Right isomerism of the brain in inversus viscerum mutant mice

Left-right (L-R) asymmetry is a fundamental feature of higher-order neural function. However, the molecular basis of brain asymmetry remains unclear. We recently reported L-R asymmetry of hippocampal circuitry caused by differential allocation of N-methyl-D-aspartate receptor (NMDAR) subunit GluRepsilon2 (NR2B) in hippocampal synapses. Using electrophysiology and immunocytochemistry, here we analyzed the hippocampal circuitry of the inversus viscerum (iv) mouse that has a randomized laterality of internal organs. The iv mouse hippocampus lacks L-R asymmetry, it exhibits right isomerism in the synaptic distribution of the epsilon2 subunit, irrespective of the laterality of visceral organs. This independent right isomerism of the hippocampus is the first evidence that a distinct mechanism downstream of the iv mutation generates brain asymmetry.     

Cisplatin differently affects amino terminal and carboxyl terminal domains of HSP90

The 90-kDa heat shock protein (HSP90) is a molecular chaperone that assists in the folding and assembly of proteins in the cytosol. We previously demonstrated that the antineoplastic reagent, cisplatin, inhibits the aggregation prevention activity of mammalian HSP90. We now show that cisplatin binds both the amino terminal and carboxyl terminal domains of the human HSP90 and differently affects these two domains. Cisplatin blocks the aggregation prevention activity of HSP90C, but not HSP90N. In contrast, cisplatin induces a conformational change in HSP90N, but not HSP90C. These results indicate that cisplatin modulates the HSP90 activities through two different mechanisms using the two distinct binding sites of the HSP90 molecule.     

Induction of apoptosis of human tumor cells by hybrid liposomes including docosahexaenoic acid

Inhibitory effects of hybrid liposomes (HL) composed of L-alpha-dimyristoylphosphatidylcholine (DMPC) and polyoxyethylene(20) sorbitan monooleate (Tween 80) including polyunsaturated fatty acids on the growth of human tumor cells were examined in vitro. Remarkably high inhibitory effects of HL including docosahexaenoic acid (HL-DHA) on the growth of lung carcinoma (RERF-LC-OK), colon tumor (WiDr), and stomach tumor (MKN45) cells were obtained. The induction of apoptosis by HL-DHA was revealed on the basis of fluorescence microscopic and flow cytometric analyses.     

Protocol for high-resolution separation of rodent myosin heavy chain isoforms in a mini-gel electrophoresis system

Skeletal muscle comprises several fiber types classified based on their contractile and metabolic properties. Skeletal muscle fiber types are classified according to their myosin heavy chain isoforms (MyHC I, IIa, IIx, and IIb). We attained good separation of MyHC isoforms in a mini-gel system by modifying a previously developed electrophoresis protocol. Increased glycerol and decreased cross-linking agent concentrations improved the separation of MyHC isoforms. Sample preparation with dithiothreitol and protease inhibitors produced clear MyHC band boundaries. This protocol included silver staining, with a linear range. The protocol provided high resolution and a highly accurate assay of rodent MyHC isoforms.     

Phylogenetic relationships among deer in China derived from mitochondrial DNA cytochromeb sequences

The phylogenetic relationships of Cervidae and Moschidae were examined using partial sequence data of mitochondrial DNA (mtDNA) cytochromeb. Ten new sequences were obtained for six species of Cervidae and Moschidae, and aligned with those previously reported for other deer species. Our results demonstrated that the phylogenetic status of the taxa inferred from molecular data was congruent with taxonomy based on morphological studies. Cervidae formed a monophyletic group that consists of four subfamilies: Cervinae, Muntiacinae, Hydropotinae, and Odocoileinae. Moschidae occurred at the base of the Cervidae clade. On the basis of molecular clocks for genetic distance, the divergence time of mtDNA haplotypes within the subfamily Cervinae, among subfamilies in Cervidae, and between Moschidae and Cervidae was estimated to date 2–7 MYA, 6–10 MYA and 8–13 MYA, respectively.     

Some experiments and analysis of a predator-prey model: Interaction between Colpidium campylum and Alcaligenes faecalis in continuous and mixed culture

Following previous work in which a mass and monoxenous culture of Vorticella microstoma had been successfully established (Water Res., 7 , 615 lpar;1973) another species of Ciliata, Colpidium campylum was subjected to continuous cultivation using Alcaligenes faecalis as the sole bacterial food and asparagine as the limiting substrate. This work was primarily undertaken to reveal the interaction and biological oscillation between these two types of organisms which simulate theecological behavior of activated sludge. The fact that the bacteria tended to flocculate and/ or deflocculate depending on the protozoan populastion density was incorporated into the rate equations to account for the oscillation in individual population density of the predator-prey system The mathematical approach presented earlier by canal and other workers forbiological oscillation used a homogeneously of the bacterial food wasoverelooked in the earlier publication.     

Discovery of novel scaffolds for γ-secretase modulators without an arylimidazole moiety

Gamma-secretase modulators (GSMs) selectively inhibit the production of amyloid-β 42 (Aβ42) and may therefore be useful in the management of Alzheimer’s disease. Most heterocyclic GSMs that are not derived from nonsteroidal anti-inflammatory drugs contain an arylimidazole moiety that potentially inhibits cytochrome P450 (CYP) activity. Here, we discovered imidazopyridine derivatives that represent a new class of scaffold for GSMs, which do not have a strongly basic end group such as arylimidazole. High-throughput screening identified 2-methyl-8-[(2-methylbenzyl)oxy]-3-(pyridin-4-yl)imidazo[1,2-a]pyridine (3a), which inhibited the cellular production of Aβ42 (IC₅₀?=?7.1?µM) without changing total production of Aβ. Structural optimization of this series of compounds identified 5-[8-(benzyloxy)-2-methylimidazo[1,2-a]pyridin-3-yl]-2-ethylisoindolin-1-one (3m) as a potent inhibitor of Aβ42 (IC₅₀?=?0.39?µM) but not CYP3A4. Further, 3m demonstrated a sustained pharmacokinetic profile in mice and sufficiently penetrated the brain.     

PET probe detecting non-small cell lung cancer susceptible to epidermal growth factor receptor tyrosine kinase inhibitor therapy

Tyrosine kinase inhibitors for epidermal growth factor receptor (EGFR-TKIs) are used as molecular targeted therapy for non-small cell lung cancer (NSCLC) patients. The therapy is applied to the patients having EGFR-primary L858R mutation, but drug tolerance caused by EGFR-secondary mutation is occurred within one and half years. For the non-invasive detection of the EGFR-TKIs treatment positive patients by positron emission tomograpy (PET) imagaing, fluorine-18 labeled thienopyrimidine derivative, [¹⁸F]FTP2 was newly synthesized. EGFR inhibition assay, cell uptake study, and blocking study indicated [¹⁸F]FTP2 binds with high and selective affinity for EGFR with L858R mutation, and not with L858R/T790M dual mutations. On animal PET study using tumor bearing mice, H3255 cells expressing L858R mutated EGFR was more clearly visualized than H1975 cells expressing L858R/T790M dual mutated EGFR. [¹⁸F]FTP2 has potential for detecting NSCLC which is susceptible to EGFR-TKI treatment.     

Triterpenoid saponins from the bark of Zizyphus joazeiro

Three new triterpenoid saponins were isolated from the barks of Zizyphus joazeiro and characterized as jujubogenin 3-O-α-l-arabinofuranosyl-(1 → 2)-[β-d-glucopyranosyl(1 → 3)]-α-l-arabinopyranoside, its 4?-O-sulphate and 3″,4?-di-O-sulphate, respectively. FAB-MS was useful in providing information on the molecular weight of the complex oligoglycoside sulphates.