Cancer chemotherapy and somatic cell mutation

The occurrence of a second neoplasm is one of the major obstacles in cancer chemotherapy. The elucidation of the genotoxic effects induced by anti-cancer drugs is considered to be helpful in identifying the degree of cancer risk. Numerous investigations on cancer patients after chemotherapy have demonstrated: (i) an increase in the in vivo somatic cell mutant frequency (Mf) at three genetic loci, including hypoxanthine–guanine phosphoribosyl-transferase (hprt), glycophorin A (GPA), and the T-cell receptor (TCR), and (ii) alterations in the mutational spectra of hprt mutants. However, the time required for and the degree of such changes are quite variable among patients even if they have received the same chemotherapy, suggesting the existence of underlying genetic factor(s). Accordingly, some cancer patients prior to chemotherapy as well as patients with cancer-prone syndrome have been found to show an elevated Mf. Based on the information obtained from somatic cell mutation assays, an individualized chemotherapy should be considered in order to minimize the risk of a second neoplasm.     

Bile acid metabolism in partially hepatectomized rats

The bile flow and the bile acid secretion, calculated on liver weight basis, increased 12 H and 24 H after 60-70% hepatectomy and returned to the initial levels thereafter. The biliary phospholipid secretion much more increased than bile acids, but the cholesterol secretion decreased. Bile acid composition changed with an increase of the cholic acid group and a decrease of the chenodeoxycholic acid group in both bile and feces. These changes almost disappeared on Day 14. The pool size of bile acid decreased maximally on Day 4 to about 40% of the initial, but the distribution of bile acids in the enterohepatic circulation was not changed. The fecal cholesterol and coprostanol markedly decreased on Day 2 but gradually returned to the initial levels according to the recovery of diet intake. The fecal bile acids decreased on Day 2, increased on Day 4, and returned to the normal range after Day 7. In conclusion, the regenerating liver secretes more bile, bile acids and phospholipids, and less cholesterol than the normal liver. Cholic acid predominates in the bile acids. These changes restored to the initial levels by about one week after the operation.     

Morphology and molecular phylogeny of the marine diatom genus Nagumoea (Bacillariophyceae) from Japan

The canal-bearing diatom genus Nagumoea, described based on only morphological evidence, was tentatively assigned to the order Bacillariales, although its phylogenetic position remained unclear. Because three isolates of Nagumoea (SK002, SK024 and SK053) were successfully established from Japanese coasts, we performed their morphological observations and molecular phylogenetic analyses to discuss the phylogeny and taxonomic position of this genus. Strains SK002 and SK024 were identified as Nagumoea africana, whereas SK053 conformed with Nagumoea serrata. There was high interspecific divergence between N. africana and N. serrata in the rbcL sequences (8.03–8.17%), indicating their distinctness. Furthermore, intraspecific variations were detected within N. africana (2.35%) in the rbcL, implying its cryptic diversity. The maximum likelihood and Bayesian phylogenetic trees inferred from the plastid rbcL, psbC and nuclear 18S rDNA genes recovered Nagumoea as monophyletic with strong statistical support and embedded within an unresolved, poorly supported lineage containing Achnanthes, Craspedostauros, Staurotropis and Undatella in the canal-bearing order Bacillariales (= the family Bacillariaceae). Although the constrained tree based on the monophyly of Nagumoea and the other canal-bearing clade (Surirellales and Rhopalodiales) was statistically rejected by the topology tests, the phylogenetic position of Nagumoea with other Bacillarialean members remains equivocal. The possession of two plastids positioned fore and aft, observed in the present study, and lack of keel, typical of the Bacillariales, indicate the possibility of Nagumoea being part of the ingroup of the Bacillariales or its closely related outgroup.     

iNKT cells in microbial immunity: recognition of microbial glycolipids

Natural killer T cells expressing an invariant T cell antigen receptor (iNKT cells) are cells of the innate immune system. After recognizing glycolipid antigens presented by CD1d molecules on antigen presenting cells (APCs), iNKT cells rapidly produce large quantities of cytokines, thereby stimulating many types of cells. Recent studies have described several mechanisms of iNKT cell activation and the contribution of these cells to antimicrobial responses. iNKT cells can be activated by endogenous antigens and/or inflammatory cytokines from APCs. However, iNKT cells also recognize certain microbial glycolipids by their invariant T cell antigen receptor (TCR), and they contribute to pathogen clearance in certain microbial infections. These findings indicate that the iNKT TCR is useful for detecting certain microbial pathogens. Moreover, recent studies suggest that iNKT cell glycolipid antigens may be useful in antimicrobial therapy and vaccines.     

A quantitative structure-activity relationship study for structurally diverse HIV-1 protease inhibitors: contribution of conformational flexibility to inhibitory activity

In this study, we investigated by linear regression model the SAR data of the 15 HIV-1 protease inhibitors possessing structurally diverse scaffolds. First, a regression model was developed only using the enzyme-inhibitor interaction energy as a term of the model, but did not provide a good correlation with the inhibitory activity (R² = 0.580 and Q² = 0.500). Then, we focused on the conformational flexibility of the inhibitors which may represent the diversity of the inhibitors, and added two conformational parameters into the model, respectively: the number of rotatable bonds of ligands (ΔSrot) and the distortion energy of ligands (ΔElig). The regression model by adding ΔElig successfully improved the quality of the model (R² = 0.771 and Q² = 0.713) while the model with ΔSrot was unsuccessful. The prediction for a training inhibitor by the ΔElig model also showed good agreement with experimental activity. These results suggest that the conformational flexibility of HIV-1 protease inhibitors directly contributes to the enzyme inhibition.     

Examination of unidentifiable spined loach individuals found in the overlap zone of two tetraploid species within a single river in Japan

An endangered tetraploid spined loach species, Cobitis takenoi (Cypriniformes: Cobitidae; hereafter called Tango loach) is known to inhabit only a single river in Kyoto Prefecture, Japan. Since Tango loach was discovered recently, in 2010, and only described in 2016, its morphology, ecology, and genetics are not well studied. Another tetraploid spined loach species Cobitis sp. BIWAE type A (hereafter, called Ohshima loach) inhabits the same river. The two loaches are reported as morphologically distinguishable from each other. Although the habitats of the two species in the river are segregated (Ohshima loach and Tango loach inhabit the upper and lower reaches, respectively), they overlap to a small degree in the boundary area. Recently, some individuals with morphological characteristics that are intermediate between the two species were found in the overlap zone. It was suspected that hybrids between the two species were produced since breeding seasons of the two species overlapped. To investigate whether the two species produce hybrids, we performed mitochondrial and nuclear DNA analyses on the unidentifiable individuals. Eight individuals unidentifiable to the species level collected in the river between 2017 and 2018 were examined and compared with the Tango and Ohshima loach species. Using mitochondrial DNA (mtDNA) cytochrome b analysis, we found that six individuals had mtDNA types identical to Tango loach and two individuals had mtDNA types identical to Ohshima loach. Furthermore, sequencing analysis of nuclear recombination activating gene 1 (RAG-1) revealed that each species had species-specific alleles. The phylogenetic analysis indicated that alleles in Tango loach were divided into two clusters and those from Ohshima loach formed a single cluster. There were no discrepancies in the combination between mtDNA and nuclear DNA species types within each specimen. DNA fingerprinting analysis (AFLP) showed that the species-unidentifiable individuals exhibited distinctly segregated genetic groups corresponding with Tango and Ohshima loaches. In summary, no hybrids were detected from among any unidentifiable individual examined in this study. New conventional genetic method for discriminating the two sympatric loach species developed here can be effective tool for the conservation of the Tango loach since there was no strict diagnostic morphological character between them.     

Sperm ultrastructure in the diatoms Melosira and Thalassiosira and the significance of the 9 + 0 configuration

The most complete account to date of the ultrastructure of flagellate cells in diatoms is given for the sperm of Thalassiosira lacustris and Melosira moniliformis var. octogona, based on serial sections. The sperm are uniflagellate, with no trace of a second basal body, and possess a 9?+?0 axoneme. The significance of the 9?+?0 configuration is discussed: lack of the central pair microtubules and radial spokes does not compromise the mastigoneme-bearing flagellum’s capacity to perform planar beats and thrust reversal and may perhaps be related to sensory/secretory function of the sperm flagellum during plasmogamy. The basal bodies of diatoms are confirmed to contain doublets rather than triplets, which may correlate with the absence of some centriolar proteins found in most cells producing active flagella. Whereas Melosira possesses a normal cartwheel structure in the long basal body, no such structure is present in Thalassiosira, which instead possesses ‘intercalary fibres’ linking the basal body doublets. No transitional helices or transitional plates are present in either species studied. Cones of microtubules are associated with the basal body and partially enclose the nucleus in M. moniliformis and T. lacustris. They do not appear to be true microtubular roots and may arise through transformation of the meiosis II spindle. A close association between cone microtubules and tubules containing mastigonemes may indicate a function in intracellular mastigoneme transport. No correlation can yet be detected between methods of spermatogenesis and phylogeny in diatoms, contrary to previous suggestions.     

Glutathione maintenance is crucial for survival of melanocytes after exposure to rhododendrol

Rhododendrol is a phenolic compound that shows a tyrosinase‐dependent toxicity for melanocytes and occasionally induces a vitiligo‐like skin depigmentation. The post‐tyrosinase mechanisms determining melanocyte death or survival, however, are far from clear. Here, we find that rhododendrol treatment leads to a reduction in the levels of cellular glutathione but also induces a cellular antioxidant response that eventually increases glutathione levels. We further find that rhododendrol toxicity is enhanced when glutathione levels are experimentally reduced and alleviated when glutathione levels are increased. Hence, it appears that the size of the preexisting glutathione pool along with the capacity to supply glutathione via the antioxidant response determines whether melanocytes survive or die after rhododendrol exposure. It is conceivable, therefore, that rhododendrol‐induced leukoderma depends on the capacity to maintain appropriate glutathione levels and that enhancement of glutathione levels may preserve a patient's melanocytes and potentially help in repigmentation.     

Associations among Erythroferrone and Biomarkers of Erythropoiesis and Iron Metabolism,and Treatment with Long-Term Erythropoiesis-Stimulating Agents in Patients on Hemodialysis

Background

We aimed to identify associations between erythroferrone (ERFE), a regulator of hepcidin 25, and biomarkers of erythropoiesis and iron metabolism. We also aimed to determine the effects of erythropoiesis-stimulating agents (ESA), continuous erythropoietin receptor activator (CERA) and darbepoetin-α (DA) on ERFE production in patients on hemodialysis (HD).

Methods

Blood samples were obtained from 59 patients before HD sessions on day 0 (baseline). Twenty patients who were injected with either CERA (N = 10) or DA (N = 10) at the end of the dialysis week (day 0), who had ferritin ≥ 100 ng/mL and/or transferrin saturation ≥ 20%, and hemoglobin > 9 g/dL were selected from among the 59 patients. Blood was sampled serially before HD sessions on days 3, 5, 7 from patients on DA and on the same days plus day 14 from those on CERA.

Results

Levels of ERFE correlated inversely with those of hepcidin 25 and ferritin, and positively with those of soluble transferrin receptor. The hepcidin 25: ERFE ratio and hepcidin 25 levels positively correlated with ferritin levels. Levels of ERFE significantly increased from day 3 of treatment with DA and CERA and decreased by days 7 and 14, respectively. Erythropoiesis-stimulating agents concomitantly decreased levels of hepcidin 25 as those of ERFE increased.

Conclusion

We identified a novel association between ESA and ERFE in patients on HD. Both DA and CERA increased levels of ERFE that regulated hepcidin 25 and led to iron mobilization from body stores during erythropoiesis.     

Human Leukocyte Antigen and Systemic Sclerosis in Japanese: The Sign of the Four Independent Protective Alleles,DRB1*13:02, DRB1*14:06, DQB1*03:01, and DPB1*02:01

ObjectiveSeveral studies on associations between human leukocyte antigen (HLA) allele frequencies and susceptibility to systemic sclerosis (SSc) have been reported. Anti-centromere antibodies (ACA) and anti-topoisomerase I antibodies (ATA) are found in SSc patients. Here, we sought to identify HLA alleles associated with SSc in Japanese, and explored their associations with SSc phenotypes including the presence of autoantibodies.MethodsAssociations of HLA-DRB1, DQB1, and DPB1 were analyzed in 463 Japanese SSc patients and 413 controls.ResultsWe found that DRB1*13:02 (P = 0.0011, Pc = 0.0319, odds ratio [OR] 0.46, 95% confidence interval [CI] 0.29–0.73), DRB1*14:06 (P = 6.60X10^-5, Pc = 0.0020, OR 0.05, 95%CI 0.01–0.41), DQB1*03:01 (P = 0.0009, Pc = 0.0150, OR 0.56, 95%CI 0.40–0.79), and DPB1*02:01 (P = 5.16X10^-6, Pc = 8.77X10^-5, OR 0.52, 95%CI 0.39–0.69) were protectively associated with SSc. In addition, these four alleles seemed to be independently associated with the protection against the susceptibility of SSc. On the other hand, we could not find predisposing alleles for overall SSc. With respect to SSc subsets, a tendency for these four alleles to be protectively associated was observed. However, there was a significant association between DRB1*01:01, DRB1*10:01, DQB1*05:01, and DPB1*04:02 and the susceptibility to SSc with ACA. On the other hand, the presence of DRB1*15:02, DQB1*06:01, DPB1*03:01, and DPB1*09:01 was associated with SSc with ATA.ConclusionThus, the present study has identified protective associations of the four HLA class II alleles with overall Japanese SSc and predisposing associations of HLA class II alleles with Japanese SSc subsets.