The Pimelyl-CoA Synthetase Responsible for the First Step in Biotin Biosynthesis by Microorganisms

Cell-free extracts of various bacteria were active in catalyzing the synthesis of pimelyl-CoA from pimelic acid and CoA. The pimelyl-CoA formed was determined in a reaction coupled with the 7-keto-8-aminopelargonic acid (KAPA) synthetase system, which is required to convert pimely-CoA to KAPA, and by microbiologically assaying the amount of KAPA formed. The enzyme synthesizing pimelyl-CoA was named pimely-CoA synthetase and should belong to EC 6.2.1. The pimelyl-CoA synthetase reaction required pimelic acid, CoA, ATP and Mg²⁺. The enzyme was partially purified from a cell-free extract of Bacillus megaterium. Using purified enzyme, characterization of the enzyme was performed. The enzyme reaction was remarkably inhibited by typical metal-chelating agents. Mn²⁺ and ADP could replace Mg²⁺ and ATP, respectively. No feedback repression was observed even with the addition of 1.0 µg per ml of biotin to the culture medium.     

Fermentative Production of CDP-Choline by Yeasts

The optimum condition for the formation of CDP-choline was studied: (1) the reaction proceeded more effectively at 35°C than at 28 or 40°C. (2) the maximum formation of CDP-choline was obtained at pH 7.5, when pH levels were kept constant throughout the reaction. (3) twenty #x03BC;moles per ml of 5′-CMP was the optimum concentration for the formation of CDP-choline. When higher concentration of 5′-CMP was employed, the substrate was decomposed to uridine, uracil, etc., and the yield of CDP-choline decreased. By the application of feeding method, 5′-CMP was utilized to the effective formation of CDP-choline without further formation of side-products.     

Purification of a Lipolytic Acyl-hydrolase from Phaseolus vulgaris Leaves by Affinity Chromatography on Palmitoylated Gauze and Its Properties

A lipolytic acyl-hydrolase was purified about 220-fold from the homogenate of the leaves of Phaseolus vulgaris L. cv. Kurodane-kinugasa by acetone precipitation, affinity chromatography on a palmitoylated gauze column and isoelectric focusing. The purified enzyme showed a single protein band by polyacrylamide gel disc electrophoresis. The enzyme had an isoelectric point of 4.4 and a molecular weight of about 90,000. It had pH optima of 5.5 and 6.5, and Km values of 0.24 and 0.53 mm for monogalactosyldiacylglycerol and phosphatidylcholine, respectively. The pH dependences were changed by Triton X–100. No separation of these two hydrolyzing activities were achieved, and the ratio of the specific activity of galactolipase to that of phospholipase (about 3/1) remained constant throughout the purification procedures. Both the activities changed in parallel with each other by the addition of reagents and by heat treatment. The enzyme clearly catalyzed the deacylation of the several classes of glyco- and phospholipids. These results suggest that a single enzyme is responsible for both the activities.     

Thermal Inactivation of Myosin A-Adenosine Triphosphatase in the Presence of F-Actin

The influence of the concentration of F-actin on the inactivation of myosin A-ATPase in solution and in suspension has been studied. The reaction departs from typical first-order behavior in that the rate decreases as the reaction proceeds. The extent of this effect varied greatly with the amount of F-actin added and slightly with pH and ionic strength. The interpretation of the experimental results is discussed. A kinetic mechanism which qualitatively accounts for the observed behavior and which suggests the occurrence of two types of actomyosin complexes with respect to susceptibility to denaturation is proposed.

The rate of denaturation of myosin A has been found to decrease greatly on an addition of magnesium and also with a decrease in ionic strength at high (10.3) or low (6.0) pH values.     

Diarylheptanoids with inhibitory effects on melanogenesis from the rhizomes of Curcuma comosa in B16 melanoma cells

The methanolic extract from the dried rhizomes of Curcuma comosa cultivated in Thailand was found to inhibit melanogenesis in theophylline-stimulated murine B16 melanoma 4A5 cells. From the methanolic extract, three new diarylheptanoids, diarylcomosols I–III, were isolated together with 12 known diarylheptanoids. Their chemical structures were elucidated on the basis of chemical and physicochemical evidence. The diarylheptanoids inhibited melanogenesis, and several structural requirements of the active constituents for the inhibition were clarified. In particular, (3R)-1,7-bis(4-hydroxyphenyl)-(6E)-6-hepten-3-ol exhibited stronger inhibitory effect [IC₅₀ = 0.36 μM] without inducing cytotoxicity. The biological effect was much stronger than that of a reference compound, arbutin [IC₅₀ = 174 μM]. We conclude that diarylheptanoid analogs are promising therapeutic agents for the treatment of skin disorders.     

Ceramicines from Chisocheton ceramicus as lipid-droplets accumulation inhibitors

In our search for lipid-droplets accumulation (LDA) inhibitors, some ceramicines, a series of limonoids isolated from the barks of Chisocheton ceramicus, were discovered to be active as anti-LDA. Preliminary structure–activity relationships (SAR) of ceramicines as LDA inhibitors based on ceramicines A–L (1–12) and ceramicine B derivatives were described.     

Synthesis and SAR study of new thiazole derivatives as vascular adhesion protein-1 (VAP-1) inhibitors for the treatment of diabetic macular edema

Vascular adhesion protein-1 (VAP-1), an amine oxidase that is also known as a semicarbazide-sensitive amine oxidase (SSAO), is present in particularly high levels in human plasma, and is considered a potential therapeutic target for various inflammatory diseases, including diabetes complications such as macular edema.In our VAP-1 inhibitor program, structural modifications following high-throughput screening (HTS) of our compound library resulted in the discovery that thiazole derivative 10, which includes a guanidine group, shows potent human VAP-1 inhibitory activity (IC₅₀ of 230 nM; rat IC₅₀ of 14 nM). Moreover, compound 10 exhibited significant inhibitory effects on ocular permeability in STZ-induced diabetic rats.     

The Ficus erecta genome aids Ceratocystis canker resistance breeding in common fig (F. carica)

Ficus erecta, a wild relative of the common fig (F. carica), is a donor of Ceratocystis canker resistance in fig breeding programmes. Interspecific hybridization followed by recurrent backcrossing is an effective method to transfer the resistance trait from wild to cultivated fig. However, this process is time consuming and labour intensive for trees, especially for gynodioecious plants such as fig. In this study, genome resources were developed for F. erecta to facilitate fig breeding programmes. The genome sequence of F. erecta was determined using single‐molecule real‐time sequencing technology. The resultant assembly spanned 331.6 Mb with 538 contigs and an N50 length of 1.9 Mb, from which 51 806 high‐confidence genes were predicted. Pseudomolecule sequences corresponding to the chromosomes of F. erecta were established with a genetic map based on single nucleotide polymorphisms from double‐digest restriction‐site‐associated DNA sequencing. Subsequent linkage analysis and whole‐genome resequencing identified a candidate gene for the Ceratocystis canker resistance trait. Genome‐wide genotyping analysis enabled the selection of female lines that possessed resistance and effective elimination of the donor genome from the progeny. The genome resources provided in this study will accelerate and enhance disease‐resistance breeding programmes in fig.     

Histamine H<Subscript>3</Subscript> Receptor Agonists Decrease Hypothalamic Histamine Levels and Increase Stereotypical Biting in Mice Challenged with Methamphetamine

The effects of the histamine H₃ receptor agonists (R)-α-methylhistamine, imetit and immepip on methamphetamine (METH)-induced stereotypical behavior were examined in mice. The administration of METH (10 mg/kg, i.p.) to male ddY mice induced behaviors including persistent locomotion and stereotypical behaviors, which were classified into four categories: stereotypical head-bobbing (1.9%), circling (1.7%), sniffing (14.3%), and biting (82.1%). Pretreatment with (R)-α-methylhistamine (3 and 10 mg/kg, i.p.) significantly decreased stereotypical sniffing, but increased stereotypical biting induced by METH, in a dose-dependent manner. This effect of (R)-α-methylhistamine on behavior was mimicked by imetit or immepip (brain-penetrating selective histamine H₃ receptor agonists; 10 mg/kg, i.p. for each drug). Hypothalamic histamine levels 1 h after METH challenge were significantly increased in mice pretreated with saline. These increases in histamine levels were significantly decreased by pretreatment with histamine H₃ receptor agonists, effects which would appear to underlie the shift from METH-induced stereotypical sniffing to biting.