Characterization of the ATP transporter in the reconstituted rough endoplasmic reticulum proteoliposomes

AbstractAdenosine triphosphate (ATP) transporter from rat liver rough endoplasmic reticulum (RER) was solubilized and reconstituted into phosphatidylcholine liposomes. The RER proteoliposomes, resulting from optimizing some reconstitution parameters, had an apparent Km value of 1.5 μM and a Vmax of 286 pmol min−1 (mg protein)−1 and showed higher affinity for ATP and a lower Vmax value than intact RER (Km of 6.5 μM and Vmax of 1 nmol). ATP transport was time- and temperature-dependent, inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid, which is known as an inhibitor of anion transporters including ATP transporter, but was not affected by atractyloside, a specific inhibitor of mitochondrial ADP/ATP carrier. The internal and external effects of various nucleotides on the ATP transport were examined. ATP transport was cis-inhibited strongly by ADP and weakly by AMP. ADP-preloaded RER proteoliposomes showed a specific increase of ATP transport activity while AMP-preloaded RER proteoliposomes did not show the enhanced overshoot peak in the ATP uptake plot. These results demonstrate the ADP/ATP antiport mechanism of ATP transport in rat liver RER

Laparoscopic low anterior resection for hematogenous rectal metastasis from gastric adenocarcinoma: A Case Report

<p>Abstract</p> <p>Background</p> <p>Gastric cancer is one of the most common malignancies in the world and is the second most common cause of cancer-related death in Korea. Colorectal metastases from gastric adenocarcinoma are known to be very rare. We report an unusual case of rectal metastasis of gastric adenocarcinoma.</p> <p>Case presentation</p> <p>We report a case of a 43-year-old female patient with gastric cancer who first presented with epigastric pain. The endoscopic and radiologic findings were suggestive of Borrmann type III advanced gastric cancer with linitis plastica. Radical total gastrectomy with D2 lymph node dissection was performed. The pathology report was AJCC TNM Stage II gastric adenocarcinoma (T3N0M0). On follow up at 34 months after surgery, the patient complained of difficulty in defecation. On colonoscopy, a hard, indurated extraluminal mass was detected 7 cm proximal to the anal verge. The biopsy demonstrated chronic nonspecific colitis. Abdominal CT, rectal MRI and PET-CT revealed rectal metastasis from gastric cancer. Laparoscopic ultralow anterior resection with diverting ileostomy was performed. The pathology report was metastatic adenocarcinoma, and this diagnosis was identical to the gastric pathology reported in the previous pathology report. The patient was discharged after the 11^thpostoperative day with no adverse events.</p> <p>Conclusion</p> <p>Rectal metastasis from gastric cancer is known to be very rare. However, metastatic gastric adenocarcinoma should be considered as a differential diagnosis for patients presenting with a colorectal mass and a past history of gastric cancer.</p

Chemical homogeneity of wide binary system: An approach from Near-Infrared spectroscopy

Wide binaries, with separations between two stars from a few AU to more than several thousand AU, are valuable objects for various research topics in Galactic astronomy. As the number of newly reported wide binaries continues to increase, studying the chemical abundances of their component stars becomes more important. We conducted high-resolution near-infrared (NIR) spectroscopy for six pairs of wide binary candidates using the Immersion Grating Infrared Spectrometer (IGRINS) at the Gemini-South telescope. One pair was excluded from the wide binary samples due to a significant difference in radial velocity between its component stars, while the remaining five pairs exhibited homogeneous properties in 3D motion and chemical composition among the pair stars. The differences in [Fe/H] ranged from 0.00 to 0.07 dex for these wide binary pairs. The abundance differences between components are comparable to the previous results from optical spectroscopy for other samples. In addition, when combining our data with literature data, it appears that the variation of abundance differences increases in wide binaries with larger separations. However, the SVO2324 and SVO3206 showed minimal differences in most elements despite their large separation, supporting the concept of multiple formation mechanisms depending on each wide binary. This study is the first approach to the chemical properties of wide binaries based on NIR spectroscopy. Our results further highlight that NIR spectroscopy is an effective tool for stellar chemical studies based on equivalent measurements of chemical abundances from the two stars in each wide binary system.Comment: 16 pages, 9 figures, accepted for publication in A

Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way

Recent spectroscopic observations of the outer halo globular cluster (GC) NGC 2419 show that it is unique among GCs, in terms of chemical abundance patterns, and some suggest that it was originated in the nucleus of a dwarf galaxy. Here we show, from the Subaru narrow-band photometry employing a calcium filter, that the red giant-branch (RGB) of this GC is split into two distinct subpopulations. Comparison with spectroscopy has confirmed that the redder RGB stars in the $hk$[=(Ca$-b)-(b-y)$] index are enhanced in [Ca/H] by $\sim$0.2 dex compared to the bluer RGB stars. Our population model further indicates that the calcium-rich second generation stars are also enhanced in helium abundance by a large amount ($\Delta$Y = 0.19). Our photometry, together with the results for other massive GCs (e.g., $\omega$ Cen, M22, and NGC 1851), suggests that the discrete distribution of RGB stars in the $hk$ index might be a universal characteristic of this growing group of peculiar GCs. The planned narrow-band calcium photometry for the Local Group dwarf galaxies would help to establish an empirical connection between these GCs and the primordial building blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ