Strigolactone signaling inhibition increases adventitious shoot formation on internodal segments of ipecac.

MAIN CONCLUSION: SL inhibited adventitious shoot formation of ipecac, whereas the SL-related inhibitors promoted adventitious shoot formation. SL-related inhibitors might be useful as new plant growth regulators for plant propagation. In most plant species, phytohormones are required to induce adventitious shoots for propagating economically important crops and regenerating transgenic plants. In ipecac (Carapichea ipecacuanha (Brot.) L. Andersson), however, adventitious shoots can be formed without phytohormone treatment. Here we evaluated the effects of GR24 (a synthetic strigolactone, SL), SL biosynthetic inhibitors, and an SL antagonist on adventitious shoot formation during tissue culture of ipecac. We found that exogenously applied GR24 suppressed indole-3-acetic acid transport in internodal segments and decreased the number of adventitious shoots formed; in addition, the distribution of adventitious shoots changed from the apical to middle region of the internodal segments. In contrast, the SL-related inhibitors promoted adventitious shoot formation on both apical and middle regions of the segments. In particular, SL antagonist treatment increased endogenous cytokinin levels and induced multiple shoot development. These results indicate that SL inhibits adventitious shoot formation in ipecac. In ipecac, one of the shoots in each internodal segment becomes dominant and auxin derived from that shoot suppresses the other shoot growth. Here, this dominance was overcome by application of SL-related inhibitors. Therefore, SL-related inhibitors might be useful as new plant growth regulators to improve the efficiency of plant propagation in vitro.

Endogenous auxin determines the pattern of adventitious shoot formation on internodal segments of ipecac.

MAIN CONCLUSION: Endogenous auxin determines the pattern of adventitious shoot formation. Auxin produced in the dominant shoot is transported to the internodal segment and suppresses growth of other shoots. Adventitious shoot formation is required for the propagation of economically important crops and for the regeneration of transgenic plants. In most plant species, phytohormones are added to culture medium to induce adventitious shoots. In ipecac (Carapichea ipecacuanha (Brot.) L. Andersson), however, adventitious shoots can be formed without phytohormone treatment. Thus, ipecac culture allows us to investigate the effects of endogenous phytohormones during adventitious shoot formation. In phytohormone-free culture, adventitious shoots were formed on the apical region of the internodal segments, and a high concentration of IAA was detected in the basal region. To explore the relationship between endogenous auxin and adventitious shoot formation, we evaluated the effects of auxin transport inhibitors, auxin antagonists, and auxin biosynthesis inhibitors on adventitious shoot formation in ipecac. Auxin antagonists and biosynthesis inhibitors strongly suppressed adventitious shoot formation, which was restored by exogenously applied auxin. Auxin biosynthesis and transport inhibitors significantly decreased the IAA level in the basal region and shifted the positions of adventitious shoot formation from the apical region to the middle region of the segments. These data indicate that auxin determines the positions of the shoots formed on internodal segments of ipecac. Only one of the shoots formed grew vigorously; this phenomenon is similar to apical dominance. When the largest shoot was cut off, other shoots started to grow. Naphthalene-1-acetic acid treatment of the cut surface suppressed shoot growth, indicating that auxin produced in the dominant shoot is transported to the internodal segment and suppresses growth of other shoots.

RhoA/ROCK, cytoskeletal dynamics, and focal adhesion kinase are required for mechanical stretch-induced tenogenic differentiation of human mesenchymal stem cells.

Human bone marrow mesenchymal stem cells (hMSCs) have the potential to differentiate into tendon/ligament-like lineages when they are subjected to mechanical stretching. However, the means through which mechanical stretch regulates the tenogenic differentiation of hMSCs remains unclear. This study examined the role of RhoA/ROCK, cytoskeletal organization, and focal adhesion kinase (FAK) in mechanical stretch-induced tenogenic differentiation characterized by the up-regulation of tendon-related marker gene expression. Our findings showed that RhoA/ROCK and FAK regulated mechanical stretch-induced realignment of hMSCs by regulating cytoskeletal organization and that RhoA/ROCK and cytoskeletal organization were essential to mechanical stretch-activated FAK phosphorylation at Tyr397. We also demonstrated that this process can be blocked by Y-27632 (a specific inhibitor of RhoA/ROCK), cytochalasin D (an inhibitor of cytoskeletal organization) or PF 573228 (a specific inhibitor of FAK). The results of this study suggest that RhoA/ROCK, cytoskeletal organization, and FAK compose a "signaling network" that senses mechanical stretching and drives mechanical stretch-induced tenogenic differentiation of hMSCs. This work provides novel insights regarding the mechanisms of tenogenesis in a stretch-induced environment and supports the therapeutic potential of hMSCs.

Effects of Individual Dietary Intervention on Nutrient Intake in Postpartum Japanese Women: A Randomized Controlled Trial.

No dietary intervention that focuses on the diet quality of postpartum women has been developed in Japan, although most postpartum women experience an insufficient intake of vitamins and minerals. We aimed to examine whether dietary intervention, based on the health belief model, at both 1 and 3 months postpartum affects nutrient intake and food group consumption at 6 months postpartum. A randomized controlled trial was conducted at a university hospital in Tokyo between 2015 and 2016. Healthy women at 1 month postpartum were randomly allocated to either an intervention group (n = 100) or a control group (n = 94). Dietary intervention included dietary assessment, individual feedback, and dietary guidance. The dietary intakes between the two groups were compared using the Mann-Whitney U test. At 6 months postpartum, the energy-adjusted intakes of protein, total dietary fiber, potassium, magnesium, phosphorus, zinc, vitamin B6, and ß-carotene were significantly higher in the intervention group than in the control group. The changes in energy-adjusted intakes of total dietary fiber and iron from 1 month postpartum to 6 months postpartum were significantly different between the two groups. Dietary intervention based on the health belief model improved nutrition at 6 months postpartum, although the impact was limited.

The Effects of a Yoga Exercise and Nutritional Guidance Program on Pregnancy Outcomes Among Healthy Pregnant Japanese Women: A Study Protocol for a Randomized Controlled Trial.

OBJECTIVES: This report provides an experimental protocol for a study designed to verify the effects of yoga exercise and a nutritional guidance program during pregnancy on several key pregnancy and birth outcomes among Japanese women. DESIGN: This is a study protocol of a randomized controlled trial. SETTING/LOCATION: This intervention will be carried out in a university hospital in Tokyo. SUBJECTS: Healthy primiparous women will be recruited at 18-23 gestational weeks in the hospital. A total of 400 participants will be randomly assigned to one of four groups in this trial, with 100 participants in each group-group with yoga exercise, with nutritional guidance, with both yoga and nutritional guidance, and with standard care alone, as the control group. Yoga exercise consists of yoga classes held at the hospital 3 or 5 days a month, duration 60 min, and home practice using a digital video disk, duration 30 or 60 min per session. We recommend participants do yoga at least 3 days a week for a total of 60 min per day. Nutritional guidance is based on individual dietary intake assessed using a brief-type diet history questionnaire. RESULTS: The primary outcome is rate of pregnant women with adequate gestational weight gain. Secondary outcomes include physiologic and psychologic status assessed via biomarkers and health-related scales, dietary nutrition intake, and birth outcomes. CONCLUSIONS: This study shows the effects of a yoga exercise and nutritional intervention. If the intervention is found to be effective, our results will be useful for healthcare providers and pregnant women.

Evaluation of stem cell-to-tenocyte differentiation by atomic force microscopy to measure cellular elastic moduli.

In the present study, we evaluated whether stem cell-to-tenocyte differentiation could be evaluated via measurement of the mechanical properties of the cell. We used mechanical uniaxial cyclic stretching to induce the differentiation of human bone marrow mesenchymal stem cells into tenocytes. The cells were subjected to cyclic elongation of 10 or 15 % at a cyclic frequency of 1 Hz for 24 or 48 h, and differentiation was assessed by real-time PCR (rtPCR) determination of messenger RNA expression levels for four commonly used markers of stem cell-to-tenocyte differentiation: type I collagen, type III collagen, tenascin-C, and scleraxis. The rtPCR results showed that cells subjected to 10 % cyclic elongation for 24 or 48 h differentiated into tenocytes. Atomic force microscopy (AFM) was then used to measure the force curves around the cell nuclei, and the AFM data were used to calculate the elastic moduli of the cell surfaces. The elastic modulus values of the control (non-stretched) cells differed significantly from those of cells stretched at 10 % for 24 or 48 h (P < 0.01). Confocal fluorescence microscopic observations of actin stress fibers suggested that the change in elastic modulus was ascribable to the development of the cellular cytoskeleton during the differentiation process. Therefore, we conclude that the atomic force microscopic measurement of the elastic modulus of the cell surface can be used to evaluate stem cell-to-tenocyte differentiation.

In vitro experimental study for the determination of cellular axial strain threshold and preferential axial strain from cell orientation behavior in a non-uniform deformation field.

Cells within connective tissues are routinely subjected to a wide range of non-uniform mechanical loads that regulate many cell behaviors. In the present study, the relationship between cell orientation angle and strain value of the membrane was comprehensively investigated using an inhomogeneous strain field. Additionally, the cellular axial strain threshold, which corresponds to the launching of cell reorientation response, was elucidated. Human bone marrow mesenchymal stem cells were used for these experiments. In this study, an inhomogeneous strain distribution was easily created by removing one side holes of an elastic chamber in a commonly used uniaxial stretching device. The strains of 2D stretched membranes were quantified on a position-by-position basis using the digital image correlation method. The normal strain in the direction of stretch was changed continuously from 2.0 to 15.0%. A 3D histogram of the cell frequency, which was correlated with the cell orientation angle and normal strain of the membrane, made it possible to determine the axial strain threshold accurately. The value of the axial strain threshold was 4.4 ± 0.3%, which was reasonable compared with previous studies based on cyclic uniaxial stretch stimulation (homogeneous strain field). Additionally, preferential axial strain of cells, which was a cell property firstly introduced, was also achieved and the value was -2.0 ± 0.1%. This study is novel in three respects: (i) it precisely and easily determined the axial strain threshold of cells; (ii) it is the first to suggest preferential axial strain of cells; and (iii) it methodically investigated cell behavior in an inhomogeneous strain field.

Determination of optimal cyclic uniaxial stretches for stem cell-to-tenocyte differentiation under a wide range of mechanical stretch conditions by evaluating gene expression and protein synthesis levels.

We examined optimal cyclic uniaxial stretches for stem cell-to-tenocyte differentiation by applying a wide range of cyclic mechanical stimuli. Human bone marrow mesenchymal stem cells (hBMSCs) were subjected to three types of cyclic elongation of 5%, 10%, or 15% at a cyclic frequency of 1 Hz for 24 h or 48 h, and differentiation into tenocytes was assessed by two methods: real-time polymerase chain reaction determination of gene expression levels and western blotting analysis of protein expression levels. The gene expression levels of the differentiation markers type I collagen (Col I), type III collagen (Col III), tenascin-C (Tnc), and scleraxis (Scx), all of which are constituents of tendon tissue, were increased when cells were exposed to 10% stretching stimulation. The levels of Col I and Tnc protein synthesis levels were also higher in the cells with 10% stretching stimulation than in those subjected to other stimuli. The results indicated that 10% stretching stimulus was efficient to induce the differentiation of hBMSCs into tenocytes. In addition, the changes in gene and protein expression levels were strongly correlated with cell orientation angle. The results presented here suggest that mesenchymal stem cell-to-tenocyte differentiation is strongly associated with cumulative elongation load on the cells. This work provides novel insights into the differentiation of tenogenesis in a strain-induced environment and supports the therapeutic potential of hBMSCs.