A novel lepidopteran sex pheromone produced by females of a Lithosiinae species, Lyclene dharma dharma, in the family of Arctiidae

Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produced three pheromone components (I-III), which strongly stimulated male antennae. Using GC-MS analysis and chemical derivatizations, the following structures were estimated: 6-methyl-2-octadecanone (I), 14-methyl-2-octadecanone (II), and 6,14-dimethyl-2-octadecanone (III). While the stereochemistry of the chiral centers could not be determined because it was difficult to collect a sufficient amount of the natural pheromone, the plain structures of I and II were confirmed by synthesis of the racemic mixtures starting from diols. These methyl-branched ketones have not been identified as a natural product, indicating that they constitute a new chemical group of lepidopteran female sex pheromones.     

The complete structure of the cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) chloroplast genome: Its composition and comparative analysis

The complete nucleotide sequence of the cucumber (C. sativus L. var. Borszczagowski) chloroplast genome has been determined. The genome is composed of 155,293 bp containing a pair of inverted repeats of 25,191 bp, which are separated by two single-copy regions, a small 18,222-bp one and a large 86,688-bp one. The chloroplast genome of cucumber contains 130 known genes, including 89 protein-coding genes, 8 ribosomal RNA genes (4 rRNA species), and 37 tRNA genes (30 tRNA species), with 18 of them located in the inverted repeat region. Of these genes, 16 contain one intron, and two genes and one ycf contain 2 introns. Twenty-one small inversions that form stem-loop structures, ranging from 18 to 49 bp, have been identified. Eight of them show similarity to those of other species, while eight seem to be cucumber specific. Detailed comparisons of ycf2 and ycf15, and the overall structure to other chloroplast genomes were performed.     

Phosphodiesterase inhibitors. Part 1: Synthesis and structure-activity relationships of pyrazolopyridine-pyridazinone PDE inhibitors developed from ibudilast

Ibudilast [1-(2-isopropylpyrazolo[1,5-a]pyridin-3-yl)-2-methylpropan-1-one] is a nonselective phosphodiesterase inhibitor used clinically to treat asthma. Efforts to selectively develop the PDE3- and PDE4-inhibitory activity of ibudilast led to replacement of the isopropyl ketone by a pyridazinone heterocycle. Structure-activity relationship exploration in the resulting 6-(pyrazolo[1,5-a]pyridin-3-yl)pyridazin-3(2H)-ones revealed that the pyridazinone lactam functionality is a critical determinant for PDE3-inhibitory activity, with the nitrogen preferably unsubstituted. PDE4 inhibition is strongly promoted by introduction of a hydrophobic substituent at the pyridazinone N(2) centre and a methoxy group at C-7′ in the pyrazolopyridine. Migration of the pyridazinone ring connection from the pyrazolopyridine 3′-centre to C-4′ strongly enhances PDE4 inhibition. These studies establish a basis for development of potent PDE4-selective and dual PDE3/4-selective inhibitors derived from ibudilast.     

Abscinazole-E1, a novel chemical tool for exploring the role of ABA 8'-hydroxylase CYP707A

We developed abscinazole-E1 (Abz-E1), a specific inhibitor of abscisic acid (ABA) 8′-hydroxylase (CYP707A). This inhibitor was designed and synthesized as an enlarged analogue of uniconazole (UNI), a well-known plant growth retardant, which inhibits a gibberellin biosynthetic enzyme (ent-kaurene oxidase, CYP701A) as well as CYP707A. Our results showed that Abz-E1 functions as a potent inhibitor of CYP707A and a poor inhibitor of CYP701A both in vitro and in vivo. Abz-E1 application to plants resulted in improved desiccation tolerance and an increase in endogenous ABA.     

Distinct roles of protein disulfide isomerase and P5 sulfhydryl oxidoreductases in multiple pathways for oxidation of structurally diverse storage proteins in rice

In the rice (Oryza sativa) endosperm, storage proteins are synthesized on the rough endoplasmic reticulum (ER), in which prolamins are sorted to protein bodies (PBs) called type-I PB (PB-I). Protein disulfide isomerase (PDI) family oxidoreductase PDIL2;3, an ortholog of human P5, contains a conserved structural disulfide in the redox-inactive thioredoxin-like (TRX) domain and was efficiently targeted to the surface of PB-I in a redox active site-dependent manner, whereas PDIL1;1, an ortholog of human PDI, was localized in the ER lumen. Complementation analyses using PDIL1;1 knockout esp2 mutant indicated that the a and a' TRX domains of PDIL1;1 exhibited similar redox activities and that PDIL2;3 was unable to perform the PDIL1;1 functions. PDIL2;3 knockdown inhibited the accumulation of Cys-rich 10-kD prolamin (crP10) in the core of PB-I. Conversely, crP10 knockdown dispersed PDIL2;3 into the ER lumen. Glutathione S-transferase-PDIL2;3 formed a stable tetramer when it was expressed in Escherichia coli, and the recombinant PDIL2;3 tetramer facilitated α-globulin(C79F) mutant protein to form nonnative intermolecular disulfide bonds in vitro. These results indicate that PDIL2;3 and PDIL1;1 are not functionally redundant in sulfhydryl oxidations of structurally diverse storage proteins and play distinct roles in PB development. We discuss PDIL2;3-dependent and PDIL2;3-independent oxidation pathways that sustain disulfide bonds of crP10 in PB-I.     

Thermoresponsive heparin bioconjugate as novel aqueous antithrombogenic coating material

A novel thermoresponsive aqueous antithrombogenic coating material comprising a heparin bioconjugate with a six-branched, star-shaped poly(2-(dimethylaminoethyl)methacrylate) (6B-PDMAEMA), which has both thermoresponsive and cationic characters, was developed to reduce the thrombogenic potential of blood-contacting materials such as synthetic polymers or tissue-engineered tissues in cardiovascular devices. 6B-PDMAEMA with M(n) of ca. 24 kDa was designed as a prototype compound by initiator-transfer agent-terminator (iniferter)-based living radical photopolymerization from hexakis(N,N-diethyldithiocarbamylmethyl)benzene. Bioconjugation of heparin with 6B-PDMAEMA occurred as soon as both aqueous solutions were simply mixed to form particles. The particle size at 25 °C was less than several hundred nanometers in diameter under a heparin/6B-PDMAEMA mixing weight ratio of over 2.5. The particles were very stable because of the prevention of hydrolysis of 6B-PDMAEMA in its bioconjugated form. Because the lower critical solution temperature of the bioconjugate ranges from approximately 20 to 36 °C for the formation of microparticles, the coating could be done in an aqueous solution at low temperatures. The excellent adsorptivity and high durability of the coating above 37 °C was demonstrated on silicone and polyethylene films by surface chemical compositional analysis. Blood coagulation was significantly reduced on the bioconjugate-coated surfaces. Therefore, the thermoresponsive bioconjugate developed here appears to satisfy the initial requirements for a biocompatible aqueous coating material.     

Generation of novel cationic antimicrobial peptides from natural non-antimicrobial sequences by acid-amide substitution

Background

The accessory gene regulator (agr) is a quorum sensing cluster of genes which control colonization and virulence in Staphylococcus aureus. We evaluated agr function in community- (CA) and healthcare-associated (HA) MRSA, to compare the pharmacodynamics and bactericidal activity of vancomycin against agr functional and dysfunctional HA-MRSA and CA-MRSA.

Methods

40 clinical isolates of MRSA from the Canadian Nosocomial Infection Surveillance Program were evaluated for delta-haemolysin production, as a surrogate marker of agr function. Time kill experiments were performed for vancomycin at 0 to 64 times the MIC against an initial inoculum of 10⁶ and 10⁸ cfu/ml of agr functional and dysfunctional CA-MRSA and HA-MRSA and these data were fit to a hill-type pharmacodynamic model.

Results

15% isolates were agr dysfunctional, which was higher among HA-MRSA (26.3%) versus CA-MRSA (4.76%). Against a low initial inoculum of 10⁶ cfu/ml of CA-MRSA, vancomycin pharmacodynamics were similar among agr functional and dysfunctional strains. However, against a high initial inoculum of 10⁸ cfu/ml, killing activity was notably attenuated against agr dysfunctional CA-MRSA (USA400) and HA-MRSA (USA100). CA-MRSA displayed a 20.0 fold decrease in the maximal reduction in bacterial counts (Emax) which was 3.71 log₁₀ CFU/ml for agr functional vs. 2.41 log₁₀ CFU/ml for agr dysfunctional MRSA (p = 0.0007).

Conclusions

Dysfunction in agr was less common among CA-MRSA vs. HA-MRSA. agr dysfunction demonstrated an impact on vancomycin bactericidal activity and pharmacodynamics against a high initial inoculum of CA-MRSA and HA-MRSA, which may have implications for optimal antimicrobial therapy against persistent, difficult to treat MRSA infections.