Sperm-borne phospholipase C zeta-1 ensures monospermic fertilization in mice

Sperm entry in mammalian oocytes triggers intracellular Ca2+ oscillations that initiate resumption of the meiotic cell cycle and subsequent activations. Here, we show that phospholipase C zeta 1 (PLCζ1) is the long-sought sperm-borne oocyte activation factor (SOAF). Plcz1 gene knockout (KO) mouse spermatozoa fail to induce Ca2+ changes in intracytoplasmic sperm injection (ICSI). In contrast to ICSI, Plcz1 KO spermatozoa induced atypical patterns of Ca2+ changes in normal fertilizations, and most of the fertilized oocytes ceased development at the 1-2-cell stage because of oocyte activation failure or polyspermy. We further discovered that both zona pellucida block to polyspermy (ZPBP) and plasma membrane block to polyspermy (PMBP) were delayed in oocytes fertilized with Plcz1 KO spermatozoa. With the observation that polyspermy is rare in astacin-like metalloendopeptidase (Astl) KO female oocytes that lack ZPBP, we conclude that PMPB plays more critical role than ZPBP in vivo. Finally, we obtained healthy pups from male mice carrying human infertile PLCZ1 mutation by single sperm ICSI supplemented with Plcz1 mRNA injection. These results suggest that mammalian spermatozoa have a primitive oocyte activation mechanism and that PLCζ1 is a SOAF that ensures oocyte activation steps for monospermic fertilization in mammals.Nozawa, K., Satouh, Y., Fujimoto, T. et al. Sperm-borne phospholipase C zeta-1 ensures monospermic fertilization in mice. Sci Rep 8, 1315 (2018). https://doi.org/10.1038/s41598-018-19497-

Cord Blood from SGA Preterm Infants Exhibits Increased GLUT4 mRNA Expression

[Background] Insulin and insulin-like growth factor (IGF) signaling plays an important role in prenatal and postnatal growth and glucose metabolism. Both small-for-gestational age (SGA) and preterm infants have abnormal growth and glucose metabolism. However, the underlying mechanism remains unknown. Recently, we showed that term SGA infants have abnormal insulin/IGF signaling in cord blood. In this study, we examined whether preterm infants show similar aberrations in cord blood insulin/IGF signaling. [Methods] A total of 41 preterm cord blood samples were collected. Blood glucose, insulin, IGF-1, and C-peptide concentrations were measured, and mRNA expression of IGF1R, INSR, IRS1, IRS2, and SLC2A4 (i.e., GLUT4) was analyzed by quantitative reverse-transcription PCR. [Results] This study included 34 appropriate-for-gestational age (AGA) and 7 SGA preterm neonates. No hyperinsulinemia or any differences in IGF1R or INSR mRNA expression were detected between the two groups. However, GLUT4 mRNA levels were increased in preterm SGA. Moreover, the expression level in hypoglycemic preterm SGA was significantly higher than that in hypoglycemic preterm AGA. IRS2 mRNA expression did not show a statistically significant difference between preterm SGA and AGA neonates. [Conclusion] SGA preterm birth does not induce hyperinsulinemia; however, it modifies insulin/IGF signaling components such as GLUT4 in umbilical cord blood. Our study suggests that prematurity or adaptation to malnutrition alters the insulin/IGF signaling pathway

Diffusion tensor model links to neurite orientation dispersion and density imaging at high b-value in cerebral cortical gray matter

Diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) are widely used models to infer microstructural features in the brain from diffusion-weighted MRI. Several studies have recently applied both models to increase sensitivity to biological changes, however, it remains uncertain how these measures are associated. Here we show that cortical distributions of DTI and NODDI are associated depending on the choice of b-value, a factor reflecting strength of diffusion weighting gradient. We analyzed a combination of high, intermediate and low b-value data of multi-shell diffusion-weighted MRI (dMRI) in healthy 456 subjects of the Human Connectome Project using NODDI, DTI and a mathematical conversion from DTI to NODDI. Cortical distributions of DTI and DTI-derived NODDI metrics were remarkably associated with those in NODDI, particularly when applied highly diffusion-weighted data (b-value = 3000 sec/mm2). This was supported by simulation analysis, which revealed that DTI-derived parameters with lower b-value datasets suffered from errors due to heterogeneity of cerebrospinal fluid fraction and partial volume. These findings suggest that high b-value DTI redundantly parallels with NODDI-based cortical neurite measures, but the conventional low b-value DTI is hard to reasonably characterize cortical microarchitecture

A new equation to estimate basal energy expenditure of patients with diabetes

[Background & aims]Predictive equations for basal energy expenditure (BEE) derived from Caucasians tend to overestimate BEE in non-Caucasians. The aim of this study was to develop a more suitable method to estimate BEE in Japanese patients with diabetes using indices readily measured in clinical practice. [Methods]BEE was measured by indirect calorimetry under a strict basal condition in 68 Japanese patients with type 1 or type 2 diabetes. The best fitting equation was investigated by multiple regression analysis using of age, sex, and anthropometric indices. The resultant new equation was tested in a separate group of 60 Japanese patients with type 1 or type 2 diabetes, and the accuracy compared with existing equations. [Results]The best-fit equation was BEE [kcal/day] = 10 × (body weight)[kg] – 3 × (age)[y] + 125 (if male) + 750. Adjusted coefficient of determination was 81.0%. Root mean squared errors and accurate prediction in the validation set were 103 kcal/day and 78% for the new equation; 184 and 50 for Harris-Benedict; 209 and 38 for Oxford; 205 and 42 for Liu; and 140 and 63 for Ganpule. [Conclusions]This new equation is simpler and estimates BEE more accurately in Japanese patients with diabetes than the presently used equations do

理科指導法における模擬授業の実践と評価

本研究の目的は，理科指導法における模擬授業の実践を通して，学生が授業観察の視点を深めることができたかどうかを 明らかにすることである。その目的を達成するために模擬授業後の学生によるコメントの分析と，全ての模擬授業が終了し た後の学生の振り返りの記述の分析を行なった。その結果，次の二つのことが分かった。 (1) 模擬授業を行うことで教師の振る舞いについて指摘する数は減り，教授について指摘する割合が顕著に増加した。小 学校教育全般に対する指摘は減少し，理科授業全般や単元固有のことについて指摘する数が増加した。 (2) 模擬授業を通して，理科の授業ができるポイントを見つけることができたと評価する学生は99 パーセントに達した。 理科の指導がうまくなったと評価する学生は半数を超えた

抗体クラススィッチ過程の活性化自由エネルギー

Membrane-bound form IgM (IgM_m) and total IgM (IgM_t) transcriptions were measured by real time PCR method in the thymus and the spleen of BALB/c male mice and the change of logIgMmagMt ratios with age were detected. Kinetics was applied and both the rate constant k_1, corresponding to the process in which IgM_mtranscribing cells differentiate into ones transcribing secretory type IgM and k_2, corresponding to the process in which those into cells transcribing other class Ig, were determined. ΔG_1^* and ΔG_2^*, free energy of activation corresponding to k_1 and k_2 process in each, were calculated from k_1 and k_2 by application of theory of absolute reaction rate. ΔG_1^* and ΔG_2^* were 110 to 120 kJ/mol both in the thymus and in the spleen. By considering the phenomenal differences in k_1 and k_2 processes, the difference of ΔG_2^* and ΔG_1^* might be able to regard as the free energy of immunoglobulin class switch process ΔG_c^* . The values of ΔG_c^* were small unexpectedly, 2. 9 kJ/mol in the thymus and 5. 7 kJ/mol in the spleen