Changes in Mitochondrial Spectra of Submerged Rice Seedlings after Exposure to Air Gaussian Deconvolution Analysis

Quantitative changes in mitochondrial cytochromes of submerged rice seedlings after exposure to air were investigated using gaussian deconvolution analysis on absorption spectrum at liquid nitrogen temperature. Differnece spectra were obtained from subtracting the absorption spectra of oxidized mitochondria from reduced mitochondria by succinate with antimycin-A. they showed three kinds of b-type cytochrome and a spectral component similar to cytochrome c1. Subtraction of the cytochrome c1-like component from the spectrum by curve analysis showed that three cytochrome bs had similar absorption maximum and that on a mitochondrial protein basis they were constant during air-adaptation. Cytochrome c per mitochontorial protein in submerged seedlings was about half of that in aerobic seedlings and increased by 1.5-fold during air-adaptation. The change in cytochrome c content was in paralleled with that of cytochrome aa3. These findings revealed that there were two groups of cytochromes in the response to air-adaptation,i.e.,three cytochrome bs were constant and cytochoromes c and aa3 increased in parallel.吸収スペクトルをカーブアナリシスの手法を用いて解析し、水中で発芽した芽生えが空気に触れたときに生じるミトコンドリアチトクロム類の量的変化を調べた。アンチマンイシンA存在下でのコハク酸還元による差スペクトルには3種のチトクロムbが見出されるが、チトクロムc1とよく似た成分がかなりの寄与で存在していることが判った。その寄与を除くといずれの芽生えから単離したミトコンドリアにおいても、3種のチトクロムbは互いにほとんど同程度の吸収を示した。また、水中芽生え、酸素適応芽生え、好気芽生えから単離したミトコンドリアの間には、3種いずれのチトクロムbの吸収（タンパク質当たり）に関しても差がなかった。チトクロムcは水中芽生えでは好気芽生えの約半分の量が存在し、酸素適応過程で1.5倍に増加した。これはチトクロムaa3の変化と全く同じであった。チトクロム類の中には、酸素適応過程において酸素に対する応答の異なる2つのグループが存在することを示した

Evaluation of Three Different Procedures for Extracting Adenylates from Barley Roots Prior to Luminometric Quantification

Three methods were compared for extracting adenylates from barley roots prior to their quantification by a lumino-metric method. In respect of efficiency in extracting adenylates and easiness in handling, the best result was obtained in the root sample which was homogenized in perchloric acid, neutralized by mixing with octylamine dissolved in 1,1,2-trichloro-1,2,2-trifluoroethane and centrifuged.高等植物根のアデニル酸をルシフェリン－ルシフェラーゼ法による定量に適する抽出法を捜すために、数種の抽出法を比べた。過塩素酸で抽出し、オクチルアミンで中和し、フロンの一種で洗う方法が最も抽出効果が高く、また比較的操作が簡便であった

Functional characterization of a novel plasma membrane intrinsic protein2 in barley

Water homeostasis is crucial to the growth and survival of plants. Plasma membrane intrinsic proteins (PIPs) have been shown to be primary channels mediating water uptake in plant cells. We characterized a novel PIP2 gene, HvPIP2;8 in barley (Hordeum vulgare). HvPIP2;8 shared 72–76% identity with other HvPIP2s and 74% identity with rice OsPIP2;8. The gene was expressed in all organs including the shoots, roots and pistil at a similar level. When HvPIP2;8 was transiently expressed in onion epidermal cells, it was localized to the plasma membrane. HvPIP2;8 showed transport activity for water in Xenopus oocytes, however its interaction with HvPIP1;2 was not observed. These results suggest that HvPIP2;8 plays a role in water homeostasis although further functional analysis is required in future

Effects of Mannosen on Hydroponically Grown Barley

To examin the effects of mannose on iron absorption of barley roots,barley was hydroponically grown for 36 days in a greenhouse. Potassium and phosphate of barley plants grown in a diluted mannose solution were obserbed at similar as the controls. On the otherhand, some morphological changes were observed in mannose-treated barley plants.薄いマンノース溶液がオオムギの養分吸収に及ぼす影響を調べるために、水耕栽培実験を行った。マンノース添加の有無は植物体のカリウム及びリン酸含量にはほとんど影響しなかったが、植物体の形態に若干の影響を与えた

Increase in Cytochorome c and a 11.9 kDa protein in Submerged Rice Seedlings after Exposure to Air

To examine the changes in cytocrome c content in submerged rice seedlings after exposure to air, antiserum was prepared against purified cytocrome c from rice bran. Western blottong analysis revealed that cytochrome c was detected 6 h after exposure to air, but not detected in submerged rice seedling. On a fresh weight basis, the same level of cytochrome c as that of the aerobic control was found in the 24-h-air adapted seedlings. judging from the high A408/A280 ratio (4.66),the cytochrome c preparation used as antigen was considered to be well purified. However, the antiserum reacted other several polypeptides. One of them reacted more strongly against the antisermu than cytochrome c and its molecular weight was estimated as 11.9 kDa. The polypeptide increased during air adaptation and the levels found in both submerged seedlings and aerobic control were lower than that in 24-h-air-adapted seedlings.イネ水中芽生えを空気に触れさせた後のチトクロムc含量の変動を調べるために、米ぬかから精製したチトクロムcを用いて抗チトクロムc血清を作成した。ウェスタンプロット分析によると、水中芽生えにはチトクロムcは検出されなかったが、空気に触れてから6時間以降に検出された。酸素適応24時間の芽生えには生重量あたりで好気対照と同レベルのチトクロムcが存在した。抗血清作成の抗原として用いたチトクロムc標品は、A408/A280比の値（4.66）が高いことから、よく精製されていると考えられるが、抗血清はいくつかの他のポリペプチドと反応した。そのうちの一つはチトクロムcよりも抗血清に強く反応し、その分子量は11.9kDaであった。このポリペプチドは酸素適応過程で増加し、水中芽生えや好気対照では24時間酸素適応芽生えよりも少なかった

Yeast functional screen to identify genes conferring salt stress tolerance in Salicornia europaea

Salinity is a critical environmental factor that adversely affects crop productivity. Halophytes have evolved various mechanisms to adapt to saline environments. Salicornia europaea L. is one of the most salt-tolerant plant species. It does not have special salt-secreting structures like a salt gland or salt bladder, and is therefore a good model for studying the common mechanisms underlying plant salt tolerance. To identify candidate genes encoding key proteins in the mediation of salt tolerance in S. europaea, we performed a functional screen of a cDNA library in yeast. The library was screened for genes that allowed the yeast to grow in the presence of 1.3 M NaCl. We obtained three full-length S. europaea genes that confer salt tolerance. The genes are predicted to encode (1) a novel protein highly homologous to thaumatin-like proteins, (2) a novel coiled-coil protein of unknown function, and (3) a novel short peptide of 32 residues. Exogenous application of a synthetic peptide corresponding to the 32 residues improved salt tolerance of Arabidopsis. The approach described in this report provides a rapid assay system for large-scale screening of S. europaea genes involved in salt stress tolerance and supports the identification of genes responsible for such mechanisms. These genes may be useful candidates for improving crop salt tolerance by genetic transformation