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Italian ryegrass ( Lolium multiflorum Lam.) is a non-native annual winter grass that has seriously infested rice paddy levees and wheat fields in Japan. Recently, glyphosate-resistant Italian ryegrass was found on paddy levees in central Japan, thereby making control of the grass by using glyphosate less effective. In this study, physical control methods were tested that combined the timing and frequency of mowing in order to more effectively control glyphosate-resistant Italian ryegrass on rice paddy levees. A 3 year field experiment was conducted from 2012 to 2014 in a western region of Shizuoka Prefecture, where glyphosate-resistant Italian ryegrass has become dominant. Five treatments were tested: (i) mowing once before the flowering of the grass (i.e. conventional mowing measure); (ii) mowing once during flowering; (iii) mowing twice during flowering; (iv) glyphosate application before flowering (i.e. one of the conventional mowing measures); and (v) no treatment. The above-ground biomass, seed production, soil seed bank and seedling occurrence of Italian ryegrass were measured to determine the effectiveness of these treatments. Mowing during the flowering period resulted in reduced above-ground biomass, seed production and soil seed bank when compared with the other treatments. Additionally, mowing twice during the flowering period resulted in a lower seedling density than mowing once. The results suggest that, in this region, physical control by mowing during the flowering period would be more effective than conventional measures for controlling glyphosate-resistant Italian ryegrass.

Recently, glyphosate-resistant Italian ryegrass (Lolium multiflorum Lam.) was found on rice paddy levees in a western region of Shizuoka Prefecture, Japan. Naturalized populations of Italian ryegrass are frequently infected with fungal Epichloe endophytes. Endophytes often confer benefits to their host grasses. This study investigated the influence of five weed management treatments on glyphosate resistance and endophyte infection in Italian ryegrass that was growing on paddy levees where glyphosate-resistant individuals were dominant. The weed management treatments were: (i) mowing once before the grass flowered; (ii) mowing once during flowering; (iii) mowing twice during flowering; (iv) glyphosate application before flowering; and (v) no treatment. The seeds were collected from the treatment plots in 2013 and 2014. The seeds were examined for endophyte infection and the seedlings that had been grown from the seeds were tested for the frequency of glyphosate resistance. The seedlings that had been derived from the glyphosate treatment showed higher frequencies of glyphosate resistance than those seedlings that had been derived from all the other treatments. Endophytes were found in all populations of the seeds from the paddy levees, with higher infection rates in the seeds that had been derived from the glyphosate treatment and the twice-mowed treatment. There was a significant relationship between the endophyte infection frequency in the seeds and glyphosate resistance in the seedlings that had been grown from the same populations. The results indicate that where glyphosate herbicides are frequently used, selection for glyphosate-resistant Italian ryegrass occurs, and along with this, the frequency of endophyte infection also increases.

The majority of hematopoietic stem cells (HSCs) are maintained in a quiescent state to minimize premature exhaustion induced by various stresses. However, quiescent HSCs are vulnerable to mutagenesis because of attenuated DNA repair and DNA damage response programs. Basal abundant expression of prosurvival BCL-2 proteins further endows HSCs with high resistance to apoptosis. In contrast, HSCs elicit strong activation of p53 upon DNA damage, resulting in enhanced activation of proapoptotic BCL-2 signals through p53. ASPP1, an apoptosis-stimulating protein of p53, is highly expressed in HSCs and preserves HSC pool integrity via selective induction of apoptosis. In this paper, we discuss the role of p53 and mitochondrial apoptosis in HSC regulation and introduce the current understanding of how p53 activity is regulated to achieve a good balance between maintaining the HSC pool and preventing hematological malignancies.

This study aimed to determine whether seedling herbivory by the field cricket, Teleogryllus emma (Ohmachi et Matsuura), promoted the mortality of Italian ryegrass (Lolium multiflorum Lam.), a non-native grass weed in Japan, whether the impact of seedling herbivory differed depending on the depth of seedling emergence and the influence of cricket density on seedling mortality. First, the seedlings at emergence depths of 0, 1 and 2 cm were exposed to the cricket for 2 days in plastic cups and the amount of seedling mortality by herbivory was calculated. The level of mortality of 60 seedlings that emerged from seeds on the soil surface was 92.4%, significantly higher than that of the seedlings that emerged from seeds at depths of 1 cm (10.8%) and 2 cm (9.6%). Second, the seedlings at the emergence depths of 0 and 1 cm were exposed to the crickets at four different densities (zero, one, two and three individuals per 5700 cm2) for 5 days in plastic containers and the amount of seedling mortality by herbivory was calculated. The level of mortality by herbivory of the seedlings that emerged from 100 seeds on the soil surface was higher (33.3–61.3%) than that of the seedlings that emerged from seeds at a depth of 1 cm (4.7–13.1%) in the containers with one-to-three crickets. The level of seedling mortality tended to increase with an increasing cricket density. These results suggest that seedling herbivory by crickets is an important factor in weed mortality, particularly in no-till fields and in field margins, where the seeds are more prevalent near the soil surface.

O-Acyl isopeptides, in which the N-acyl linkage on the hydroxyamino acid residue (e.g. Ser and Thr) is replaced by an O-acyl linkage, generally suppress unfavorable aggregation properties derived from the corresponding parent peptides. Here, we report the synthesis of an O-acyl isopeptide of 34-mer pyroGlu-ADan (2), a component of amyloid deposits in hereditary familial Danish dementia, by using native chemical ligation. Native chemical ligation of pyroGlu(1) -ADan(1-21)-SCH2 CH2 SO3 (-) Na(+) (3) and Cys(22) -O-acyl isopeptide (4), in which the amino group of the Ser(29) residue at the isopeptide moiety was protected by an allyloxycarbonyl group, proceeded well in an aqueous solvent to yield a ligated O-acyl isopeptide (5). Subsequent disulfide bond formation and deprotection of the allyloxycarbonyl group followed by HPLC purification gave 2 with a reasonable overall yield. 2 was converted to the parent peptide 1 via an O-to-N acyl migration reaction. The sequential method, namely (i) native chemical ligation of the O-acyl isopeptide, (ii) HPLC purification as the O-acyl isopeptide form, and (iii) O-to-N acyl migration into the desired polypeptide, would be helpful to solve problems with HPLC purification of hydrophobic polypeptides in the process of chemical protein synthesis.

Guided by the known molecular recognition interactions between N-acetylglucosaminyltransferase V (GnT-V) and certain synthetic substrates, we synthesized a radiolabeled double-stranded glycolipid composed of a long-chain alkyl unit and a radioiodinated phenylalkyl unit, [(125)I]-2-[N-(2-hydroxy-3-hexadecyloxy)propyl-15-(4-iodophenyl)pentadecanecarboxamido]ethyl 2-acetamido-2-deoxy-β-D-glucopyranosyl-(1→2)-α-D-mannopyranosyl-(1→6)-β-D-glucopyranoside ([(125)I]2), as a novel intravital glycolipid mimic substrate of GnT-V. The radioactive iodine ((125)I) was incorporated via iododestannylation of the phenyltributyltin derivative, 2-[N-(2-acetoxy-3-hexadecyloxy)propyl-15-(4-tributylstannylphenyl)pentadecanecarboxamido]ethyl 3,4,6-tri-O-acetyl-2-acetamido-2-deoxy-β-D-glucopyranosyl-(1→2)-3,4,6-O-acetyl-α-D-mannopyranosyl-(1→6)-2,3,4-tri-O-acetyl-β-D-glucopyranoside (26). Subsequent deacetylation at the final step afforded [(125)I]2.

A skeletal transformation of α-pyrones having electron-withdrawing groups at the 3,5-positions into dihydrofurans was developed. Using dimethylsulfoxonium methylide as the methylene-transfer reagent, the α-pyrones were converted into dihydrofurans as major products and 1-methylthiopyran-1-oxides as minor products. The selectivity of the dihydrofuran formation was improved by optimizing the reaction conditions.

The potential impact of postdispersal seed predation by the field cricket, Teleogryllus emma (Ohmachi et Matsuura), on the seedling emergence of Italian ryegrass (Lolium multiflorum Lam.), a non-native grass weed in Japan, was determined. The relationship between cricket density and the proportion of seedling emergence was investigated by conducting manipulative experiments in duplicate, using enclosures. One-thousand seeds of Italian ryegrass were exposed to adult crickets at different densities (zero, one, two, four and eight individuals per 2.25 m2 enclosure) for 2 weeks. The proportion of seedling emergence decreased with increasing cricket density. The proportion of seedling emergence in the enclosures without the crickets was 90.9–97.2%, whereas the seedling emergence in the enclosures with eight crickets greatly decreased, to 0.5–2.5%. These results suggest that postdispersal seed predation by T. emma can substantially decrease the abundance of Italian ryegrass at an early life stage and reduce its population in environments with a high density of crickets.

Neotyphodium endophytes often confer benefits to their host grasses and may enhance invasiveness of some grasses. The knowledge of infection frequencies of endophytes among invading weed populations is necessary to understand the relationships between endophyte infection and invasiveness. Here we present data on infection frequencies of Italian ryegrass (Lolium multiflorum Lam.), an important weed in some farmlands in Japan, persisting in contrasting farmlands: a terraced paddy field and a wheat-soybean double-cropped field in the western region of Shizuoka prefecture, Japan. The terraced paddy site is a mosaic of several landscape elements such as paddy fields, levees, fallow and abandoned fields, with a high percentage of non-crop area. Rice (Oryza sativa L.) has been cultivated for more than a decade with no application of chemical fertilizers, pesticides and fungicides. The wheat-soybean field is characterized by the aggregation of large-scaled fields that were originally reconstructed paddy fields, showing a low percentage of non-crop area. Wheat and soybean have been grown as winter and summer crops, respectively, using chemical fertilizers and herbicides. We examined the presence or absence of endophytes in a total of 1200 seeds sampled from the two Italian ryegrass populations. The terraced paddy population exhibited a markedly high infection frequency (91.0%), due possibly to selective feeding of non-infected seeds by insects. In contrast, the wheat-soybean farmland population showed almost no infection (1.1%), whereas the putative source of the invasion in the proximity exhibited a relatively high infection rate (64.4%). Such a micro-scale variation in infection frequencies may be attributable to a loss in endophyte viability within the wheat-soybean field. The findings suggest that endophyte infection frequency may markedly differ among the Italian ryegrass populations even within the same region, presumably depending on the abundance of the seed-eating insects, farmland management regimes and/or environmental conditions such as soil humidity.

Increases in intracellular [Ca2+] occur synchronously between cells in the neuroepithelium. If neuroepithelial cells were capable of generating action potentials synchronized by gap junctions (direct current electrical coupling), the influx of Ca2+ through voltage-activated Ca2+ channels would lead to a synchronous increase in intracellular [Ca2+]. However, no action potential is generated in neuroepithelial cells, and the [Ca2+] increase is instead produced by the release of Ca2+ from intracellular Ca2+ stores. Recently, synchronous fluctuations in the membrane potential of Ca2+ stores were recorded using an organelle-specific voltage-sensitive dye. On the basis of these recordings, a capacitative [alternating current (AC)] electrical coupling model for the synchronization of voltage fluctuations of Ca2+ store potential was proposed [Yamashita M (2006) FEBS Lett580, 4979–4983; Yamashita M (2008) FEBS J275, 4022–4032]. Ca2+ efflux from the Ca2+ store and K+ counterinflux into the store cause alternating voltage changes across the store membrane, and the voltage fluctuation induces ACs. In cases where the store membrane is closely apposed to the plasma membrane and the cells are tightly packed, which is true of neuroepithelial cells, the voltage fluctuation of the store membrane is synchronized between the cells by the AC currents through the series capacitance of these membranes. This article provides a short review of the model and its relationship to the structural organization of the Ca2+ store. This is followed by a discussion of how the mode of synchronization of [Ca2+] increase may change during central nervous system development and new molecular insights into the synchronicity of [Ca2+] increase.

Italian ryegrass (Lolium multiflorum Lam.) is an exotic winter annual weed that recently has seriously infested wheat fields in central Japan. To understand the influence of tillage systems on the germination ecology and seedbank dynamics of naturalized Italian ryegrass, we compared the fate of the seeds that were after-ripened in the soil with that of the seeds on the soil surface, and then examined the germination characteristics of the seeds retrieved from both treatments by germination tests in both a light/dark (12 h photoperiod) condition and in constant darkness. The seedling emergence was greater initially for the seeds after-ripened on the soil surface than for the seeds in the soil. The component of emergent seeds after-ripened on the soil surface increased as time passed during the summer, whereas that of emergent seeds in the soil scarcely increased. This contrasting emergence was, in part, attributable to the ability of the seeds to germinate at higher temperatures in the light/dark condition than in constant darkness. These results suggest that untilled systems, which leave many seeds on the soil surface, might promote the rapid depletion of Italian ryegrass seeds through germination before wheat sowing in early winter. In contrast, seed burial by tillage might inhibit the germination of the seeds and form a large transient seed bank available to germinate during the wheat-growing season.

Synchronous Ca2+ oscillation occurs in various cell types to regulate cellular functions. However, the mechanism for synchronization of Ca2+ increases between cells remains unclear. Recently, synchronous oscillatory changes in the membrane potential of internal Ca2+ stores were recorded using an organelle-specific voltage-sensitive dye [Yamashita et al. (2006) FEBS J273, 3585–3597], and an electrical coupling model of the synchronization of store potentials and Ca2+ releases has been proposed [Yamashita (2006) FEBS Lett580, 4979–4983]. This model is based on capacitative coupling, by which transient voltage changes can be synchronized, but oscillatory slow potentials cannot be communicated. Another candidate mechanism is synchronization of action potentials and ensuing Ca2+ influx through voltage-dependent Ca channels. The present study addresses the question of whether Ca2+ increases are synchronized by action potentials, and how oscillatory store potentials are synchronized across the cells. Electrophysiological and Ca2+-sensitive fluorescence measurements in early embryonic chick retina showed that synchronous Ca2+ oscillation was caused by releases of Ca2+ from Ca2+ stores without any evidence of action potentials in retinal neuroepithelial cells or newborn neurons. High-speed fluorescence measurement of store membrane potential surprisingly revealed that the synchronous oscillatory changes in the store potential were periodic repeats of a burst of high-frequency voltage fluctuations. The burst coincided with a Ca2+ increase. The present study suggests that synchronization of Ca2+ release is mediated by the high-frequency fluctuation in the store potential. Close apposition of the store membrane and plasma membrane in an epithelial structure would allow capacitative coupling across the cells.

Introduced Lolium species, including perennial ryegrass (Lolium perenne) and Italian ryegrass (Lolium multiflorum), have been widely utilized in Japan for forage, turf and soil conservation. These ryegrasses have escaped from cultivated areas and become naturalized, and this has become a serious issue in recent years. Interspecific hybrids between perennial ryegrass and Italian ryegrass have often been found in naturalized populations. It has also been suggested that hybridization between plant species might serve as a stimulus for the evolution of invasiveness. We surveyed the genetic structure of naturalized ryegrass populations in Japan using genetic markers that distinguished perennial ryegrass and Italian ryegrass. Of the 55 naturalized populations surveyed, 41 exhibited morphological traits of Italian ryegrass. DNA analysis using simple sequence repeat and chloroplast DNA markers characterized 20 of these 41 populations as Italian ryegrass, with the remaining populations as interspecific hybrid derivatives. Approximately half of the naturalized ryegrasses populations in Japan were inferred to include interspecific hybrids.

Pyrrolophenanthridinone derivatives including the natural products were readily synthesized by samarium(II)-mediated reductive cyclization of aryl radical onto a benzene ring under mild reaction conditions. This methodology was applied to the concise synthesis of anhydrolycorinone, a natural pyrrolophenanthridinone and a precursor of hippadine and anhydrolycorine.

A novel method for indole skeleton synthesis under mild conditions mediated by samarium(II) diiodide has been developed. The reaction of N-allenyl-2-iodoaniline derivatives with SmI2 in the presence of HMPA and i-PrOH at 0 °C afforded indole derivatives in high yields.

Endophytic fungi belonging to the genus Neotyphodium that form mutualistic associations with grasses of the subfamily Pooideae are ecologically and agriculturally important, producing mycotoxins that affect grazing animals and some insect pests. After our first report of naturalized Italian ryegrasses (Lolium multiflorum, annual ryegrass) infected with a Neotyphodium endophyte in Japan, the identity of this endophyte, the nature of its association with host grasses and its distribution, as well as the possible presence of toxic alkaloids have been of interest. To answer these questions we conducted surveys covering the western part of Japan to determine the distribution of infected Italian ryegrasses. Further, to identify the endophyte we used microscopy to determine its distribution in infected grasses and we applied DNA analysis using the ribosomal RNA gene (rDNA) to compare strains of this endophyte obtained from different geographic locations. Finally, we examined seed obtained from endophyte-infected Italian ryegrasses using high-performance liquid chromatograph (HPLC) and gas chromatograph. These studies indicated that naturalized Italian ryegrass in all three islands surveyed; Honshu, Kyushu and Shikoku, was frequently infected with N. occultans. N-formyl loline, an insect toxin, and peramine, a feeding deterrent were detected in the infected seed samples, but neither ergovaline nor lolitrem B (causal agents of grazing animal toxicity) were detected. These chemical analyses indicated that N. occultans infection of Italian ryegrasses may provide some influence on the insect fauna of the area through the chemicals active against insects, but was unlikely to be toxic to grazing animals.

Ca(2+) release from intracellular Ca(2+) stores, a pivotal event in Ca(2+) signaling, is a 'quantal' process; it terminates after a rapid release of a fraction of stored Ca(2+). To explain the 'quantal' nature, 'all-or-none' model and 'steady-state' model were proposed. This article shortly reviews these hypotheses and considers a recently proposed mechanism, 'luminal potential' model, in which the membrane potential of Ca(2+) store regulates Ca(2+) efflux. By reassessing the 'quantal' nature, other important features of Ca(2+) signaling, oscillation and synchronization, are highlighted. The mechanism for 'quantal' Ca(2+) release may underlie the temporal and spatial control of Ca(2+) signaling.

To clarify whether the unique postural control of the upside-down swimming catfish (Synodontis nigriventris, family Mochokidae) is related to the histological characteristics of the otolith organs, we performed light microscopic observation of the utricle, the saccule and the lagena. The histological aspects of the otolith organs were compared between S. nigriventris and Synodontis multipunctatus, which belong to the same genus. S. multipunctatus usually shows upside-up swimming posture except for feeding behaviour near water surface. As controls, we additionally used a miniature catfish, Corydoras paleatus and goldfish, Carassius auratus, which shows upside-up swimming posture. We concluded that the structural aspects of the otolith organs did not cause the unique postural control of S. nigriventris. Light microscopic observation clarified the following aspects: (1) The utricle of S. nigriventris was located at the anterior region of the otocyst and under the semicircular canals, and the saccule and the lagena were located at the posteroventral region of the otocyst like those of S. multipunctatus and the other two fishes. (2) The hair cells of the utricle were arranged on the horizontal plane of the fishes with a variation in cell size at the ventral and ventrolateral sites in S. nigriventris, S. multipunctatus and the other two fishes. (3) The hair cells of the saccule and lagena of S. nigriventris, S. multipunctatus and C. auratus presented perpendicular to the horizontal plane of the fish. (4) Region-specific differences in the size and shape of the hair cells of S. nigriventris were observed along the three-dimensional axes of the otolith organs like those of S. multipunctatus and the other two fishes. It is unlikely that the unique postural control of upside-down catfish is related to the localization of the utricle, the saccule and the lagena and the distribution of the different types of hair cell of the otolith organs. Furthermore, the distribution of the hair cells suggests that the otolith organs in S. nigriventris can detect three-dimensional postural changes like the organs of other fishes showing generally observed upside-up swimming posture.

Reaction of 2-(1-chloro-2,2-dimethylpropyl)-1-methyl-1H-irnidazoles with diethyl methylmalonate in the presence of NaH gave a normal SN product, 2-[(1,1-diethoxycarbonylethyl)-2,2-dimethylpropyl]-1-methyl-1H-imidazole (2a), and two tele-reaction products, 5-(1,1-diethoxycarbonylethyl)-1-methyl-2-(2,2-dimethylpropyl)-1H-imidazole (3a) and trans-4,5-di-(1,1-diethoxycarbonylethyl)-4,5-dihydro-1-methyl-2-(2,2-dimethylpropyl)-1H-imidazole (4a) in 5, 17 and 70% yields, respectively. The scope and mechanism of this reaction are discussed.

An efficient synthesis of 6-substituted 3-(alkoxycarbonyl)-5-aryl-α-pyrones is reported. This methodology consists of the successive manipulation of an addition–elimination reaction between benzyl ketone derivatives and dimethyl methoxymethylenemalonate, and an acid-catalyzed condensation reaction. The synthesis is applicable to various 5-p-substituted-aryl 6-substituted α-pyrones and good to excellent yields were obtained over two steps from benzyl ketone derivatives that were easily prepared from phenylacetic acid by the Negishi coupling or the Claisen decarboxylation reaction.

Dimethylsulfoxonium methylide (II) is prepared in situ from trimethylsulfoxonium iodide and sodium hydride.

Lysophosphatidic acid (LPA) plays various roles in the regulation of cell growth as a lipid mediator. We studied the effect of LPA on intracellular Ca(2+) concentration ([Ca2+]i) with Fura-2 in the neural retina of chick embryo during neurogenesis. Bath application of LPA (1-100 microM) to the embryonic day 3 (E3) chick retina caused an increase in [Ca2+](i) in a dose-dependent manner, with an EC(50) value of 9.2 microM. The Ca(2+) rise was also evoked in a Ca(2+)-free medium, suggesting that release of Ca(2+) from intracellular Ca(2+) stores (Ca(2+) mobilization) was induced by LPA. U-73122, a blocker of phospholipase C (PLC), inhibited the Ca(2+) rise to LPA. Pertussis toxin partially inhibited the Ca(2+) rise to LPA, indicating that G(i)/G(o) protein was at least partially involved in the LPA response. The developmental profile of the LPA response was studied from E3 to E13. The Ca(2+) rise to LPA declined drastically from E3 to E7, in parallel with decrease in mitotic activity of retinal progenitor cells. The signal transduction pathway and developmental profile of the Ca(2+) response to LPA were the same as those of the Ca(2+) response to adenosine triphosphate (ATP), which enhances the proliferation of retinal progenitor cells. The coapplication of LPA with ATP resulted in enhancement of Ca(2+) rise in the E3 chick retina. Our results show that LPA induces Ca(2+) mobilization in the embryonic chick retina during neurogenesis.

Neurotransmitters affect neuronal development by regulating intracellular Ca2+ concentrations. We studied spatiotemporal pattern of the development of glutamate-induced intracellular Ca2+ rise in the embryonic chick retina, where developmental changes in mitotic activity, cell death, and synapse formation have been well established. Glutamate was bath-applied to the central part of the retina dissected at embryonic day 3 (E3) to E13, and changes in intracellular Ca2+ concentration were measured with Fura-2 fluorescence. The Ca2+ rise to glutamate first appeared at E6, reached a maximum at E9–10, and then declined before the appearance of synaptic structures (E12). Ca2+ rises to kainate (KA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) appeared earlier and were larger in amplitude than those to N-methyl-D-aspartic acid. The KA/AMPA receptor of the E9 chick retina was permeable for Ca2+, suggesting the functional expression of Ca2+-permeable KA/AMPA receptors at the stage of retinal cell death. The Ca2+rise to glutamate and KA occurred intensely at the inner plexiform layer, the inner part of inner nuclear layer, and the ganglion cell layer, where the cell death occurs. The Ca2+ rise to high K2+, in contrast, occurred intensely at the nerve fiber layer and the ganglion cell layer, developing continuously from E3 until E11. Our study shows that the Ca2+ rise to glutamate develops with the decline of the mitotic activity of the retinal cells and is transiently enhanced during the period of cell death in the embryonic chick retina. © 1998 John Wiley & Sons, Inc. J Neurobiol 34: 113–125, 1998

Depletion of intracellular Ca2+ stores induces a capacitative Ca2+ influx in non-neural cells. It has been unknown whether the capacitative Ca2+ influx occurs in the cells of nervous systems. We found the capacitative Ca2+ influx in the neural retina of early embryonic chick with Fura-2 fluorescence measurements. A Ca(2+)-free medium containing thapsigargin (500 nM), an inhibitor of Ca(2+)-ATPase of intracellular Ca2+ stores, was applied to the neural retina of embryonic day 3 (E3) chick. A rise in intracellular Ca2+ concentration was evoked after the reintroduction of extracellular Ca2+, and this Ca2+ rise was suppressed by Zn2+ (1 mM) and Ni2+ (5 mM). The developmental changes in the Ca2+ rise induced by thapsigargin (250 nM) were studied from E3 to E13. The thapsigargin-induced Ca2+ rise was largest at E3, declined rapidly toward E6, and then decreased gradually until E13, when the Ca2+ rise almost disappeared. This developmental profile correlated with the decline in the mitotic activities of the retinal cells studied by Prada et al. The fluorescence imaging with the vertical slice of the E9 retina showed that the site at which the thapsigargin-induced Ca2+ rise was largest was the most outer layer of the retina, where proliferating cells are located. This spatial distribution and the above developmental profile may suggest that the capacitative Ca2+ influx occurs at the early period of neurogenesis when the cells have mitotic activities.

In situ generated dimethylsulfoxonium methylide is used to synthesize the title compounds in moderate yields.

Acetylcholine and adenosine triphosphate (ATP) raise intracellular Ca 2+ concentration via muscarinic receptors and P 2U purinoceptors by releasing Ca 2+ from intracellular Ca 2+ stores in the neural retina of early embryonic chick. The signal transduction mechanisms for the muscarinic and purinergic Ca 2+ responses with fura-2 fluorescence measurements were studied. Li + (1 mM), which inhibits phosphatidylinositol metabolism, enhanced both the Ca 2+ rises to carbamylcholine (CCh, 30 μM), a muscarinic agonist, and ATP (200 μM). Thapsigargin (250 nM), an inhibitor of Ca 2+ -ATPase of inositol trisphosphate (IP 3 )-sensitive Ca 2+ stores, abolished both the Ca 2+ rises to CCh (100 μM) and ATP (500 μM). U-73122 (2 μM), an inhibitor of phospholipase C b , suppressed the Ca 2+ rise to ATP (500 μM), but its analog U-73343 (2 μM) did not suppress it. In contrast, both U-73122 and U-73343 suppressed the Ca 2+ rise to CCh (100 μM). Pertussis toxin (250 ng/ml) suppressed the ATP-induced Ca 2+ rise at least partly, whereas no inhibition was observed on the CCh-induced Ca 2+ rise. Cross-talk occurred between the muscarinic and purinergic Ca 2+ mobilizations but they were not occlusive. This study suggests that the muscarinic and purinergic Ca 2+ mobilizations utilize IP 3 -sensitive Ca 2+ stores, but different signal transduction pathways are involved in between the muscarinic and purinergic Ca 2+ responses.

involving the stereoconvergent skeleton transformation from benzocyclobutapyranone (III) to dibenzofuran derivative (V) with dimethylsulfoxonium methylide as the key step

The action of acetylcholine on cytoplasmic Ca2+ concentration ([Ca2+]i) was studied in early embryonic chick retinae. Whole neural retinae were isolated from embryonic day 3 (E3) chicks and loaded with a Ca(2+)-sensitive fluorescent dye (Fura-2). Increases in [Ca2+]i were evoked by the puff application of acetylcholine at concentrations higher than 0.1 microM. The Ca2+ response became larger in a dose-dependent manner up to 10 microM of acetylcholine applied. The rise in [Ca2+]i was not due to the influx of Ca2+ through calcium channels, but to the release of Ca2+ from internal stores. A calcium channel antagonist, nifedipine, which completely blocks the Ca2+ rise caused by depolarization with 100 mM K+, had no effects on the acetylcholine response and the Ca2+ response to acetylcholine occurred even in a Ca(2+)-free medium. The Ca2+ response to acetylcholine was mediated by muscarinic receptors. Atropine of 1 microM abolished the response to 10 microM acetylcholine, whereas d-tubocurarine of 100 microM had no effects. Two muscarinic agonists, muscarine and carbamylcholine (100 microM each), evoked comparable responses with that to 10 microM acetylcholine. The developmental change of the muscarinic response was examined from E3 to E13. The Ca2+ response to 100 microM carbamylcholine was intense at E3-E5, then rapidly declined until E8. The muscarinic Ca2+ mobilization we found in the early embryonic chick retina may be regarded as a part of the "embryonic muscarinic system" proposed by Drew's group, which appears transiently and ubiquitously at early embryonic stages in relation to organogenesis.

The synthesis proceeds via ketyl radical attack on the aromatic ring, single electron transfer, and nucleophilic attack of the resulting dienyl anion to the ester group.

Pyrido[1,2-a] benzimidazole derivatives (12a and 19a) were synthesized in moderate yields via an intramolecular aldol-condensation of 2-acetyl-1-formylmethylbenzimidazole (11) and an intramolecular acylation of the acylimidzolide (18) prepared from 2-ethoxycarbonylmethyl-1-(2-carboxyethyl)-benzimidazole (17), respectively

Photochemical Fries rearrangement of 1-phenyl-2-pyrrolidone (1) proceeded smoothly in methanol especially in the presence of piperylene. Continuous photo-irradiation of 1 successfully was carried out to raise the yield by utilizing a reaction mixture-circulation system consisting of a spiral quartz cell, a pump, a uv light source and a column packed with appropriate absorbents for the Fries rearranged product (3) and pigments

The reactions of 2-halogenonaphthoquinones (5, 13, 14 and 15) and 2-methyl-1, 4-naphthoquinone (20; vitamin K3) with primary and secondary amines were examined. 1, 3-Dialkyl-1, 2, 3, 4-tetrahydrobenzo[g]quinazoline-5, 10-diones (9) were obtained in moderate yields by treating 20 with formaldehyde in primary amines. A plausible reaction path-way is also presented.

Synthesis of 3-alkylamino-1, 4-naphthoquinone-2-carboxylic acid (2) was attempted. Although 3-(1-piperidinyl)-1, 4-naphthoquinone-2-carboxylic acid (2a) was not obtained, probably because of its instability, the esters (18a, b)of 2a could be prepared. 2-Alkylamino-3-hydroxymethyl-1, 4-naphthoquinones (9a-g) were photochemically cyclized to the 1, 4, 5, 10-tetrahydro-5, 10-2H-naphth[2, 3-d][1, 3]oxazines (19a-g), containing a novel heterocyclic ring system in moderate yields. Anti-bacterial activity of the prepared compounds was weak or insignificant.

3-Ethoxycarbonylcoumarin ( 4 ) was treated with 2.4 equivalent of dimethylsulfoxonium methylide in DMF at room temperature to give a novel tricyclic product, ethyl (3 a R ∗ , 8 b S ∗ )- 3a,8b-dihydro-3-hydroxy -1H- cyclopenta [b] benzofuran-2-carboxylate ( 5 ), in 64% yield. This reaction could be applied to several 3-substituted coumarins.

Cyclopropane ring of 2- and 2,3-substituted cyclopropanecarboxylates (1) was regioselectively cleaved using SmI 2 -HMPA-THF system in the presence of tert-BuOH to give 4- and 3,4-substituted butyrates (2) in moderate to good yields

Cyclic ketone O-trimethylsilylcyanohydrins (2) were prepared and converted to various compounds : α-hydroxyketones (3), dehydroxylated ketones (4), α, β-unsaturated ketones (9), tricyclic ketones (10), 1-ethoxycarbonyl-4-phenyl-1, 2, 4a, 5, 6, 7, 8, 8a-octahydro-2-naphthalenone (13), 1-phenylperhydroisocoumarin (18) and 1, 2, 3, 4, 4a, 10, 11, 11a-octahydro-5H-benzo[a, d]cyclohepten-10-one (20).