Onset of hepatic erythropoiesis after malarial infection in mice

Plasmodium yoelii-infected erythrocytes were injected into mice with or without 6.5 Gy irradiation. This irradiation suppressed erythropoiesis and induced severe immunosuppression. However, these mice showed a rather delayed infection, suggesting that fresh erythrocytes may become malarial targets. In other words, malarial infection did not persist without newly generated erythrocytes in mice. We then examined erythropoiesis in the liver and bone marrow of mice with malaria. Surprisingly, erythropoiesis began in the liver. At this time, the serum level of erythropoietin (EPO) was prominently elevated and the EPO mRNA also became detectable in the kidney. Many clusters of red blood cells appeared de novo in the parenchymal space of the liver. These results revealed that malarial infection had a potential to induce the onset of hepatic erythropoiesis in mice.     

Pyrrolidinium fullerene induces apoptosis by activation of procaspase-9 via suppression of Akt in primary effusion lymphoma

Primary effusion lymphoma (PEL) is a subtype of non-Hodgkin’s B-cell lymphoma and is an aggressive neoplasm caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients. In general, PEL cells are derived from post-germinal center B-cells and are infected with KSHV. To evaluate potential novel anti-tumor compounds against KSHV-associated PEL, seven water-soluble fullerene derivatives were evaluated as potential drug candidates for the treatment of PEL. Herein, we discovered a pyrrolidinium fullerene derivative, 1,1,1′,1′-tetramethyl [60]fullerenodipyrrolidinium diiodide, which induced apoptosis of PEL cells via a novel mechanism, the caspase-9 activation by suppressing the caspase-9 phosphorylation, causing caspase-9 inactivation. Pyrrolidinium fullerene treatment reduced significantly the viability of PEL cells compared with KSHV-uninfected lymphoma cells, and induced the apoptosis of PEL cells by activating caspase-9 via procaspase-9 cleavage. Pyrrolidinium fullerene additionally reduced the Ser473 phosphorylation of Akt and Ser196 of procaspase-9. Ser473-phosphorylated Akt (i.e., activated Akt) phosphorylates Ser196 in procaspase-9, causing inactivation of procaspase-9. We also demonstrated that Akt inhibitors suppressed the proliferation of PEL cells compared with KSHV-uninfected cells. Our data therefore suggest that Akt activation is essential for cell survival in PEL and a pyrrolidinium fullerene derivative induced apoptosis by activating caspase-9 via suppression of Akt in PEL cells. In addition, we evaluated whether pyrrolidinium fullerene in combination with the HSP90 inhibitor (geldanamycin; GA) or valproate, potentiated the cytotoxic effects on PEL cells. Compared to treatment with pyrrolidinium fullerene alone, the addition of low-concentration GA or valproate enhanced the cytotoxic activity of pyrrolidinium fullerene. These results indicate that pyrrolidinium fullerene could be used as a novel therapy for the treatment of PEL.     

Analysis of Gas Chromatographic Profiles of “Katsuobushi” (Dried Bonito) Flavor by Pattern Similarity Analysis Method

Katsuobushi (dried bonito) flavor was prepared by vacuum ethanolic distillation (VED) without losing its original organoleptic characteristics. Gas chromatographic (GLC) profiles of the prepared Katsuobushi flavor were analyzed by calculating the pattern similarity coefficients and radian distances. The GLC profile of the phenolic fraction was the most similar to that of the whole flavor among the separated four fractions. The GLC profiles of Katsuobushi and Niboshi (dried sardine) mixtures blended at different ratios were compared, and the pattern similarity coefficients were found to be changed in proportion to the mixed ratios. These results show a good agreement with organoleptic evaluations and suggested that Katsuobushi flavor was ascribed to an integrated effect of many aroma compounds.     

Expression of TCR alpha beta partly rescues developmental arrest and apoptosis of alpha beta T cells in Bcl11b-/- mice

Bcl11b(-/-) mice show developmental arrest at the CD44(-)CD25(+) double-negative 3 (DN3) or immature CD8(+)single-positive stage of alphabeta T cell. We have performed detailed analysis of sorted subsets of Bcl11b(-/-) thymocytes, DN3 and CD44(-)CD25(-) double-negative 4 (DN4) cells. Surface expression of TCRbeta proteins was not detected in DN3 thymocytes and markedly reduced in DN4 thymocytes, whereas expression within the cell was detected in both, suggesting some impairment in processing of TCRbeta proteins from the cytoplasm to the cell surface. This lack of expression, resulting in the absence of pre-TCR signaling, could be responsible for the arrest, but the transgenic TCRbeta or TCRalphabeta expression on the cell surface failed to promote transition from the DN3 to CD4(+)CD8(+) double-positive stage of development. This suggests that the pre-TCR signal cannot compensate the deficiency of Bcl11b for development. Bcl11b(-/-) DN3 thymocytes showed normal DNA rearrangements between Dbeta and Jbeta segments but limited DNA rearrangements between Vbeta and DJbeta without effect of distal or proximal positions. Because this impairment may be due to chromatin accessibility, we have examined histone H3 acetylation in Bcl11b(-/-) DN3 cells using chromatin immunoprecipitation assay. No change was observed in acetylation at the Vbeta and Dbeta gene locus. Analysis of Bcl11b(-/-) DN4 thymocytes showed apoptosis, accompanied with lower expression of anti-apoptotic proteins, Bcl-x(L) and Bcl-2, than wild-type DN4 thymocytes. Interestingly, the transgenic TCRalphabeta in those cells reduced apoptosis and raised their protein expression without increased cellularity. These results suggest that Bcl11b deficiency affects many different signaling pathways leading to development arrests.     

Randomly interesterified triacylglycerol containing medium- and long-chain fatty acids stimulates fatty acid metabolism in white adipose tissue of rats

We have reported previously that randomly interesterified triacylglycerol containing medium- and long-chain fatty acids in the same glycerol molecule (MLCT) resulted in significantly lower body fat accumulation and higher hepatic fatty acid oxidation than from long-chain triacylglycerol (LCT) in rats. To understand the metabolic changes occurring in white adipose tissue, the fatty acid oxidation and synthesis, and the adipocytokine level were measured in rats fed with MLCT or LCT for 2 weeks. In comparison with LCT, MLCT lowered not only the fatty acid synthase and glycerol-3-phosphate dehydrogenase activities in perirenal adipose tissue, but also the serum insulin and leptin levels, in addition to significantly reducing the body fat accumulation. In contrast, fatty acid oxidation measured as the carnitine palmitoyltransferase activity in the tissue was significantly higher in the MLCT-fed rats than in the LCT-fed rats. It seems that the altered fatty acid metabolism in adipose tissue per se was also responsible for the lower adiposity by dietary MLCT.     

Phosphoinositides suppress gamma-secretase in both the detergent-soluble and -insoluble states

gamma-Secretase is an aspartic protease that hydrolyzes type I membrane proteins within the hydrophobic environment of the lipid bilayer. Using the CHAPSO-solubilized gamma-secretase assay system, we previously found that gamma-secretase activity was sensitive to the concentrations of detergent and phosphatidylcholine. This strongly suggests that the composition of the lipid bilayer has a significant impact on the activity of gamma-secretase. Recently, level of secreted beta-amyloid protein was reported to be attenuated by increasing levels of phosphatidylinositol 4,5-diphosphate (PI(4,5)P2) in cultured cells. However, it is not clear whether PI(4,5)P2 has a direct effect on gamma-secretase activity. In this study, we found that phosphoinositides directly inhibited CHAPSO-solubilized gamma-secretase activity. Interestingly, neither phosphatidylinositol nor inositol triphosphate altered gamma-secretase activity. PI(4,5)P2 was also found to inhibit gamma-secretase activity in CHAPSO-insoluble membrane microdomains (rafts). Kinetic analysis of beta-amyloid protein production in the presence of PI(4,5)P2 suggested a competitive inhibition. Even though phosphoinositides are minor phospholipids of the membrane, the concentration of PI(4,5)P2 within the intact membrane has been reported to be in the range of 4-8 mm. The presence of PI(4,5)P2-rich rafts in the membrane has been reported in a range of cell types. Furthermore, gamma-secretase is enriched in rafts. Taking these data together, we propose that phosphoinositides potentially regulate gamma-secretase activity by suppressing its association with the substrate.     

Thrombopoietin upregulates nucleolin mRNA and protein in thrombopoietin-dependent megakaryocytic cell line,UT-7/TPO

In a randomized, double-blind, controlled trial, the effects of oral treatment with coenzyme Q10 (CoQ10, 120 mg/day), a bioenergetic and antioxidant cytoprotective agent, were compared for 1 year, on the risk factors of atherosclerosis, in 73 (CoQ, group A) and 71 (B vitamin group B) patients after acute myocardial infarction (AMI). After 1 year, total cardiac events (24.6 vs. 45.0%, p < 0.02) including non-fatal infarction (13.7 vs. 25.3%, p < 0.05) and cardiac deaths were significantly lower in the intervention group compared to control group. The extent of cardiac disease, elevation in cardiac enzymes, left ventricular enlargement, previous coronary artery disease and elapsed time from symptom onset to infarction at entry to study showed no significant differences between the two groups. Plasma level of vitamin E (32.4 ± 4.3 vs. 22.1 ± 3.6 umol/L) and high density lipoprotein cholesterol (1.26 ± 0.43 vs. 1.12 ± 0.32 mmol/L) showed significant (p < 0.05) increase whereas thiobarbituric acid reactive substances, malondialdehyde (1.9 + 0.31 vs. 3.1 + 0.32 pmol/L) and diene conjugates showed significant reduction respectively in the CoQ group compared to control group. Approximately half of the patients in each group (n = 36 vs. 31) were receiving lovastatin (10 mg/day) and both groups had a significant reduction in total and low density lipoprotein cholesterol compared to baseline levels. It is possible that treatment with CoQ10 in patients with recent MI may be beneficial in patients with high risk of atherothrombosis, despite optimal lipid lowering therapy during a follow-up of 1 year. Adverse effect of treatments showed that fatigue (40.8 vs. 6.8%, p < 0.01) was more common in the control group than CoQ group.     

Distribution of chloropigments in suspended particulate matter and benthic microbial mat of a meromictic lake, Lake Kaiike, Japan

We investigated the distribution of chloropigments in a small meromictic lake, Lake Kaiike, south-west Japan. In the water-column, concentrations of Chl a related to cyanobacteria, BChl a related to purple sulphur bacteria, and three types of BChl e homologues (BChls e1, e2 and e3) related to brown-coloured green sulphur bacteria, were maximal at the redox boundary. Below the redox boundary, absolute concentrations of Chl a and BChl a gradually decreased with depth, whereas BChls e remained rather constant. Suspended particulate matter (SPM) at the deeper region of the anoxic water-column was enriched in highly alkylated BChl e homologues compared with SPM at the redox boundary. The shift in the relative content of highly alkylated BChl e homologues beneath the boundary was associated with community related adaptation of brown-coloured green sulphur bacteria to changes in light quality/quantity, resulting from the optical absorption and reflectance of SPMs in the overlying water-column. Benthic microbial mats were characterized by high abundances of BChls e, in which highly alkylated homologues were substantially abundant. This suggests that the BChls e in the microbial mat may be derived from the low-light adapted brown-coloured green sulphur bacteria forming the bacterial mat.