ABSTRACT
Highly functionalized spirobisnaphthalenes, preussomerins N (1) and O (2), and simpler compounds, such as 2,3-α-epoxypalmarumycin CP18 (3), 3α-hydroxy-CJ-12,372 (4), and 16 known structurally related congeners, were isolated from a culture broth of Roussoella sp. KT4147. Structural analysis revealed that 1 was a dimer of preussomerin G (6), connected by a nitrogen atom, and 2 was a derivative of 6 with a macommelin substructure. Preussomerin N (1) was considered to be biosynthetically derived via the Michael-type 1,4-addition of ammonia to 6, followed by another Michael addition to another molecule of 6. Contrarily, 2 was suggested to be derived through an endo-Diels-Alder cycloaddition between a diene derived from the (E)-enol form of macommelinal via an ene-reaction and dienophile 6. Compounds 1 and 2 exhibited potent cytotoxicity against COLO-201 human colorectal cancer cells.
Subject(s)
Naphthalenes , Spiro Compounds , Humans , Molecular Structure , Spiro Compounds/chemistry , Spiro Compounds/isolation & purification , Spiro Compounds/pharmacology , Naphthalenes/chemistry , Naphthalenes/pharmacology , Naphthalenes/isolation & purification , Drug Screening Assays, Antitumor , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/isolation & purification , Cycloaddition Reaction , Cell Line, TumorABSTRACT
Conventional techniques for sharing paper documents in teleconferencing tend to introduce two inconsistencies: 1) media inconsistency: a paper document is converted into a digital image on the remote site; 2) space inconsistency: a workspace deliberately inverts the partner's handwriting to make a document easy to read. In this paper, we present a novel system that eliminates these inconsistencies. The media and space inconsistencies are resolved by reproducing a real paper document on a remote site and allowing a user to handover the paper document to a remote partner across a videoconferencing display. From a series of experiments, we found that reproducing a real paper document contributes to a higher sense of information sharing. We also found that handing over a document enhances a sense of space sharing, regardless of whether the document is digital or paper-based. These findings provide insights into designing systems for sharing paper documents across distances.
ABSTRACT
Morphological comparisons and multi locus phylogenetic analyses (base on the combined genes of ITS, LSU, rpb2 and tub) demonstrated that three new saprobic taxa isolated from bamboo belong to Cainiaceae. These taxa comprise a novel genus Paramphibambusa (P.bambusicolasp. nov.) and two new species, Arecophilaxishuangbannaensis and A.zhaotongensis. The three new taxa belong to Cainiaceae (Xylariales, Sordariomycetes) a poorly studied family, which now comprises eight genera. Paramphibambusa can be distinguished from other Cainiaceae genera in having ascomata with a neck and ascospores lacking longitudinal striation, germ slits or germ pores. The two new Arecophila species clustered in a clade with Arecophila sp. and A.bambusae. Detailed morphological descriptions, illustrations, and an updated phylogenetic tree are provided for the new taxa.
ABSTRACT
In recent years, virtual idols have garnered considerable attention because they can perform activities similar to real idols. However, as they are fictitious idols with nonphysical presence, they cannot perform physical interactions such as handshake. Combining a robotic hand with a display showing virtual idols is the one of the methods to solve this problem. Nonetheless a physical handshake is possible, the form of handshake that can effectively induce the desirable behavior is unclear. In this study, we adopted a robotic hand as an interface and aimed to imitate the behavior of real idols. To test the effects of this behavior, we conducted step-wise experiments. The series of experiments revealed that the handshake by the robotic hand increased the feeling of intimacy toward the virtual idol, and it became more enjoyable to respond to a request from the virtual idol. In addition, viewing the virtual idols during the handshake increased the feeling of intimacy with the virtual idol. Moreover, the method of the hand-shake peculiar to idols, which tried to keep holding the user's hand after the conversation, increased the feeling of intimacy to the virtual idol.
ABSTRACT
Paraphaeoketones A-C (1-3) were isolated from the culture broth of Paraphaeosphaeria sp. KT4192. Their structures and relative configurations were determined using spectroscopic analysis and verified through density functional theory (DFT)-based chemical shift calculations. The absolute configurations of these compounds were determined by comparing the experimental electronic circular dichroism (ECD) spectra with those based on DFT calculations. We also propose a plausible biosynthetic route to 1-3. While our prior studies on the isolation and structural elucidation of paraphaeolactones (e.g., 4) led us to suggest a Favorskii rearrangement for their biosynthesis, the isolation of 2 prompted the proposal of an alternative biosynthesis for 4, featuring a benzilic acid rearrangement of 2. Moreover, an in vitro conversion of 2 into 4 was achieved successfully, suggesting that a biosynthetic pathway for paraphaeolactones involving a benzilic acid rearrangement is more plausible than the previously presumed Favorskii rearrangement pathway. Arguments based on DFT calculations for these pathways are also described.
Subject(s)
Ascomycota , Ketones , Ascomycota/chemistry , Ascomycota/metabolism , Lactones/chemistry , Lactones/metabolism , Molecular Structure , Ketones/chemistry , Ketones/metabolismABSTRACT
Neuronal differentiation of adipose tissue-derived stem cells (ASCs) is greatly promoted by valproic acid (VPA) with cAMP elevating agents thorough NO signaling pathways, but its mechanism is not fully understood. In the present study, we investigate the involvement of protein S-nitrosylation in the VPA-promoted neuronal differentiation of ASCs. The whole amount of S-nitrosylated protein was increased by the treatment with VPA alone for three days in ASCs. An inhibitor of thioredoxin reductase (TrxR), auranofin, further increased the amount of S-nitrosylated protein and enhances the VPA-promoted neuronal differentiation in ASCs. On the contrary, another inhibitor of TrxR, dinitrochlorobenzene, inhibited the VPA-promoted neuronal differentiation in ASCs even with cAMP elevating agents, which was accompanied by unexpectedly decreased S-nitrosylated protein. It was considered from these results that increased protein S-nitrosylation is involved in VPA-promoted neuronal differentiation of ASCs. By the proteomic analysis of S-nitrosylated protein in VPA-treated ASCs, no identified proteins could be specifically related to VPA-promoted neuronal differentiation. The identified proteins, however, included those involved in the metabolism of substances regulating neuronal differentiation, such as aspartate and glutamate.