Tyrokeradines A and B,new bromotyrosine alkaloids with an imidazolyl-quinolinone moiety from a Verongid sponge

Two new bromotyrosine alkaloids, tyrokeradines A (1) and B (2), with an imidazolyl-quinolinone moiety have been isolated from an Okinawan marine sponge of the order Verongida. The structures of 1 and 2 were elucidated on the basis of spectroscopic data.     

Applications of luciferin biosynthesis: Bioluminescence assays for l-cysteine and luciferase

Based on the biosynthetic pathway of firefly bioluminescence substrate d-luciferin, the concentration of l-cysteine can be quantified using a simple protocol and a conventional luminescence detector. The lower limit of quantification (signal/noise ratio [S/N] = 10) was 0.26 μM. Using our method, the total amount of free/reduced and disulfide/oxidized l-cysteine could be measured successfully in human serum. In addition, biosynthetic precursors such as 2-cyano-6-hydroxybenzothiazole and l-luciferin could replace d-luciferin in the cell-based luciferase assay. Our results suggest that the bioluminescence reaction associated with the biosynthesis of bioluminescence substrates can provide a fast and cost-effective assay method.     

Modelling population dynamics of the pelagic larval shrimp Metapenaeus ensis in the Osaka Bay estuary

Aiming at providing numerical tools useful to assess the impacts of coastal development pressures on marine life, a Lagrangian model for population dynamics of pelagic eggs and larvae of the greasyback shrimp, Metapenaeus ensis, in Osaka Bay was developed and improved based on laboratory experiments. The model was combined with a 3-D Eulerian numerical model that predicts physical and biological conditions of the habitat. A series of numerical experiments was done to investigate their transport processes from the spawning grounds, and the concentration process of full-grown larvae towards the mouth of Yodo River that flows into the innermost basin. Model results revealed, as a general tendency, that the early larval developmental stages through nauplius to zoea continue to drift like a passive tracer, and begin to concentrate at the river mouth area after the mysis stage, mainly avoiding low saline environment in the surface layer. This suggests that the full-grown larvae may be favored with chance to take advantage of the river-induced gravitational circulation that dominates the innermost estuarine basin. In addition, it was found that tidal condition around the spawning period also exerts a considerable influence upon the fate of pelagic larvae.     

Microglia and astroglia prevent oxidative stress-induced neuronal cell death: implications for aceruloplasminemia

We partially characterized the transferrin-independent iron uptake (Tf-IU) of neuronal and glial cells in the previous report. In the present study, we further examined a mechanism of which glial cells protect neuronal cells against iron stress using neuron-microglia (N-MG) and neuron-astrocyte (N-AS) co-cultures. When each solely purified cell was treated with iron citrate, cell death occurred in N and MG. However, AS proliferated under the same condition. Both N-MG and N-AS co-cultures were effective in resistance to excessive iron. The total and specific Tf-IU activities of N-MG co-cultures similar to those of N did not increase in a density-dependent manner. Contrarily, the total activity of AS was extremely high and the specific activity was extremely low as a result of proliferation. Regarding of effect of co-cultures on H(2)O(2)-induced cell death, N-MG co-cultures were less effective, but N-AS co-cultures were more effective in protecting N from the oxidative stress. These results suggest that N-MG co-cultures suppress the Tf-IU and N-AS co-cultures stimulate AS proliferation to protect neuronal cells. Brain cells from aceruloplasminemia with mutations in the ceruloplasmin gene take up iron by Tf-IU. Therefore, the different mechanisms of neuronal cell protection by MG and AS may explain the pathophysiological observations in the brains of patient with aceruloplasminemia.     

Ig L-chain shuffling for affinity maturation of phage library-derived human anti-human MCP-1 antibody blocking its chemotactic activity

Monocyte chemotactic protein-1 (MCP-1, CC-chemokine ligand 2; CCL2) is involved in the development of various forms of chronic inflammations. Employing the naive human single-chain Fv displaying phage library, we established seven MCP-1-specific scFvs. The MC8 and MC32 clones exhibited blocking activity for the MCP-1-induced chemotaxis of THP-1 cells, in spite of their monovalency. The analysis of V gene usage showed that all clones bore the identical Vh1 gene, IGHV1-24*01, with variable DJ joining sequences, while their Vl usage was relatively varied, suggesting the preferential contribution of the Vh gene. Based on these findings, to minimize the deteriorative influences on the MCP-1 specificity of MC32, we aimed to achieve the affinity maturation of MC32 using MC32 L-chain shuffling library and select MC32 variants. Most MC32 variants increased their affinity by reducing the k(off) value with no influence of the antigen specificity. MC32 variants #22 or #56 showed approximately 15-fold higher affinity than MC32, indicating that the L-chain shuffling library is useful if the Vh is dominantly involved in the determination of the antigen specificity.     

URB is abundantly expressed in adipose tissue and dysregulated in obesity

Dysregulated production of adipocytokines in obesity is involved in the development of metabolic syndrome. URB/DRO1 contains N-terminal signal sequence and is thought to play a role in apoptosis of tumor cells. In the present study, we investigated the expression pattern of URB mRNA in adipose tissue and secretion from cultured adipocytes. In human and mouse, URB mRNA was predominantly expressed in adipose tissue and was downregulated in obese mouse models, such as ob/ob, KKAy, and diet-induced obese mice. In 3T3L1 adipocytes, insulin, TNF-α, H₂O₂ and hypoxia decreased URB mRNA level. This regulation was similar to that for adiponectin and opposite to MCP-1. URB protein was secreted in media of URB cDNA-stably transfected cells and endogenous URB was detected in media of cultured human adipocytes. In conclusion, the expression pattern of URB suggests its role in obesity and the results suggest that URB is secreted, at least in part, from adipocytes.