DNA methylation and epigenetic inheritance during plant gametogenesis

In plants, newly acquired epigenetic states of transcriptional gene activity are readily transmitted to the progeny. This is in contrast to mammals, where only rare cases of transgenerational inheritance of new epigenetic traits have been reported (FASEB J 12:949-957, 1998; Nat Genet 23:314-318, 1999; Proc Natl Acad Sci U S A 100:2538-2543, 2003). Epigenetic inheritance in plants seems to rely on cytosine methylation maintained through meiosis and postmeiotic mitoses, giving rise to gametophytes. In particular, maintenance of CpG methylation (mCpG) appears to play a central role, guiding the distribution of other epigenetic signals such as histone H3 methylation and non-CpG DNA methylation. The evolutionarily conserved DNA methyltransferase MET1 is responsible for copying mCpG patterns through DNA replication in the gametophytic phase. The importance of gametophytic MET1 activity is illustrated by the phenotypes of met1 mutants that are severely compromised in the accuracy of epigenetic inheritance during gametogenesis. This includes elimination of imprinting at paternally silent loci such as FWA or MEDEA (MEA). The importance of DNA methylation in gametophytic imprinting has been reinforced by the discovery of DEMETER (DME), encoding putative DNA glycosylase involved in the removal of mC. DME opposes transcriptional silencing associated with imprinting activities of the MEA/FIE polycomb group comple

Direct Estimation of Valence Electron Distribution Around an Ion in Liquid Metals

Liquid metals consist of ions and electrons. However, the bare ions in liquid metals are recognized to be partially screened by electrons so as to produce the effective ion-ion potential of the long-range oscillatory type and then liquid metals are likely the binary mixtures of ions with some electrons for partial screening and the valence electrons giving a strongly coupled plasma. An attempt is made in this paper to present the valence electron distribution around an ion in liquid metals. The principle of a new method for estimating such information in liquid metals from measured structural data has been described with some selected examples

Histological Studies on Some Organs of Two Male Dealfishes, Trachipterus ishikawae, Caught on the Beach of Shirahama, Wakayama Prefecture, Pacific Coast of Japan

The testis, thyroid, kidney, exocrine pancreas, endocrine pancreas (=Brockmann body), spleen and liver of two dealfishes, Trachipterus ishikawae, collected on the beach of Shirahama, Wakayama Prefecture, Pacific coast of Honshu, Japan, were examined histologically. The specimens measured 2.30 m (specimen A) and 1.65 m (specimen B) in total length. The testicular lobes were atrophied and sclerotized, having the appearance of an aggregation of numerous protuberances (or spherules), each spherule corresponding to a lobule containing a number of cysts, although some of the latter had collapsed and/or merged with each other. Each cyst contained sperms and spermatids, relict sperms being found in the spermiduct. The thyroid gland, an amorphously soft body, located dorsally on the ventral aorta and its afferent branchial arteries, was composed of many variously-sized follicles. Each follicle comprised a large amount of smooth colloid, surrounded by a flat epithelium consisting of cubic cells. The overall condition indicated an inactive state. In the kidney, a great deal of stromatous tissue, including AF positive lipid grains, and a small number of glomeruli were apparent. In both specimens, the thread-like loose connective tissue comprising the exocrine pancreas attached to and running parallel with the liver, stomach, Brockmann body and spleen, were composed of acini with zymogen-rich pyramidal cells. Details of cell types in the Brockmann body were difficult to determine. Fatty deposits were absent from the liver of specimen A, which was characterized by rich stromatous tissue and dilated sinusoids. However, rich fatty deposits were found in several portions of the liver of specimen B. Well-developed stromatous tissue and nodules of red- and white pulps were recognized. It was concluded that the two specimens were spent and debilitated males

KINETIC ANALYSIS OF START MOTION ON STARTING BLOCK IN COMPETITIVE SWIMMING

The aim of this study was to investigate kinetic features of start motion with use of an instrumented starting block. This is the first study that quantified joint torques of the whole body during start motion. Six male swimmers dived from the instrumented starting block, which contains force plates and sensors. Four high-speed cameras were used to obtain kinematics data of the swimmers. Inverse dynamics calculation was carried out with use of the kinetics and kinematics data. The results showed that 1) the large pulling up forces exerted by both hands were generated by extension toques of the shoulder joints, 2) the rear side lower limb joints exerted large extension torque to obtain horizontal reaction force, and 3) the knee joint of the front side lower limb exerted large flexion torque to maintain the large vertical reaction force until 60% normalized start motion time

Gender-specific regulation of response to thyroid hormone in aging

<p>Abstract</p> <p>Background</p> <p>Similar to other systems, the endocrine system is affected by aging. Thyroid hormone, the action of which is affected by many factors, has been shown to be associated with longevity. The most useful marker for the assessment of thyroid hormone action is TSH level. Although age and gender are believed to modify the pituitary set point or response to free thyroid hormone concentration, the precise age- and gender-dependent responses to thyroid hormone have yet to be reported.</p> <p>Methods</p> <p>We analyzed the results of 3564 thyroid function tests obtained from patients who received medication at both out- and inpatient clinics of Shinshu University Hospital. Subjects were from among those with thyroid function test results in the normal or mildly abnormal range. Based on a log-linear relationship between the concentrations of FHs and TSH, we established the putative resistance index to assess the relation between serum FH and TSH levels.</p> <p>Results</p> <p>Free thyroid hormone and TSH concentration showed an inverse log-linear relation. In males, there was a negative relationship between the free T3 resistance index and age. In females, although there were no relationships between age and FHs, the indices were positively related to age.</p> <p>Conclusions</p> <p>These findings indicated that there is a gender-specific response to thyroid hormone with aging. Although the TSH level is a useful marker for the assessment of peripheral thyroid hormone action, the values should be interpreted carefully, especially with regard to age- and gender-related differences.</p