Identification of Ornithine-lactam Converted from Arginine in Streptomyces incarnatus NRRL8089

Sinefungin is a nucleoside antibiotic, in which a molecule of L-ornithine is linked to the 5' end of adenosine through a C-C bond. The antibiotic was isolated from the culture broth of Streptomyces incarnatus. For the purpose of detecting intermediate of sinefungin biosynthesis, resting cell suspensions were incubated with supplemental L-arginine, and L-ornithine. 50mM Arginine was converted to a compound X that has low polarity. 50mM ornithine was not converted and remained in reaction solution. Compound X was purified using HPLC, and analyzed using (1)H-NMR and FAB-MS. These analyses showed that a compound X is "ornithine-lactam" (Mw＝114), which has a structure of circularized ornithine. These results indicated that S. incarnatus has an enzyme that converts arginine to ornithine-lactam. Such an enzyme has never been reported, and suggested that it may be relevant to sinefungin biosynthesis.シネフンギンは抗真菌，抗マラリア活性を有する核酸系抗生物質であり，放線菌 S. incarnatus により生合成される．シネフンギンはアデノシンとオルニチンがＣﾝＣ結合した構造であり，無細胞抽出液での取り込み実験からＬﾝアルギニンと ATP から生合成されると推測される．Ｌﾝアルギニン，Ｌﾝオルニチンを S. incarnatus の休止菌体反応系への投与を行いシネフンギン中間体の探索を行った．その結果50ﾋアルギニンは24時間以内に低極性化合物へと変換された．一方50ﾋオルニチンは変換されず反応液中に残存した．HPLC で化合物を精製し，1HﾝNMR，FABﾝMS での分析の結果オルニチン環状モノペプチド，「オルニチンラクタム」（分子量114）であることを明らかにした．この結果は S. incarnatus がアルギニンからオルニチンラクタムへの変換酵素を有する事を示唆する．このような酵素の報告例はこれまでになく，ニ次代謝酵素であることが示唆され，シネフンギン生合成との関連性に興味が持たれる

Phosphoinositide-dependent regulation of VAN3 ARF-GAP localization and activity essential for vascular tissue continuity in plants

ACAP-type ARF GTPase activating proteins (ARF-GAPs) regulate multiple cellular processes, including endocytosis, secretion, phagocytosis, cell adhesion and cell migration. However, the regulation of ACAP functions by other cellular proteins is poorly understood. We have reported previously that a plant ACAP, VAN3, plays a pivotal role in plant venation continuity. Here, we report on newly identified VAN3 regulators: the CVP2 (cotyledon vascular pattern 2) 5 PTase, which is considered to degrade IP3 and also to produce PtdIns(4) P from PtdIns(4,5) P-2; and a PH domain-containing protein, VAB (VAN3 binding protein). Combinational mutations of both CVP2 and its closest homologue CVL1 (CVP2 like 1) phenocopied the strong allele of van3 mutants, showing severe vascular continuity. The phenotype of double mutants between van3, cvp2 and vab suggested that VAN3, CVP2 and VAB function in vascular pattern formation in the same pathway. Localization analysis revealed that both CVP2 and VAB colocalize with VAN3 in the trans-Golgi network (TGN), supporting their functions in the same pathway. The subcellular localization of VAN3 was dependent on its PH domain, and mislocalization of VAN3 was induced in cvp2 or vab mutants. These results suggest that CVP2 and VAB cooperatively regulate the subcellular localization of VAN3 through the interaction between its PH domain and phosphoinositides and/or inositol phosphates. In addition, PtdIns(4) P, to which VAN3 binds preferentially, enhanced the ARF-GAP activity of VAN3, whereas IP3 inhibited it. These results suggest the existence of PtdIns(4) P and/or IP3-dependent subcellular targeting and regulation of VAN3 ACAP activity that governs plant vascular tissue continuity

Changes in sagittal spinal alignment and comparison of deep trunk muscles contraction rate in low back pain of male high school soccer players

In spinal alignment, the posture cannot be maintained only by the bones and ligaments, and trunk rigidity is maintained by the presence of the surrounding trunk muscles. However, there are no reports of spinal alignment and trunk muscles in male high school soccer players. Purpose：In this study, we focused on spinal alignment and deep trunk muscles, to clarify the mechanism of low back pain （LBP） in male high school soccer players. Methods : The participants were 90 male high school soccer players. The presence of LBP was evaluated using a questionnaire. We assigned the participants into two groups : the non-LBP group （n = 58） and the LBP group （n = 32）.Results：Comparing the upright position with spinal alignment, a correlation was found between thoracic kyphotic angle （TKA） and lumbar lordosis angle （LLA） and between LLA and sacral inclination angle （SIA） in the non-LBP group. Conversely, in the LBP group, a correlation was found only between LLA and SIA, and no correlation was found between TKA and LLA. With regard to spinal alignment using the amount of change in the forward and backward bending positions, a correlation was found between LLA and SIA in the non-LBP group. By contrast, in the LBP group, a correlation was found between TKA and LLA, but no correlation was found between LLA and SIA. In addition, compared with the deep trunk muscles, the lumbar multifidus （LM） muscle contraction rate was lower in the LBP group than in the non-LBP group. Conclusion：This study suggests that changes in spinal alignment and decreased LM contraction rate may be involved in LBP in male high school soccer players