Monitoring of white-rot fungus during bioremediation of polychlorinated dioxin-contaminated fly ash

Bioremediation is a low-cost treatment alternative for the cleanup of polychlorinated-dioxin-contaminated soils and fly ash when pollution spread is wide-ranging. An interesting fungus, Ceriporia sp. MZ-340, with a high ability to degrade dioxin, was isolated from white rotten wood of a broadleaf tree from Kyushu Island in Japan. We have attempted to use the fungus for bioremediation of polychlorinated-dioxin-contaminated soil on site. However, we have to consider that this trial has the potential problem of introducing a biohazard to a natural ecosystem if this organism is naturalized. We have therefore developed a monitoring system for the introduced fungus as a part of the examination and evaluation of bioremediation in our laboratory. We have also developed a PCR-based assay to reliably detect the fungus at the bioremediation site. DNA isolated from the site was amplified by PCR using a specific primer derived from internal transcribed spacer region (ITS: ITS1, 5.8S rDNA and ITS2) sequences of Ceriporia sp. MZ-340. We successfully monitored Ceriporia sp. MZ-340 down to 100 fg/µl DNA and down to 2 mg/g mycelium. We also successfully monitored the fungus specifically at the bioremediation site. The polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran content was observed to decrease in response to treatment with the fungus. The species-specific PCR technique developed in the present work is useful in evaluating the possibility of on-site bioremediation using the fungus Ceriporia sp. MZ-340.     

The expression of platelet endothelial cell adhesion molecule-1 in mouse primordial germ cells during their migration and early gonadal formation

The platelet endothelial cell adhesion molecule-1 (PECAM-1), or CD31, a member of the immunoglobulin superfamily, is located on the plasma membrane of endothelial and hematopoietic cells and involved in vascular development and inflammation. In this study, by use of immunohistochemistry at light and electron microscopic levels in combination with enzyme histochemistry for alkaline phosphatase, we demonstrated that PECAM-1/CD31 is expressed in the mouse primordial germ cell (PGC). Up to 8 days postcoitum (dpc), PGCs with alkaline phosphatase activity showed no PECAM-1/CD31 immunoreactivity. At 9 dpc, PECAM-1/CD31 immunoreactivity was first detected with low intensity in some PGCs located in the hindgut. Between 10 and 11 dpc, intense immunoreactivity was shown on the entire surface of PGCs migrating along the dorsal wall. After arrival and settlement of PGCs in the genital ridges around 11.5 dpc, the intense immunoreactivity was maintained on the entire surface of PGCs. By electron microscopy, the immunoreactivity was localized exclusively on the plasma membrane of PGCs, being as strong at the portions adjacent to neighboring PGCs as those adjacent to somatic cells. As the male and female gonads began to differentiate, PECAM-1/CD31 immunoreactivity remained strong in germ cells until 13 dpc, after which it gradually decreased in intensity and disappeared by 16 dpc. These results suggested that cell-to-cell interaction through PECAM-1/CD31 plays roles in the development of PGCs during their migration on the dorsal wall and homing in the gonads.     

Melting Curve Analysis after T Allele Enrichment (MelcaTle) as a Highly Sensitive and Reliable Method for Detecting the JAK2V617F Mutation

Detection of the JAK2V617F mutation is essential for diagnosing patients with classical myeloproliferative neoplasms (MPNs). However, detection of the low-frequency JAK2V617F mutation is a challenging task due to the necessity of discriminating between true-positive and false-positive results. Here, we have developed a highly sensitive and accurate assay for the detection of JAK2V617F and named it melting curve analysis after T allele enrichment (MelcaTle). MelcaTle comprises three steps: 1) two cycles of JAK2V617F allele enrichment by PCR amplification followed by BsaXI digestion, 2) selective amplification of the JAK2V617F allele in the presence of a bridged nucleic acid (BNA) probe, and 3) a melting curve assay using a BODIPY-FL-labeled oligonucleotide. Using this assay, we successfully detected nearly a single copy of the JAK2V617F allele, without false-positive signals, using 10 ng of genomic DNA standard. Furthermore, MelcaTle showed no positive signals in 90 assays screening healthy individuals for JAK2V617F. When applying MelcaTle to 27 patients who were initially classified as JAK2V617F-positive on the basis of allele-specific PCR analysis and were thus suspected as having MPNs, we found that two of the patients were actually JAK2V617F-negative. A more careful clinical data analysis revealed that these two patients had developed transient erythrocytosis of unknown etiology but not polycythemia vera, a subtype of MPNs. These findings indicate that the newly developed MelcaTle assay should markedly improve the diagnosis of JAK2V617F-positive MPNs.     

Charade of the SR K-Channel: Two Ion-Channels, TRIC-A and TRIC-B, Masquerade as a Single K-Channel

The presence of a sarcoplasmic reticulum (SR) K⁺-selective ion-channel has been known for >30 years yet the molecular identity of this channel has remained a mystery. Recently, an SR trimeric intracellular cation channel (TRIC-A) was identified but it did not exhibit all expected characteristics of the SR K⁺-channel. We show that a related SR protein, TRIC-B, also behaves as a cation-selective ion-channel. Comparison of the single-channel properties of purified TRIC-A and TRIC-B in symmetrical 210 mM K⁺ solutions, show that TRIC-B has a single-channel conductance of 138 pS with subconductance levels of 59 and 35 pS, whereas TRIC-A exhibits full- and subconductance open states of 192 and 129 pS respectively. We suggest that the K⁺-current fluctuations observed after incorporating cardiac or skeletal SR into bilayers, can be explained by the gating of both TRIC-A and TRIC-B channels suggesting that the SR K⁺-channel is not a single, distinct entity. Importantly, TRIC-A is regulated strongly by trans-membrane voltage whereas TRIC-B is activated primarily by micromolar cytosolic Ca²⁺ and inhibited by luminal Ca²⁺. Thus, TRIC-A and TRIC-B channels are regulated by different mechanisms, thereby providing maximum flexibility and scope for facilitating monovalent cation flux across the SR membrane.     

Peripheral tolerance and the qualitative characteristics of autoreactive T cell clones in primary biliary cirrhosis

Primary biliary cirrhosis is characterized by autoreactive T cells specific for the mitochondrial Ag PDC-E2(163-176). We studied the ability of eight T cell clones (TCC) specific for PDC-E2(163-176) to proliferate or become anergic in the presence of costimulation signals. TCC were stimulated with either human PDC-E2(163-176), an Escherichia coli 2-oxoglutarate dehydrogenase mimic (OGDC-E2(34-47)), or analogs with amino acid substitutions using HLA-matched allogeneic PBMC or mouse L-DR53 fibroblasts as APC. Based on their differential responses to these peptides (human PDC-E2(163-176), E. coli OGDC-E2(34-47)) in the different APC systems, TCC were classified as costimulation dependent or independent. Only costimulation-dependent TCC could become anergic. TCC with costimulation-dependent responses to OGDC-E2 become anergic to PDC-E2 when preincubated with mimic, even if costimulation is independent for PDC-E2(163-176). Anergic TCC produced IL-10. One selected TCC could not become anergic after preincubation with PDC-E2(163-176)-pulsed L-DR53 but became anergic using L-DR53 pulsed with PDC-E2 peptide analogs with a substitution at a critical TCR binding site. TCC that only respond to peptide-pulsed PBMC, but not L-DR53, proliferate with peptide-pulsed CD80/CD86-transfected L-DR53; however, anergy was not induced with peptide-pulsed L-DR53 transfected with only CD80 or CD86. These data highlight that costimulation plays a dominant role in maintaining peripheral tolerance to PBC-specific Ags. They further suggest that, under specific circumstances, molecular mimicry of an autoantigen may restore rather than break peripheral tolerance.     

Macrophage inflammatory protein-1α (MIP-1α) enhances a receptor activator of nuclear factor κB ligand (RANKL) expression in mouse bone marrow stromal cells and osteoblasts through MAPK and PI3K/Akt pathways

Osteolytic lesions are rapidly progressive during the terminal stages of myeloma, and the bone pain or bone fracture that occurs at these lesions decreases the patients’ quality of life to a notable degree. In relation to the etiology of this bone destruction, it has been reported recently that MIP-1α, produced in large amounts in myeloma patients, acts indirectly on osteoclastic precursor cells, and activates osteoclasts by way of bone-marrow stromal cells or osteoblasts, although the details of this process remain obscure. In the present study, our group investigated the mechanism by which RANKL expression is induced by MIP-1α and the effects of MIP-1α on the activation of osteoclasts. RANKL mRNA and RANKL protein expressions increased in both ST2 cells and MC3T3–E1 cells in a MIP-1α concentration-dependent manner. RANKL mRNA expression began to increase at 1 h after the addition of MIP-1α; the increase became remarkable at 2 h, and continuous expression was observed subsequently. Both ST2 and MC3T3-E1 cells showed similar levels of increased RANKL protein expression at 1, 2, and 3 days after the addition of MIP-1α. After the addition of MIP-1α, the amount of phosphorylated ERK1/2 and Akt protein expressions showed an increase, as compared to the corresponding amount in the control group. On the other hand, the amount of phosphorylated p38MAPK protein expression showed a decrease from the amount in the control group after the addition of MIP-1α. U0126 (a MEK1/2 inhibitor) or LY294002 (a PI3K inhibitor) was added to ST2 and MC3T3-E1 cells, and was found to inhibit RANKL mRNA and RANKL protein expression in these cells. When SB203580, a p38MAPK inhibitor, was added, RANKL mRNA and RANKL protein expression were increased in these cells. MIP-1α was found to promote osteoclastic differentiation of C7 cells, an osteoclastic precursor cell line, in a MIP-1α concentration-dependent manner. MIP-1α promoted differentiation into osteoclasts more extensively in C7 cells incubated together with ST2 and MC3T3-E1 cells than in C7 cells incubated alone. These results suggested that MIP-1α directly acts on the osteoclastic precursor cells and induces osteoclastic differentiation. This substance also indirectly induces osteoclastic differentiation through the promotion of RANKL expression in bone-marrow stromal cells and osteoblasts. The findings of this investigation suggested that activation of the MEK/ERK and the PI3K/Akt pathways and inhibition of p38MAPK pathway were involved in RANKL expression induced by MIP-1α in bone-marrow stromal cells and osteoblasts. This finding may be useful in the development of an osteoclastic inhibitor that targets intracellular signaling factors.     

Overexpression of B7-H1 (PD-L1) significantly associates with tumor grade and postoperative prognosis in human urothelial cancers

PURPOSE: The programmed death-1 (PD-1)/B7-H1 (also called PD-L1) pathway negatively regulates T cell activation and has been suggested to play an important role in regulating antitumor host immunity. To investigate the clinical significance of B7-H1 expression to the tumor grade and postoperative prognosis of patients with urothelial cancer, we analyzed the relationship between B7-H1 expression and various clinicopathological features and postoperative prognosis. EXPERIMENTAL DESIGN: Sixty-five urothelial cancer cases were examined. B7-H1 expression in tumors and the numbers and phenotypes of tumor-infiltrating lymphocytes were evaluated by immunohistochemistry and flow cytometry. RESULTS: A substantial expression of B7-H1 was observed in all urothelial cancers investigated. Tumor specimens from patients with higher WHO grade or primary tumor classifications showed significantly higher percentages of tumor-associated B7-H1. Tumor-associated B7-H1 expression was significantly associated with a high frequency of postoperative recurrence and poor survival rate. Furthermore, multivariate analysis indicated that tumor-associated B7-H1 was more significant prognostic factor than WHO grade. CONCLUSIONS: Our results demonstrate that the aberrant expression of B7-H1 in urothelial cancer is associated with aggressive tumors, suggesting a regulatory role of tumor-associated B7-H1 in antitumor immunity. Therefore, the manipulation of tumor-associated B7-H1 may become a beneficial target for immunotherapy in human urothelial cancer.