Derivation of Human Trophoblast Stem Cells

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Microbiological Redox Potential Control to Improve the Efficiency of Chalcopyrite Bioleaching

The effect of controlling the redox potential (E_h) on chalcopyrite bioleaching kinetics was studied as a new aspect of redox control during chalcopyrite bioleaching, and its mechanism was investigated by employing the “normalized” solution redox potential (E_normal) and the reaction kinetics model. Different E_h ranges were established by use of different acidophiles (Sulfobacillus acidophilus YTF1; Sulfobacillus sibiricus N1; Acidimicrobium ferrooxidans ICP; Acidiplasma sp. Fv-AP). Cu dissolution was very susceptible to real-time change in E_h during the reaction. It was found that efficiency of bioleaching of chalcopyrite can be effectively evaluated on the basis of E_normal, since it is normalized for real-time fluctuations of concentrations of major metal solutes during bioleaching. For steady Cu solubilization during bioleaching at a maximum rate, it was important to maintain a redox potential range of 0 ≤ E_normal ≤ 1 (?0.35 mV optimal) at the mineral surface by employing a “weak” ion-oxidizer. This led to a copper recovery of > 75%. At higher E_normal levels (E_normal > 1 by “strong” microbial Fe²⁺ oxidation), Cu solubilization was slowed by diffusion through the product film at the mineral surface (< 50% Cu recovery) caused by low reactivity of the chalcopyrite and by secondary passivation of the chalcopyrite surface, mainly by jarosite.     

The Rare Disease Bank of Japan: establishment,current status and future challenges

Research on rare diseases cannot be performed without appropriate samples from patients with such diseases. Due to the limited number of such patients, securing biosamples of sufficient quality for extensive research is a challenge and represents an important barrier to the advancement of research on rare diseases. To tackle this problem, the Rare Disease Bank (RDB) was established in 2009 at the National Institute of Biomedical Innovation (NIBIO; currently, the National Institutes of Biomedical Innovation, Health and Nutrition in Japan). Since then, the RDB has focused on three objectives: (1) emphasizing the importance of collecting biosamples from patients with rare diseases, together with appropriate clinical information, from various medical facilities nationwide; (2) maintaining strict high-quality sample management standards; and (3) sharing biosamples with research scientists across Japan for the advancement of research on rare diseases. As of August 2017, the bank has collected 4147 biosamples from patients with rare diseases, including DNA, serum, plasma, and cell samples from various university hospitals and other medical institutions across the country, and provided various research institutions with 13,686 biosample aliquots from 2850 cases. In addition, the management committee has successfully established a bank system that provides high-quality biosamples together with the results of human leukocyte antigen analysis. It is anticipated that the RDB, through the collection and sharing of biosamples with the medical research community, will enhance the understanding, prevention, and treatment of rare diseases in Japan and the world at large.     

Nutrient deficiency promotes male-biased apparent sex ratios at the ramet level in the dioecious plant <Emphasis Type="Italic">Myrica gale</Emphasis> var. <Emphasis Type="Italic">tomentosa</Emphasis> in oligotrophic environments in bogs

In populations of dioecious plants, the differences in the cost of reproduction between male and female plants can promote a male-biased sex ratio. In this study, we examine the macronutrient levels in tissues of the dioecious wetland shrub Myrica gale to identify the cost of reproduction for male and female plants and to examine the effect of nutrients on the apparent sex ratio at the ramet level. We examined plants across 12 populations of M. gale inhabiting bogs and fens in Japan. For each population, we used line transects to estimate the apparent sex ratio and measured the concentrations of nitrogen (N), phosphorus (P), and potassium (K) in the leaves sampled from male and female plants and in the fruits from female plants. For five of the populations, we calculated the flowering frequency, mortality, and the recruitment rate (as the rate of clonal propagation). We found that the proportion of females was positively affected, and the male bias of sex ratios reduced, by increases in P concentration in leaves sampled from female plants. Neither mortality nor recruitment was affected by sex or by the nutrient concentration (P, K). The flowering frequency was not affected by sex or by K concentration, but decreased with decreases in the P concentration measured in leaves. This study confirmed that reproduction in M. gale is P-limited. We found no distinct differences in the flowering frequency, mortality, or recruitment rate between the male and female plants.     

Involvement of Cyanogens in the Promotion of Germination of Cocklebur Seeds in Response to Various Nitrogenous Compounds, Inhibitors of Respiratory and Ethylene

Nitrogenous inhibitors of respiration, namely, KCN, NaN₃ andNH₂OH, which promote the germination of cocklebur (Xanthiumpennsylvanücum Wallr.) seeds, enhanced the accumulationof cyanogenic compounds. Urea and cyanamide, which were ineffective,did not. Part of the exogenously applied KCN was converted tocyanogenic glycosides and lipids, but these compounds were onlyproduced at low levels in NaN₃-treated seeds. Exposure to NH₂OHcaused a slight accumulation of both types of cyanogenic compounds.Thiourea, effective in stimulating germination, did not increasethe cyanogenic compounds, which suggests that the mechanismof its effect on germination is different from that of othernitrogenous compounds. Thiocyanate had a slightly promotiveeffect and caused minor increases in the levels of cyanogeniccompounds. Ethylene increased the metabolic utilization of the accumulatedcyanogens in response to KCN or NaN₃. The response to ethyleneof seeds in secondary dormancy was restored only after pre-treatmentwith KCN or NaN₃. The response occurred once the level of cyanogenshad increased. By contrast, enhancement of the effects of KCNand NaN₃ on germination by propyl gallate or benzohydroxamate,inhibitors of CN-resistant respiration, was accompanied by theincreased accumulation of cyanogens within the seeds that hadbeen exposed to KCN or NaN₃ in combination with the other typesof respiratory inhibitors. Thus, it is suggested that endogenouscyanogens might be involved in the germination of cockleburseeds. (Received December 20, 1995; Accepted April 9, 1996)     

Optical isolation of individual mitochondria ofPhysarum polycephalum for PCR analysis

Summary We attempted to amplify a specific region of mitochondrial DNA (mtDNA) using the polymerase chain reaction (PCR) from fewer than ten mitochondria isolated individually by microdissection or use of an optical tweezer. We selected preliminarily isolated mitochondria fromPhysarum polycephalum as the model materials and tried to amplify the mtDNA region corresponding to the specific mitochondrial plasmid of this true slime mould. For separation of a few mitochondria from the mitochondrial population, we initially used a destruction method in which excluded mitochondria were disrupted by a UV laser. However, mtDNA was still amplified, although weakly, from mitochondria that had been destroyed by the UV laser. Therefore, we used an optical tweezer to trap individual mitochondria and separate them from the others. The required number of mitochondria were separated from the mitochondrial suspension through a narrow canal of isolation buffer and used directly for PCR amplification. The results showed that the mtDNA could be amplified from at least 9 mitochondria trapped by the optical tweezer.Abbreviations DAPI 4,6-diamidino-2-phenylindole - EDTA ethylenediaminetetraacetic acid - mtDNA mitochondrial DNA - PCR polymerase chain reaction     

Mapping of the Gene for Machado-Joseph Disease within a 3.6-cM Interval Flanked by D14S291/D14S280 and D14S81, on the Basis of Studies of Linkage and Linkage Disequilibrium in 24 Japanese Families

The gene locus of Machado-Joseph disease (MJD) has recently been mapped within a 29-cM subregion of 14q chromosome. We did a linkage study of 24 multigenerational MJD Japanese pedigrees, in an attempt to narrow the candidate region of this gene. Pairwise and multipoint linkage analysis, together with haplotype segregation analysis, led to the conclusion that the MJD gene is located at the 6.8-cM interval between D14S256 and D14S81 (Z_max = 24.78, multipoint linkage analysis). D14S291 and D14S280, located at the center of this interval, showed no obligate recombination with the MJD gene (Z_max = 5.93 for D14S291 and 9.99 for D14S280). A weak, but significant, linkage disequilibrium of MJD gene was noted with D14S81 (P < .05) but not with D14S291 or D14S280. These results suggest that a 3.6-cM interval flanked by D14S291/D14S280 and D14S81 is the most likely location of the MJD gene and that it is closest to D14S81.     

Erythropoietin processing in erythropoietic system and central nervous system

We describe possible functions of carbohydrates attached to growth factors and strategies to examine the functions, concentrating on erythropoietin, a major regulator of erythropoiesis. Erythropoietin in erythropoiesis functions as an endocrine hormone; it is produced by kidney cells and transferred into the circulation to hemopoietic sites. In the brain, erythropoietin acts on neurons in a paracrine fashion. Comparison of glycosylation has been made between kidney and brain erythropoietins.Abbreviations BHK Baby Hamster Kidney - Epo Erythropoietin - Epo-R erythropoietin receptor     

A monoclonal antibody against T-cell receptor αβ induces endogenous cytokines and prevents mice from a lethal infection with Listeria monocytogenes

Abstract In vivo induction of cytokines by a monoclonal antibody (mAb) against T-cell receptor (TCR) αβ and the protective effect induced by the mAb on a lethal infection with Listeria monocytogenes were studied. Injection of anti-TCR αβ mAb induced rapid production of endogenous tumour necrosis factor in the spleens, and gamma interferon and interleukin-6 in the bloodstreams and spleens of mice. Administration of anti-CD4 mAb, anti-CD8 mAb, or anti-Thy1.2 mAb resulted in suppression of anti-TCR αβ mAb-induced endogenous cytokine production. Mice were protected against lethal L. monocytogenes infection when treated with anti-TCR αβ mAb. The protective effect was not demonstrated in CD4 + cell- or CD8 + cell-depleted mice. These results suggest that anti-TCR αβ mAb shows a protective effect on a lethal infection with L. monocytogenes in mice and that the mAb-induced endogenous cytokines might be involved in the effect of anti-TCR αβ mAb.