Characterization of embryoid bodies of mouse embryonic stem cells formed under various culture conditions and estimation of differentiation status of such bodies

Various types of embryoid body (EB) that were formed from mouse embryonic stem (ES) cells under various culture conditions were characterized in terms of gene expression pattern to estimate the differentiation status of the bodies. The gene expression of typical markers (i.e., GATA-4, GATA-6, transthyretin [TTR], alpha-fetoprotein [AFP], Nkx2.5, and alpha-myosin heavy chain [alpha-MHC]) was quantitatively analyzed in various types of EB, and the gene expression pattern of those marker genes was graphically shown for each EB. The gene expression pattern accurately represented the differentiation status of the EBs. The gene expression pattern indicated that the Nkx2.5 and alpha-MHC genes were highly expressed in the EBs formed from 1000 ES cells in a low-adherence 96-well plate. By transferring the EBs into an attachment culture, cardiomyocytes were more efficiently generated in the outgrowth of the EBs. When we increased the seeding cell number from 1000 to 4000 ES cells, the gene expression pattern changed, that is, the expression levels of the TTR and AFP genes increased, whereas those of the Nkx2.5 and alpha-MHC genes decreased, and the trend of differentiation changed from cardiomyogenesis to visceral yolk-sac-like structure formation.     

Magnetic separation of cells from developing embryoid bodies using magnetite cationic liposomes

Embryoid bodies resemble post-implantation egg-cylinder stage embryos and are used to differentiate embryonic stem cells in vitro. In this study, we enriched mouse vasa homolog-positive germ cells from embryoid bodies after 8d of differentiation using a magnetic separation method with magnetite cationic liposomes.     

Simultaneous induction of calcium transients in embryoid bodies using microfabricated electrode substrates

Precise control of differentiation processes of pluripotent stem cells is a key component for the further development of regenerative medicine. For this purpose, combining a cell-aggregate-size treatment for regulating intercellular signal transmissions and an electrical stimulation technique for inducing cellular responses is a promising approach. In the present study, we developed microfabricated electrode substrates that allow simultaneous stimulation of embryoid bodies (EBs) of P19 cells. Mouse embryonal carcinoma P19 cells can be induced to differentiate into three germ layers and serve as a promising stem cell model. Microcavity–array patterns were fabricated onto indium–tin–oxide (ITO) substrates using a standard photo-lithography technique, and uniform-sized EBs of P19 cells were inserted into each microcavity. Electrical stimulation was applied to the EBs through substrate electrodes and stimulus-induced intracellular calcium transients were monitored. We confirmed that the developed electrode device could simultaneously stimulate smaller (200 μm diameter) and larger (500 μm diameter) EBs inserted in the microcavities and induce specific spatio-temporal patterns of intracellular calcium transients in the EBs with fine reproducibility. We concluded that the developed microcavity array with embedded electrodes could simultaneously and effectively stimulate uniform-sized EBs inserted in it. Therefore, it is a promising experimental tool for precisely controlling cell differentiation processes.     

Methods for inducing embryoid body formation: in vitro differentiation system of embryonic stem cells

When cultured in suspension without antidifferentiation factors, embryonic stem (ES) cells spontaneously differentiate and form three-dimensional multicellular aggregates called embryoid bodies (EBs). EBs recapitulate many aspects of cell differentiation during early embryogenesis, and play an important role in the differentiation of ES cells into a variety of cell types in vitro. There are several methods for inducing the formation of EBs from ES cells. The three basic methods are liquid suspension culture in bacterial-grade dishes, culture in methylcellulose semisolid media, and culture in hanging drops. Recently, the methods using a round-bottomed 96-well plate and a conical tube are adopted for forming EBs from predetermined numbers of ES cells. For the production of large numbers of EBs, stirred-suspension culture using spinner flasks and bioreactors is performed. Each of these methods has its own peculiarity; thus, the features of formed EBs depending on the method used. Therefore, we should choose an appropriate method for EB formation according to the objective to be attained. In this review, we summarize the studies on in vitro differentiation of ES cells via EB formation and highlight the EB formation methods recently developed including the techniques, devices, and procedures involved.     

聚丙烯腈/氯化钴纳米纤维比色湿度传感器的制备及其性能

为获得具有比色效果的纳米纤维湿度传感器,以聚丙烯腈(PAN)和氯化钴(CoCl₂)为原料,采用静电纺丝技术制备了PAN/CoCl₂复合纳米纤维膜,并组装成纳米纤维比色湿度传感器。借助扫描电子显微镜、傅里叶红外光谱仪、能量色散X射线光谱仪对纳米纤维膜的微观结构和表面形态进行表征和分析,利用紫外-可见分光光度计分析纤维在不同湿度下以及不同有机溶剂饱和蒸汽氛围下的反射光谱,并采用电化学工作站测试传感器在不同湿度环境下的响应和恢复能力。结果表明:在相对湿度由11%增加至98%时,PAN/CoCl₂纳米纤维膜可由蓝色变至粉色,且该颜色变化过程可逆,响应和恢复速度快;在11%~75%的相对湿度环境下,PAN/CoCl₂纳米纤维比色湿度传感器的电流在12 s内可达1 023 nA左右;当相对湿度降至11%时,2 s内电流可从2 187 nA降至10 nA,具有快速的响应和恢复能力。     

Parthenolide inhibits lipid accumulation via activation of Nrf2/Keap1 signaling during adipocyte differentiation

Food Science and Biotechnology - The effects of parthenolide (PL), a sesquiterpene lactone obtained from feverfew plant, on lipid accumulation and signaling pathway in adipocytes were investigated....     

Soybean (Glycine max) oil bodies and their associated phytochemicals

Soybean oil bodies were isolated from 3 cultivars (Ustie, K98, and Elena) and the occurrence of 2 classes of phytochemicals (tocopherol isoforms and isoflavones) and strength of their association with isolated oil bodies was evaluated. Tocopherol is shown to be closely associated with soybean oil bodies; δ-tocopherol demonstrated a significantly greater association with oil bodies over other tocopherol isoforms. Isoflavones do not show a significant physical association with oil bodies, although there is some indication of a passive association of the more hydrophobic aglycones during oil body isolation. PRACTICAL APPLICATION: Oil bodies are small droplets of oil that are stored as energy reserves in the seeds of oil seeds, and have the potential to be used as future food ingredients. If oil body suspensions are commercialized on a large scale, knowledge of the association of phytochemicals with oil bodies will be valuable in deciding species of preference and predicting shelf life and nutritional value.     

Edible mushroom (Flammulina velutipes) extract inhibits melanosis in Kuruma shrimp (Marsupenaeus japonicus)

This study compared the potential of an aqueous extract of an edible mushroom (Flammulina velutipes) to prevent melanosis in cultured Kuruma shrimp (Marsupenaeus japonicus) with other antimelanosic compounds in vivo. The mushroom extract contained 9.1 mg/mL ergothioneine (ESH). Immersion of live full-grown shrimp in a 0.5% w/v solution of mushroom extract significantly reduced PPO activity in shrimp hemolymph. In addition, expression of the prophenoloxidase (proPO) gene decreased in hemocytes, suggesting that the extract blocked the activation of the proPO cascade. Consequently, the development of melanosis in the treated shrimp was significantly suppressed during ice storage. Treatment with a 0.05% w/v solution of sodium ascorbate and 4-hexyl-1,3-benzenediol had the same effect. In vitro experiments showed that ESH effectively inhibited PPO activity and activation of the proPO cascade in hemocyte lysate supernatant. This study suggests that in vivo application of F. velutipes mushroom extract is an effective natural alternative to synthetic antimelanosic agents to inhibit postmortem melanosis in shrimp. Practical Application: The extract of an edible mushroom (F. velutipes) containing ergothioneine can be a promising natural alternative to synthetic antimelanosic agents used to prevent postharvest melanosis in shrimp and other crustaceans. Furthermore, utilization of the mushroom trimmings could also help address the growing concerns on the disposal of such agricultural wastes and instead use it into a novel purpose as a source of antimelanosic and antioxidants for food and industrial application.     

Applications of artificial neural networks (ANNs) in food science

Artificial neural networks (ANNs) have been applied in almost every aspect of food science over the past two decades, although most applications are in the development stage. ANNs are useful tools for food safety and quality analyses, which include modeling of microbial growth and from this predicting food safety, interpreting spectroscopic data, and predicting physical, chemical, functional and sensory properties of various food products during processing and distribution. ANNs hold a great deal of promise for modeling complex tasks in process control and simulation and in applications of machine perception including machine vision and electronic nose for food safety and quality control. This review discusses the basic theory of the ANN technology and its applications in food science, providing food scientists and the research community an overview of the current research and future trend of the applications of ANN technology in the field.     

Gamma irradiation inhibits browning in ready-to-cook (RTC) ash gourd (Benincasa hispida) during storage

Inhibition of browning in gamma irradiated (2 kGy) RTC ash gourd during storage (10 °C, 12 days) was investigated. Irradiation resulted in a significant increase in the content of α-resorcylic acid that was correlated with decreased PPO activity. Nature of the PPO inhibition was found to be of mixed and reversible type with K_i, 0.09 mM; K_is, 27.33 mM and IC₅₀ of 25 mM. During storage, the non-irradiated control samples exhibited increased oxidation of leached phenolic compounds at the surface as a consequence of changes in tissue micro-structure compared to the irradiated samples. Unlike control samples that exhibited enhanced PAL activity, quinone formation and browning, no increase in PAL activity and browning was noted in the irradiated samples during storage. Browning inhibition in stored radiation-processed (2 kGy) RTC ash gourd was thus proposed to be a synergistic effect of decreased quinone formation and reduced enzyme (PPO and PAL) activities.Industrial relevanceThe present study demonstrates the feasibility of gamma irradiation for browning inhibition in ready-to-cook (RTC) ash gourd during storage. Use of gamma irradiation for optimizing the post-processing conditions for improved visual appeal and storability of the fresh-cut produce in food industry is thus recommended. The possible use of alpha resorcylic acid as a natural browning inhibitor in fruits and vegetables is also of industrial relevance. The various approaches proposed in the study can be utilized by the food industry for maintaining visual quality of fresh-cut produce during storage thereby improving marketability of such produce.