Restoration of G1 chemo/radioresistance and double-strand-break repair proficiency by wild-type but not endonuclease-deficient Artemis

Deficiency in Artemis is associated with lack of V(D)J recombination, sensitivity to radiation and radiomimetic drugs, and failure to repair a subset of DNA double-strand breaks (DSBs). Artemis harbors an endonuclease activity that trims both 5'- and 3'-ends of DSBs. To examine whether endonucleolytic trimming of terminally blocked DSBs by Artemis is a biologically relevant function, Artemis-deficient fibroblasts were stably complemented with either wild-type Artemis or an endonuclease-deficient D165N mutant. Wild-type Artemis completely restored resistance to γ-rays, bleomycin and neocarzinostatin, and also restored DSB-repair proficiency in G0/G1 phase as measured by pulsed-field gel electrophoresis and repair focus resolution. In contrast, cells expressing the D165N mutant, even at very high levels, remained as chemo/radiosensitive and repair deficient as the parental cells, as evidenced by persistent γ-H2AX, 53BP1 and Mre11 foci that slowly increased in size and ultimately became juxtaposed with promyelocytic leukemia protein nuclear bodies. In normal fibroblasts, overexpression of wild-type Artemis increased radioresistance, while D165N overexpression conferred partial repair deficiency following high-dose radiation. Restoration of chemo/radioresistance by wild-type, but not D165N Artemis suggests that the lack of endonucleolytic trimming of DNA ends is the principal cause of sensitivity to double-strand cleaving agents in Artemis-deficient cells.     

Development of an Umami Taste Sensitivity Test and Its Clinical Use

There is a close relationship between perception of umami, which has become recognized as the fifth taste, and the human physical condition. We have developed a clinical test for umami taste sensitivity using a filter paper disc with a range of six monosodium glutamate (MSG) concentrations. We recruited 28 patients with taste disorders (45–78 years) and 184 controls with no taste disorders (102 young [18–25 years] and 82 older [65–89 years] participants). Filter paper discs (5 mm dia.) were soaked in aqueous MSG solutions (1, 5, 10, 50, 100 and 200 mM), then placed on three oral sites innervated by different taste nerves. The lowest concentration participants correctly identified was defined as the recognition threshold (RT) for MSG. This test showed good reproducibility for inter- and intra-observer variability. We concluded that: (1) The RT of healthy controls differed at measurement sites innervated by different taste nerves; that is, the RT of the anterior tongue was higher than that of either the posterior tongue or the soft palate in both young and older individuals. (2) No significant difference in RT was found between young adults and older individuals at any measurement site. (3) The RT of patients with taste disorders was higher before treatment than that of the healthy controls at any measurement site. (4) The RT after treatment in these patients improved to the same level as that of the healthy controls. (5) The cutoff values of RT, showing the highest diagnostic accuracy (true positives + true negatives), were 200 mM MSG for AT and 50 mM MSG for PT and SP. The diagnostic accuracy at these cutoff values was 0.92, 0.87 and 0.86 for AT, PT and SP, respectively. Consequently, this umami taste sensitivity test is useful for discriminating between normal and abnormal umami taste sensations.     

Bone morphogenetic proteins in dentin regeneration for potential use in endodontic therapy

The human dentition is indispensable for nutrition and physiology. The teeth have evolved for mastication of food. Caries is a common dental problem in which the dentin matrix is damaged. When the caries is deep and the dental pulp is exposed, the pulp has to be removed in many cases, resulting ultimately in loss of the tooth. Therefore, the regeneration of dentin-pulp complex is the long-term goal of operative dentistry and endodontics. The key elements of dentin regeneration are stem cells, morphogens such as bone morphogenetic proteins (BMPs) and a scaffold of extracellular matrix. The dental pulp has stem/progenitor cells that have the potential to differentiate into dentin-forming odontoblasts in response to BMPs. Pulpal wound healing consists of stem/progenitor cells release from dental pulp niche after noxious stimuli such as caries, migration to the injured site, proliferation and differentiation into odontoblasts. There are two main strategies for pulp therapy to regenerate dentin: (1) in vivo method of enhancing the natural healing potential of pulp tissue by application of BMP proteins or BMP genes, (2) ex vivo method of isolation of stem/progenitor cells, differentiation with BMP proteins or BMP genes and transplantation to the tooth. This review summarizes recent advances in application of BMPs for dentin regeneration and possible use in endodotic therapy.     

Fatty acid composition of a new marine picoplankton species of the Chromophyta

A marine yellowish picoplankton, strain PP301, which was newly isolated from the surface seawater of the western Pacific Ocean was an eminent producer of polyunsaturated fatty acids. Its fatty acids were mostly shared by the shortest saturated form (14:0, 20–30%) and polyunsaturated forms (20:4, EPA and DHA) which accounted for about 50% of the total fatty acids. The amount of intermediate forms in 16 and 18 carbon chains were very little. This composition was consistently observed irrespective of the growth temperatures (15–35 °C).     

Isolation and amino acid composition of human angiotensin I

1. Angiotensin, the most powerful pressor substance known, suspected to be a causal substance in renal hypertension and previously isolated from animal sources, has now been isolated from human sources and the amino acid composition was analysed. 2. The procedures followed in the successful isolation of human angiotensin include: (a) preparation of stable materials to obtain maximum formation of human angiotensin; (b) a relatively selective adsorption of the formed angiotensin on Dowex 50W (X2); (c) gel filtration through Sephadex G-25; (d) cation-exchange chromatography on CM-cellulose; (e) anion-exchange gel filtration on DEAE-Sephadex A-25; (f) molecular-sieve chromatography through Bio-Gel P-2. 3. The homogeneity of the human angiotensin isolated was confirmed by paper and thin-layer chromatography and paper electrophoresis. 4. The biological activity observed indicates the substance isolated to be human angiotensin I. 5. The amino acid analysis suggested the following proportional composition: Asp, 1; Pro, 1; Val, 1; Ile, 1; Leu, 1; Tyr, 1; Phe, 1; His, 2; Arg, 1. This composition is similar to that of horse angiotensin I, i.e. isoleucine(5)-angiotensin I.     

Protection by dexamethasone from a lethal infection with Listeria monocytogenes in mice

Abstract The effects of dexamethasone (DEX) on a lethal infection with Listeria monocytogenes were studied in mice. Mice were completely protected against the lethal infection when treated with 3.3 mg per kg of DEX. The effect was observed only when DEX was injected before infection. The control mice died from day 3 to day 5 of infection, whereas DEX-treated mice could eliminate L. monocytogenes cells from the organs by day 11 of infection. High titres of endogenous tumour necrosis factor (TNF), interleukin-6 (IL-6) and gamma interferon (IFN-γ) were induced in the bloodstreams and organs of the drug-free mice. DEX suppressed IL-6 production, but augmented TNF and IFN-γ production within 24 h of infection, whereas production of all three endogenous cytokines was suppressed in the DEX-treated mice on day 3 of infection when the control mice began to die. These results suggest that DEX shows a protective effect on a lethal infection with L. monocytogenes in mice and that regulation of production of endogenous cytokines might be involved in the effect of DEX.     

Male-female interactions of sika deer (cervus nippon) in nara park through allogrooming during breeding and rutting seasons

The frequency and pattern of interactions between males and females of sika deerCervus nippon were surveyed in 3 sites of Nara Park, central Japan, mainly via observation of allogrooming frequency and aggressive behavior throughout the breeding and rutting seasons. In the breeding season, the Daibutsuden group contained several adult males while Ukimido and Hakuba groups contained only a few. Most allogroomers were adult and subadult females. Females groomed the same sex more than the opposite sex at Daibutsuden, but at the other 2 sites, there was no such difference. In general, male-female interactions through allogrooming frequencies in the breeding season were not significantly fewer than intra-sex interactions. Males that attacked females tended to be groomed by females in the breeding season. In the rutting season, all adult males identified in the breeding season were absent at the usual observation sites, and newly arrived males showed defensive and/or mating behaviors. Females groomed adult males in the rutting season regardless of group status or display of sexual interactions. This suggests that male-female allogrooming in the breeding season does not relate to mating in the following rutting season, but may reduce tension in the group during the current breeding season.