The LHRH neuronal system in female rats: relation to the medial preoptic nucleus

Previously we have found that small lesions confined to the medial preoptic nucleus (MPN) or the suprachiasmatic nucleus (SCN) blocked the cyclic release of gonadotropins in the female rat, inducing a persistent estrous state. Since the MPN is located just caudal to the organum vasculosum of the lamina terminalis (OVLT) where LHRH cell bodies are most concentrated, we applied an immunocytochemical technique to examine the possibility that the lesions had simply disrupted LHRH neurons or fibers. Using a new anti-LHRH provided by Dr. V. D. Ramirez, we found that the distribution pattern of immunoreactive LHRH cell bodies and fibers was similar to that previously reported, although the staining was more intense and extensive with low background. There was no concentration of LHRH cell bodies and fibers in the MPN or SCN and, in fact, these nuclei generally showed a lower density of stained elements than did surrounding tissue. In persistent estrous animals with lesions confined to the MPN there was no detectable reduction of stained fibers in the median eminence. These results, along with the results of other workers, suggest that persistent estrus following lesions of the MPN or SCN is not due to reduction of LHRH neurons or fibers. Rather, they support the hypothesis that these nuclei are critical for triggering the ovulatory release of LHRH.     

Hyrtioreticulins A-E, indole alkaloids inhibiting the ubiquitin-activating enzyme, from the marine sponge Hyrtios reticulatus

Hyrtioreticulins A-E (1-5) were isolated from the marine sponge Hyrtios reticulatus, along with a known alkaloid, hyrtioerectine B (6). Structural elucidation on the basis of spectral data showed that 1, 2, and 5 are new tetrahydro-β-carboline alkaloids, while 3 and 4 are new azepinoindole-type alkaloids. Hyrtioreticulins A and B (1 and 2) inhibited ubiquitin-activating enzyme (E1) with IC(50) values of 0.75 and 11μg/mL, respectively, measured by their inhibitory abilities against the formation of an E1-ubiquitin intermediate. So far, only five E1 inhibitors, panapophenanthrine, himeic acid A, largazole, and hyrtioreticulins A and B (1 and 2), have been isolated from natural sources and, among them, 1 is the most potent E1 inhibitor.     

Quinolone derivatives containing strained spirocycle as orally active glycogen synthase kinase 3β (GSK-3β) inhibitors for type 2 diabetics

The design, synthesis, and evaluation of 6-6-7 tricyclic quinolones containing the strained spirocycle moiety aiming at the GSK-3β inhibitor were described. Among the synthesized compounds, 44, having a cyclobutane ring on a spirocycle, showed excellent GSK-3β inhibitory activity in both cell-free and cell-based assays (IC(50) = 36nM, EC(50) = 3.2μM, respectively). Additionally, 44 decreased the plasma glucose concentration dose-dependently after an oral glucose tolerance test in mice.     

Regulation of nuclear translocation of extracellular signal-regulated kinase 5 by active nuclear import and export mechanisms

Extracellular signal-regulated kinase 5 (ERK5), a member of the mitogen-activated protein kinase family, plays an important role in growth factor signaling to the nucleus. However, molecular mechanisms regulating subcellular localization of ERK5 have remained unclear. Here, we show that nucleocytoplasmic shuttling of ERK5 is regulated by a bipartite nuclear localization signal-dependent nuclear import mechanism and a CRM1-dependent nuclear export mechanism. Our results show that the N-terminal half of ERK5 binds to the C-terminal half and that this binding is necessary for nuclear export of ERK5. They further show that the activating phosphorylation of ERK5 by MEK5 results in the dissociation of the binding between the N- and C-terminal halves and thus inhibits nuclear export of ERK5, causing its nuclear import. These results reveal the mechanism by which the activating phosphorylation of ERK5 induces its nuclear import and suggest a novel example of a phosphorylation-dependent control mechanism for nucleocytoplasmic shuttling of proteins.     

Identification of catalytic amino acids of cyclodextran glucanotransferase from Bacillus circulans T-3040

In glycoside hydrolase family 66 (see http://afmb.cnrs-mrs.fr/CAZY/), cyclodextran glucanotransferase (CITase) is the only transglycosylation enzyme, all the other family 66 enzymes being dextranases. To analyze the catalytic amino acids of CITase, we modified CITase chemically from the T-3040 strain of Bacillus circulans with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). EDC inactivated the enzyme by following pseudo-first order kinetics. In addition, the substrates of an isomaltooligosaccharide and a cyclodextran inhibited EDC-induced enzyme inactivation, implicating the carboxyl groups of CITase as the catalytic amino acids of the enzyme. When two conserved aspartic acid residues, Asp145 and Asp270, were replaced with Asn in T-3040 mature CITase, CIT-D270N was completely inactive, and CIT-D145N had reduced activity. The V(max) of CIT-D145N was 1% of that of wild-type CITase, whereas the K(m) of CIT-D145N was about the same as that of the wild-type enzyme. These findings indicate that Asp145 and Asp270 play an important role in the enzymatic reaction of T-3040 CITase.     

MOV10 as a novel telomerase-associated protein

A novel telomerase-associated protein was isolated from porcine testis. The 115-kDa protein, purified with telomerase activity, was molecular cloned using human cDNA library, and identified as MOV10. The expression levels of both MOV10 mRNA and MOV10 protein in cancer cells were 2-3 times higher than that of the normal cells, and MOV10 mRNA was highly expressed in human testis and ovary. The anti-MOV10 antibody precipitated the telomerase activity from cancer cell extracts, and inhibited the telomerase activity in vitro. Sf9-expressed MOV10 protein bound to G-rich strand of both single- and double-stranded telomere-sequenced DNA, but not to single C-rich strand. ChIP assay showed the binding of MOV10 to telomere region in vivo. These data suggest that MOV10 is involved in the progression of telomerase-catalyzing reaction via the interaction of telomerase protein and telomere DNA.     

Intra-Platform Repeatability and Inter-Platform Comparability of MicroRNA Microarray Technology

Over the last decade, DNA microarray technology has provided a great contribution to the life sciences. The MicroArray Quality Control (MAQC) project demonstrated the way to analyze the expression microarray. Recently, microarray technology has been utilized to analyze a comprehensive microRNA expression profiling. Currently, several platforms of microRNA microarray chips are commercially available. Thus, we compared repeatability and comparability of five different microRNA microarray platforms (Agilent, Ambion, Exiqon, Invitrogen and Toray) using 309 microRNAs probes, and the Taqman microRNA system using 142 microRNA probes. This study demonstrated that microRNA microarray has high intra-platform repeatability and comparability to quantitative RT-PCR of microRNA. Among the five platforms, Agilent and Toray array showed relatively better performances than the others. However, the current lineup of commercially available microRNA microarray systems fails to show good inter-platform concordance, probably because of lack of an adequate normalization method and severe divergence in stringency of detection call criteria between different platforms. This study provided the basic information about the performance and the problems specific to the current microRNA microarray systems.     

Spatio-temporal gap analysis of OBIS-SEAMAP project data: assessment and way forward

The OBIS-SEAMAP project has acquired and served high-quality marine mammal, seabird, and sea turtle data to the public since its inception in 2002. As data accumulated, spatial and temporal biases resulted and a comprehensive gap analysis was needed in order to assess coverage to direct data acquisition for the OBIS-SEAMAP project and for taxa researchers should true gaps in knowledge exist. All datasets published on OBIS-SEAMAP up to February 2009 were summarized spatially and temporally. Seabirds comprised the greatest number of records, compared to the other two taxa, and most records were from shipboard surveys, compared to the other three platforms. Many of the point observations and polyline tracklines were located in northern and central Atlantic and the northeastern and central-eastern Pacific. The Southern Hemisphere generally had the lowest representation of data, with the least number of records in the southern Atlantic and western Pacific regions. Temporally, records of observations for all taxa were the lowest in fall although the number of animals sighted was lowest in the winter. Oceanographic coverage of observations varied by platform for each taxa, which showed that using two or more platforms represented habitat ranges better than using only one alone. Accessible and published datasets not already incorporated do exist within spatial and temporal gaps identified. Other related open-source data portals also contain data that fill gaps, emphasizing the importance of dedicated data exchange. Temporal and spatial gaps were mostly a result of data acquisition effort, development of regional partnerships and collaborations, and ease of field data collection. Future directions should include fostering partnerships with researchers in the Southern Hemisphere while targeting datasets containing species with limited representation. These results can facilitate prioritizing datasets needed to be represented and for planning research for true gaps in space and time.     

Suramin prevents fulminant hepatic failure resulting in reduction of lethality through the suppression of NF-kappaB activity

AIM: Suramin is a symmetrical polysulfonated naphthylamine derivative of urea. There have been few studies on the effect of suramin on cytokines. We examined the effects of suramin on production of inflammatory cytokines. METHODS: We made an acute liver injury model treated with d-galactosamine (GalN) and lipopolysaccharide (LPS). Plasma AST, ALT, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 levels were measured. We compared with survival rate, histological found and NF-kappaB activity between with and without treatment of suramin. In macrophage like cell line, TNF-alpha and IL-6 production, TNF-alpha and IL-6 mRNA expression, and NF-kappaB activity was measured. RESULTS: The lethality of mice administered suramin with GalN/LPS was significantly decreased compared with that in mice without suramin. Changes of hepatic necrosis and apoptosis were slight in suramin-treated mice. Serum AST, ALT, TNF-alpha, IL-6 levels and NF-kappaB activity in the liver were significantly lower in mice administered suramin. In an in vitro model, suramin preincubation inhibited TNF-alpha and IL-6 production, TNF-alpha and IL-6 mRNA expression, and NF-kappaB activity. CONCLUSIONS: Suramin inhibits TNF-alpha and IL-6 production through the suppression of NF-kappaB activity from macrophages and shows therapeutic effects on acute liver damage.     

Growth-related changes in the mechanical properties of collagen fascicles from rabbit patellar tendons

Growth-related changes in the mechanical properties of collagen fascicles (approximately 300 microm in diameter) were studied using patellar tendons obtained from skeletally immature 1 and 2 months old and matured 6 months old rabbits. Tensile properties were determined using a specially designed micro-tensile tester. In each age group, there were no significant differences in the properties among cross-sectional locations in the tendon. Tangent modulus and tensile strength significantly increased with age; the rates of their increases between 1 and 2 months were higher than those between 2 and 6 months. The tangent modulus and tensile strength were positively correlated with the body weight of animals. However, growth-related changes in the mechanical properties were different between collagen fascicles and bulk patellar tendons, which may be attributable to such non-collagenous components as ground substances and also to mechanical interactions between collagen fascicles.