Role for piRNAs and noncoding RNA in de novo DNA methylation of the imprinted mouse Rasgrf1 locus

Genomic imprinting causes parental origin-specific monoallelic gene expression through differential DNA methylation established in the parental germ line. However, the mechanisms underlying how specific sequences are selectively methylated are not fully understood. We have found that the components of the PIWI-interacting RNA (piRNA) pathway are required for de novo methylation of the differentially methylated region (DMR) of the imprinted mouse Rasgrf1 locus, but not other paternally imprinted loci. A retrotransposon sequence within a noncoding RNA spanning the DMR was targeted by piRNAs generated from a different locus. A direct repeat in the DMR, which is required for the methylation and imprinting of Rasgrf1, served as a promoter for this RNA. We propose a model in which piRNAs and a target RNA direct the sequence-specific methylation of Rasgrf1.     

普通小麦与山羊草叶绿体基因组长度热点突变区的核苷酸序列分析

 检测了Ae. speltoides和Ae. ovata叶绿体基因组的一个长度热点突变区的核苷酸序列，并与普通小麦、四倍体Ae. crassa 以及Ae. squarrosa的相应序列进行了比较分析。从rbcL基因的终止密码子到cemA基因内的HindIII位点，Ae. speltoides和Ae. ovata的核苷酸序列长度分别为2 808 和 2 810bp。与四倍体Ae. crassa的序列相比，在普通小麦和Ae. speltoides中各有一个791 bp的大片段缺失，在Ae. ovata中存在一个793 bp的大片段缺失。Ae. ovata的缺失片段比普通小麦和Ae. speltoides的长2个碱基，推测Ae. ovata的大片段缺失在进化上是独立发生的。Ae. speltoides的大片段缺失与普通小麦的完全相同，支持Ae. speltoides是普通小麦叶绿体基因组供体的假说。除了大片段缺失外，在这个区域还检测到了7 个插入/缺失和15个碱基替换突变。研究结果表明，这个长度热点突变区的核苷酸序列分析是研究小麦与山羊草叶绿体基因组之间遗传变异关系的一个非常有效的途径。     

Oxygen isotopic compositions of asteroidal materials returned from Itokawa by the Hayabusa mission

Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa spacecraft. Compositions of the particles are depleted in (16)O relative to terrestrial materials and indicate that Itokawa, an S-type asteroid, is one of the sources of the LL or L group of equilibrated ordinary chondrites. This is a direct oxygen-isotope link between chondrites and their parent asteroid.     

Synthesis of morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) by dipeptidyl aminopeptidase IV derived from Aspergillus oryzae

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)), tetrapeptide, was synthesized using dipeptidyl aminopeptidase IV (DP IV, EC 3.4.14.5) derived from Aspergillus oryzae RIB 915 as a catalyst. Tyr-Pro-OEt was incubated with Phe-Pro-NH(2) in the presence of DP IV under various conditions of temperature, concentrations of ethylene glycol, pH, reaction time, and others. Morphiceptin was obtained at 40% yield under the optimal reaction conditions: substrate, 4 mM Tyr-Pro-OEt.HCl and 20 mM Phe-Pro-NH(2).HCl; enzyme, DP IV, 0.275 nkat; solvent, 60% ethylene glycol containing 20 mM phosphate buffer at pH 7.0; amine, 4.2 mM diisopropylamine at 4 degrees C for 24 h. Amino group protection was unnecessary for synthesis of morphiceptin by DP IV.     

Characteristics of fertilizer uptake and biodistribution in strawberry plants in two Japanese cultivars in hydroponic culture

ABSTRACT

The fertilizer absorption characteristics of strawberries are not clear, although appropriate fertilization is definitely necessary to ensure produce quality and quantity. This study aimed to determine the amounts of macro- and micronutrients absorbed during cultivation of strawberries and their biodistribution and utilization in the plant body. We cultivated Japanese strawberries ‘Benihoppe’ and ‘Kirapika’ in small hydroponic equipment containing a nutrient solution and determined the amounts of N, P, K, Ca, Mg, Fe, Mn, B, Zn, Cu, and Mo absorbed during and at the end of cultivation. The results revealed the adsorption levels of these elements during the cultivation period. The nutrient concentrations varied greatly among plant organs. In particular, P and B accumulated at high levels in the leaves and stem, K, Ca, Mg, Mn, Zn, and Cu accumulated in the crown, and N, Fe, and Mo accumulated in the roots. In addition, the uptake levels of N, P, K, Mg, Mn, Zn, and Cu differed between Benihoppe and Kirapika. Our results provide useful information for determining fertilizer application rates in strawberry cultivation.     

Analysis of hop-derived terpenoids in beer and evaluation of their behavior using the stir bar-sorptive extraction method with GC-MS

Hop aroma components, which mainly comprise terpenoids, contribute to the character of beers. However, pretreatments are necessary before analyzing these components because of their trace levels and complicated matrixes. Here, the stir bar-sorptive extraction (SBSE) method was used to detect and quantify many terpenoids simultaneously from small samples. This simple technique showed low coefficients of variation, high accuracy, and low detection limits. An investigation of the behavior of terpenoids identified two distinct patterns of decreasing concentration during wort boiling. The first, which was seen in myrcene and linalool, involved a rapid decrease that was best fitted by a quadratic curve. The second, which was observed in beta-eudesmol, humulene, humulene epoxide I, beta-farnesene, caryophyllene, and geraniol, involved a gentle linear decrease. Conversely, the concentration of beta-damascenone increased after boiling. As the aroma composition depended on the hop variety, we also examined the relationship between terpenoid content and sensory analysis in beer.     

Primary cardiac fibrosarcoma in a dog

A primary cardiac fibrosarcoma in the right atrium of a 6-year-old Chihuahua dog is described. At necropsy, there was a firm, whitish and spherical mass in the right atrium. Histopathologically, the mass had moderate cellularity composed of spindle-shaped cells with scattered multinucleated giant cells. The tumor cells were arranged in interwoven bundles and sheets in the collagenous stroma. No metastases were observed. Ultrastructurally, the tumor cells mainly consisted of fibroblasts. Multinucleated giant cells did not have any certain organelles that would indicate a higher order of differentiation. Primary cardiac sarcomas in dogs are extremely rare.     

Generation and characterization of anti-leptin antisera against synthetic peptides and recombinant protein

The objective of this study was to generate antisera against recombinant bovine leptin and synthetic oligopeptides corresponding to the amino acid sequence 21-40 and 91-110 of bovine leptin. Recombinant bovine leptin was raised in the 293 cells and purified from 10 L of conditioned medium and utilized for immunization. The synthetic peptides were conjugated with keyhole limpet hemocyanin and inoculated into rabbits for antibody generation. Antibody titer was monitored by enzymeimmunoassay, immunoblotting and sandwich binding assay techniques. Each of the antisera, against three different antigens, was found to react with bovine leptin. The titers of anti-peptide antisera were lower than that of anti-recombinant leptin antiserum. Since anti-recombinant leptin antiserum was not neutralized by the leptin peptides 21-40 and 91-110, it is suggested that each antiserum recognizes a distinct epitope. In immunoblot analyses, all antisera exhibited cross-reactivity with human and mouse leptins. However, in the sandwich binding assay, the combination of anti-peptide antisera and anti-recombinant leptin antiserum, originated from bovine leptin, did not cross-react with either human or mouse leptin. The discrepancy of antigenic recognition between the immunoblot analyses and sandwich assay is thought to be dependent on the conformational status of leptin molecules between the species. The antisera generated in this study, which recognized distinct epitopes of bovine leptin, will provide a useful tool for studies of bovine leptin functions.     

Simultaneous observation of the GnRH pulse generator activity and plasma concentrations of metabolites and insulin during fasting and subsequent refeeding periods in Shiba goats

The time course of GnRH pulse generator activity and plasma concentrations of energy substrates and insulin were simultaneously observed in female goats during 4-day fasting and subsequent refeeding in the presence or absence of estrogen for a better understanding of the mechanism of energetic control of gonadotropin secretion in ruminants. The GnRH pulse generator activity was electrophysiologically assessed with the intervals of characteristic increases in multiple-unit activity (MUA volleys) in the mediobasal hypothalamus. In estradiol-treated ovariectomized (OVX+E2) goats, the MUA volley intervals increased as fasting progressed. Plasma concentrations of non-esterified fatty acid and ketone body increased, while those of acetic acid and insulin decreased during fasting. The MUA volley intervals and plasma concentrations of those metabolites and insulin were restored to pre-fasting levels after subsequent refeeding. In ovariectomized (OVX) goats, changes in plasma metabolites and insulin concentrations were similar to those in OVX+E2 goats, but the MUA volley intervals were not altered. The present results demonstrated that fasting suppressed GnRH pulse generator activity in an estrogen-dependent manner. Changes in plasma concentrations of energy substrates and insulin during fasting were associated with the GnRH pulse generator activity in the presence of estrogen, but not in the absence of the steroid in female goats.