Absence of the PsbQ protein results in destabilization of the PsbV protein and decreased oxygen evolution activity in cyanobacterial photosystem II

We have previously reported that cyanobacterial photosystem II (PS II) contains a protein homologous to PsbQ, the extrinsic 17-kDa protein found in higher plant and green algal PS II (Kashino, Y., Lauber, W. M., Carroll, J. A., Wang, Q., Whitmarsh, J., Satoh, K., and Pakrasi, H. B. (2002) Biochemistry 41, 8004-8012) and that it has regulatory role(s) on the water oxidation machinery (Thornton, L. E., Ohkawa, H., Roose, J. L., Kashino, Y., Keren, N., and Pakrasi, H. B. (2004) Plant Cell 16, 2164-2175). In this work, the localization and the function of PsbQ were assessed using the cyanobacterium Synechocystis sp. PCC 6803. From the predicted sequence, cyanobacterial PsbQ is expected to be a lipoprotein on the luminal side of the thylakoid membrane. Indeed, experiments in this work show that upon Triton X-114 fractionation of thylakoid membranes, PsbQ partitioned in the hydrophobic phase, and trypsin digestion revealed that PsbQ was highly exposed to the luminal space of thylakoid membranes. Detailed functional assays were conducted on the psbQ deletion mutant (ΔpsbQ) to analyze its water oxidation machinery. PS II complexes purified from ΔpsbQ mutant cells had impaired oxygen evolution activity and were remarkably sensitive to NH2OH, which indicates destabilization of the water oxidation machinery. Additionally, the cytochrome c550 (PsbV) protein partially dissociated from purified ΔpsbQ PS II complexes, suggesting that PsbQ contributes to the stability of PsbV in cyanobacterial PS II. Therefore, we conclude that the major function of PsbQ is to stabilize the PsbV protein, thereby contributing to the protection of the catalytic Mn 4-Ca1-Clx cluster of the water oxidation machinery. © 2006 by The American Society for Biochemistry and Molecular Biology, Inc

車椅子利用下における路面の影響調査

【目的】車椅子利用者の安楽に及ぼす影響の１つとして「声かけ」に注目して，バリアが車椅子利用者の体感にどのような影響を及ぼすのかを知ることとを目的とした研究を行った． 【方法】対象者は，２０歳代女性の看護学生で，車椅子利用時の体感に体重が影響することを考慮し標準体重に近い者を選定した．路面の状態については，観察，自走介助兼用車椅子に装着した振動計，座席用振動ピックアップを用い客観的測定を行った．声かけによる路面の状態による主観的反応の相違は，対象者６０人を無作為にA群の「声かけあり群（n＝３０）」と，B群の「声かけなし群（n＝３０）」の２群に分けて把握した． 【倫理的配慮】対象者に本研究の目的及び方法を説明し，同意書に署名してもらった． 【分析方法】アンケート調査結果について２群を比較した．ゆれ・恐怖感・乗り心地の段階評価においてはウィルコクソンの符号順位和検定を行った． 【結果および考察】路面の見かけと振動値は概ね一致していたが，見かけは平らであっても振動値は高い場所もあった．路面に対する反応は以下の通りである． １．振動が大きいところでは対象者の全身に振動を与え，不快をもたらしていた． ２．傾斜があるところでは対象者に恐怖感をもたらしていた． ３．声かけは対象者が振動を予測して，態勢を整えることに役立っていた． ４．声かけは安心感や気分転換等にもつながっていた． 以上のことから，車椅子利用者の介助に当たって声かけをすることは重要であることが明らかになった．また，多様な路面の性状下でも快適な車椅子利用ができるような介助の方法を探究していきたい．さらに，今回の結果は，車椅子以外にもシルバーカーや自走車椅子利用者の支援のあり方を示唆するものと考えられる．Aim : A research was conducted to investigate the influence by barriers of road surface on the bodily sensation of wheelchair users, while paying attention to “calling” as a factor influencing the comfort of the users. Method : The subjects were chosen from student nurses in their twenties. The objective measurement of the conditions of road surface was carried out through the use of observation, a vibrograph equipped on wheelchairs designed for both self-propelling and attendant-propelling, and a vibration pickup set on the seat of the wheelchairs. In order to grasp the differences emerged from calling in the subjective responses to road surface conditions, the 60 subjects were divided randomly into 2 groups of A and B, the former was “the group with calling（n=30）” whereas the latter was “the group without calling（n=30）”. Ethical consideration : The subjects were explained about the aim and method of the research, and requested to sign the agreement of participation. Analysis method : A comparison between the two groups on the results of the questionnaire was carried out. For the stage assessment of the vibration, fear and feeling of using a wheelchair, the Wilcoxon signedrank test was performed. Results and Discussion : There was a general concordance between the appearance of the road surface and the vibration level, but there were some spots where the vibrational levels were high although the surface appeared to be flat. The followings were the responses to the road surface. 1. Where the vibration levels were high, shakes were caused to the subjects’ bodies and made them feel uncomfortable. 2. Besides vibration, slopes on the road also caused the feeling of fear to the subjects. 3. Calling helped the subjects to predict a vibration and to be ready for it. 4. Calling related to the feeling of relief and mood changes, as well. From those findings, it has been clarified that calling is essential in assisting a wheelchair user. Also, it is a future theme to search for a way to assist in a comfortable use of wheelchairs under various conditions of the road surface

車椅子利用下における路面の影響調査

【目的】車椅子利用者の安楽に及ぼす影響の１つとして「声かけ」に注目して，バリアが車椅子利用者の体感にどのような影響を及ぼすのかを知ることとを目的とした研究を行った． 【方法】対象者は，２０歳代女性の看護学生で，車椅子利用時の体感に体重が影響することを考慮し標準体重に近い者を選定した．路面の状態については，観察，自走介助兼用車椅子に装着した振動計，座席用振動ピックアップを用い客観的測定を行った．声かけによる路面の状態による主観的反応の相違は，対象者６０人を無作為にA群の「声かけあり群（n＝３０）」と，B群の「声かけなし群（n＝３０）」の２群に分けて把握した． 【倫理的配慮】対象者に本研究の目的及び方法を説明し，同意書に署名してもらった． 【分析方法】アンケート調査結果について２群を比較した．ゆれ・恐怖感・乗り心地の段階評価においてはウィルコクソンの符号順位和検定を行った． 【結果および考察】路面の見かけと振動値は概ね一致していたが，見かけは平らであっても振動値は高い場所もあった．路面に対する反応は以下の通りである． １．振動が大きいところでは対象者の全身に振動を与え，不快をもたらしていた． ２．傾斜があるところでは対象者に恐怖感をもたらしていた． ３．声かけは対象者が振動を予測して，態勢を整えることに役立っていた． ４．声かけは安心感や気分転換等にもつながっていた． 以上のことから，車椅子利用者の介助に当たって声かけをすることは重要であることが明らかになった．また，多様な路面の性状下でも快適な車椅子利用ができるような介助の方法を探究していきたい．さらに，今回の結果は，車椅子以外にもシルバーカーや自走車椅子利用者の支援のあり方を示唆するものと考えられる．Aim : A research was conducted to investigate the influence by barriers of road surface on the bodily sensation of wheelchair users, while paying attention to “calling” as a factor influencing the comfort of the users. Method : The subjects were chosen from student nurses in their twenties. The objective measurement of the conditions of road surface was carried out through the use of observation, a vibrograph equipped on wheelchairs designed for both self-propelling and attendant-propelling, and a vibration pickup set on the seat of the wheelchairs. In order to grasp the differences emerged from calling in the subjective responses to road surface conditions, the 60 subjects were divided randomly into 2 groups of A and B, the former was “the group with calling（n=30）” whereas the latter was “the group without calling（n=30）”. Ethical consideration : The subjects were explained about the aim and method of the research, and requested to sign the agreement of participation. Analysis method : A comparison between the two groups on the results of the questionnaire was carried out. For the stage assessment of the vibration, fear and feeling of using a wheelchair, the Wilcoxon signedrank test was performed. Results and Discussion : There was a general concordance between the appearance of the road surface and the vibration level, but there were some spots where the vibrational levels were high although the surface appeared to be flat. The followings were the responses to the road surface. 1. Where the vibration levels were high, shakes were caused to the subjects’ bodies and made them feel uncomfortable. 2. Besides vibration, slopes on the road also caused the feeling of fear to the subjects. 3. Calling helped the subjects to predict a vibration and to be ready for it. 4. Calling related to the feeling of relief and mood changes, as well. From those findings, it has been clarified that calling is essential in assisting a wheelchair user. Also, it is a future theme to search for a way to assist in a comfortable use of wheelchairs under various conditions of the road surface

Ycf12 is a core subunit in the photosystem II complex

AbstractThe latest crystallographic model of the cyanobacterial photosystem II (PS II) core complex added one transmembrane low molecular weight (LMW) component to the previous model, suggesting the presence of an unknown transmembrane LMW component in PS II. We have investigated the polypeptide composition in highly purified intact PS II core complexes from Thermosynechococcus elongatus, the species which yielded the PS II crystallographic models described above, to identify the unknown component. Using an electrophoresis system specialized for separation of LMW hydrophobic proteins, a novel protein of ∼5 kDa was identified as a PS II component. Its N-terminal amino acid sequence was identical to that of Ycf12. The corresponding gene is known as one of the ycf (hypothetical chloroplast reading frame) genes, ycf12, and is widely conserved in chloroplast and cyanobacterial genomes. Nonetheless, the localization and function of the gene product have never been assigned. Our finding shows, for the first time, that ycf12 is actually expressed as a component of the PS II complex in the cell, revealing that a previously unidentified transmembrane protein exists in the PS II core complex

Significant association between high serum CCL5 levels and better disease‐free survival of patients with early breast cancer

Analysis of anticancer immunity aids in assessing the prognosis of patients with breast cancer. From 250 operated breast cancers, we focused on serum levels of C-C motif chemokine ligand 5 (CCL5), which is involved in cancer immune reactions. Serum levels of CCL5 were measured using a cytometric bead-based immunoassay kit and CCL5 expression in cancer cells was determined using immunohistochemical staining. In addition, mRNA in cancer and stromal cells was analyzed by microdissection and comparison with the public dataset. Disease-free survival (DFS) of patients with high CCL5 levels (cut-off, 13.87 ng/mL; n = 192) was significantly better than those with low CCL5 levels (n = 58; hazard ratio, 0.20; 95% confidence interval, 0.10- 0.39; P < .0001). An improved overall survival was observed in patients with high CCL5 levels compared to those with low CCL5 levels (P = .024). On the contrary, high immunohistochemical expression of CCL5 in cancer cells was significantly associated with decreased DFS. As serum CCL5 levels did not correlate with CCL5 expression in cancer cells and the relative expression of mRNA CCL5 was elevated in stromal cells in relation to cancer cells, serum CCL5 might be derived not from cancer cells, but from stromal cells. Expression of CCL5 in serum, but not in cancer cells, might contribute to improved patient prognosis mediating through not only immune reaction, but through other mechanisms. Determination of circulating CCL5 levels could be useful for predicting patient prognosis

MUTYH Gln324His gene polymorphism and genetic susceptibility for lung cancer in a Japanese population

<p>Abstract</p> <p>Background</p> <p>Genetic polymorphisms of DNA repair enzymes in the base excision repair (BER) pathway, may lead to genetic instability and lung cancer carcinogenesis. We investigated the interactions among the gene polymorphisms in DNA repair genes and lung cancer.</p> <p>Methods</p> <p>We analyzed associations among <it>OGG1 </it>Ser326Cys and <it>MUTYH </it>Gln324His gene polymorphisms in relation to lung cancer risk using PCR-RFLP. The study involved 108 lung cancer patients and 121 non-cancer controls divided into non-smokers, smokers according to pack-years smoked in Japanese.</p> <p>Results</p> <p>The results showed that the <it>MUTYH His/His </it>genotype compared with <it>Gln/Gln </it>genotype showed an increased risk for lung cancer (adjusted odds ratio [OR] 3.03, confidence interval [95%CI], 1.31–7.00, p = 0.010), whereas there was no significant increase for the <it>Gln/His </it>genotype (adjusted OR 1.35, 95%CI 0.70–2.61, p = 0.376). The <it>MUTYH His/His </it>genotype was at a borderline increased risk for both adenocarcinoma and squamous cell carcinoma (adjusted OR 2.50, 95%CI 0.95–6.62, p = 0.065 for adenocarcinoma; adjusted OR 3.20, 95%CI 0.89–11.49, p = 0.075 for squamous cell carcinoma, respectively). However, the <it>OGG1 Ser/Cys </it>or <it>Cys/Cys </it>genotypes compared with the <it>Ser/Ser </it>genotype did not have significantly increased risk for lung cancer, containing either adenocarcinoma or squamous cell carcinoma. The joint effect of tobacco exposure and the <it>MUTYH His/His </it>genotype compared with the <it>Gln/Gln </it>genotype showed a significant association with lung cancer risk in smokers, and there was not significantly increased in non-smokers (adjusted OR 3.82, 95%CI 1.22–12.00, p = 0.022 for smokers; adjusted OR 2.60, 95%CI 0.60–11.25, p = 0.200 for non-smokers, respectively). The effect of tobacco exposure and the <it>OGG1 </it>Ser326Cys showed also no significant risk for lung cancer.</p> <p>Conclusion</p> <p>Our findings suggest that the <it>MUTYH </it>Gln324His polymorphism appear to play an important role in modifying the risk for lung cancer in the Japanese population.</p

Structure of the far-red light utilizing photosystem I of Acaryochloris marina

赤外光駆動型光合成をクライオ電顕で捉えることに成功 --低いエネルギーで通常の光化学反応が駆動される仕組み--. 京都大学プレスリリース. 2021-04-21.Acaryochloris marina is one of the cyanobacterial species that can use far-red light to drive photochemical reactions for oxygenic photosynthesis. Here, we report the structure of A. marina photosystem I (PSI) reaction center, determined by cryo-electron microscopy at 2.58 Å resolution. The structure reveals an arrangement of electron carriers and light-harvesting pigments distinct from other type I reaction centers. The paired chlorophyll, or special pair (also referred to as P740 in this case), is a dimer of chlorophyll d and its epimer chlorophyll d′. The primary electron acceptor is pheophytin a, a metal-less chlorin. We show the architecture of this PSI reaction center is composed of 11 subunits and we identify key components that help explain how the low energy yield from far-red light is efficiently utilized for driving oxygenic photosynthesis

Repertoires of G protein-coupled receptors for Ciona-specific neuropeptides

Neuropeptides play pivotal roles in various biological events in the nervous, neuroendocrine, and endocrine systems, and are correlated with both physiological functions and unique behavioral traits of animals. Elucidation of functional interaction between neuropeptides and receptors is a crucial step for the verification of their biological roles and evolutionary processes. However, most receptors for novel peptides remain to be identified. Here, we show the identification of multiple G protein-coupled receptors (GPCRs) for species-specific neuropeptides of the vertebrate sister group, Ciona intestinalis Type A, by combining machine learning and experimental validation. We developed an original peptide descriptor-incorporated support vector machine and used it to predict 22 neuropeptide-GPCR pairs. Of note, signaling assays of the predicted pairs identified 1 homologous and 11 Ciona-specific neuropeptide-GPCR pairs for a 41% hit rate: the respective GPCRs for Ci-GALP, Ci-NTLP-2, Ci-LF-1, Ci-LF-2, Ci-LF-5, Ci-LF-6, Ci-LF-7, Ci-LF-8, Ci-YFV-1, and Ci-YFV-3. Interestingly, molecular phylogenetic tree analysis revealed that these receptors, excluding the Ci-GALP receptor, were evolutionarily unrelated to any other known peptide GPCRs, confirming that these GPCRs constitute unprecedented neuropeptide receptor clusters. Altogether, these results verified the neuropeptide-GPCR pairs in the protochordate and evolutionary lineages of neuropeptide GPCRs, and pave the way for investigating the endogenous roles of novel neuropeptides in the closest relatives of vertebrates and the evolutionary processes of neuropeptidergic systems throughout chordates. In addition, the present study also indicates the versatility of the machine-learning-assisted strategy for the identification of novel peptide-receptor pairs in various organisms

Association of MUTYH Gln324His and APEX1 Asp148Glu with colorectal cancer and smoking in a Japanese population

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