 and 2 were approximately 10- to 150-times less potent than lyngbyatoxin A. Additionally, the binding activities of 1 and 2 possessed 10,000-times lower affinity for the protein kinase Cδ (PKCδ)-C1B peptide when compared to lyngbyatoxin A. These findings suggest that these new lyngbyatoxin derivatives may mediate their acute toxicities through a non-PKC activation pathway.     

Soil hardness regulates the root penetration by trees planted on anthropogenic growing bases in coastal forests in Japan: new endeavors to reforest the coastal disaster prevention forests with high resilience for tsunami

Journal of Soils and Sediments - To restore the disaster resilience of coastal forests in tsunami-prone areas, growing bases have been artificially constructed with embanking before afforestation...