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

Photoreaction of N560 intermediate in the photocycle of bacteriorhodopsin

AbstractSophisticated measurements were made on the nanosecond time-resolved absorbance change of the purple membrane of Halobacterium halobium under cw background light irradiation (440–800 nm, 11–441 mW/cm2). A red-shifted transient species R660 (KN, Q) was found in alkaline conditions (pH > 9.3). Background light intensity effect shows that (i) R660 is photochemically formed from N560 intermediate which is accumulated under background light irradiation because of the elongated lifetime in alkaline suspension, and that (ii) the slow decaying M412 is not photochemically formed from N560 but from bR

Cellular mechanisms for cargo delivery and polarity maintenance at different polar domains in plant cells

The asymmetric localization of proteins in the plasma membrane domains of eukaryotic cells is a fundamental manifestation of cell polarity that is central to multicellular organization and developmental patterning. In plants, the mechanisms underlying the polar localization of cargo proteins are still largely unknown and appear to be fundamentally distinct from those operating in mammals. Here, we present a systematic, quantitative comparative analysis of the polar delivery and subcellular localization of proteins that characterize distinct polar plasma membrane domains in plant cells. The combination of microscopic analyses and computational modeling revealed a mechanistic framework common to diverse polar cargos and underlying the establishment and maintenance of apical, basal, and lateral polar domains in plant cells. This mechanism depends on the polar secretion, constitutive endocytic recycling, and restricted lateral diffusion of cargos within the plasma membrane. Moreover, our observations suggest that polar cargo distribution involves the individual protein potential to form clusters within the plasma membrane and interact with the extracellular matrix. Our observations provide insights into the shared cellular mechanisms of polar cargo delivery and polarity maintenance in plant cells

The PIN-FORMED (PIN) protein family of auxin transporters

The PIN-FORMED (PIN) proteins are secondary transporters acting in the efflux of the plant signal molecule auxin from cells. They are asymmetrically localized within cells and their polarity determines the directionality of intercellular auxin flow. PIN genes are found exclusively in the genomes of multicellular plants and play an important role in regulating asymmetric auxin distribution in multiple developmental processes, including embryogenesis, organogenesis, tissue differentiation and tropic responses. All PIN proteins have a similar structure with amino- and carboxy-terminal hydrophobic, membrane-spanning domains separated by a central hydrophilic domain. The structure of the hydrophobic domains is well conserved. The hydrophilic domain is more divergent and it determines eight groups within the protein family. The activity of PIN proteins is regulated at multiple levels, including transcription, protein stability, subcellular localization and transport activity. Different endogenous and environmental signals can modulate PIN activity and thus modulate auxin-distribution-dependent development. A large group of PIN proteins, including the most ancient members known from mosses, localize to the endoplasmic reticulum and they regulate the subcellular compartmentalization of auxin and thus auxin metabolism. Further work is needed to establish the physiological importance of this unexpected mode of auxin homeostasis regulation. Furthermore, the evolution of PIN-based transport, PIN protein structure and more detailed biochemical characterization of the transport function are important topics for further studies

Blood-pressure-lowering effect of fermented buckwheat sprouts in spontaneously hypertensive rats

A practical antihypertensive food, neo-fermented buckwheat sprouts (neo-FBS), was produced from buckwheat sprouts by lactic fermentation. The neo-FBS preparation gave a 12.7 times better yield and had a 10 times more potent blood-pressure-lowering (BPL) effect than conventionally prepared products. Neo-FBS decreased both systolic and diastolic blood pressure in spontaneously hypertensive rats (SHRs) at a dose of 0.010 mg/kg, an effect comparable to 1.0 mg/kg captopril, an anti-hypertensive drug. Orally administered neo-FBS (10 mg/kg) significantly decreased angiotensin I-converting enzyme (ACE) activity in the lung, thoracic aorta, heart, kidney, and liver of SHRs. Neo-FBS had a detectable relaxing effect on a phenylephrine-precontracted thoracic aorta in SHRs at 0.5 mu g/mL and the EC50 value was 8.3 +/- 1.4 mu g/mL. The ACE inhibition and vasorelaxation activities were found to be responsible for the excellent BPL effect of neo-FBS. As SHR is a standard model for human hypertension, neo-FBS may also have BPL effects in human patients.ArticleJOURNAL OF FUNCTIONAL FOODS. 5(1):406-415 (2013)journal articl

Ultrastructure of glomerular basement membrane by quick-freeze and deep-etch methods

Ultrastructure of glomerular basement membrane by quick-freeze and deep-etch methods. The glomerular basement membrane of rat kidneys were three-dimensionally observed by quick-freeze and deep-etch replica methods at high resolution. The middle layer (lamina densa) was composed of 6 to 10nm fibrils which formed a meshwork structure. The space between the fibrils had polygonal shape. The average long dimension of the space between fibrils was 17nm and the short one was 13nm. At the outer layer (lamina rara externa), fibrils connected podocytes perpendicularly with the meshwork of the middle layer. At the inner layer (lamina rara interna), similar perpendicular fibrils also connected endothelial cells with the meshwork of the middle layer. This is the first report to visualize the three-dimensional meshwork structure of the middle layer (the lamina densa) in situ. The function of anchoring podocytes to the lamina densa was suggested in the perpendicularly arranged fibrils of the outer layer. The quick-freeze and deep-etch method is useful in analyzing filamentous ultrastructure in glomeruli, and will be applied to clarifying pathological ultrastructure in kidney diseases

Karakterisasi Film Tipis Cu-c60/mgo Akibat Penuaan(ageing)dengan Teknik Hamburan Raman

KARAKTERISASI FILM TIPIS Cu-C60/MgO AKIBAT PENUAAN(AGEING)DENGAN TEKNIK HAMBURAN RAMAN. Film tipis campuran antara Cu dan C60 telah dianalisis dengan menggunakan spektroskopi Raman. Campuran secara atomik dideposit pada substrat Mg(001). Pengujian topografi dengan mikroskop optik menunjukkan bahwa warna film di sebagian besar sisi luar adalah coklat muda dan berubah menjadi coklat tua pada bagian tengah film. Terjadinya Perubahan warna dapat diatributkan dengan baberapa jenis interaksi kimia antara Cu-Cu, Cu-C60, C60-C60 dan Perubahan alotrop molekul C60. Dari analisis spektroskopik Raman dapat disimpulkan bahwa ciri spektrum secara kuat berkorelasi dengan variasi warna yang bergantung pada daerah pengamatan. Pada tepi filmdengan warna coklat terang (ditunjukkan pada daerah 2 dan 3) atom-atom Cu berinteraksi secara kimia dengan fullerene (Cu-C60). Pada iteraksi ini terjadi pergeseran puncak kira-kira 6 cm-1dari puncak pristine C60 yang diamati untuk puncak-puncak Ag(2) dan Hg(8). Pada pusat film dengan warna coklat gelap (ditunjukkan pada daerah 3, daerah 4 dan daerah 5) terlihat sebagai puncak baru yanang secara tipikal seperti puncak D dan G yang secara umum berkaitan dengan formasi disordered graphite melalui konversi kimia dari C60 dibawah pengaruh oksidasi

Pengaruh Iluminasi Laser Pada Film Campuran Emas-fullerene (Auc60) Dalam Analisis Spectroskopi Raman

PENGARUH ILUMINASI LASER PADA FILM CAMPURAN EMAS-FULLERENE (AUC60) DALAM ANALISIS SPECTROSKOPI RAMAN. Analisis Raman secara rinci pada campuran antara emas danfullerene (C60) telah dilakukan dengan cara mengubah intensitas laser secara sistematik untuk mempelajari pengaruh agitasi termal pada campuran. Analisis pergeseran Raman menunjukkan bahwa Perubahan secara sistematik daya laser menyebabkan pergeseran dan penyempitan puncak Raman. Kenaikan daya laser dari 0,5 miliwatt ke 3 miliwatt akan menyebabkan pergeseran-penurunan frekuensi Raman. Besarnya pergeseran frekuensi Raman kira-kira 2 cm" dan 5,4 cm", masing-masing untuk mode Ag(2) dan Hg(8). Penurunan pergeseran yang diamati berkaitan dengan beberapa macam interaksi antara atom Au dan molekul C60, seperti Au dan C60 ,,softly bound'' yang peka pada suhu sehingga kemungkinan terjadi difusi Au dalam campuran, Nano-kristal Au menunjukkan sifat kimia yang bergantung ukuran (tergantung jumlah atom Au) dan hal penting dari nano-Au adalah kemungkinan penggunaan untuk penandaan DNA, dan posisi-sensitif spektroskopi Raman memberikan kita kesempatan untuk menganalisis reaksi bio-kimia dalam ruang topologi. Kenaikan daya iluminasi menyebabkan pergeseran frekswensi teramati. Iluminasi 0,5 miliwatt dipilih sebagai satu kondisi moderat

Three–dimensional analysis of lip and cheek movements during smile in patients with unilateral lip and cleft palate

松本歯科大学大学院歯学独立研究科博士（歯学）学位申請論文;硬組織疾患制御再建学講座（主指導教員:各務　秀明教授