Close Relationships Between the PSII Repair Cycle and Thylakoid Membrane Dynamics

In chloroplasts, a three-dimensional network of thylakoid membranes is formed by stacked grana and interconnecting stroma thylakoids. The grana are crowded with photosynthetic proteins, where PSII-light harvesting complex II (LHCII) supercomplexes often show semi-crystalline arrays for efficient energy trapping, transfer and use. Although light is essential for photosynthesis, PSII is damaged by reactive oxygen species that are generated from primary photochemical reactions when plants are exposed to excess light. Because PSII complexes are embedded in the lipid bilayers of thylakoid membranes, their functions are affected by the conditions of the lipids. Electron paramagnetic resonance (EPR) spin trapping measurements showed that singlet oxygen was formed through peroxidation of thylakoid lipids, suggesting that lipid peroxidation can damage proteins, including the D1 protein. After photodamage, PSII is restored by a specific repair system in thylakoid membranes. In the PSII repair cycle, phosphorylation and dephosphorylation of the PSII proteins control the timing of PSII disassembly and subsequent degradation of the D1 protein. Under light stress, stacked grana turn into unstacked thylakoids with bent grana margins. These structural changes may be closely linked to the mechanisms of the PSII repair cycle because PSII can move more easily from the grana core to the stroma thylakoids through an expanded stromal gap between each thylakoid. Thus, plants modulate the structure of thylakoid membranes under high light to carry out efficient PSII repair. This review focuses on the behavior of the PSII complex and the active role of structural changes to thylakoid membranes under light stress

Quality control of photosystem II: The molecular basis for the action of FtsH protease and the dynamics of the thylakoid membranes

Abstract The reaction center-binding D1 protein of Photosystem II is damaged by excessive light, which leads to photoinhibition of Photosystem II. The damaged D1 protein is removed immediately by specific proteases, and a metalloprotease FtsH located in the thylakoid membranes is involved in the proteolytic process. According to recent studies on the distribution and organization of the protein complexes/supercomplexes in the thylakoid membranes, the grana of higher plant chloroplasts are crowded with Photosystem II complexes and light-harvesting complexes. For the repair of the photodamaged D1 protein, the majority of the active hexameric FtsH proteases should be localized in close proximity to the Photosystem II complexes. The unstacking of the grana may increase the area of the grana margin and facilitate easier access of the FtsH proteases to the damaged D1 protein. These results suggest that the structural changes of the thylakoid membranes by light stress increase the mobility of the membrane proteins and support the quality control of Photosystem II. (159 words

Flying-seed-like liquid crystals. Part 4:dagger a novel series of bulky substituents inducing mesomorphism instead of using long alkyl chains

We synthesized a novel series of flying-seed-like derivatives (3a-g) based on phthalocyaninato copper(II) (abbreviated as PcCu) substituted by bulky groups {PhO (a), (o-C-1)PhO (b), (m-C-1)PhO (c), (p-C-1)PhO (d), [m, p-(C-1)(2)]PhO (e), [m, m'-(C-1)(2)]PhO (f), and [m,p,m'-(C-1)(3)]PhO (g)} instead of using long alkyl chains, in order to investigate their mesomorphism. Their phase transition behaviour and the mesophase structures were established using a polarizing optical microscope, a differential scanning calorimeter, a thermogravimetry analyser and a temperature-dependent small angle X-ray diffractometer. It was demonstrated that (PhO)(8)PcCu (3a) and [(p-C-1)PhO](8)PcCu (3d) show no mesophase, whereas [(m-C-1)PhO](8)PcCu (3c), {[m,p-(C-1)(2)]PhO}(8)PcCu (3e), {[m,m'-(C-1)(2)]PhO}(8)PcCu (3f), and {[m, p, m'-(C-1)(3)] PhO}(8)PcCu (3g) show various kinds of columnar mesophases of Col(ro)(P2(1)/a), Col(ro)(P2(1)/a), Col(ro)(C2/m) and Col(tet.o), respectively, while [(o-C-1)PhO](8)PcCu (3b) shows a monotropic Col(ro)(P2m) mesophase. Thus, we revealed that mesomorphism could be induced by these novel bulky substituents instead of using long alkyl chains, and that the mesophase structures were greatly affected by the number and position of the methoxy groups. In particular, it is very interesting that the derivatives with methoxy group(s) at the meta position(s), namely, 3c, 3e, 3f and 3g, tend to show enantiotropic mesophase(s), whereas neither the derivative with no methoxy group, 3a, nor the derivative with a methoxy group at the para position, 3d, show a mesophase.ArticleRSC ADVANCES. 5(18):13828-13839 (2015)journal articl

Flying-seed-like liquid crystals 3: new guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains

In our previous work, we synthesized a series of phthalocyanine-based flying-seed-like compounds, (nPh-PhO)(4)PcCu (n = 3, 2, 1 and 0 in nPh-PhO: a-d), and revealed that each of them shows a columnar liquid crystalline phase (Col(ho) or Col(rho)) from rt to an extremely high temperature near 500 degrees C. Thus, we could obtain columnar liquid crystalline phases for discotic compounds by using bulky substituents (a-d) instead of long alkyl chains. In order to further study the utility of these bulky substituents (a-d) on the induction of mesomorphism for other shaped molecules, we have synthesized novel flying-seed-like calamitic phenoxybenzoic acid derivatives, nPh-PhOBA (3a-d), and their Mitsubishi-Mark-shaped terbium complexes, (nPh-PhOBA)(3)Tb center dot mMeOH (4a-d), in this work. Very interestingly, the mesomorphism of the phenoxybenzoic aids derivatives nPh-PhOBA (n = 0-3) was induced to show a mesophase (M-x) only by the bulky substituent d (n = 0), whereas the mesomorphism of their corresponding terbium complexes (nPh-PhOBA)(3)Tb(III) (n = 0-3) was induced to show rectangular columnar (Col(r)) mesophases by the bulky substituents c and d (n = 1, 0). On the other hand, the mesomorphism of the PcCu complexes (nPh-PhOBA)(4)PcCu (n = 0-3) in our previous work was induced by all the bulky substituents a, b, c and d (n = 0-3). Thus, it becomes apparent that both calamitic and columnar mesomorphism can be induced by the substitution of bulky groups instead of long alkyl chains, and that the balance of the core size and the bulkiness of the substituents is very important to obtain mesomorphism in flying-seed-like compounds. We believe that this is a new guideline for the induction of mesomorphism by using bulky groups instead of long alkyl chains.ArticleJOURNAL OF MATERIALS CHEMISTRY C. 1(34):5315-5321 (2013)journal articl

Discotic liquid crystals of transition metal complexes 51(dagger): Synthesis and mesomorphism of flat-pumpkin-shaped phthalocyanine-fullerene dyads

We have synthesized a novel type of donor-acceptor liquid crystalline material, phthalocyanine-fullerene (Pc-C-60) dyad, [m,p,m'-(C14O)(3)PhO](6)PcCu-C-60 (7), and the Pc precursors, [m,p,m'-(C14O)(3)PhO](6)PcCu-OFBA (6) and [m,p,m'-(C14O)(3)PhO](6)PcCu-OH (5), and established their mesomorphism by using a polarizing optical microscope, a differential scanning calorimeter and a small angle X-ray diffractometer. Very interestingly, their corresponding previous parent Pc derivative, [m,p,m'-(C14O)(3)PhO](8)PcCu (4), shows a very wide temperature region ca. 90 degrees C of a bicontinuous Cub(Pn3m) mesophase, whereas the present children Pc precursors (5 and 6) and Pc-C-60 dyad 7 show not the Cub mesophase but a Col(ho) mesophase. It is also noteworthy that the staking distance in the Col(ho) mesophase of the Pc-C-60 dyad 7 was a very big value of ca. 9.1 angstrom, which is the biggest in discotic liquid crystals to our best knowledge. It may be originated from the biggest excluded volume caused by thermal fluctuation of peripheral long alkoxy chains at m, m'-positions. The excluded volume caused by thermal fluctuation of the peripheral long chains is so big that the molecular shape of the Pc derivative 4 and the Pc-C-60 dyad 7 very resembles a flat pumpkin.ArticleJOURNAL OF PORPHYRINS AND PHTHALOCYANINES. 18(10-11):856-868 (2014)journal articl

Quality control of Photosystem II: The molecular basis for the action of FtsH protease and the dynamics of the thylakoid membranes

The reaction center-binding D1 protein of Photosystem II is damaged by excessive light, which leads to photoinhibition of Photosystem II. The damaged D1 protein is removed immediately by specific proteases, and a metalloprotease FtsH located in the thylakoid membranes is involved in the proteolytic process. According to recent studies on the distribution and organization of the protein complexes/supercomplexes in the thylakoid membranes, the grana of higher plant chloroplasts are crowded with Photosystem II complexes and light-harvesting complexes. For the repair of the photodamaged D1 protein, the majority of the active hexameric FtsH proteases should be localized in close proximity to the Photosystem II complexes. The unstacking of the grana may increase the area of the grana margin and facilitate easier access of the FtsH proteases to the damaged D1 protein. These results suggest that the structural changes of the thylakoid membranes by light stress increase the mobility of the membrane proteins and support the quality control of Photosystem II

Multiplex Polymerase Chain Reaction Assay for Early Diagnosis of Viral Infection

Viral reactivation is one of the most serious complications for immunocompromised patients. Under immunosuppressive conditions, some viruses can be reactivated solely or simultaneously and may thus cause life-threatening infection. Therefore, the prompt and proper diagnosis of viral reactivation is important for the initiation of preemptive therapy. For this purpose, we recently developed a multiplex-virus polymerase chain reaction (PCR) assay. The multiplex PCR assay is designed to qualitatively measure the genomic DNA of 12 viruses at once: cytomegalovirus (CMV), human herpesvirus type 6 (HHV-6), HHV-7, HHV-8, Epstein-Barr virus (EBV), varicella-zoster virus (VZV), BK virus (BKV), JC virus (JCV), parvovirus B19 (ParvoB19), herpes simplex virus type 1 (HSV-1), HSV-2, and hepatitis B virus (HBV). When a specific PCR signal is obtained, the viral load is determined by a quantitative real-time PCR. The qualitative multiplex and quantitative real-time PCR procedures take only 3 hours to complete. With this assay system, we can identify viremia at the early stage and thereby prevent it from progressing to overt and symptomatic viral infection in immunocompromised patients, such as those receiving hematopoietic stem cell transplantation

Marbles from Tokushima Prefecture, used in the National Diet Building : Part 1: locality and geological framework

The quarries of marbles for the construction of the National Diet Building (Nagata-cho, Chiyodaku, Tokyo) were identified in Tokushima Prefecture. The geological setting and microfossil age of the marbles were studied. Seven brands, "Akebono", "Kito-ishi ", "Hototogisu", "Kamo-sarasa", "Awayuki ", "Kotajima" and "Shin-awayuki" were used in the House of Councilors and the Central part of the building. The "Akebono", used for the wall along the Councilor's Second Stairway, is Silurian limestone from the Hiakari-yama lenticular body of the Kurosegawa Tectonic Zone in the Koyama-daira area (Kisawa Village). The "Kito-ishi" from the Misago-yama area (Kisawa Village), used for the fireplace in the reception room of the Vice-president of the House of Councilors, is the limestone and greenstone breccia intercalated in the Upper Carboniferous alternation of chert and pelagic limestone in the Permian accretion terrene (Masaki Belt of the Kurosegawa Terrane). The "Hototogisu", used for the well-ornamented entrance gate of the Emperor's room "Gokyujo", is the Upper Triassic dolimitic limestone in the Late Jurassic-earliest Cretaceous accretion mélange of the South Chichibu Terrane (Tsunomine Subbelt) from the Arida area (Asebi-cho, Anan City). The "Kamo-sarasa", used for the inside wall of the central entrance of the building, is the Upper Triassic limestone with some green reticulation in Late Jurassic-earliest Cretaceous accretion mélange of the South Chichibu Terrane (Tsunomine Subbelt) from the Oji area (Kuwano-cho, Anan City). The "Awayuki", used for the lower part of the wall along the square in front of the Emperor's room, and the lower part of the wall around the assembly hall of the House of Councilors, presumed to be a kind of "Kamo-sarasa", is proved to be the Upper Triassic Megalodon limestone with hexacoral-bearing dark limestone blocks in the accretion mélange of the South Chichibu Terrane (Tsunomine Subbelt) from the Kurogo area (Kamo-cho, Anan City). The "Kotajima", used for the lower part of the wall along the passage of the second floor, and the wall along the "Kisha Kaidan" stairway, is proved to be the Upper Triassic limestone with reticulation of black cleavages in Late Jurassic-earliest Cretaceous accretion mélange of the South Chichibu Terrane (Tsunomine Subbelt) from the Higashibun area (Tsunomine-cho, Anan City). The "Shin-awayuki", used for the mosaic on the floor of the Central Hall and the lower part of the wall along the passage of the southern central part of the first floor, is the Upper Carboniferous limestone in Jurassic accretion mélange of the South Chichibu Belt (Hosono Subbelt) from the Izeki area (Takarada-cho, Anan City)

トクシマ ダイガク ビョウイン ニュウイン カンジャ ノ シカテキ ニーズ : コウクウ カンリ センター ニオケル ウケイレ ジョウキョウ カラ

Tokushima University Hospital Oral Health Management Center was created in April 2006 in order that medical inpatients could be easily referred to the dental section. From April 2007 to August 2009, among the 658 inpatients referred by the Oral Health Management Center, 210 requested professional oral healthcare. Requests for professional oral healthcare are currently increasing. Among 244 patients who asked for a bedside visit, 184 requested professional oral healthcare. Most inpatients were referred from the Division of Blood Internal Medicine; and the second Division referring numerous inpatients was that of Neurological Disorders. The increased tendency for professional oral healthcare requests might be related to the closer working relations among NST staff in the hospital, and/or better knowledge regarding the importance of oral health by medical doctors and nurses. The needs for dental services for inpatients varies. It is important for dental professionals to cooperate with medical care staff, and to be capable of dealing with various general conditions