The Center for Biostabilization at UC Davis is attempting to stabilize mammalian cells in the dry state. We review here some of the lessons from nature that we have been applying to this enterprise, including the use of trehalose, a disaccharide found at high concentrations in many anhydrobiotic organisms, to stabilize biological structures, both in vitro and in vivo. Trehalose has useful properties for this purpose and in at least in one case-human blood platelets-introducing this sugar may be sufficient to achieve useful stabilization. Nucleated cells, however, are stabilized by trehalose only during the initial stages of dehydration. Introduction of a stress protein obtained from an anhydrobiotic organism, Artemia, improves the stability markedly, both during the dehydration event and following rehydration. Thus, it appears that the stabilization will require multiple adaptations, many of which we propose to apply from studies on anhydrobiosis.

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Human induced pluripotent stem cells (hiPSCs) hold great potential for use in regenerative medicine, novel drug development, and disease progression/developmental studies. Here, we report highly efficient differentiation of hiPSCs toward a relatively homogeneous population of functional hepatocytes. hiPSC-derived hepatocytes (hiHs) not only showed a high expression of hepatocyte-specific proteins and liver-specific functions, but they also developed a functional biotransformation system including phase I and II metabolizing enzymes and phase III transporters. Nuclear receptors, which are critical for regulating the expression of metabolizing enzymes, were also expressed in hiHs. hiHs also responded to different compounds/inducers of cytochrome P450 as mature hepatocytes do. To follow up on this observation, we analyzed the drug metabolizing capacity of hiHs in real time using a novel ultraperformance liquid chromatography-tandem mass spectrometry. We found that, like freshly isolated primary human hepatocytes, the seven major metabolic pathways of the drug bufuralol were found in hiHs. In addition, transplanted hiHs engrafted, integrated, and proliferated in livers of an immune-deficient mouse model, and secreted human albumin, indicating that hiHs also function in vivo. In conclusion, we have generated a method for the efficient generation of hepatocytes from induced pluripotent stem cells in vitro and in vivo, and it appears that the cells function similarly to primary human hepatocytes, including developing a complete metabolic function. These results represent a significant step toward using patient/disease-specific hepatocytes for cell-based therapeutics as well as for pharmacology and toxicology studies. STEM CELLS TRANS- LATIONAL MEDICINE 2013;2:409 -419

Orthotropic liver transplantation is the only established treatment for end-stage liver diseases. Utilization of hepatocyte transplantation and bio-artificial liver devices as alternative therapeutic approaches requires an unlimited source of hepatocytes. Stem cells, especially embryonic stem cells, possessing the ability to produce functional hepatocytes for clinical applications and drug development, may provide the answer to this problem. New discoveries in the mechanisms of liver development and the emergence of induced pluripotent stem cells in 2006 have provided novel insights into hepatocyte differentiation and the use of stem cells for therapeutic applications. This review is aimed towards providing scientists and physicians with the latest advancements in this rapidly progressing field.

The NAC transcription factor family participates in responses to various kinds of environmental stimuli in plants. Responses of NAC genes to abiotic stresses have been widely studied, but their functions in response to biotic stress are little reported in plants, especially in crops. In the present study, we examined the functions of a novel tomato (Solanum lycopersicum) NAC protein (SlNAC35) in abiotic and biotic stress resistance by using transgenic tobacco. Expression analysis found that SlNAC35 expression was induced by drought stress, salt stress, bacterial pathogen, and signaling molecules, suggesting its involvement in plant responses to biotic and abiotic stimuli. Moreover, transgenic lines exhibited a greater number of lateral roots and longer root length compared with Vec lines (empty vector lines) after drought and salt treatment. These results indicate that overexpression of SlNAC35 promoted root growth and development under drought and salt stresses. Higher expressions of NtARF1, NtARF2 and NtARF8 were observed under drought and salt stresses in transgenic lines, suggesting that overexpression of SlNAC35 promoted growth and development of roots in transgenic lines possibly by involving auxin signaling and by regulating NtARF expression. In addition, SlNAC35 overexpression improved resistance to bacterial pathogen in transgenic tobacco, and reactive oxygen species may be in the upstream of salicylic acid (SA) signaling in transgenic tobacco during defense response.

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Summary Despite widespread anthropogenic nutrient enrichment, it remains unclear how nutrient enrichment influences plant–arbuscular mycorrhizal fungi (AMF) symbiosis and ecosystem multifunctionality at the global scale. Here, we conducted a meta‐analysis to examine the worldwide effects of nutrient enrichment on AMF and plant diversity and ecosystem multifunctionality using data of field experiments from 136 papers. Our analyses showed that nutrient addition simultaneously decreased AMF diversity and abundance belowground and plant diversity aboveground at the global scale. The decreases in AMF diversity and abundance associated with nutrient addition were more pronounced with increasing experimental duration, mean annual temperature (MAT) and mean annual precipitation (MAP). Nutrient addition‐induced changes in soil pH and available phosphorus (P) predominantly regulated the responses of AMF diversity and abundance. Furthermore, AMF diversity correlated with ecosystem multifunctionality under nutrient addition worldwide. Our findings identify the negative effects of nutrient enrichment on AMF and plant diversity and suggest that AMF diversity is closely linked with ecosystem function. This study offers an important advancement in our understanding of plant–AMF interactions and their likely responses to ongoing global change.

p26, an abundantly expressed small heat shock protein, is thought to establish stress resistance in oviparously developing embryos of the crustacean Artemia franciscana by preventing irreversible protein denaturation, but it might also promote survival by inhibiting apoptosis. To test this possibility, stably transfected mammalian cells producing p26 were generated and their ability to resist apoptosis induction determined. Examination of immunofluorescently stained transfected 293H cells by confocal microscopy demonstrated p26 is diffusely distributed in the cytoplasm with a minor amount of the protein in nuclei. As shown by immunoprobing of Western blots, p26 constituted approximately 0.6% of soluble cell protein. p26 localization and quantity were unchanged during prolonged culture, and the protein had no apparent ill effects on transfected cells. Molecular sieve chromatography in Sepharose 6B revealed p26 oligomers of about 20 monomers, with a second fraction occurring as larger aggregates. A similar pattern was observed in sucrose gradients, but overall oligomer size was smaller. Mammalian cells containing p26 were more thermotolerant than cells transfected with the expression vector only, and as measured by annexin V labeling, Hoescht 33342 nuclear staining and procaspase-3 activation, transfected cells effectively resisted apoptosis induction by heat and staurosporine. The ability to confer thermotolerance and limit heat-induced apoptosis is important because Artemia embryos are frequently exposed to high temperature in their natural habitat. p26 also blocked apoptosis in transfected cells during drying and rehydration, findings with direct relevance to Artemia life history characteristics because desiccation terminates cyst diapause. Thus, in addition to functioning as a molecular chaperone, p26 inhibits apoptosis, an activity shared by other small heat shock proteins and with the potential to play an important role during Artemia embryo development.