Bioactive jatrophane diterpenes from Euphorbia guyoniana

Chromatographic investigation of the methylenechloride/methanol extract of the aerial parts of Euphorbia guyoniana afforded two jatrophane diterpenes, designated guyonianins E and F, in addition to a known jatrophane diterpene. The structures of the compounds were determined by comprehensive NMR analyses, including DEPT, COSY, HMQC, HMBC, NOESY and HRMS. These compounds exhibited cytotoxicity against human embryonic kidney 293 (HEK293) cells with IC₅₀ values of 35–100 μM.     

Relative abundance of Δ5-sterols in plasma membrane lipids of root-tip cells correlates with aluminum tolerance of rice

We investigated variations in aluminum (Al) tolerance among rice plants, using ancestor cultivars from the family line of the Al-tolerant and widely cultivated Japonica cultivar, Sasanishiki. The cultivar Rikuu-20 was Al sensitive, whereas a closely related cultivar that is a descendant of Rikuu-20, Rikuu-132, was Al tolerant. These two cultivars were compared to determine mechanisms underlying variations in Al tolerance. The sensitive cultivar Rikuu-20 showed increased permeability of the plasma membrane (PM) and greater Al uptake within 1 h of Al treatment. This could not be explained by organic acid release. Lipid composition of the PM differed between these cultivars, and may account for the difference in Al tolerance. The tolerant cultivar Rikuu-132 had a lower ratio of phospholipids to Δ⁵-sterols than the sensitive cultivar Rikuu-20, suggesting that the PM of Rikuu-132 is less negatively charged and less permeabilized than that of Rikuu-20. We used inhibitors of Δ⁵-sterol synthesis to alter the ratio of phospholipids to Δ⁵-sterols in both cultivars. These inhibitors reduced Al tolerance in Rikuu-132 and its Al-tolerant ancestor cultivars Kamenoo and Kyoku. In addition, Rikuu-132 showed a similar level of Al sensitivity when the ratio of phospholipids to Δ⁵-sterols was increased to match that of Rikuu-20 after treatment with uniconazole-P, an inhibitor of obtusifoliol-14α-demethylase. These results indicate that PM lipid composition is a factor underlying variations in Al tolerance among rice cultivars.     

Growth process of the human body considered in connection with basal metabolism and specific surface area

The work tests the applicability of two empirical equations to the analysis of membranes, and is motivated by a long recognized need for a characterization of membrane phenomenology by a physical model. Empirical relations are often used to describe the phenomenology of complicated systems and are also used as starting points for a detailed molecular analysis of systems like solutions and liquids. We apply here coefficients of the empirical Collander's equation, which is related to the physiological characteristics of membranes, and of the Barclay-Butler relation, which was successfully used as a starting point for the construction of a molecular model of solutions. These coefficients we use to analyze the phospholipid membrane. In the analysis we use three sets of solutes: noble gases, paraffins and aliphatic alcohols and test whether conclusions drawn from simple, but basic, physiochemical considerations agree with results obtained by more direct methods. We also ask ourselves what information can be obtained by the parametric analysis which is not available already by other methods. The results of our analysis agree with results obtained by direct physical methods and bear a close relation to membrane physiology. This type of analysis may therefore bridge a gap between biological phenomenology and purely physical methods.     

ADAMTS9 activation by interleukin 1β via NFATc1 in OUMS-27 chondrosarcoma cells and in human chondrocytes

ADAMTS9 is a member of the disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) genes, with aggrecan-degrading activity. It has also been characterized to be reactive and highly activated ADAMTS by IL-1β in both chondrosarcoma cells and human chondrocytes (Demircan et al. Arthritis Rheum 52:1451–1460, 2005). In order to understand the regulation of ADAMTS9 gene expression a functional 3.0 kb human ADAMTS9 promoter has been cloned and characterized. A sequence analysis of the promoter revealed the presence of putative binding sites for Nuclear Factor of Activated T cells (NFAT), which is commonly found in the ADAMTS4 and ADAMTS5 promoters. NFATc1 was up-regulated in an activated form by IL-1β in human chondrocytes. The IL-1β inducible ADAMTS9 expression was inhibited by NFAT inhibitors, FK506 and 11Arg (11R)-VIVIT. Furthermore, direct binding of NFATc1 on distal and proximal promoters of ADAMTS9 was demonstrated by a chromatin immunoprecipitation assay. Promoter-reporter assays supported those results. These findings may provide a better understanding of the regulation of ADAMTS9 expression induced by inflammatory cytokines.     

Factors controlling hypolimnetic ammonia accumulation in a lake

The factors controlling the degree of hypolimnetic ammonia accumulation in Lake Onogawa are discussed based on periodic observations since 1993. The standing stock of ammonia in the bottom 9 m of the water column was a good measurement for determining the extent of the hypolimnetic ammonia accumulation. It varied threefold from 144 mmol m⁻² in 1998 to 429 mmol m⁻² in 1996. The correlation between the annual maxima of the ammonia standing stocks and the annual maxima of the thickness of anoxic layers was significant at P = 0.01. This fact suggests that the degree of development of the anoxic layer is the primary factor controlling the extent of hypolimnetic ammonia accumulation. Sporadic local heavy rainfalls in 1998 perturbed the water column, and the formation of the anoxic layer was postponed more than one month, resulting in a lower level of hypolimnetic ammonia accumulation in 1998. A thick mineral deposit apparently formed during the local heavy rainfall and seemed to enclose the freshly deposited organic matter, which might be an effective source material of the hypolimnetic ammonia, and resulted in a low level of ammonia accumulation in 1999. By 2000, the lake seems to have recovered from the perturbation, suggesting that the major part of the hypolimnetic ammonia is derived from fresh organic matter deposited within a year. Received: March 11, 2001 / Accepted: August 26, 2001