Large-Scale Gene Disruption in Magnaporthe oryzae Identifies MC69, a Secreted Protein Required for Infection by Monocot and Dicot Fungal Pathogens

To search for virulence effector genes of the rice blast fungus, Magnaporthe oryzae, we carried out a large-scale targeted disruption of genes for 78 putative secreted proteins that are expressed during the early stages of infection of M. oryzae. Disruption of the majority of genes did not affect growth, conidiation, or pathogenicity of M. oryzae. One exception was the gene MC69. The mc69 mutant showed a severe reduction in blast symptoms on rice and barley, indicating the importance of MC69 for pathogenicity of M. oryzae. The mc69 mutant did not exhibit changes in saprophytic growth and conidiation. Microscopic analysis of infection behavior in the mc69 mutant revealed that MC69 is dispensable for appressorium formation. However, mc69 mutant failed to develop invasive hyphae after appressorium formation in rice leaf sheath, indicating a critical role of MC69 in interaction with host plants. MC69 encodes a hypothetical 54 amino acids protein with a signal peptide. Live-cell imaging suggested that fluorescently labeled MC69 was not translocated into rice cytoplasm. Site-directed mutagenesis of two conserved cysteine residues (Cys36 and Cys46) in the mature MC69 impaired function of MC69 without affecting its secretion, suggesting the importance of the disulfide bond in MC69 pathogenicity function. Furthermore, deletion of the MC69 orthologous gene reduced pathogenicity of the cucumber anthracnose fungus Colletotrichum orbiculare on both cucumber and Nicotiana benthamiana leaves. We conclude that MC69 is a secreted pathogenicity protein commonly required for infection of two different plant pathogenic fungi, M. oryzae and C. orbiculare pathogenic on monocot and dicot plants, respectively

ユタンポ ノ ヒョウメン オンド ノ ケイジテキ ヘンカ カラ ミタ アンゼンセイ ノ ケントウ ユタンポ ノ シュルイ ト ユオン ノ チガイ カラ

臨床や家庭で多く使用されている3種類の湯たんぽ(ゴム製、プラスチック製、金属製湯たんぽ)について、湯温の違いによる湯たんぽの表面温度の経時的変化から安全性の検討を行った。その結果、ゴム製湯たんぽは、ネルカバーを掛けた場合には湯温50℃で、パスタオルで3層に巻いた場合には湯温55℃で安全性が確認された。蓋付きのプラスチック製湯たんぽは、湯温60℃で安全であると思われたが、80℃の湯温では低温熱傷を起こす可能性が示唆された。市販のネルカバーで覆った金属製湯たんぽは容量が2000cc、湯温60℃の場合でも低温熱傷を生じる危険性が高く、3種類の湯たんぽのなかで使用に際しては最も注意が必要である。This experimental study was performed to examine the safety of three types of hot-water bottles commonly used in hospitals and at home: rubber, plastic, and metal hot-water bottles in relation to temperature changes of the water. As a result of this study, the rubber hot-water bottle was confirmed to be safe when covered with flannel and the temperature of hot water was 50℃, or when it was wrapped in three bath towels, one over the other, with the temperature of hot water at 55℃. The capped plastic hot-water bottle was considered to be safe at 60℃, but there was apossibility that a moderate temperature burn might be caused at 80℃. The commercial, flannel covered, metal hot-water bottle with a capacity of 2,OOOcc was at great risk of a moderate temperature burn even at 60oC. It was found that the metal hot-water bottle was the most dangerous of the three types of hot-water bottles

Intracellular nucleotide-mediated gating of SUR/Kir6.0 complex potassium channels expressed in a mammalian cell line and its modification by pinacidil

We have examined the properties of intracellular nucleotide-mediated gating of K+ channel constructs composed of the sulphonylurea receptor 2B and the inwardly rectifying K+ channel subunits Kir6.1 and Kir6.2 (SUR2B/Kir6.1 and SUR2B/Kir6.2 complex K+ channels) heterologously expressed in human embryonic kidney (HEK) 293T cells. In the cell-attached form, both types of K+ channel were activated by pinacidil.In inside-out (IO) patches, the SUR2B/Kir6.2 channels opened spontaneously and were inhibited by intracellular ATP (ATPi). Pinacidil attenuated the ATPi-mediated channel inhibition in a concentration-dependent manner. In contrast, the SUR2B/Kir6.1 channels required intracellular nucleoside di- or tri-, but not mono-, phosphates for opening. The potency of adenine, guanine or uracil nucleotides to activate SUR2B/Kir6.1 channels was enhanced by pinacidil.In the presence of pinacidil, adenine and guanine, but not uracil, nucleotides exhibited bell-shaped concentration-dependent activating effects on SUR2B/Kir6.1 channels. This was due to channel inhibition caused by adenine and guanine nucleotides, which was unaffected by pinacidil.From power density spectrum analysis of SUR2B/Kir6.1 currents, channel activation could be described by the product of two gates, a nucleotide-independent fast channel gate and a nucleotide-dependent slow gate, which controlled the number of functional channels. Pinacidil specifically increased the potency of nucleotide action on the slow gate.We conclude that Kir6.0 subunits play a crucial role in the nucleotide-mediated gating of SUR/Kir6.0 complex K+ channels and may determine the molecular mode of pinacidil action