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When suitability of sites for parent is incompatible with that for their eggs, parent–offspring conflict occurs — the parent must choose between the optimal oviposition site for eggs and that suitable for itself. We examined effects of predator cue on parental habitat use and oviposition site in Physa acuta. We assessed desiccation risk in eggs and the relationship between water depth and predation risk. Predator cues induced the elevation of parental habitat away from the bottom but had no effect on the oviposition site. Oviposition site choice is not by-product of escape response. Eggs that were exposed to desiccation failed to hatch, indicating high desiccation risk. Eggs laid at deeper levels were at higher risk of stripping from oviposition substrates by crayfishes. Although the middle-water level would be suitable oviposition sites, the parents selected an oviposition site in the upper level. There are other benefits and costs of oviposition site selection.

Platelets are essential for blood circulation and coagulation. Previous study indicated that overexpression of Gata2 in differentiated mouse embryonic stem cells (ESCs) resulted in robust induction of megakaryocytes (Mks). To evaluate platelet production capacity of the Gata2-induced ESC-derived Mks, we generated iGata2-ESC line carrying the doxycycline-inducible Gata2 expression cassette. When doxycycline was added to day 5 hemogenic endothelial cells in the in vitro differentiation culture of iGata2-ESCs, c-Kit(-)Tie2(-)CD41(+) Mks were predominantly generated. These iGata2-ESC-derived Mks efficiently produced CD41(+)CD42b(+)CD61(+) platelets and adhered to fibrinogen-coated glass coverslips in response to thrombin stimulation. Transmission electron microscopy analysis demonstrated that the iGata2-ESC-derived platelets were discoid-shaped with α-granules and an open canalicular system, but were larger than peripheral blood platelets in size. These results demonstrated that an enforced expression of Gata2 in late HECs of differentiated ESCs efficiently promotes megakaryopoiesis followed by platelet production. This study provides valuable information for ex vivo platelet production from human pluripotent stem cells in future.

LIM-homeobox transcription factor Lhx2 induces ex vivo amplification of adult hematopoietic stem cells (HSCs) in mice. We previously showed that engraftable HSC-like cells are generated from mouse embryonic stem cells (ESCs) and induced pluripotent stem cells by enforced expression of Lhx2. However, when these HSC-like cells were transplanted into irradiated congenic mice, donor-derived T cells were barely detectable, whereas other lineages of hematopoietic cells were continuously produced. Here we investigated T-cell differentiation potential of the Lhx2-induced HSC-like cells using ESCs carrying doxycycline (dox)-inducible Lhx2 expression cassette. Dox-mediated over-expression of Lhx2 conferred a self-renewing activity to ESC-derived c-Kit(+) CD41(+) embryonic hematopoietic progenitor cells (HPCs), thereby converting them to HSC-like cells. When these HSC-like cells were transplanted into irradiated immunodeficient mice and they were supplied with a dox-containing water, CD4/8 double negative T cells were detected in their thymi. Once the Lhx2 expression was terminated, differentiation of CD4/8 double positive and single positive T cells was initiated in the thymi of transplanted mice and mature T cells were released in the peripheral blood. These results showed that engraftable HSC-like cells with full hematopoietic potential can be obtained from ESCs by the conditional expression of Lhx2.

We previously demonstrated that hematopoietic stem cell (HSC)-like cells are robustly expanded from mouse embryonic stem cells (ESCs) by enforced expression of Lhx2, a LIM-homeobox domain (LIM-HD) transcription factor. In this study, we analyzed the functions of Lhx2 in that process using an ESC line harboring an inducible Lhx2 gene cassette. When ESCs are cultured on OP9 stromal cells, hematopoietic progenitor cells (HPCs) are differentiated and these HPCs are prone to undergo rapid differentiation into mature hematopoietic cells. Lhx2 inhibited differentiation of HPCs into mature hematopoietic cells and this effect would lead to accumulation of HSC-like cells. LIM-HD factors interact with LIM domain binding (Ldb) protein and this interaction abrogates binding of LIM-only (Lmo) protein to Ldb. We found that one of Lmo protein, Lmo2, was unstable due to dissociation of Lmo2 from Ldb1 in the presence of Lhx2. This effect of Lhx2 on the amount of Lmo2 contributed into accumulation of HSC-like cells, since enforced expression of Lmo2 into HSC-like cells inhibited their self-renewal. Expression of Gata3 and Tal1/Scl was increased in HSC-like cells and enforced expression of Lmo2 reduced expression of Gata3 but not Tal1/Scl. Enforced expression of Gata3 into HPCs inhibited mature hematopoietic cell differentiation, whereas Gata3-knockdown abrogated the Lhx2-mediated expansion of HPCs. We propose that multiple transcription factors/cofactors are involved in the Lhx2-mediated expansion of HSC-like cells from ESCs. Lhx2 appears to fine-tune the balance between self-renewal and differentiation of HSC-like cells. Stem Cells 2013;31:2680–2689

Capsinoids are a novel group of compounds produced by the Capsicum plant. We synthesized a capsinoid by the lipase-catalyzed esterification of vanillyl alcohol with fatty acid derivatives in an organic solvent. The use of seven out of 17 commercially available lipases, especially Novozym 435, was applicable to the synthesis of vanillyl nonanoate, a model compound of capsinoids. The yield of vanillyl nonanoate under the optimum conditions of 50 mM vanillyl alcohol and 50 mM methyl nonanoate in 500 microl of dioxane, using 20 mg of Novozym 435 and 50 mg of 4 A molecular sieves at 25 degrees C, was 86% in 20 h. Several capsinoid homologues having various acyl chain lengths (C6-C18) were synthesized at 64-86% yields from the corresponding fatty acid methyl ester. The natural capsinoids, capsiate and dihydrocapsiate, were obtained by a 400-fold-scale reaction at these optimum conditions in 60% and 59% isolated yields, respectively.