Formation of Desthiobiotin from Oleic Acid by Brevibacterium sp.

Microbial formation of biotin-vitamers from oleic acid was investigated. Many strains of bacteria which were able to utilize oleic acid as a sole carbon source were isolated from soils and other natural materials. Among these bacteria, some strains formed a biotin-vitamer from oleic acid in the culture broth during the cultivation. The vitamer was purified from the culture broth of strain No. 23, and identified as desthiobiotin by chromatographical and biological methods.

From the results of investigation on the taxonomical characteristics, the bacterial strain No. 23 was assumed to be Brevibacterium sp.     

Biotin-vitamer Formation from Salicylic Acid by Pseudomonas sp.

Biotin-vitamer formation from salicylic acid was investigated. Strains of Pseudomonas sp., No. 102 and No. 362, isolated from soil samples utilized well salicylic acid as a sole source of carbon, and formed biotin-vitamers in culture broth. The metabolites were partially purified by the methods of active carbon adsorption and anion-exchange column chromatography, and clarified as desthiobiotin, bisnordesthiobiotin and 7-keto-8-aminopelargonic acid.     

Functional characterisation of OsCPK21, a calcium-dependent protein kinase that confers salt tolerance in rice

Calcium acts as a messenger in various signal transduction pathways in plants. Calcium-dependent protein kinases (CDPKs) play important roles in regulating downstream components in calcium signaling pathways. In rice, the CDPKs constitute a large multigene family consisting of 29 genes, but the biological functions and functional divergence or redundancy of most of these genes remain unclear. Using a mini-scale full-length cDNA overexpressor (FOX) gene hunting system, we generated 250 independent transgenic rice plants overexpressing individual rice CDPKs (CDPK FOX-rice lines). These CDPK FOX-rice lines were screened for salt stress tolerance. The survival rate of the OsCPK21-FOX plants was higher than that of wild-type (WT) plants grown under high salinity conditions. The inhibition of seedling growth by abscisic acid (ABA) treatment was greater in the OsCPK21-FOX plants than in WT plants. Several ABA- and high salinity-inducible genes were more highly expressed in the OsCPK21-FOX plants than in WT plants. These results suggest that OsCPK21 is involved in the positive regulation of the signaling pathways that are involved in the response to ABA and salt stress.     

Microtubule stabilization triggers the plus-end accumulation of Kif18A/kinesin-8

The precise control of spindle microtubule (MT) dynamics is essential for chromosome capture and alignment. Kif18A/kinesin-8, an essential regulator of kinetochore MT dynamics, accumulates at its plus-ends in metaphase but not prometaphase cells. The underlying mechanism of time-dependent and kinetochore MT-specific plus-end accumulation of Kif18A is unknown. Here, we examined the factors required for the MT plus-end accumulation of Kif18A. In Eg5 inhibitor-treated cells, Kif18A localized along the MTs in the monopolar spindle and rarely accumulated at their plus-ends, indicating that MT-kinetochore association was not sufficient to induce Kif18A accumulation. In contrast, taxol treatment triggered the rapid MT plus-end accumulation of Kif18A regardless of kinetochore association. Furthermore, Aurora B inhibitor-induced stabilization of the plus-ends of kinetochore MTs promoted the plus-end accumulation of Kif18A. In the absence of Kif18A, treatment with taxol but not Eg5 inhibitor causes highly elongated mitotic MTs, suggesting the importance of plus-end accumulation for the MT length-controlling activity of Kif18A. Taken together, we propose that there is a mutual regulation of kinetochore MT plus-end dynamics and Kif18A accumulation, which may contribute to the highly regulated and ordered changes in kinetochore MT dynamics during chromosome congression and oscillation.     

The novel cargo Alcadein induces vesicle association of kinesin-1 motor components and activates axonal transport

Alcadeinalpha (Alcalpha) is an evolutionarily conserved type I membrane protein expressed in neurons. We show here that Alcalpha strongly associates with kinesin light chain (K(D) approximately 4-8x10(-9) M) through a novel tryptophan- and aspartic acid-containing sequence. Alcalpha can induce kinesin-1 association with vesicles and functions as a novel cargo in axonal anterograde transport. JNK-interacting protein 1 (JIP1), an adaptor protein for kinesin-1, perturbs the transport of Alcalpha, and the kinesin-1 motor complex dissociates from Alcalpha-containing vesicles in a JIP1 concentration-dependent manner. Alcalpha-containing vesicles were transported with a velocity different from that of amyloid beta-protein precursor (APP)-containing vesicles, which are transported by the same kinesin-1 motor. Alcalpha- and APP-containing vesicles comprised mostly separate populations in axons in vivo. Interactions of Alcalpha with kinesin-1 blocked transport of APP-containing vesicles and increased beta-amyloid generation. Inappropriate interactions of Alc- and APP-containing vesicles with kinesin-1 may promote aberrant APP metabolism in Alzheimer's disease.     

CDPK-mediated abiotic stress signaling

Calcium-dependent protein kinases (CDPKs) constitute a large multigene family in various plant species. CDPKs have been shown to have important roles in various physiological processes, including plant growth and development and abiotic and biotic stress responses in plants. Functional analysis using gain-of-function and loss-of-function mutants has revealed the biological function of CDPKs in planta. Several CDPKs have been shown to be essential factors in abiotic stress tolerance, positively or negatively regulating stress tolerance by modulating ABA signaling and reducing the accumulation of reactive oxygen species (ROS). This review summarizes recent results describing the biological function of CDPKs that are involved in abiotic stress tolerance.     

Transgenic rice with low sucrose-phosphate synthase activities retain more soluble protein and chlorophyll during flag leaf senescence

We investigated whether changes in sucrose-phosphate synthase (EC 2.4.1.14, SPS) activity could alter N remobilization during leaf senescence. Transgenic rice (Oryza sativa L. cv. Nipponbare) with low SPS activities and wild-type rice plants were grown with basal N (1.0 mM NH₄NO₃) until the late vegetative stage. Subsequently, half of the plants were transferred to a low N (0.1 mM NH₄NO₃) condition to accelerate leaf senescence, and the others were continuously grown with basal N. With low N supply, the amounts of chlorophyll and soluble protein in flag leaf blades decreased after anthesis in both the low SPS plants and wild-type plants, although the decrease was less in the low SPS plants. Panicle weights were significantly lower in the low SPS plant than in the wild-type plant. These results suggest that the remobilization of N from flag leaves was diminished by suppressing the development of reproductive sinks in the low SPS plant.     

IL-6 activity in feline infectious peritonitis

Involvement of IL-6 in the development of vasculitis and polyclonal gammopathy in feline infectious peritonitis (FIP) was investigated, by using the proliferative responses of two IL-6-dependent murine hybridoma cell clones, B3B1 and MH60.BSF-2 cells. A significant IL-6 activity was found in sera and ascitic fluids of cats with FIP, whereas no IL-6 activity was detected in sera from healthy cats. In these FIP cats, IL-6 activity in ascitic fluids was significantly higher than that in sera. Peritoneal exudate cells from FIP cats were also found to release a high level of IL-6 to the culture supernatant. The ascitic IL-6 activity was eluted into the fractions corresponding to the m.w. of 30,000 to 40,000 in gel filtration, and into the fractions at the salt concentration from 0.2 to 0.3 M NaCl in anion exchange chromatography. The level of ascitic IL-6 activity was inversely correlated to serum albumin/globulin ratio in these FIP cats. These findings indicate that IL-6 accumulated in the ascites might leaked into the systemic circulation, and be linked to systemic alterations such as enhanced synthesis of Ig and acute phase proteins.