HCN to HCO^+ Millimeter Line Diagnostics of AGN Molecular Torus I : Radiative Transfer Modeling

We explore millimeter line diagnostics of an obscuring molecular torus modeled by a hydrodynamic simulation with three-dimensional nonLTE radiative transfer calculations. Based on the results of high-resolution hydrodynamic simulation of the molecular torus around an AGN, we calculate intensities of HCN and HCO^{+} rotational lines as two representative high density tracers. The three-dimensional radiative transfer calculations shed light on a complicated excitation state in the inhomogeneous torus, even though a spatially uniform chemical structure is assumed. Our results suggest that HCN must be much more abundant than HCO^{+} in order to obtain a high ratio ($R_{HCN/HCO+}\sim 2$) observed in some of the nearby galaxies. There is a remarkable dispersion in the relation between integrated intensity and column density, indicative of possible shortcomings of HCN(1-0) and HCO^{+}(1-0) lines as high density tracers. The internal structures of the inhomogeneous molecular torus down to subparsec scale in external galaxies will be revealed by the forthcoming Atacama Large Millimeter/submillimeter Array (ALMA). The three-dimensional radiative transfer calculations of molecular lines with high-resolution hydrodynamic simulation prove to be a powerful tool to provide a physical basis for molecular line diagnostics of the central regions of external galaxies.Comment: 29 pages, 13 figures, Accepted for publication in ApJ, For high resolution figures see http://alma.mtk.nao.ac.jp/~masako/MS72533v2.pd

Dynamin 2 Cooperates with Amphiphysin 1 in Phagocytosis in Sertoli Cells

Testicular Sertoli cells highly express dynamin 2 and amphiphysin 1. Here we demonstrate that dynamin 2 is implicated in phosphatidylserine (PS)-dependent phagocytosis in Sertoli cells. Immunofluorescence and dual-live imaging revealed that dynamin 2 and amphiphysin 1 accumulate simultaneously at ruffles. These proteins are specifically bound in vitro. Over-expression of dominant negative dynamin 2 (K44A) inhibits liposome-uptake and leads to the mis-localization of amphiphysin 1. Thus, the cooperative function of dynamin 2 and amphiphysin 1 in PS-dependent phagocytosis is strongly suggested.</p

Localization of CD26/DPPIV in nucleus and its nuclear translocation enhanced by anti-CD26 monoclonal antibody with anti-tumor effect

<p>Abstract</p> <p>Background</p> <p>CD26 is a type II, cell surface glycoprotein known as dipeptidyl peptidase (DPP) IV. Previous studies have revealed CD26 expression in T cell leukemia/lymphoma and malignant mesothelioma, and an inhibitory effect of anti-CD26 monoclonal antibody (mAb) against the growth of CD26+ cancer cells in vitro and in vivo. The function of CD26 in tumor development is unknown and the machinery with which the CD26 mAb induces its anti-tumor effect remains uncharacterized.</p> <p>Results</p> <p>The localization of CD26 in the nucleus of T cell leukemia/lymphoma cells and mesothelioma cells was shown by biochemical and immuno-electron microscopic analysis. The DPPIV enzyme activity was revealed in the nuclear fraction of T cell leukemia/lymphoma cells. These expressions of intra-nuclear CD26 were augmented by treatment with the CD26 mAb, 1F7, with anti-tumor effect against the CD26+ T cell leukemia/lymphoma cells. In contrast, the CD26 mAb, 5F8, without anti-tumor effect, did not augment CD26 expressions in the nucleus. Biotin-labeled, cell surface CD26 translocated into the nucleus constantly, and this translocation was enhanced with 1F7 treatment but not with 5F8.</p> <p>Conclusion</p> <p>These results indicate that the intra-nuclear CD26 which moves from plasma membrane may play certain roles in cell growth of human cancer cells.</p

A novel ER export signal of STP transporters

Membrane trafficking is highly organized to maintain cellular homeostasis in any organisms. Membrane-embedded transporters are targeted to various organelles to execute appropriate partition and allocation of their substrates, such as ions or sugars. To ensure the fidelity of targeting and sorting, membrane proteins including transporters have sorting signals that specify the subcellular destination and the trafficking pathway by which the destination is to be reached. Here, we have identified a novel sorting signal (called the tri-aromatic motif) which contains three aromatic residues, two tryptophans and one histidine, for the plasma membrane localization of sugar transporters in the STP family in Arabidopsis. We firstly found that a C-terminal deletion disrupted the sugar uptake activity of STP1 in yeast cells. Additional deletion and mutation analyses demonstrated that the three aromatic residues in the C-terminus, conserved among all Arabidopsis STP transporters, were critical for sugar uptake by not only STP1 but also another STP transporter STP13. We observed that, when the tri-aromatic motif was mutated, STP1 was largely localized at the endomembrane compartments in yeast cells, indicating that this improper subcellular localization led to the loss of sugar absorption. Importantly, our further analyses uncovered that mutations of the tri-aromatic motif resulted in the endoplasmic reticulum (ER) retention of STP1 and STP13 in plant cells, suggesting that this motif is involved at the step of ER exit of STP transporters to facilitate their plasma membrane localization. Together, we here identified a novel ER export signal, and showed that appropriate sorting via the tri-aromatic motif is important for sugar absorption by STP transporters

Recruitment of Irgb6 to the membrane is a direct trigger for membrane deformation

Irgb6 is a member of interferon gamma-induced immunity related GTPase (IRG), and one of twenty "effector" IRGs, which coordinately attack parasitophorous vacuole membrane (PVM), causing death of intracellular pathogen. Although Irgb6 plays a pivotal role as a pioneer in the process of PVM disruption, the direct effect of Irgb6 on membrane remained to be elucidated. Here, we utilized artificial lipid membranes to reconstitute Irgb6-membrane interaction in vitro, and revealed that Irgb6 directly deformed the membranes. Liposomes incubated with recombinant Irgb6 were drastically deformed generating massive tubular protrusions in the absence of guanine nucleotide, or with GMP-PNP. Liposome deformation was abolished by incubating with Irgb6-K275A/R371A, point mutations at membrane targeting residues. The membrane tubules generated by Irgb6 were mostly disappeared by the addition of GTP or GDP, which are caused by detachment of Irgb6 from membrane. Binding of Irgb6 to the membrane, which was reconstituted in vitro using lipid monolayer, was stimulated at GTP-bound state. Irgb6 GTPase activity was stimulated by the presence of liposomes more than eightfold. Irgb6 GTPase activity in the absence of membrane was also slightly stimulated, by lowering ionic strength, or by increasing protein concentration, indicating synergistic stimulation of the GTPase activity. These results suggest that membrane targeting of Irgb6 and resulting membrane deformation does not require GTP, but converting into GTP-bound state is crucial for detaching Irgb6 from the membrane, which might coincident with local membrane disruption

SlIAA9 Controls Tomato Elongation

Tomato INDOLE-3-ACETIC ACID9 (SlIAA9) is a transcriptional repressor in auxin signal transduction, and SlIAA9 knockout tomato plants develop parthenocarpic fruits without fertilization. We generated sliaa9 mutants with parthenocarpy in several commercial tomato cultivars (Moneymaker, Rio Grande, and Ailsa Craig) using CRISPR-Cas9, and null-segregant lines in the T1 generation were isolated by self-pollination, which was confirmed by PCR and Southern blot analysis. We then estimated shoot growth phenotypes of the mutant plants under different light (low and normal) conditions. The shoot length of sliaa9 plants in Moneymaker and Rio Grande was smaller than those of wild-type cultivars in low light conditions, whereas there was not clear difference between the mutant of Ailsa Craig and the wild-type under both light conditions. Furthermore, young seedlings in Rio Grande exhibited shade avoidance response in hypocotyl growth, in which the hypocotyl lengths were increased in low light conditions, and sliaa9 mutant seedlings of Ailsa Craig exhibited enhanced responses in this phenotype. Fruit production and growth rates were similar among the sliaa9 mutant tomato cultivars. These results suggest that control mechanisms involved in the interaction of AUX/IAA9 and lights condition in elongation growth differ among commercial tomato cultivars

The Latent Risk of Acidosis in Commercially Available Total Parenteral Nutrition (TPN) Products: a Randomized Clinical Trial in Postoperative Patients

To evaluate the latent risk of acidosis in commercially available total parenteral nutrition (TPN) products, three types of commercially available TPN products were compared in postoperative patients. Sixty-four hospitalized patients with gastro-intestinal disease who undertook curative gastro intestinal resection were studied prospectively and administered with TPN solutions. Three types of commercially available TPN products were assigned randomly to eligible patients. Serial studies of blood acid-base status, serum electrolytes, and urinary acid-base status were conducted in the three groups administered with different TPN solutions. Patients received appropriate electrolytic solutions on the operation day and TPN solution from 2 to 7 days after operation. There were no differences among any of the serum electrolytes in the three groups. In one group, urinary pH decreased slightly and urinary net acid excretion (NAE) increased significantly after administration. This TPN product contains about 40 mEq/L of non-metabolizable acid to avoid the Maillard reaction that produces a complex of glucose and amino acids. Urinary NAE did not change in the other two groups. These TPN products do not use non-metabolizable acid to adjust pH. The present results suggest that the non-metabolizable acid may be a risk factor of metabolic acidosis