Analytical Method for Diacylglycerol Kinase ζ Activity in Cells Using Protein Myristoylation and Liquid Chromatography–Tandem Mass Spectrometry

Specific inhibitors of diacylglycerol kinase (DGK) ζ can be promising anticancer medications via the activation of cancer immunity. Although the detection of cellular activities of target enzymes is essential for drug screening in addition to in vitro assays, it is difficult to detect the activity of DGKζ in cells. In the present study, we generated AcGFP-DGKζ cDNA with a consensus N-myristoylation sequence at the 5′ end (Myr-AcGFP-DGKζ) to target DGKζ to membranes. Using liquid chromatography (LC)-tandem mass spectrometry (MS/MS) (LC–MS/MS), we showed that Myr-AcGFP-DGKζ, but not AcGFP-DGKζ without the myristoylation sequence, substantially augmented the levels of several phosphatidic acid (PtdOH) species. In contrast to Myr-AcGFP-DGKζ, its inactive mutant did not exhibit an increase in PtdOH production, indicating that the increase in PtdOH production was DGK activity-dependent. This method will be useful in chemical compound selection for the development of drugs targeting DGKζ and can be applicable to various soluble (nonmembrane bound) lipid-metabolizing enzymes, including other DGK isozymes.     

Soil stiffness as a function of dry density and the degree of saturation for compaction control

A data set of the coefficient of vertical subgrade reaction for a plate diameter of 30 cm, K_P.FWD, measured by Portable Falling Weight Deflectometer tests in full-scale compaction tests on sandy soil using various types of compaction machines was analysed. Based on this analysis and the previous analysis of a CBR data set from another full-scale compaction test series, a set of conclusions could be drawn. The soil stiffness indexes (SSIs), CBR and K_P.FWD, can be expressed by, respectively, an empirical equation multiplying a function of ρ_d and another of S_r, where CBR and K_P.FWD decrease significantly as S_r increases. As such, ρ_d values cannot be estimated from SSI alone. By fixing the field ρ_d – w compaction curve by keeping the soil type and the field compaction energy level, CEL_f, to those in the field compaction tests in which the SSI – ρ_d – S_r correlation has been calibrated, field compacted ρ_d & w states can be estimated by measuring the SSI values. Then, by the upper-bound and lower-bound control of SSI, the field compacted states approach the specified target, where, typically, ρ_d = the maximum dry density for CEL_f and S_r = the optimum degree of saturation, (S_r)_opt. A method to incorporate this indirect but fast SSI-based compaction control into the conventional ρ_d & w-based compaction control is proposed.     

Editorial

Mobile Networks and Applications -     

Development of high temperature structural materials for the HTGR

In accordance with the HTGR program in Japan, a series of R&D for high temperature structural materials in particular with respect to the HTTR design code has been performed in JAERI for more than 20 years. This paper introduces R&D results of the pressure retaining low alloy steel 2 1/4Cr-1Mo and the high temperature structural alloys Hastelloy XR and Ni-Cr-W superalloy for the design code together with some fruits of recent studies.     

Preparation and magnetic properties of Ti1−xVxPO4

The solid solutions of Ti_1?xV_xPO₄ were prepared under the reductive circumstance, although there seems to be immiscibility near x=0.5. Their magnetic susceptibility was analysed by the temperature-independent and Curie-Weiss contribution. The temperature-independent contribution increased gradually with x until x=0.4 and then decreased to 0 at x=1.0. A bent was observed at x=0.5 in the curve for the Curie constant against x and at x>0.5 the Curie temperature became strongly negative with x.In the region of x≦0.4, the Curie constant corresponded to the electronic configuration of d¹ for a vanadium ion. On the other hand, the Curie constant reflected the d² configuration for a vanadium ion in the range of $\text{x}\text{≧0.6}$. This fact indicates that Ti³⁺/1bV³⁺ homopolar bonds are formed in accordance with the replacement of Ti³⁺ with V³⁺ at x≦0.4. Vanadium ions added further, which substitute for Ti³⁺ in Ti³⁺/1bV³⁺ pairs, do not form the homopolar bond with V³⁺ ions and both V³⁺ ions contribute magnetically as ions with d² configuration.     

Assessment of insulin resistance in acromegaly associated with diabetes mellitus before and after transsphenoidal adenomectomy

With a euglycemic hyperinsulinemic clamp method, whole-body insulin resistance was assessed in 6 cases with acromegaly associated with diabetes mellitus before and after transsphenoidal adenomectomy. The glucose infusion rate (GIR) correlated well with the plasma IGF-I level but poorly with that of GH. Further improvement in insulin sensitivity occurred 3-4 months after operation without substantial changes in plasma levels of both GH and IGF-I or glycemic control. These results indicate that GH excess can induce insulin resistance in association with plasma IGF-I and also through undefined secondary effect.