A water-borne sex pheromone and trail following in the apple snail, Pomacea canaliculata

We investigated whether individuals of the apple snail Pomaceacanaliculata were attracted by conspecifics or follow mucustrails of other individuals. The snails' behaviour was studiedby a series of choice experiments in a T-maze and in Petri dishes.Both males and females chose the side with a snail of the oppositesex significantly more frequently than the control side withouta snail. Males were attracted by water conditioned with femalesmore frequently than unconditioned water, whereas females didnot show a preference for male-conditioned water. Moreover,juveniles were not attracted by water conditioned with a male,a female and a juvenile. These data indicate that males wereattracted by female odour, which contains one or more water-bornesex pheromones. In addition, both males and females follow mucustrails of snails of the opposite sex. Since females also followedtrails of females, the function of trail following is not necessarilyrelated to reproduction. In these experiments P. canaliculatadid not distinguish the direction of the trail. (Received 10 March 2007; accepted 12 July 2007)     

Asymmetric anionic polymerization of 2,7-bis(4-t-butylphenyl)fluoren-9-ylmethyl methacrylate and photoinduced structural transition of the obtained polymer

2,7-Bis(4-t-butylphenyl)fluoren-9-ylmethyl methacrylate (BBPFMMA) was synthesized as a new candidate of a bulky monomer suitable for asymmetric anionic polymerization (IUPAC nomenclature: asymmetric helix-chirogenic polymerization) leading to a preferred-handed helical, optically active polymer. The new monomer was polymerized using the complex of 9-fluorenyllithium and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine in toluene at -78 °C. As opposed to the original intention to obtain a polymethacrylate, the monomer seemed to undergo structural transition (decomposition) giving 2,7-bis(4-t-butylphenyl)dibenzofulvene and the obtained polymer was most probably a terpolymer of BBPFMMA, 2,7-bis(4-t-butylphenyl)dibenzofulvene, and methacrylic acid. The obtained polymer showed circular dichroism (CD) spectra, indicating that chirality had been introduced to the copolymer chain during the course of polymerization. On photo irradiation, the polymer underwent a structural transition involving a remarkable decrease in apparent molecular weight measured by size-exclusion chromatography (SEC) and changes in FT-IR spectral patterns. However, the CD spectrum of the polymer was not obviously altered by irradiation, indicating that polymer chirality is not affected by light.     

Hyperresponsivity to low-dose endotoxin during progression to nonalcoholic steatohepatitis is regulated by leptin-mediated signaling

Although bacterial endotoxin, such as lipopolysaccharide (LPS), plays a key role in the pathogenesis of nonalcoholic steatohepatitis (NASH), detailed mechanisms of this pathogenesis remain unclear. Here, we demonstrate that upregulation of CD14 by leptin-mediated signaling is critical to hyperreactivity against endotoxin during NASH progression. Upregulation of CD14 in Kupffer cells and hyperreactivity against low-dose LPS were observed in high-fat diet (HFD)-induced steatosis mice, but not chow-fed-control mice. Hyperresponsivity against low-dose LPS led to accelerated NASH progression, including liver inflammation and fibrosis. Administering leptin in chow-fed mice caused increased hepatic expression of CD14 via STAT3 signaling, resulting in hyperreactivity against low-dose LPS without steatosis. In contrast, a marked decrease in hepatic CD14 expression was observed in leptin-deficient ob/ob mice, despite severe steatosis. Our results indicate that obesity-induced leptin plays a crucial role in NASH progression via enhanced responsivity to endotoxin, and we propose a mechanism of bacteria-mediated progression of NASH.     

Mechanism of radiation-induced reactions in aqueous solution of coumarin-3-carboxylic acid: effects of concentration, gas and additive on fluorescent product yield

The radiation-induced reactions of a water-soluble coumarin derivative, coumarin-3-carboxyl acid (C3CA), have been investigated in aqueous solutions by pulse radiolysis with a 35 MeV electron beam, final product analysis following (60)Co γ-irradiations and deterministic model simulations. Pulse radiolysis revealed that C3CA reacted with both hydroxyl radicals ((?)OH) and hydrated electrons (e(-) (aq)) with near diffusion-controlled rate constants of 6.8 × 10(9) and 2.1 × 10(10) M(-1) s(-1), respectively. The reactivity of C3CA towards O(2)(? -) was not confirmed by pulse radiolysis. Production of the fluorescent molecule, 7-hydroxy-coumarin-3-carboxylic acid (7OH-C3CA), was confirmed by final product analysis with a fluorescence spectrometer coupled to a high performance liquid chromatography (HPLC) system. Production yields of 7OH-C3CA following (60)Co γ-irradiations depended on the irradiation conditions and ranged from 0.025 to 0.18 (100 eV) (-1). Yield varied with saturating gas, additive and C3CA concentration, implying the presence of at least two pathways capable of providing 7OH-C3CA as a stable product following the scavenging reaction of C3CA with (?)OH, including a peroxidation/elimination sequence and a disproportionation pathway. A reaction mechanism for the two pathways was proposed and incorporated into a deterministic simulation, showing that the mechanism can explain experimentally measured 7OH-C3CA yields with a constant conversion factor of 4.7% from (?)OH scavenging to 7OH-C3CA production, unless t-BuOH was added.     

Adjuvant activity of alum in inducing antigen specific IgE antibodies in BALB/c mice: a reevaluation

The IgE production was compared in the presence and absence of aluminum hydroxide gel (alum). Without alum, the IgE production was induced within a suitable range of the antigen dosage; however, alum enhanced it. Alum did not affect the minimum requirement for the antigen dosage, indicating that alum may not take part in the efficiency of antigen presentation.     

Molecular design of DABNTf as a highly efficient resolving reagent for racemic Pd complex with Tropos biphenylphosphine (BIPHEP) ligand: circular dichroism (CD) spectra of enantiopure BIPHEP-Pd complex

The racemic Pd complexes with chirally flexible (tropos) biphenylphosphine (BIPHEP) ligands can be resolved but transformed into the enantio- and diastereo-pure complex. The enantiopure metal complex of BIPHEP ligand is thus obtained through enantiomer-selective complexation of a racemic BIPHEP-Pd complex with enantiopure 1,1'-binaphthyl-2,2'-di(triflyl)amide, DABNTf. The differential CD spectra of the enantiopure BIPHEP-Pd complex is also reported.     

A snail with unbiased population sex ratios but highly biased brood sex ratios

Extraordinary sex ratio patterns and the underlying sex-determining mechanisms in various organisms are worth investigating, particularly because they shed light on adaptive sex-ratio adjustment. Here, we report an extremely large variation in the brood sex ratio in the freshwater snail, Pomacea canaliculata. In eight rearing series originating from three wild populations, sex ratios were highly variable among broods, ranging continuously from almost exclusively males to almost exclusively females. However, sex ratios were similar between broods from the same mating pair, indicating that sex ratio is a family trait. Irrespective of the large variations, the average sex ratios in all rearing series were not significantly different from 0.5. We argue that Fisher's adaptive sex-ratio theory can explain the equal average sex ratios, and the results, in turn, directly support Fisher's theory. Polyfactorial sex determination (in which sex is determined by three or more genetic factors) is suggested as the most likely mechanism producing the variable brood sex ratio.