Phenotypic stability of the P-M system in wild populations of Drosophila melanogaster

The P element appears to be one of the most recently invaded transposons of D. melanogaster. To study the dynamics and long-term fate of P elements in natural populations of D. melanogaster, 472 isofemale lines newly collected from 27 localities of Japan were examined for the P element-associated characteristics (abilities to induce and repress of P element transposition) and genomic P element composition (size classes and their numbers). There was variation in the P element-related phenotypes among local populations, but genomic P composition did not correlate strongly with the phenotype of each line: full-size P and KP elements predominated in their genomes (FP+ KP predominance). Comparison with previous results suggests a stability in the P-M system in local populations over about 15 years. In some populations, phenotypic stability for particularly long times was found: for 30 years or more Q strains predominated in Hikone and Tanushimaru, P or Q strains around Inakadate, and M' or Q strains around Tozukawa. There was no clear evidence of structural destruction underlying functional variation of P elements during this period. These results suggest that the current evolutionary status of P elements in the gene pool of D. melanogaster is not intermediary stage predicted by the original recent invasion hypothesis, and that several other factors such as the position effect play important roles.     

A novel isoindoline,porritoxin sulfonic acid,from Alternaria porri and the structure-phytotoxicity correlation of its related compounds

Novel zinniol-related compound 3, named porritoxin sulfonic acid, with an isoindoline skeleton was isolated from the culture liquid of Alternaria porri. The structure was determined to be 2-(2"-sulfoethyl)-4-methoxy-5-methyl-6-(3'-methyl-2'-butenyloxy)-2,3-dihydro-1H-isoindol-1-one. The phytotoxic activities of three isoindolines (1-3) were evaluated in a seedling-growth assay against stone leek and lettuce.     

Genetic Variations Revealed by Microsatellite Markers ina Small Population of the Sika Deer (Cervus nippon)on Kinkazan Island, Northern Japan

Genetic variations within a population of the Japanese sika deer, Cervus nippon, on Kinkazan Island were studied by microsatellite analysis. Seventeen pairs of polymerase chain reaction primers designed for several species of ungulates successfully amplified polymorphic microsatellite DNA in sika deer. About 20% of the Kinkazan population was sampled and genotyped for nine diagnostic microsatellite loci. Alleles at those loci in the Kinkazan population were found to be under the Hardy-Weinberg equilibrium. To determine whether the Kinkazan deer have a reduced level of genetic variability, an average heterozygosity in the population was calculated and compared with the values determined for other populations from Hyogo, Yamaguchi, Shimane, Tsushima, and Nagasaki. Neither the observed nor the expected heterozygosity in the Kinkazan deer significantly differed from that in the other populations. Our result indicated that, despite its small population size, the Kinkazan deer preserve extensive microsatellite variations.     

Low-intensity pulsed ultrasound promotes bone morphogenic protein 9-induced osteogenesis and suppresses inhibitory effects of inflammatory cytokines on cellular responses via Rho-associated kinase 1 in human periodontal ligament fibroblasts

Periodontal ligament fibroblasts (PDLFs) have osteogenic capacity, producing bone matrix proteins. Application of bone morphogenic proteins (BMPs) to PDLFs is a promising approach for periodontal regeneration. However, in chronic bone metabolic disorders, such as periodontitis, proper control of accompanying inflammation is essential for optimizing the effects of BMPs on PDLFs. We have previously shown that low-intensity pulsed ultrasound (LIPUS), a medical technology that induces mechanical stress using sound waves, significantly promotes osteogenesis in mesenchymal stem cells. Here, we demonstrate that LIPUS promotes the BMP9-induced osteogenic differentiation of PDLFs. In contrast, BMP2-induced osteogenic differentiation was not altered by LIPUS, probably due to the LIPUS-induced secretion of Noggin, a BMP2 antagonist, from PDLFs. To examine if LIPUS affects inflammatory responses of PDLFs to lipopolysaccharide (LPS) derived from Porphyromonas gingivalis (LPS-PG), we also simultaneously treated PDLFs with LIPUS and LPS-PG. Treatment with LIPUS significantly inhibited the phosphorylation of ERKs, TANK-binding kinase 1, and interferon regulatory factor 3 in LPS-PG-stimulated PDLFs, in addition to inhibiting the degradation of IκB. Furthermore, LIPUS treatment reduced messenger RNA (mRNA) expression of interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, IL-8, C-C motif chemokine ligand 2, C-X-C motif chemokine ligand 1 (CXCL1), CXCL10 and receptor activator of nuclear factor kappa-B ligand, and also diminished IL-1ß and tumor necrosis factor a (TNFa)-induced inflammatory reactions. Phosphorylation of Rho-associated kinase 1 (ROCK1) was induced by LIPUS, while ROCK1-specific inhibitor prevented the promotive effects of LIPUS on p38 phosphorylation, mRNA expression of CXCL1 and Noggin, and osteogenesis. The suppressive effects of LIPUS on LPS-PG-stimulated inflammatory reactions were also prevented by ROCK1 inhibition. Moreover, LIPUS treatment blocked inhibitory effects of LPS-PG and IL-1ß on osteogenesis. These results indicate that LIPUS suppresses inflammatory effects of LPS-PG, IL-1ß, and TNFa and also promotes BMP9-induced osteogenesis through ROCK1 in PDLFs.     

Basal and angiotensin II-inhibited neuronal delayed-rectifier K+ current are regulated by thioredoxin

In previous studies, we determined that macrophage migration inhibitory factor (MIF), acting intracellularly via its intrinsic thiol-protein oxidoreductase (TPOR) activity, stimulates basal neuronal delayed-rectifier K⁺ current (I_Kv) and inhibits basal and angiotensin (ANG) II-induced increases in neuronal activity. These findings are the basis for our hypothesis that MIF is a negative regulator of ANG II actions in neurons. MIF has recently been recategorized as a member of the thioredoxin (Trx) superfamily of small proteins. In the present study we have examined whether Trx influences basal and ANG II-modulated I_Kv in an effort to determine whether the Trx superfamily can exert a general regulatory influence over neuronal activity and the actions of ANG II. Intracellular application of Trx (0.8–80 nM) into rat hypothalamic/brain stem neurons in culture increased neuronal I_Kv, as measured by voltage-clamp recordings. This effect of Trx was abolished in the presence of the TPOR inhibitor PMX 464 (800 nM). Furthermore, the mutant protein recombinant human C32S/C35S-Trx, which lacks TPOR activity, failed to alter neuronal I_Kv. Trx applied at a concentration (0.08 nM) that does not alter basal I_Kv abolished the inhibition of neuronal I_Kv produced by ANG II (100 nM). Given our observation that ANG II increases Trx levels in neuronal cultures, it is possible that Trx (like MIF) has a negative regulatory role over basal and ANG II-stimulated neuronal activity via modulation of I_Kv. Moreover, these data suggest that TPOR may be a general mechanism for negatively regulating neuronal activity. thiol-protein oxidoreductase; patch clamp; neuronal activity     

The difficulty of estimating the electron transport rate at photosystem I

It is still a controversial issue how the electron transport reaction is carried out around photosystem I (PSI) in the photosynthetic electron transport chain. The measurable component in PSI is the oxidized P700, the reaction center chlorophyll in PSI, as the absorbance changes at 820–830 nm. Previously, the quantum yield at PSI [Y(I)] has been estimated as the existence probability of the photo-oxidizable P700 by applying the saturated-pulse illumination (SP; 10,000–20,000 µmol photons m^?2 s^?1). The electron transport rate (ETR) at PSI has been estimated from the Y(I) value, which was larger than the reaction rate at PSII, evaluated as the quantum yield of PSII, especially under stress-conditions such as CO₂-limited and high light intensity conditions. Therefore, it has been considered that the extra electron flow at PSI was enhanced at the stress condition and played an important role in dealing with the excessive light energy. However, some pieces of evidence were reported that the excessive electron flow at PSI would be ignorable from other aspects. In the present research, we confirmed that the Y(I) value estimated by the SP method could be easily misestimated by the limitation of the electron donation to PSI. Moreover, we estimated the quantitative turnover rate of P700⁺ by the light-to-dark transition. However, the turnover rate of P700 was much slower than the ETR at PSII. It is still hard to quantitatively estimate the ETR at PSI by the current techniques.

     

3-Hydroxy-1,5-dihydro-pyrrol-2-one derivatives as advanced inhibitors of HIV integrase

The two-metal binding model we previously reported as an inhibition mechanism of HIV integrase (HIV IN) produced a new direction in modification of 2-hydroxy-3-heteroaryl acrylic acid inhibitors (HHAAs). Here we present a novel series of HIV IN inhibitors having a 3-hydroxy-1,5-dihydro-pyrrol-2-one moiety (HDPO) as an advanced analog of HHAAs. This cyclic modification of the chelating region of HHAA produces a favorable configuration to coordinate two-metal ions in HIV IN, which consequently gave improvements in not only enzymatic assay but also antiviral cell based assay in many cases.     

Phenotypes of IRS-2 deficient mice produced by reproductive technology are stable.

We studied the impact of "IVF - ET" on the glucose tolerance test (GTT), insulin tolerance test (ITT) and adiponectin to investigate differences in the phenotypes of B6J- Irs2(-/-) mice. The B6J-Irs2(-/-) mice (KO-Nat group) were prepared by natural mating. Other mice were produced by IVF-ET used ICR strain recipients and surrogate mothers (KO-IVF group). Measurement of body weight, GTT, ITT and blood sampling were performed at the ages of 6, 14 and 24 weeks after birth. Body weights, impaired glucose tolerance, insulin resistance and plasma adiponectin concentrations did not differ for each gender between the KO-IVF and KO-Nat groups. Therefore, we concluded that phenotypes of Irs2(-/-) mice produced by reproductive technology are stable.