Aminoadipate reductase gene: a new fungal-specific gene for comparative evolutionary analyses

BACKGROUND: In fungi, aminoadipate reductase converts 2-aminoadipate to 2-aminoadipate 6-semialdehyde. However, other organisms have no homologue to the aminoadipate reductase gene and this pathway appears to be restricted to fungi. In this study, we designed degenerate primers for polymerase chain reaction (PCR) amplification of a large fragment of the aminoadipate reductase gene for divergent fungi. RESULTS: Using these primers, we amplified DNA fragments from the archiascomycetous yeast Saitoella complicata and the black-koji mold Aspergillus awamori. Based on an alignment of the deduced amino acid sequences, we constructed phylogenetic trees. These trees are consistent with current ascomycete systematics and demonstrate the potential utility of the aminoadipete reductase gene for phylogenetic analyses of fungi. CONCLUSIONS: We believe that the comparison of aminoadipate reductase among species will be useful for molecular ecological and evolutionary studies of fungi, because this enzyme-encoding gene is a fungal-specific gene and generally appears to be single copy

Molecular evolution of adenylating domain of aminoadipate reductase

BACKGROUND: Aminoadipate reductase (Lys2) is a fungal-specific protein. This enzyme contains an adenylating domain. A similar primary structure can be found in some bacterial antibiotic/peptide synthetases. In this study, we aimed to determine which bacterial adenylating domain is most closely related to Lys2. In addition, we analyzed the substitution rate of the adenylating domain-encoding region. RESULTS: Some bacterial proteins contain more than two similar sequences to that of the adenylating domain of Lys2. We compared 67 amino acid sequences from 37 bacterial and 10 fungal proteins. Phylogenetic trees revealed that the lys2 genes are monophyletic; on the other hand, bacterial antibiotic/peptide synthase genes were not found to be monophyletic. Comparative phylogenetic studies among closely related fungal lys2 genes showed that the rate of insertion/deletion in these genes was lower and the nucleotide substitution rate was higher than that in the internal transcribed spacer (ITS) regions. CONCLUSIONS: The lys2 gene is one of the most useful tools for revealing the phylogenetic relationships among fungi, due to its low insertion/deletion rate and its high substitution rate. Lys2 is most closely related to certain bacterial antibiotic/peptide synthetases, but a common ancestor of Lys2 and these synthetases evolutionarily branched off in the distant past

ソンガイ バイショウガク ノ サンテイ ニオケル トウジョウシャ ショウガイ ホケンキン ノ コウジョ ノ カヒ

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シンライ ノ ゲンソク ノ ミンジジョウ ノ テキヨウ ニカンスル イチコウサツ

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シンガポール ノ カンキョウホウ ノ コウリョク ジッコウセイ タンポ ノ シサク オ ショウテン トシテ

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ユウシシャ セキニン ニカンスル イチシロン

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Twenty barrel in situ pipe gun type solid hydrogen pellet injector for the Large Helical Device

A 20 barrel solid hydrogen pellet injector, which is able to inject 20 cylindrical pellets with a diameter and length of between 3.0 and 3.8 mm at the velocity of 1200 m/s, has been developed for the purpose of direct core fueling in LHD (Large Helical Device). The in situ pipe gun concept with the use of compact cryo-coolers enables stable operation as a fundamental facility in plasma experiments. The combination of the two types of pellet injection timing control modes, i.e., pre-programing mode and real-time control mode, allows the build-up and sustainment of high density plasma around the density limit. The pellet injector has demonstrated stable operation characteristics during the past three years of LHD experiments

Tim23–Tim50 pair coordinates functions of translocators and motor proteins in mitochondrial protein import

Mitochondrial protein traffic requires coordinated operation of protein translocator complexes in the mitochondrial membrane. The TIM23 complex translocates and inserts proteins into the mitochondrial inner membrane. Here we analyze the intermembrane space (IMS) domains of Tim23 and Tim50, which are essential subunits of the TIM23 complex, in these functions. We find that interactions of Tim23 and Tim50 in the IMS facilitate transfer of precursor proteins from the TOM40 complex, a general protein translocator in the outer membrane, to the TIM23 complex. Tim23–Tim50 interactions also facilitate a late step of protein translocation across the inner membrane by promoting motor functions of mitochondrial Hsp70 in the matrix. Therefore, the Tim23–Tim50 pair coordinates the actions of the TOM40 and TIM23 complexes together with motor proteins for mitochondrial protein import

FoxO1 Gain of Function in the Pancreas Causes Glucose Intolerance, Polycystic Pancreas, and Islet Hypervascularization

Genetic studies revealed that the ablation of insulin/IGF-1 signaling in the pancreas causes diabetes. FoxO1 is a downstream transcription factor of insulin/IGF-1 signaling. We previously reported that FoxO1 haploinsufficiency restored β cell mass and rescued diabetes in IRS2 knockout mice. However, it is still unclear whether FoxO1 dysregulation in the pancreas could be the cause of diabetes. To test this hypothesis, we generated transgenic mice overexpressing constitutively active FoxO1 specifically in the pancreas (TG). TG mice had impaired glucose tolerance and some of them indeed developed diabetes due to the reduction of β cell mass, which is associated with decreased Pdx1 and MafA in β cells. We also observed increased proliferation of pancreatic duct epithelial cells in TG mice and some mice developed a polycystic pancreas as they aged. Furthermore, TG mice exhibited islet hypervascularities due to increased VEGF-A expression in β cells. We found FoxO1 binds to the VEGF-A promoter and regulates VEGF-A transcription in β cells. We propose that dysregulation of FoxO1 activity in the pancreas could account for the development of diabetes and pancreatic cysts

Protein kinase C (Pkc)-δ mediates arginine-induced glucagon secretion in pancreatic α-cells

The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine-threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Th