The APC/C activator Cdh1 regulates the G2/M transition during differentiation of placental trophoblast stem cells

Differentiation of placental trophoblast stem (TS) cells to trophoblast giant (TG) cells is accompanied by transition from a mitotic cell cycle to an endocycle. Here, we report that Cdh1, a regulator of the anaphase-promoting complex/cyclosome (APC/C), negatively regulates mitotic entry upon the mitotic/endocycle transition. TS cells derived from homozygous Cdh1 gene-trapped (Cdh1^GT/GT) murine embryos accumulated mitotic cyclins and precociously entered mitosis after induction of TS cell differentiation, indicating that Cdh1 is required for the switch from mitosis to the endocycle. Furthermore, the Cdh1^GT/GT TS cells and placenta showed aberrant expression of placental differentiation markers. These data highlight an important role of Cdh1 in the G2/M transition during placental differentiation.     

Fractionation of chromosomal proteins of pea seedlings using procedures which avoid denaturation

Chromatin was prepared from the buds and cotyledons of Alaskapea seedlings. The dissociated chromosomal components in thepresence of 2 M NaCl and 5 M urea were completely fractionatedinto DNA and proteins with a Bio-Gel A50 column. The proteinswere recovered by (NH₄)₂SO₄ and further fractionated into histonesand non-histone proteins using a Bio-Rex 70(Na⁺) column. Thedifference in the ratios of histones to non-histone proteinsbefore and after chromatography with the Bio-Rex 70 was lessthan 10%. The histones and non-histone proteins thus preparedshowed typical protein absorption spectra. Polyacrylamide gelelectrophoresis of histones showed that the histone compositionsin buds and cotyledon were similar, but the amount of HI histoneswas a little less in cotyledons than in buds. Unlike histones,non-histone proteins fractionated by SDS-polyacrylamide gelelectrophoresis indicated distinct differences between the twotissues. Buds had more heterogeneous non-histone proteins, atleast 13 polypeptides, than cotyledons did. On the other hand,non-histone proteins of cotyledons showed less heterogeneityand lacked proteins of high molecular weight which were foundin buds. (Received May 6, 1976; )     

Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort

ABSTRACT

Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients.     

Purification of Protein Body-I of Rice Seed and its Polypeptide Composition

Protein body type one (PB-I) was isolated and purified fromdeveloping rice grain by a combination of sucrose density gradientcentrifugation and treatment with pepsin. SDS-PAGE analysisshowed that isolated PB-I contains several polypeptide groups,the largest having an apparent molecular size of 13 kDa andtwo smaller ones of 10 kDa and 16 kDa. The 13-kDa group wasfound to be composed of two polypeptides of slightly differentmolecular sizes, 13a (larger component) and 13b (smaller component).Most of the 13a and 13b polypeptides were shown to be largelyprolamins, although there were also some salt- and alcohol-insolublepolypeptides with an apparent molecular size of 13 kDa. It wasconcluded that PB-I is the accumulation site of rice prolamin.It was further estimated that the protein amount in PB-I accountedfor about 20% of the total protein of rice endosperm. (Received March 20, 1987; Accepted September 8, 1987)     

Effect of Exogenous Gangliosides on Amino Acid Uptake and Na+,K+-ATPase Activity in Superior Cervical and Nodose Ganglia of Rats

The effects of some gangliosides on active uptake of nonmetabolizable alpha-aminoisobutyric acid (AIB) and Na+, K+-ATPase and Ca2+, Mg2+-ATPase activities in superior cervical ganglia (SCG) and nodose ganglia (NG) excised from adult rats were examined during aerobic incubation at 37 degrees C for 2 h. In NG, amino acid uptake was greatly accelerated with the addition of galactosyl-N-acetylgalactosaminyl-[N-acetylneuraminyl]-galactosylgluc osyl ceramide (GM1) (85%) and also with N-acetylgalactosaminyl-[N-acetylneuraminyl]-galactosylglucosyl ceramide (GM2) or [N-acetylneuraminyl]-galactosyl-N-acetylgalactosaminyl-[N-acetyl- neuraminyl]-galactosylglucosyl ceramide (GD1a) (43% each) compared with a nonaddition control at a 5 nM concentration. Under identical conditions, Na+, K+-ATPase activity was strongly stimulated with GM1 (180%) and GD1a (93%), whereas Ca2+, Mg2+-ATPase activity showed no change. In SCG, on the other hand, AIB uptake was apparently inhibited (-27%) by addition of GM1, with a slight decrease in Na+, K+-ATPase but no change in Ca2+, Mg2+-ATPase activity in the tissue. Both asialo-GM1, in which N-acetylneuraminic acid is deficient, and Forssman glycolipid, which is not present in nervous tissue, failed to produce any significant increase in both SCG and NG not only in amino acid uptake, but also in Na+, K+-ATPase activity. A kinetic study of active AIB uptake showed that GM1 ganglioside produced an increase in Km with no change in Vmax in SCG, whereas it caused a decrease in Km with a slight increase in Vmax in NG. Treatment of NG and SCG with neuraminidase from Vibrio cholerae, an enzyme that split off sialic acid from polysialoganglioside, leaving GM1 intact, caused little inhibition of the amino acid uptake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Orientation of Wall Microfibrils in Avena Coleoptiles and Mesocotyls and in Pisum Epicotyls

Microfibrils (MFs) on the inner surface of the walls of Avenacoleoptile and mesocotyl cells and of Pisum epicotyl cells wereexamined by a replica method. In the elongating epidermis ofthese three organs, cells having MFs that were transverse, obliqueor longitudinal to the elongation axis were intermingled. Inthe elongating parenchymal tissues, all cells deposited MFstransversely. In non-elongating cells of Avena coleoptiles andPisum epicotyls, the orientation of MFs on the inner wall surfaceof both epidermal and parenchymal cells was more longitudinalthan in elongating cells. These observations on the orientationsof MFs are compatible with those our previously reported observationson the orientations of microtubules (MT) (Iwata and Hogetsu1988). Disruption of MTs of Avena coleoptiles by treatment withamiprophosmethyl caused changes in the orientation of depositionof MFs. These results support the idea that MFs are usuallyco-aligned with MTs in organ cells and that the orientationof MFs is controlled by MTs. The averaged direction of MFs, visualized under polarized light,showed a clear difference between the epidermal and inner-tissuecell walls in the elongating regions of the three organs. Inalmost all elongating and non-elongating epidermal cells, theaveraged direction of MFs was longitudinal, while it was transversein all inner-tissue cells. (Received December 16, 1988; Accepted April 28, 1989)     

NADPH production from NADP+ with a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans

Summary A convenient and efficient method of NADPH production from NADP⁺ has been established using a glucose dehydrogenase system involving whole cells and immobilized cells of Gluconobacter suboxydans IFO 3172. Using airdried cells of the bacterium, the optimum conditions for NADPH production were examined, including the cell and glucose concentrations, NADP⁺ concentration, pH, buffer and reaction temperature. Under suitable conditions, the conversion ratio and the amount of NADPH accumulated reached about 100% and 73 mg/ml of the reaction mixture, respectively, after 1-h reaction. Intact cells of the bacterium also showed high NADPH production even in the reaction mixture without a surfactant. The addition of Triton X-100 to the reaction mixture and freeze-thawing treatment of intact cells enhanced the production. The NADPH production method was further improved by using cells of the bacterium immobilized by entrapment in a -carrageenan gel lattice. The immobilized cells had almost the same enzymatic properties as the air-dried cells. The conditions for the continuous production of NADPH with an immobilized cell column were also investigated. NADPH was produced in a good yield (about 95%) with this continuous process.     

Characterization of the glycosphingolipids of pig cortical bone and cartilage

Neutral glycosphingolipids and gangliosides were extracted from pig cortical bone and cartilage. To ensure the completeness of extraction, the cortical bone was demineralized and reextracted. Globotriaosylceramide and globoside were noted to be present at high content in the cortical bone. It contained glucosylceramide, lactosylceramide, globotriaosylceramide and globoside as neutral glycosphingolipids at a ratio of 1:0.7:3.1:2.7. In articular cartilage, the ratio was 1:0.7:0.4:0.8. GM3 and GD3 were the major gangliosides in both these tissues. GM3, GM1, GD3, GD1 and GT1 were present at ratios of 1:0.9:0.9:0.1:0.1 in the cortical bone and 1:0:1.2:0.06:0.02 in the cartilage. Neutral glycosphingolipids could be extracted from the cortical bone without the need for demineralization, while most of the gangliosides were extracted after this treatment, implying the occurrence of interactions between gangliosides and minerals in the bone.     

Detection of point mutation in the tyrosinase gene of a Japanese albino patient by a direct sequencing of amplified DNA

Summary Enzymatic DNA amplification and direct DNA sequencing were used to detect a mutation in the tyrosinase gene of an albino patient. Single-base change could be detected by direct sequencing. This base change (G to A) is thought to result in an amino acid change (Arg to Gln) in tyrosinase of the patient.