Copy-number mutants of the plasmid carrying the replication origin of the Escherichia coli chromosome: evidence for a control region of replication.

A composite plasmid (pXX11) was constructed by joining of an oriC plasmid (pMCR115) carrying the replication origin (oriC) of the Escherichia coli chromosome and a mini-F plasmid (pSC138) carrying the ampicillin-resistance gene (bla). Plasmid pXX11 can replicate, by using oriC, in Hfr cells and mafA mutant cells that cannot support replication of an F plasmid. This plasmid is stably maintained in these host cells during cell growth even under nonselective conditions by use of the partition mechanism of the mini-F genome. In contrast to other oriC plasmids reported previously, pXX11 has no detectable effect on host cell growth. Higher copy-number (Cop-) mutants of pXX11 were isolated, and some of them were found to carry an insertion or deletion within a region derived from the E. coli chromosome. This region, designated cop (copy number), covers about 0.7 kilobase pair and is located approximately 3 kilobase pairs away from the oriC region at the side opposite the asn gene. Evidence suggests that the normal cop region locted on the oriC plasmid acts to reduce the copy number of the plasmid. Plasmid pXX11 complements the uncB402 mutation located on the host chromosome, but some of the Cop- plasmids do not, suggesting that the cop region is vey closely linked to uncB.     

The Reverse-Direction Method Links Mass Experimental Data to Human Diseases

Genome-wide analyses such as DNA microarray, RNA sequencing and RNA interference-based high-throughput screening are prevalent to decipher a biological process of interest, and provide a large quantity of data to be processed. An ultimate goal for researchers must be extrapolation of their data to human diseases. We have conducted functional genome-wide screenings to elucidate molecular mechanisms of the inflammation amplifier, a NFκB/STAT3-dependent machinery that potently drives recruitment of immune cells to promote inflammation. Using a public database of genome-wide association studies (GWAS), we recently reported the reverse-direction method by which our mass screening data were successfully linked to many human diseases. As an example, the epiregulin–epidermal growth factor receptor pathway was identified as a regulator of the inflammation amplifier, and associated with human diseases by GWAS. In fact, serum epiregulin levels were higher in patients with chronic inflammatory disorders. The reverse-direction method can be a useful tool to narrow mass data down to focus on human disease-related genes.     

A multicentre phase II study of vorinostat in patients with relapsed or refractory indolent B‐cell non‐Hodgkin lymphoma and mantle cell lymphoma

Although initial rituximab‐containing chemotherapies achieve high response rates, indolent B‐cell non‐Hodgkin lymphoma (B‐NHL), such as follicular lymphoma (FL), is still incurable. Therefore, new effective agents with novel mechanisms are anticipated. In this multicentre phase II study, patients with relapsed/refractory indolent B‐NHL and mantle cell lymphoma (MCL) received vorinostat 200 mg twice daily for 14 consecutive days in a 21‐d cycle until disease progression or unacceptable toxicity occurred. The primary endpoint was overall response rate (ORR) in FL patients and safety and tolerability in all patients. Secondary endpoints included progression‐free survival (PFS). Fifty‐six eligible patients were enrolled; 50 patients (39 with FL, seven with other B‐NHL, and four with MCL) were evaluable for ORR, and 40 patients had received rituximab‐containing prior chemotherapeutic regimens. For the 39 patients with FL, the ORR was 49% [95% confidence interval (CI): 32·4, 65·2] and the median PFS was 20 months (95% CI: 11·2, 29·7). Major toxicities were manageable grade 3/4 thrombocytopenia and neutropenia. Vorinostat offers sustained antitumour activity in patients with relapsed or refractory FL with an acceptable safety profile. Further investigation of vorinostat for clinical efficacy is warranted.     

Zinc transporter SLC39A10/ZIP10 facilitates antiapoptotic signaling during early B-cell development

The immune system is influenced by the vital zinc (Zn) status, and Zn deficiency triggers lymphopenia; however, the mechanisms underlying Zn-mediated lymphocyte maintenance remain elusive. Here we investigated ZIP10, a Zn transporter expressed in the early B-cell developmental process. Genetic ablation of Zip10 in early B-cell stages resulted in significant reductions in B-cell populations, and the inducible deletion of Zip10 in pro-B cells increased the caspase activity in parallel with a decrease in intracellular Zn levels. Similarly, the depletion of intracellular Zn by a chemical chelator resulted in spontaneous caspase activation leading to cell death. Collectively, these findings indicated that ZIP10-mediated Zn homeostasis is essential for early B-cell survival. Moreover, we found that ZIP10 expression was regulated by JAK-STAT pathways, and its expression was correlated with STAT activation in human B-cell lymphoma, indicating that the JAK-STAT-ZIP10-Zn signaling axis influences the B-cell homeostasis. Our results establish a role of ZIP10 in cell survival during early B-cell development, and underscore the importance of Zn homeostasis in immune system maintenance.Zinc (Zn) has wide-ranging effects on immunity. Zn deficiency has uncovered the importance of Zn homeostasis in immune cell maintenance and function (1). Dramatic effects of Zn on immunity have been observed in several immune and allergy-related cells, including lymphocytes such as B cells (2–6). B cells develop in the bone marrow (BM); the initial commitment to pro-B cells is followed by their differentiation into pre-B cells, and subsequently into immature B cells, which express the B-cell receptor on their surface (7). The immature B cells reach the spleen as transitional B cells, further differentiating into follicular or marginal zone mature B cells (7). Although the perturbation of Zn homeostasis causes splenic atrophy associated with lymphocyte reduction, and compromises cellular and humoral immune responses (6), the mechanisms underlying how Zn controls immune cell function, and in particular, the impact on early B-cell development, have been largely unknown.Zn homeostasis is tightly controlled by Zn transporter family members, Zrt- and Irt-like proteins (ZIPs, Zn importers) and zinc transporters (ZnTs, Zn exporters) (8), and recent studies revealed that alterations in Zn homeostasis mediated by specific Zn transporters play indispensable roles in a variety of cellular events (9). The intestinal Zn transporter ZIP4 is important for the initial absorption of dietary Zn, and patients with mutations in the SLC39A4/ZIP4 gene suffer from the inherited disorder acrodermatitis enteropathica (10, 11). ZIP13 controls the formation of bone, teeth, and connective tissues by modulating BMP/TGF-β signaling (12), and its loss-of-function mutation causes spondylocheiro dysplastic Ehlers-Danlos syndrome in humans (12, 13). ZIP14 controls systemic growth by regulating G protein-coupled receptor (GPCR) signaling (14), and ZIP8 is involved in osteoarthritis (15) and negatively manipulates NF-κB activation (16). In addition, ZnT5 regulates cytokine production by controlling the activation of protein kinase C upon antigen exposure in mast cells (17). Thus, Zn homeostasis mediated by Zn transporters is linked to a wide variety of biological and regulatory functions, and the disruption of a Zn transporter-Zn axis can lead to various symptoms in the absence of redundant machinery (18).Here we demonstrate a definitive role of ZIP10 in early B-cell development. We found that a loss of ZIP10 during an early B-cell stage specifically abrogated cell survival, resulting in the absence of mature B cells, which led to splenoatrophy and reduced Ig levels. The inducible deletion of Zip10 in pro-B cells increased the caspase activity because of the reduced intracellular Zn level, leading to cell death. This phenomenon was mimicked by the intracellular chelation of Zn. These findings indicated that Zn homeostasis via ZIP10 plays an indispensable role in early B-cell survival. We also demonstrated that the ZIP10 expression levels were regulated by STAT3/STAT5 activation, and that ZIP10 was highly expressed in human B-cell lymphoma samples in which both STAT proteins were activated, indicating that the JAK-STAT-ZIP10-Zn signaling axis is important for B-cell maintenance. Our results establish a functional link between ZIP10 and the survival of early stages of B cells, revealing a molecular mechanism underlying the requirement of Zn for maintenance of the immune system.     

Efficacy of Granulocyte and Monocyte Adsorption Apheresis for Treatment of Palmoplantar Pustulosis

Palmoplantar pustulosis (PPP) is characterized by neutrophilic pustules with erythema, which are limited to the hands and feet. Although granulocyte and monocyte adsorption apheresis (GMA) has shown remarkable effects on generalized pustular psoriasis, there are few reports of PPP treated with GMA. We treated three refractory PPP patients using GMA weekly for 5 weeks. The skin eruptions were assessed by a 5‐grade score for scales, pustules, and erythema. GMA decreased the total grade from 9 to 2 in patients 1 and 2, and from 7 to 3 in patient 3. The GMA effects were estimated to be excellent in all three patients. Pustule formation and pain disappeared in all cases. The treatment effect lasted for at least 5 months after GMA. GMA was also effective for relieving the arthralgia in one patient, but it recurred at 6 weeks. Based on these findings, GMA could be an effective therapy for refractory PPP.     

Wear and mechanical properties of composite resins consisting of different filler particles

To investigate the effects of different fillers and their contents on the wear of composite resins, four composites (CS: non-porous spherical silica, AS: porous spherical silica, AZ: porous spherical zirconium silicate, and IS: non-porous irregular-shaped silica) were experimentally prepared using different fillers (CS, AZ, AS and IS). Simulated occlusal wear and toothbrush wear were evaluated for these composites and their worn surfaces were observed. The mechanical properties (flexural strength, elastic modulus and hardness) of these composites were determined to examine the relationships between wear and these mechanical properties. CS showed the highest occlusal wear, but the lowest toothbrush wear among four composites. AS and AZ had lower occlusal wear than CS and IS, while their toothbrush wear was higher than CS and close to that of IS. All composites showed increase in the occlusal wear as filler content increased. CS and IS showed decrease in the toothbrush wear as the filler content increased, whereas AS and AZ did not. The occlusal wear surfaces of CS and IS had concavities, while those of AZ and AS were relatively smooth with flattened filler. The toothbrush wear surfaces of CS and IS revealed the extrusion of filler from resin matrix, whereas those of AZ and AS were smooth with flattened filler. The toothbrush wear of CS and IS decreased as the mechanical properties increased, whereas those of AS and AZ did not. The occlusal wear of all composites increased as the mechanical properties increased, which would not reflect effects of these mechanical properties.