Development of 18 novel polymorphic microsatellite markers for the mysid crustacean Mesopodopsis orientalis

Conservation Genetics Resources - We have developed microsatellite DNA markers for Mesopodopsis orientalis (Tattersall 1908), a widely distributed mysid crustacean in shallow waters of the coastal...     

Glycine residues in potassium channel-like selectivity filters determine potassium selectivity in four-loop-per-subunit HKT transporters from plants

Plant HKT proteins comprise a family of cation transporters together with prokaryotic KtrB, TrkH, and KdpA transporter subunits and fungal Trk proteins. These transporters contain four loop domains in one polypeptide with a proposed distant homology to K(+) channel selectivity filters. Functional expression in yeast and Xenopus oocytes revealed that wheat HKT1 mediates Na(+)-coupled K(+) transport. Arabidopsis AtHKT1, however, transports only Na(+) in eukaryotic expression systems. To understand the molecular basis of this difference we constructed a series of AtHKT1/HKT1 chimeras and introduced point mutations to AtHKT1 and wheat HKT1 at positions predicted to be critical for K(+) selectivity. A single-point mutation, Ser-68 to glycine, was sufficient to restore K(+) permeability to AtHKT1. The reverse mutation in HKT1, Gly-91 to serine, abrogated K(+) permeability. This glycine in P-loop A of AtHKT1 and HKT1 can be modeled as the first glycine of the K(+) channel selectivity filter GYG motif. The importance of such filter glycines for K(+) selectivity was confirmed by interconversion of Ser-88 and Gly-88 in the rice paralogues OsHKT1 and OsHKT2. Surprisingly, all HKT homologues known from dicots have a serine at the filter position in P-loop A, suggesting that these proteins function mainly as Na(+) transporters in plants and that Na(+)/K(+) symport in HKT proteins is associated with a glycine in the filter residue. These data provide experimental evidence that the glycine residues in selectivity filters of HKT proteins are structurally related to those of K(+) channels.     

O-nitroso aldol synthesis: Catalytic enantioselective route to alpha-aminooxy carbonyl compounds via enamine intermediate

The approach using pyrrolidine enamine as substrate has been studied for this synthesis, and an important catalyst structural feature has been developed. After survey of pyrrolidine-based Br?nsted acid catalyst, tetrazole catalyst (3f) was found to be optimal in synthesis of aminooxy carbonyl compounds in high yields, with complete enantioselectivity not only for aldehydes but also for ketones.     

Transgenic rescue of GATA-1-deficient mice with GATA-1 lacking a FOG-1 association site phenocopies patients with X-linked thrombocytopenia

Association of GATA-1 and its cofactor Friend of GATA-1 (FOG-1) is essential for erythroid and megakaryocyte development. To assess functions of GATA-1-FOG-1 association during mouse development, we used the GATA-1 hematopoietic regulatory domain to generate transgenic mouse lines expressing a mutant GATA-1, which contains a substitution of glycine 205 for valine (V205G) that abrogates its association with FOG-1. We examined whether the transgenic expression of mutant GATA-1 rescues GATA-1 germ line mutants from embryonic lethality. In high-expressor lines we observed that the GATA-1(V205G) rescues GATA-1-deficient mice from embryonic lethality at the expected frequency, revealing that excess GATA-1(V205G) can eliminate the lethal anemia that is due to GATA-1 deficiency. In contrast, transgene expression comparable to the endogenous GATA-1 level resulted in much lower frequency of rescue, indicating that the GATA-1-FOG-1 association is critical for normal embryonic hematopoiesis. Rescued mice in these analyses exhibit thrombocytopenia and display dysregulated proliferation and impaired cytoplasmic maturation of megakaryocytes. Although anemia is not observed under steady-state conditions, stress erythropoiesis is attenuated in the rescued mice. Our findings reveal an indispensable role for the association of GATA-1 and FOG-1 during late-stage megakaryopoiesis and provide a unique model for X-linked thrombocytopenia with inherited GATA-1 mutation.     

Effect of furosemide on renal excretion of oxypurinol and purine bases

To examine whether furosemide affects the plasma concentration and urinary excretion of purine bases and oxypurinol, we administered allopurinol (300 mg) orally to 6 healthy subjects and then administered furosemide (20 mg) intravenously 10 hours later. Furosemide (20 mg) decreased the urinary excretion of uric acid by 40% (P < .01), oxypurinol by 39% (P < .05), and xanthine by 43% (P < .05) and the fractional clearance of uric acid by 45% (P < .01) and oxypurinol by 34% (P < .05) when measured 1 to 2 hours after administration. Moreover, furosemide increased the plasma concentration of uric acid by 6% at 1.5 hours after administration. These results indicate that furosemide may decrease the urinary excretion of uric acid and oxypurinol by acting on their common renal transport pathway(s). In addition, it is suggested that the effect of furosemide on oxypurinol is clinically important, since the hypouricemic effect of allopurinol may become more potent as a result.     

Mantle cell lymphoma of the rectum at an early stage: a case report.

We report a very rare early-stage case of mantle cell lymphoma, which arose from the rectum. A 60-year-old man presented with a small elastically hard polypoid lesion in the rectum. The lesion was 1.2 x 1.2 cm in size. As a preoperatively barium enema and endoscopy suggested a benign tumor of the rectum, he underwent local excision of a rectal polypoid mass transanally under spinal anesthesia. However, histological examination revealed a malignant lymphoma, because the lesion was histologically characterized by solid growths of small to medium-sized round cells. Furthermore, immunohistochemical tests revealed B-cell marker positivity and CD5 positivity, but cyclin D1 negativity. Since it was reported that lymphomas with a mantle cell lymphoma morphology and CD5 expression, but without cyclin D1 overexpression, exist in about 10% of mantle cell lymphoma cases, we diagnosed his disease as mantle cell lymphoma. To our knowledge, this is the first reported case of an early-stage mantle cell lymphoma, originating from the rectum.