Pattern of natural 15N abundance in lakeside forest ecosystem affected by cormorant-derived nitrogen

Waterbirds are one of the most important groups of organisms inhabiting the land–water interface, especially with regard to mediating the transport of materials from the aquatic to the terrestrial environment. The great cormorant (Phalacrocorax carbo) is a colonial piscivorous bird that transports nutrients from fresh water to forest. We measured cormorant-derived nitrogen at two nesting colonies on the Isaki Peninsula and Chikubu Island at Lake Biwa, Japan, and analyzed the long-term effects of cormorant colonization on the forest nitrogen cycle, and the mechanisms of nitrogen retention. Three sites were examined in each colony: a currently occupied area, a previously occupied but now abandoned area, and a control area never colonized by cormorants. High nitrogen stable isotope ratios of cormorant excreta, the forest floor, mineral soil, and living plants showed cormorant-derived nitrogen in both occupied and abandoned areas. The relationship between δ¹⁵N and N content showed that the high δ¹⁵N of the excreta and N turnover in the soil were important at the occupied sites, whereas high δ¹⁵N of litter was important at the abandoned sites. Physiological changes of various organisms are also important for the N decomposition process. In conclusion, cormorant-derived nitrogen remains in the forest ecosystem as a result of two cormorant activities: heavy deposition of excreta and collection of nitrogen-rich nest material. Colony stage (occupied, abandoned, or never inhabited) and historical change of N decomposition process of an area can be identified from the relationship between δ¹⁵N and N content.     

Mapping of quantitative trait loci for carcass traits in a Japanese Black (Wagyu) cattle population

To detect quantitative trait loci (QTL) that influence economically important traits in a purebred Japanese Black cattle population, we performed a preliminary genome-wide scan using 187 microsatellite markers across a paternal half-sib family composed of 258 offspring. We located six QTL at the 1% chromosome-wise level on bovine chromosomes (BTA) 4, 6, 13, 14 and 21. A second screen of these six QTL regions using 138 additional paternal offspring half-sib from the same sire, provided further support for five QTL: carcass weight on BTA14 (22-39 cM), one for rib thickness on BTA6 (27-58 cM) and three for beef marbling score (BMS) on BTA4 (59-67 cM), BTA6 (68-89 cM) and BTA21 (75-84 cM). The location of QTL for subcutaneous fat thickness on BTA13 was not supported by the second screen (P > 0.05). We determined that the combined contribution of the three QTLs for BMS was 10.1% of the total variance. The combined phenotypic average of these three Q was significantly different (P < 0.001) from those of other allele combinations. Analysis of additional half-sib families will be necessary to confirm these QTL.     

Suppression of AGE precursor formation following unilateral ureteral obstruction in mouse kidneys by transgenic expression of alpha-dicarbonyl/L-xylulose reductase

Unilateral ureteral obstruction (UUO) of kidneys causes acute generation of carbonyl stress. By electrospray ionization/liquid chromatography/mass spectrometry (ESI/LC/MS) we measured the content of methyl glyoxal, glyoxal, and 3-deoxyglucosone in mouse kidney extracts following UUO. UUO resulted in elevation of these dicarbonyls in the obstructed kidneys. Furthermore, the accumulation of 3-deoxyglucosone was significantly reduced in the kidneys of mice transgenic for alpha-dicarbonyl/L-xylulose reductase (DCXR) as compared to their wild-type littermates, demonstrating 4.91+/-2.04 vs. 6.45+/-1.85 ng/mg protein (P=0.044) for the obstructed kidneys, and 3.68+/-1.95 vs. 5.20+/-1.39 ng/mg protein (P=0.026) for the contralateral kidneys. On the other hand, collagen III content in kidneys showed no difference as monitored by in situ hybridization. Collectively, DCXR may function in the removal of renal alpha-dicarbonyl compounds under oxidative circumstances, but it was not sufficient to suppress acute renal fibrosis during 7 d of UUO by itself.     

Modulation of Protein Phosphorylation by M r 25,000 Protein Partially Overlapping Phosvitin and Lipovitellin 2 in Xenopus laevis Vitellogenin B1 Protein

A phosphorylated protein with molecular mass of 25,000 (pp25) is a component of Xenopus laevis vitellogenin B1. In an attempt to elucidate the physiological role of pp25, its effect on protein phosphorylation was studied. In vitro phosphorylation of some endogenous proteins from the cytoplasm and membrane fraction of Xenopus oocytes by casein kinase II and protein kinase C (PKC) was inhibited by increasing the concentration of pp25. By Western blot analysis using an antibody against phospho-(Ser/Thr) PKC substrate, phosphorylation of some endogenous proteins, especially in the cytoplasm, of Xenopus embryos was seen to increase when pp25 disappeared during developmental stages 35–45. These results suggest that pp25 may have a role as an inhibitory modulator of some protein phosphorylation in Xenopus oocytes and embryos.     

Role of COX-1 and COX-2 on skin PGs biosynthesis by mechanical scratching in mice

We examined the involvement of cyclooxygenase (COX)-1 and COX-2 on mechanical scratching-induced prostaglandins (PGs) production in the skin of mice. The dorsal regions of mice were scratched using a stainless brush. COXs expressions in the skin were analyzed using real-time PCR and Western blotting. The effect of acetylsalicylic acid (ASA) on the ability of PGs production were determined based on skin PGs level induced by arachidonic acid (AA) application. Mechanical scratching increased PGD2, PGE2, PGI2 and PGF(2 alpha). COX-1 was constitutively expressed and COX-2 expression was enhanced by scratching. Intravenous administration of ASA inhibited PGs biosynthesis in the normal skin. PGs levels of the skin 6h after ASA administration (ASA 6 h) were almost equal to those of the skin 10 min after ASA administration (ASA 10 min). In the scratched skin, AA-induced PGE2 and PGI2 of ASA 6 h were significantly higher than those of ASA 10 min. The skin PGD2 and PGF(2 alpha) of ASA 10 min were almost same to those of ASA 6 h. In the normal skin of COX-1-deficient mice, skin PGD2 level was lower than that of wild-type mice, although PGE2, PGI2 and PGF(2 alpha) levels were almost equal to those of wild type. In the scratched skin of COX-1-deficient mice, PGD2, PGE2, PGI2 and PGF(2 alpha) levels were lower than those of wild-type mice. These results suggested that cutaneous PGD2 could be mainly produced by COX-1, and PGE2 and PGI2 could be produced by COX-1 and COX-2, respectively, in mice.     

Evolution of BK Virus Based on Complete Genome Data

The human polyomavirus BK virus (BKV) is ubiquitous in humans, infecting children asymptomatically. BKV is the only primate polyomavirus that has subtypes (I–IV) distinguishable by immunological reactivity. Nucleotide (nt) variations in a major capsid protein (VP1) gene region (designated the epitope region), probably responsible for antigenic diversity, have been used to classify BKV isolates into subtypes. Here, with all the protein-encoding gene sequences, we attempted to elucidate the evolutionary relationships among 28 BKV isolates belonging to subtypes I, III, and IV (no isolate belonging to subtype II, a minor one, was included). First, using the GTR + Γ + I model, maximum likelihood trees were reconstructed for individual viral genes as well as for concatenated viral genes. On the resultant trees, the 28 BKV isolates were consistently divided into three clades corresponding to subtypes I, III, and IV, although bootstrap probabilities are not always high. Then we used more sophisticated likelihood models, one of which takes account of codon structure, to elucidate the phylogenetic relationships among BKV subtypes, but the phylogeny of the deep branchings remained ambiguous. Furthermore, the possibility of positive selection in the evolution of BKV was examined using the nonsynonymous/synonymous rate ratio as a measure of selection. An analysis based on entire genes could not detect any strong evidence for positive selection, but that based on the epitope region identified a few sites potentially under positive selection (these sites were among those showing subtype linked polymorphisms). These author Yuriko Nishimoto and Tomokazu Takasaka contributed equally to this article. [Reviewing Editor: Dr. Rasmus Nielsen]