Enhanced fusogenicity and pathogenicity of SARS-CoV-2 Delta P681R mutation.

During the current coronavirus disease 2019 (COVID-19) pandemic, a variety of mutations have accumulated in the viral genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, at the time of writing, four variants of concern are considered to be potentially hazardous to human society1. The recently emerged B.1.617.2/Delta variant of concern is closely associated with the COVID-19 surge that occurred in India in the spring of 2021 (ref. 2). However, the virological properties of B.1.617.2/Delta remain unclear. Here we show that the B.1.617.2/Delta variant is highly fusogenic and notably more pathogenic than prototypic SARS-CoV-2 in infected hamsters. The P681R mutation in the spike protein, which is highly conserved in this lineage, facilitates cleavage of the spike protein and enhances viral fusogenicity. Moreover, we demonstrate that the P681R-bearing virus exhibits higher pathogenicity compared with its parental virus. Our data suggest that the P681R mutation is a hallmark of the virological phenotype of the B.1.617.2/Delta variant and is associated with enhanced pathogenicity.

[A Case of Solitary Inguinal Lymph Node Metastasis 15 Years after Colorectal Cancer Surgery].

The patient is a 69-year-old man. 17 years ago, a colectomy was performed for colorectal cancer, and a disseminated nodule was found during the operation, so the disseminated nodule was also resected. After the surgery, 12 courses of FOLFOX4 were administered, and there was no recurrence thereafter. He was diagnosed with hepatocellular carcinoma 12 years after the colectomy and underwent liver resection. Fifteen years after the colectomy, a mass shadow appeared in the right inguinal region, and inguinal lymph node metastasis of hepatocellular carcinoma or colorectal cancer was suspected. In the same year, he underwent the tumor resection and histopathological diagnosis revealed colon cancer inguinal lymph node metastasis. After the lymph node resection, he has been followed up for 2 years with no recurrence of colorectal cancer. It is extremely rare to have a solitary inguinal lymph node recurrence 15 years after colon surgery.

CAGE-seq reveals that HIV-1 latent infection does not trigger unique cellular responses in a Jurkat T cell model.

The cure for HIV-1 is currently stalled by our inability to specifically identify and target latently infected cells. HIV-1 viral RNA/DNA or viral proteins are recognized by cellular mechanisms and induce interferon responses in virus producing cells, but changes in latently infected cells remain unknown. HIVGKO contains a GFP reporter under the HIV-1 promoter and an mKO2 reporter under the internal EF1α promoter. This viral construct enables direct identification of HIV-1 both productively and latently infected cells. In this study we aim to identify specific cellular transcriptional responses triggered by HIV-1 entry and integration using Cap Analysis of Gene Expression (CAGE).We deep sequenced CAGE tags in uninfected, latently and productively infected cells and compared their differentially expressed transcription start site (TSS) profiles. Virus producing cells had differentially expressed TSSs related to T-cell activation and apoptosis when compared to uninfected cells or latently infected cells. Surprisingly, latently infected cells had only 33 differentially expressed TSSs compared to uninfected cells. Among these, SPP1 and APOE were down-regulated in latently infected cells. SPP1 or APOE knockdown in Jurkat T cells increased susceptibility to HIVGKO infection, suggesting that they have anti-viral properties. Components of the PI3K/mTOR pathway, MLST8, 4EBP and RPS6, were significant TSSs in productively infected cells, and S6K phosphorylation was increased compared to latently infected cells, suggesting that mTOR pathway activity plays a role in establishing the latent reservoir. These findings indicate that HIV-1 entry and integration do not trigger unique transcriptional responses when infection becomes latent.Importance: Latent HIV-1 infection is established as early as the first viral exposure and remains the most important barrier in obtaining the cure for HIV-1 infection. Here, we used CAGE to compare the transcriptional landscape of latently infected cells with that of non-infected or productively infected cells. We found that latently infected cells and non-infected cells show quite similar transcriptional profiles. Our data suggest that T-cells cannot recognize incoming viral components nor the integrated HIV-1 genome when infection remains latent. These findings should guide future research into widening our approaches to identify and target latent HIV-1 infected cells.

Alterations in UPR Signaling by Methylmercury Trigger Neuronal Cell Death in the Mouse Brain.

Methylmercury (MeHg), an environmental toxicant, induces neuronal cell death and injures specific areas of the brain. MeHg is known to induce oxidative and endoplasmic reticulum (ER) stress. The unfolded protein response (UPR) pathway has a dual nature in that it regulates and protects cells from an overload of improperly folded proteins in the ER, whereas excessively stressed cells are eliminated by apoptosis. Oxidative stress/ER stress induced by methylmercury exposure may tilt the UPR toward apoptosis, but there is little in vivo evidence of a direct link to actual neuronal cell death. Here, by using the ER stress-activated indicator (ERAI) system, we investigated the time course signaling alterations of UPR in vivo in the most affected areas, the somatosensory cortex and striatum. In the ERAI-Venus transgenic mice exposed to MeHg (30 or 50 ppm in drinking water), the ERAI signal, which indicates the activation of the cytoprotective pathway of the UPR, was only transiently enhanced, whereas the apoptotic pathway of the UPR was persistently enhanced. Furthermore, detailed analysis following the time course showed that MeHg-induced apoptosis is strongly associated with alterations in UPR signaling. Our results suggest that UPR modulation could be a therapeutic target for treating neuropathy.

[Three Cases in Which Long-Term Survival Was Obtained by Irradiation for Postoperative Lymph Node Metastasis].

Case 1: Left total mastectomy was performed for a 58-year-old woman for diagnosis of left breast cancer. Seven years after surgery, left internal mammary node metastasis revealed. Irradiation was performed on the left chest wall and left supraclavicular area. Six months later, the lymph node swelling disappeared. Thereafter 8 years have passed without recurrence. Case 2: A 65-year-old man had a semi-emergency total gastrectomy for bleeding from gastric cancer. Three years after surgery, anterior pancreatic lymph node metastasis was detected. Radiation therapy was selected because his general condition was not so good. Three months later, lymph node swelling disappeared. Thereafter 4 and a half years have passed without recurrence. Case 3: A 67-year-old man underwent surgery for middle thoracic esophageal cancer after neoadjuvant chemotherapy. Seven months after surgery, left tracheobronchial lymph node metastasis was found. Irradiation was performed to bilateral supraclavicular area and mediastinum in combination with chemotherapy. Three months later, the lymph node normalized, and 6 and a half years have passed without recurrence. All 3 cases in this study were recurrences of regional lymph node. Radiation therapy may be effective for regional lymph node recurrence outside the dissected area or in areas that have been inadequately dissected.

APOBEC3B is preferentially expressed at the G2/M phase of cell cycle.

APOBEC3B (A3B) is a cytosine deaminase that converts cytosine to uracil in single-stranded DNA. Cytosine-to-thymine and cytosine-to-guanine base substitution mutations in trinucleotide motifs (APOBEC mutational signatures) were found in various cancers including lymphoid hematological malignancies such as multiple myeloma and A3B has been shown to be an enzymatic source of mutations in those cancers. Although the importance of A3B is being increasingly recognized, it is unclear how A3B expression is regulated in cancer cells as well as normal cells. To answer these fundamental questions, we analyzed 1276 primary myeloma cells using single-cell RNA-sequencing (scRNA-seq) and found that A3B was preferentially expressed at the G2/M phase, in sharp contrast to the expression patterns of other APOBEC3 genes. Consistently, we demonstrated that A3B protein was preferentially expressed at the G2/M phase in myeloma cells by cell sorting. We also demonstrated that normal blood cells expressing A3B were also enriched in G2/M-phase cells by analyzing scRNA-seq data from 86,493 normal bone marrow mononuclear cells. Furthermore, we revealed that A3B was expressed mainly in plasma cells, CD10+ B cells and erythroid cells, but not in granulocyte-macrophage progenitors. A3B expression profiling in normal blood cells may contribute to understanding the defense mechanism of A3B against viruses, and partially explain the bias of APOBEC mutational signatures in lymphoid but not myeloid malignancies. This study identified the cells and cellular phase in which A3B is highly expressed, which may help reveal the mechanisms behind carcinogenesis and cancer heterogeneity, as well as the biological functions of A3B in normal blood cells.

Spatiotemporal analysis of the UPR transition induced by methylmercury in the mouse brain.

Methylmercury (MeHg), an environmental toxicant, induces neuronal cell death and injures a specific area of the brain. MeHg-mediated neurotoxicity is believed to be caused by oxidative stress and endoplasmic reticulum (ER) stress but the mechanism by which those stresses lead to neuronal loss is unclear. Here, by utilizing the ER stress-activated indicator (ERAI) system, we investigated the signaling alterations in the unfolded protein response (UPR) prior to neuronal apoptosis in the mouse brain. In ERAI transgenic mice exposed to MeHg (25 mg/kg, S.C.), the ERAI signal, which indicates activation of the cytoprotective pathway of the UPR, was detected in the brain. Interestingly, detailed ex vivo analysis showed that the ERAI signal was localized predominantly in neurons. Time course analysis of MeHg exposure (30 ppm in drinking water) showed that whereas the ERAI signal was gradually attenuated at the late phase after increasing at the early phase, activation of the apoptotic pathway of the UPR was enhanced in proportion to the exposure time. These results suggest that MeHg induces not only ER stress but also neuronal cell death via a UPR shift. UPR modulation could be a therapeutic target for treating neuropathy caused by electrophiles similar to MeHg.

The Emerging Role of Electrophiles as a Key Regulator for Endoplasmic Reticulum (ER) Stress.

The unfolded protein response (UPR) is activated by the accumulation of misfolded proteins in the endoplasmic reticulum (ER), which is called ER stress. ER stress sensors PERK, IRE1, and ATF6 play a central role in the initiation and regulation of the UPR; they inhibit novel protein synthesis and upregulate ER chaperones, such as protein disulfide isomerase, to remove unfolded proteins. However, when recovery from ER stress is difficult, the UPR pathway is activated to eliminate unhealthy cells. This signaling transition is the key event of many human diseases. However, the precise mechanisms are largely unknown. Intriguingly, reactive electrophilic species (RES), which exist in the environment or are produced through cellular metabolism, have been identified as a key player of this transition. In this review, we focused on the function of representative RES: nitric oxide (NO) as a gaseous RES, 4-hydroxynonenal (HNE) as a lipid RES, and methylmercury (MeHg) as an environmental organic compound RES, to outline the relationship between ER stress and RES. Modulation by RES might be a target for the development of next-generation therapy for ER stress-associated diseases.

[Successful treatment with recombinant thrombomodulin in transplant-associated thrombotic microangiopathy following HLA-haploidentical transplantation].

In March 2009, a 17-year-old woman was first diagnosed with acute myelogenous leukemia and myelodysplasia-related changes. She underwent chemotherapy and allogeneic hematopoietic stem cell transplantation, which resulted in complete remission. However, she experienced relapse, and remission was achieved each time with repeated transplantation. In September 2014, a human leukocyte antigen (HLA)-haploidentical transplantation, which was the fifth allogeneic transplantation, was performed to treat the third relapse. Platelet transfusion refractoriness, hemolytic anemia with schistocytes, and renal dysfunction were observed from approximately the day of engraftment; therefore, transplantation-associated thrombotic microangiopathy (TA-TMA) was diagnosed. Recombinant human soluble thrombomodulin (rTM) was administered, and fresh-frozen plasma (FFP) was infused; this resulted in gradual improvement of TA-TMA. Treatment with rTM and FFP was discontinued on the 70th day after transplantation. Because the HLA-haploidentical transplantation was the fifth allogeneic transplantation, the risk of aggravation of TA-TMA was very high. Combined treatment with rTM and FFP, however, resulted in improvement of TA-TMA. Further investigation of similar cases is necessary for clarifying the usefulness of rTM for TA-TMA.

[Autologous peripheral blood stem cell transplantation for treating primary central nervous system lymphoma: a single-center retrospective study].

Primary central nervous system lymphoma (PCNSL) is more difficult to treat than other lymphomas. Recently, it has been suggested that high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is effective for treating PCNSL. In the present study, we retrospectively analyzed 12 patients with PCNSL at our hospital. Five young patients with good performance status (PS) received upfront ASCT. The conditioning regimen prior to ASCT with busulfan ＋ cyclophosphamide ＋ etoposide showed good prognosis (complete remission rate of 100%). In addition, the PS improved in patients treated with high-dose chemotherapy followed by ASCT, while it worsened in those treated without ASCT. Further investigations are needed to clarify inclusion/exclusion criteria and optimize conditioning regimens for ASCT.

Diagnosis and Management of Patients with Paroxysmal Sympathetic Hyperactivity following Acute Brain Injuries Using a Consensus-Based Diagnostic Tool: A Single Institutional Case Series.

Paroxysmal sympathetic hyperactivity (PSH) is a distinct syndrome of episodic sympathetic hyperactivities following severe acquired brain injury, characterized by paroxysmal transient fever, tachycardia, hypertension, tachypnea, excessive diaphoresis and specific posturing. PSH remains to be an under-recognized condition with a diagnostic pitfall especially in the intensive care unit (ICU) settings due to the high prevalence of concomitant diseases that mimic PSH. A consensus set of diagnostic criteria named PSH-Assessment Measure (PSH-AM) has been developed recently, which is consisted of two components: a diagnosis likelihood tool derived from clinical characteristics of PSH, and a clinical feature scale assigned to the severity of each sympathetic hyperactivity. We herein present a case series of patients with PSH who were diagnosed and followed by using PSH-AM in our tertiary institutional medical and surgical ICU between April 2015 and March 2017 in order to evaluate the clinical efficacy of PSH-AM. Among 394 survivors of 521 patients admitted with acquired brain injury defined as acute brain injury at all levels of severity regardless of the presence of altered consciousness, including traumatic brain injury, stroke, infectious disease, and encephalopathy, 6 patients (1.5%) were diagnosed as PSH by using PSH-AM. PSH-AM served as a useful scoring system for early objective diagnosis, assessment of severity, and serial evaluation of treatment efficacy in the management of PSH in the ICU settings. In conclusion, critical care clinicians should consider the possibility of PSH and can use PSH-AM as a useful diagnostic and guiding tool in the management of PSH.

Complete closure of artificial gastric ulcer after endoscopic submucosal dissection by combined use of a single over-the-scope clip and through-the-scope clips (with videos).

BACKGROUND: A 5-7 day hospital stay is usually needed after endoscopic submucosal dissection (ESD) of gastric tumor because of the possibility of delayed perforation or bleeding. The aim of this study was to evaluate the efficacy of combined use of a single over-the-scope clip (OTSC) and through-the-scope clips (TTSCs) to achieve complete closure of artificial gastric ulcer after ESD. METHODS: We prospectively studied 12 patients with early gastric cancer or gastric adenoma. We performed complete closure of post-ESD artificial gastric ulcer using a combination of a single OTSC and TTSCs. RESULTS: Mean size of post-ESD artificial ulcer was 54.6 mm. The mean operating time for the closure procedure was 15.2 min., and the success rate was 91.7 % (11/12). Patients who underwent complete closure of post-ESD artificial gastric ulcer could be discharged the day after ESD and the closing procedure. CONCLUSIONS: Complete closure of post-ESD artificial gastric ulcer using a combination of a single OTSC and TTSCs is useful for shortening the period of hospitalization and reducing treatment cost.

Efficacy of a high FFP:PRBC transfusion ratio on the survival of severely injured patients: a retrospective study in a single tertiary emergency center in Japan.

PURPOSE: Recent studies have shown increased survival benefits when a high fresh frozen plasma (FFP) to packed red blood cell (PRBC) ratio is used during trauma resuscitation. However, some reports have raised questions about the effect of higher FFP:PRBC transfusion ratios. The aim of this study was to examine the efficacy of high FFP:PRBC ratios in injured patients with regard to survival and morbidity in a single tertiary emergency center in Japan. METHODS: This study examined severe trauma patients who received 10 or more PRBC units during the first 24 h of admission. We examined the relationship between the FFP:PRBC ratios during the first 6 h and the patient outcome. RESULTS: The severity was similar among all groups. The mortality rate was 44.4% in the high (>1:1.5), 16.7% in the middle (1:1.5-1:2) and 33.3% in the low (<1:2) F:P ratio groups. Only one patient in the high group developed sepsis, and none of the patients developed ARDS. CONCLUSIONS: The current results indicate that the FFP:PRBC ratios during the first 6 h after admission might not affect the mortality or morbidity. However, differences between trauma care systems in Japan and other countries, along with other study limitations, necessitate that a subsequent prospective multicenter study be undertaken before any definitive conclusions can be made.

[Endoscopic gallbladder stenting for acute cholecystitis].

Acute cholecystitis is an inflammatory disease of the gallbladder. Inflammation often remains in the gallbladder, but some patients may take a fatal course with exacerbation of inflammation. Although laparoscopic cholecystectomy is recommended for moderate and severe acute cystitis, sometimes cholecystectomy is impossible in elder patients. Because many elder patients have bad general conditions, cholecystectomy should not be performed. Such patients are generally treated by percutaneous transhepatic gallbladder drainage (PTGBD), but PTGBD has the risk of intra-abdominal bleeding. In previous reports, endoscopic gallbladder stenting (EGBS) has been shown to be an effective strategy in cirrhosis patients with symptomatic cholelithiasis as a bridge to transplantation. Recent studies on EGBS have demonstrated an effective long-term management of acute cholecystitis in elderly patients who are poor surgical candidates. Here, we reviewed EGBS for the management of acute cholecystitis.

Enrichment and characterization of a bacterial culture that can degrade 4-aminopyridine.

BACKGROUND: The agrichemical 4-aminopyridine is used as a bird repellent in crop fields and has an epileptogenic action in a variety of animals, including man and mouse. 4-Aminopyridine is biodegraded in the environment through an unknown mechanism. RESULTS: A 4-aminopyridine-degrading enrichment culture utilized 4-aminopyridine as a carbon, nitrogen, and energy source, generating 4-amino-3-hydroxypyridine, 3,4-dihydroxypyridine, and formate as intermediates. 4-Amino-3-hydroxypyridine could not be further metabolized and probably accumulated as a dead-end product in the culture. Biodegradability tests and partial sequence analysis of the enrichment culture indicated that 4-aminopyridine was mainly degraded via 3,4-dihydroxypyridine and that the metabolite is probably cleaved by 3-hydroxy-4-pyridone dioxygenase. Seven culturable predominant bacterial strains (strains 4AP-A to 4AP-G) were isolated on nutrient agar plates. Changes in the bacterial populations of 4-aminopyridine, 3,4-dihydroxypyridine, or formate/ammonium chloride enrichment cultures were monitored by denaturing gradient gel electrophoresis (DGGE) profiling of PCR-amplified 16S rRNA gene fragments. Sequence analysis of the 16S rRNA gene fragments derived from predominant DGGE bands indicated that Pseudomonas nitroreducens 4AP-A and Enterobacter sp. 4AP-G were predominant in the three tested enrichment cultures and that the unculturable strains Hyphomicrobium sp. 4AP-Y and Elizabethkingia sp. 4AP-Z were predominant in 4-aminopyridine and formate/ammonium chloride enrichment cultures and in the 3,4-dihydroxypyridine enrichment culture, respectively. Among the culturable strains, strain 4AP-A could utilize 3,4-dihydroxypyridine as a growth substrate. Although we could not isolate strain 4AP-Y on several media, PCR-DGGE analysis and microscopy indicated that the unique bi-polar filamentous bacterial cells gradually became more dominant with increasing 4-aminopyridine concentration in the medium. CONCLUSIONS: Hyphomicrobium sp. 4AP-Y, P. nitroreducens 4AP-A, and Elizabethkingia sp. 4AP-Z probably play important roles in 4-aminopyridine degradation in crop fields. In the enrichment culture, 3,4-dihydroxypyridine and its metabolites including formate might be shared as growth substrates and maintain the enrichment culture, including these indispensable strains.

Endoscopic gallbladder stenting for acute cholecystitis: a retrospective study of 46 elderly patients aged 65 years or older.

BACKGROUND: Endoscopic transpapillary pernasal gallbladder drainage and endoscopic gallbladder stenting (EGS) have recently been reported to be useful in patients with acute cholecystitis for whom a percutaneous approach is contraindicated. The aim of this study was to evaluate the efficacy of permanent EGS for management of acute cholecystitis in elderly patients who were poor surgical candidates. METHODS: We retrospectively studied 46 elderly patients aged 65 years or older with acute cholecystitis who were treated at Japan Labour Health and Welfare Organization Niigata Rosai Hospital. In 40 patients, acute cholecystitis was diagnosed by transabdominal ultrasonography and computed tomography, while 6 patients were transferred from other hospitals after primary management of acute cholecystitis. All patients underwent EGS, with a 7Fr double pig-tail stent being inserted into the gallbladder. If EGS failed, percutaneous transhepatic gallbladder drainage or percutaneous transhepatic gallbladder aspiration was subsequently performed. The main outcome measure of this study was the efficacy of EGS. RESULTS: Permanent EGS was successful in 31 patients (77.5%) with acute cholecystitis, without any immediate postprocedural complications such as pancreatitis, bleeding, perforation, or cholangitis. The most common comorbidities of these patients were cerebral infarction (n=14) and dementia (n=13). In 30 of these 31 patients (96.7%), there was no recurrence of cholecystitis and 29 patients (93.5%) remained asymptomatic until death or the end of the study period (after 1 month to 5 years). CONCLUSIONS: EGS can be effective for elderly patients with acute cholecystitis who are poor surgical candidates and can provide a solution for several years.

Pivotal role for S-nitrosylation of DNA methyltransferase 3B in epigenetic regulation of tumorigenesis.

DNA methyltransferases (DNMTs) catalyze methylation at the C5 position of cytosine with S-adenosyl-L-methionine. Methylation regulates gene expression, serving a variety of physiological and pathophysiological roles. The chemical mechanisms regulating DNMT enzymatic activity, however, are not fully elucidated. Here, we show that protein S-nitrosylation of a cysteine residue in DNMT3B attenuates DNMT3B enzymatic activity and consequent aberrant upregulation of gene expression. These genes include Cyclin D2 (Ccnd2), which is required for neoplastic cell proliferation in some tumor types. In cell-based and in vivo cancer models, only DNMT3B enzymatic activity, and not DNMT1 or DNMT3A, affects Ccnd2 expression. Using structure-based virtual screening, we discovered chemical compounds that specifically inhibit S-nitrosylation without directly affecting DNMT3B enzymatic activity. The lead compound, designated DBIC, inhibits S-nitrosylation of DNMT3B at low concentrations (IC50 ≤ 100 nM). Treatment with DBIC prevents nitric oxide (NO)-induced conversion of human colonic adenoma to adenocarcinoma in vitro. Additionally, in vivo treatment with DBIC strongly attenuates tumor development in a mouse model of carcinogenesis triggered by inflammation-induced generation of NO. Our results demonstrate that de novo DNA methylation mediated by DNMT3B is regulated by NO, and DBIC protects against tumor formation by preventing aberrant S-nitrosylation of DNMT3B.

Micafungin concentrations in the plasma and burn eschar of severely burned patients.

Micafungin concentrations in plasma and burn eschar after daily intravenous infusion (1 h) of micafungin (200 to 300 mg) were investigated for six patients with severe burns. Micafungin treatment was initiated more than 72 h after the burn injuries. The peak and trough levels in the plasma after the initial administration and repeated administrations for more than 4 days were comparable with or slightly lower than the reported values for healthy volunteers. Micafungin concentrations in the plasma and burn eschar were between 3.6 and >1,000 times higher than the reported MIC(90)s of micafungin against clinically important Candida and Aspergillus species.

Determination of nitrite, nitrate, bromide, and iodide in seawater by ion chromatography with UV detection using dilauryldimethylammonium-coated monolithic ODS columns and sodium chloride as an eluent.

A method was developed for determination of inorganic anions, including nitrite (NO(2)(-)), nitrate (NO(3)(-)), bromide (Br(-)), and iodide (I(-)), in seawater by ion chromatography (IC). The IC system used two dilauryldimethylammonium bromide (DDAB)-coated monolithic ODS columns (50 × 4.6 mm i.d. and 100 × 4.6 mm i.d.) connected in series for separation of the ions. Aqueous NaCl (0.5 mol/L; flow rate, 3 mL/min) containing 5 mmol/L phosphate buffer (pH 5) was used as the eluent, and detection was with a UV detector at 225 nm. The monolithic ODS columns were coated and equilibrated with a 1-mmol/L DDAB solution (in H(2)O/methanol, 90:10 v/v). The hydrophilic ions (NO(2)(-), NO(3)(-), and Br(-)) were separated within 3 min and the retention time of I(-) was 16 min. No interferences from matrix ions, such as chloride and sulfate ions, were observed in 35 ‰ artificial seawater. The detection limits were 0.6 µg/L for NO(2)(-), 1.1 µg/L for NO(3)(-), 70 µg/L for Br(-), and 1.6 µg/L for I(-) with a 200-µL sample injection. The performance of the coated columns was maintained without addition of DDAB in the eluent. The IC system was successfully applied to real seawater samples with recovery rates of 94-108 % for all ions.

ILF2 enhances the DNA cytosine deaminase activity of tumor mutator APOBEC3B in multiple myeloma cells.

DNA cytosine deaminase APOBEC3B (A3B) is an endogenous source of mutations in many human cancers, including multiple myeloma. A3B proteins form catalytically inactive high molecular mass (HMM) complexes in nuclei, however, the regulatory mechanisms of A3B deaminase activity in HMM complexes are still unclear. Here, we performed mass spectrometry analysis of A3B-interacting proteins from nuclear extracts of myeloma cell lines and identified 30 putative interacting proteins. These proteins are involved in RNA metabolism, including RNA binding, mRNA splicing, translation, and regulation of gene expression. Except for SAFB, these proteins interact with A3B in an RNA-dependent manner. Most of these interacting proteins are detected in A3B HMM complexes by density gradient sedimentation assays. We focused on two interacting proteins, ILF2 and SAFB. We found that overexpressed ILF2 enhanced the deaminase activity of A3B by 30%, while SAFB did not. Additionally, siRNA-mediated knockdown of ILF2 suppressed A3B deaminase activity by 30% in HEK293T cell lysates. Based on these findings, we conclude that ILF2 can interact with A3B and enhance its deaminase activity in HMM complexes.