Tottori University

The budding of human immunodeficiency virus from an infected host cell is induced by the modification of structural proteins bearing long-chain fatty acids, followed by their anchoring to the cell membrane. Although many model budding systems using giant unilamellar vesicles (GUVs) induced by various stimuli have been developed, constructing an artificial viral budding system of GUVs using only synthesized molecules remains challenging. Herein, we report the construction of an artificial viral capsid budding system from a lipid bilayer of GUV. The C-terminus of the β-annulus peptide was modified using an octyl chain as an alkyl anchor via a disulfide bond. The self-assembly of the β-annulus peptide with an octyl chain formed an artificial viral capsid aggregate. The fluorescence imaging and transmission electron microscopy observations revealed that the addition of the tetramethylrhodamine (TMR)-labeled octyl chain-bearing β-annulus peptide to the outer aqueous phase of GUV induced the budding of the capsid-encapsulated daughter vesicle outside-to-inside the mother GUV. Conversely, the encapsulation of the TMR-labeled octyl chain-bearing β-annulus peptide in the inner aqueous phase of GUV induced the budding of the capsid-encapsulated daughter vesicle inside-to-outside the mother GUV. Contrarily, the addition of the TMR-labeled β-annulus peptide to GUV barely induced budding. It was demonstrated that the higher the membrane fluidity of GUV, the more likely budding would be induced by the addition of the alkyl anchor-modified artificial viral capsid. The simple virus-mimicking material developed in this study, which buds off through membrane anchoring, can provide physicochemical insights into the mechanisms of natural viral budding from cells.

Gibberellin (GA) is a classical plant hormone that regulates many physiological processes, such as plant growth, development, and environmental responses. GA inhibits arbuscular mycorrhizal (AM) symbiosis, the most ancient and widespread type of mycorrhizal symbiosis. Knowledge about mycorrhizal symbioses at the molecular level has been obtained mainly in model plants such as legumes and rice. In contrast, molecular mechanisms in non-model plants are still unclear. Recent studies have revealed the novel roles of GA in mycorrhizal symbioses: its positive effect in Paris-type AM symbiosis in Eustoma grandiflorum and its negative effect on both seed germination and mycorrhizal symbiosis in orchids. This review focuses on the recent data on GA function in AM and orchid mycorrhizal symbioses.

The pituitary gland is the master endocrine gland, harboring stem cells with various genetic characteristics; however, data from non-rodent and non-human sources are scarce.In this study, we isolated putative stem cells from the bovine pituitary gland and investigated their potential for differentiation into hormone-producing cells.Immunohistochem. anal. revealed that in calves and heifers, stem cell marker sex-determining region Y-box 2 (SOX2)-pos. cells were widely present in the pituitary gland and partially co-localized with anterior pituitary hormones.Next, a single-cell suspension of primary anterior lobe cells from bovines aged 0 and 12 mo was subjected to two-dimensional culture.Consequently, some cells proliferated in the culture dishes.The expression levels of Sox2 and several other stem cell markers were higher in these cells after culture.In addition, almost all proliferating cells were pos. for SOX2, whereas all were neg. for hormones.In three-dimensional cultures, SOX2-pos. cells presented a spheroid-like morphol. and differentiated into endocrine cells.These results provide evidence that SOX2-pos. cells are pituitary stem cells with the potential to differentiate into hormone-producing cells, regardless of age.Our data lay a theor. foundation for further studies on controlling fundamental processes, such as body growth, reproduction, and lactation.