Metabolism of Hydrocarbons in Microorganisms

The fatty acid composition of the lipid of yellowfin tuna (Thunnus albacares) caught in two different localities, Philippine Sea (a tropical zone) and the Pacific coast area of Japan (a temperate zone) is described. The total lipids of various organs (dorsal ordinary muscle, ventral ordinary muscle, dark muscle, liver, heart, pyloric cecum, and orbital region) and of the stomach contents were extracted, and the fatty acid comosition was analyzed by gas-liquid chromatography (GLC).

Docosahexaenoic acid (DHA; 22:6n-3) was the major unsaturated fatty acid in the lipid of all organs in the specimens examined from both localities, the mean DHA content accounting for more than 25% (mean ± S.D. of 26.9 ±5.7%) of the total fatty acids. This value is markedly different from the fatty acid profile of other fish species, because, in general, the fatty acid composition of other species is variable and the DHA content is less than 20% of total fatty acids.

Although the mean DHA content of the total fatty acids in the lipid of yellowfin tuna caught in the tropical and temperate zones was markedly higher than that in other fish species, there was a small difference between that in the northern samples (temperate waters, 30.5 ±6.1%) and the southern samples (tropical waters, 25.9 ± 5.2%). It is suggested that this difference may be due to environmental effects, e.g., the fatty acid composition of the lipids of prey organisms, because there is also a small difference between the mean DHA content of northern prey fish (22.7 ±6.1%) and that of southern prey fish (19.2 ±4.0%).     

Roles of dopa decarboxylase and phenoloxidase in the melanization of the tobacco hornworm and their control by 20-hydroxyecdysone

Summary WhenManduca sexta larvae are allatectomized 5 h before head capsule slippage (HCS) in the final larval molt, the new larval cuticle contains granules that melanize 3 h before ecdysis when the ecdysteroid titer falls (Curtis et al. 1984). In both the epidermis and hemolymph of these allatectomized larvae dopamine was higher than dopa prior to and at the time of melanization. Dopamine also increased in the new cuticle as melanization began. Dopa decarboxylase (DDC) activity increased in the epidermis, cuticle, and fat body beginning 16 h after HCS, with a two-fold greater increase in the epidermis of allatectomized larvae. Both -MDH and -fluoromethyl-dopa inhibited epidermal DDC activity and inhibited melanization in vitro when dopa was used as a precursor. Addition of dopamine to the medium allowed melanization in the presence of the inhibitors. All these results indicate that dopamine is likely the primary precursor of cuticular melanin. The diphenoloxidase in the premelanin granules was activated in vivo between 19 and 21 h after HCS and was found to prefer dopamine to dopa and not to convert tyrosine to melanin. The activation of the prophenoloxidase was inhibited by 20-hydroxyecdysone (20-HE), both in vivo and in vitro, if hormone was given by 16 h after HCS. Infusion of 1.2 g/ml 20-HE into allatectomized larvae for 24 h from HCS prevented both the increase in DDC activity and the activation of the premelanin granules. Although the larvae ecdysed after a 15 h delay, melanization never occurred.Abbreviations -MDH L-3-(3,4 dihydroxyphenyl)-2-hydrazine-methylpropionic acid - -FM-dopa R-S--fluoromethyl-dopa - DCC dopa decarboxylase - 20-HE 20-hydroxyecdysone - JH juvenile hormone - HCS head capsule slippage     

Monoclonal antibody to rat brain actin antigenically enhanced with HVJ (Sendai Virus) M protein

Summary Monoclonal antibody to rat brain actin was easily produced using HVJ (Sendai Virus) M protein to enhance the antigenicity of the actin. This monoclonal antibody was determined to be IgM with a kappa light chain. By immunoblot analysis the antibody was also shown to react with rat brain actin but not with HVJ M protein on nitrocellulose sheets. Utilizing the antibody, neuronal cytoplasm in the cerebral cortex, the anterior and posterior horns in the spinal cord, the spinal ganglion and astrocytes showed positive immunohistochemical staining by light microscopy. However, Purkinje cells showed variable staining, some staining intensely, while others were negative. All of neurons in specific anatomical locations showed always positive staining but variable intensities. Vascular walls were stained only faintly. By electron microscopy, neuronal cytoplasm showed diffuse positive staining. Other areas showed a positive reaction, including dendrites, the postsynaptic densities, and a few capillary endothelial cells and arterial smooth muscle cells. The results suggest that the HVJ M protein was effective for producing monoclonal antibody to brain actin, and that the antibody could be utilized for the immunohistochemical study of neuronal elements in both normal and pathological conditions.     

Design,synthesis and evaluation of γ-turn mimetics as LSD1-selective inhibitors

Lysine-specific demethylase 1 (LSD1) is an attractive molecular target for cancer therapy. We have previously reported potent LSD1-selective inhibitors (i.e., NCD18, NCD38, and their analogs) consisting of trans-2-phenylcyclopropylamine (PCPA) or trans-2-arylcyclopropylamine (ACPA) and a lysine moiety that could form a γ-turn structure in the active site of LSD1. Herein we report the design, synthesis and evaluation of γ-turn mimetic compounds for further improvement of LSD1 inhibitory activity and anticancer activity. Among a series of γ-turn mimetic compounds synthesized by a Mitsunobu-reaction-based amination strategy, we identified 1n as a potent and selective LSD1 inhibitor. Compound 1n induced cell cycle arrest and apoptosis through histone methylation in human lung cancer cells. The γ-turn mimetics approach should offer new insights into drug design for LSD1-selective inhibitors.     

Evaluation of pest control efficiencies for different banker plant systems with a simple predator–prey model

The banker plant system has been introduced for the biological control of various pest species in Japanese greenhouses. With the banker plant system, non-crop plants infested with a host insect (a non-commercial crop pest) are placed in the greenhouse to provide alternative resources for the parasitoids or predators. We want to evaluate the effectiveness for controlling pests on the crop in a quantitative way by immigrating predators from the banker plant. Therefore, we developed a simple model for the interaction of the pest and predator in the crop and included the banker plant only as a source for predators. For three different pest-predator systems we parameterised the model and used these models to predict under what conditions biological control in a banker plant system is successful. We defined successful as keeping the pest below the economic injury level of the crop estimated from damage analysis. Because the crop is mostly grown during a period that lasts less than a year our analysis should not only focus on the equilibrium dynamics. In contrast, it should also focus on the transient dynamics. Our main analytical result, from the equilibrium analysis, is that for successful control the maximum lifetime consumption of immigrating predators should exceed the daily prey growth at half the value of the maximum consumption rate. For practical purpose this translates into the fact that the immigration of predators at a low initial pest density is crucial for successful control.     

Structural basis of reversine selectivity in inhibiting Mps1 more potently than aurora B kinase

Monopolar spindle 1 (Mps1, also known as TTK) is a protein kinase crucial for ensuring that cell division progresses to anaphase only after all chromosomes are connected to spindle microtubules. Incomplete chromosomal attachment leads to abnormal chromosome counts in the daughter cells (aneuploidy), a condition common in many solid cancers. Therefore Mps1 is an established target in cancer therapy. Mps1 kinase inhibitors include reversine (2‐(4‐morpholinoanilino)‐6‐cyclohexylaminopurine), a promiscuous compound first recognized as an inhibitor of the Aurora B mitotic kinase. Here, we present the 3.0‐Å resolution crystal structure of the Mps1 kinase domain bound to reversine. Structural comparison of reversine bound to Mps1 and Aurora B, indicates a similar binding pose for the purine moiety of reversine making three conserved hydrogen bonds to the protein main chain, explaining the observed promiscuity of this inhibitor. The cyclohexyl and morpholinoaniline moieties of reversine however, have more extensive contacts with the protein in Mps1 than in Aurora B. This is reflected both in structure‐based docking energy calculations, and in new experimental data we present here, that both confirm that the affinity of reversine towards Mps1 is about two orders of magnitude higher than towards Aurora B. Thus, our data provides detailed structural understanding of the existing literature that argues reversine inhibits Mps1 more efficiently than Aurora B based on biochemical and in‐cell assays. Proteins 2016; 84:1761–1766. © 2016 Wiley Periodicals, Inc.     

Danger peptide receptor signaling in plants ensures basal immunity upon pathogen‐induced depletion of BAK1

Pathogens infect a host by suppressing defense responses induced upon recognition of microbe‐associated molecular patterns (MAMPs). Despite this suppression, MAMP receptors mediate basal resistance to limit host susceptibility, via a process that is poorly understood. The Arabidopsis leucine‐rich repeat (LRR) receptor kinase BAK1 associates and functions with different cell surface LRR receptors for a wide range of ligands, including MAMPs. We report that BAK1 depletion is linked to defense activation through the endogenous PROPEP peptides (Pep epitopes) and their LRR receptor kinases PEPR1/PEPR2, despite critical defects in MAMP signaling. In bak1‐knockout plants, PEPR elicitation results in extensive cell death and the prioritization of salicylate‐based defenses over jasmonate‐based defenses, in addition to elevated proligand and receptor accumulation. BAK1 disruption stimulates the release of PROPEP3, produced in response to Pep application and during pathogen challenge, and renders PEPRs necessary for basal resistance. These findings are biologically relevant, since specific BAK1 depletion coincides with PEPR‐dependent resistance to the fungal pathogen Colletotrichum higginsianum. Thus, the PEPR pathway ensures basal resistance when MAMP‐triggered defenses are compromised by BAK1 depletion.     

Phosphorylation of 4EBP by oral leucine administration was suppressed in the skeletal muscle of PGC-1α knockout mice

Leucine is known to increase mTOR-mediated phosphorylation of 4EBP. In this study, leucine was administered to skeletal muscle-PGC-1α knockout mice. We observed attenuated 4EBP phosphorylation in the skeletal muscle, but not in the liver, of the PGC-1α knockout mice. These data suggest that skeletal muscle-PGC-1α is important for leucine-mediated mTOR activation and protein biosynthesis.