鼻咽癌组织中氧化性DNA损伤标志物8-硝基鸟嘌呤和8-羟基脱氧鸟苷的检测及与iNOS的关系

8-硝基鸟嘌呤（8-nitroguanine, 8-NitroG）和8-羟基脱氧鸟苷（8-hydroxy-2′-deoxyguanosine, 8-OHdG）是2个氧化性DNA损伤生物标志物,而诱导型一氧化氮合酶(iNOS)在病理状态下催化细胞合成与氧化性DNA损伤有关的 氧自由基NO.本研究通过检测鼻咽癌组织中8-NitroG、8-OHdG和iNOS的免疫反应强度,初步探究鼻咽癌的发生和发展是否与氧化性DNA损伤有关以及8-NitroG、8-OHdG与iNOS表达的关系.利用多克隆抗体8-NitroG和单克隆抗体8-OHdG、iNOS,采用双色荧光免疫组织化学方法检测鼻咽癌组织中8-NitroG、8-OHdG和iNOS的免疫反应,秩和检验统计学方法分析鼻咽癌和慢性咽炎鼻咽组织之间8-NitroG、8-OHdG和iNOS免疫反应强度的差异.结果显示,19例鼻咽癌组织细胞中,8-NitroG、8-OHdG和iNOS均为强免疫反应,8-NitroG和8-OHdG阳性率100%,iNOS阳性率94.7 %,与13例慢性咽炎组织比较差异显著(P.<0.05).结果提示,鼻咽癌的发生和发展与氧化性DNA损伤有关,其原因与炎症等病理刺激下鼻咽组织高表达的iNOS催化细胞合成氧自由基NO引起的8-NitroG和8-OHdG DNA损伤密切相关.另外,8-NitroG和8-OHdG有望成为辅助鼻咽癌诊断的生物标志物.     

Leaf Anatomy and Carbon Discrimination in NAD-malic Enzyme Panicum Species and their Hybrids Differing in Bundle Sheath Cell Ultrastructure

The relationship between leaf anatomy, ultrastructure and carbondiscrimination was investigated in leaves of two F₁hybrids (F₁-1and F₁-2) between two different types of the grassPanicum [anNAD-malic enzyme (ME) C₄species], which differ in bundle sheathultrastructure. The female parent was Kabulabula grass, whichhas centrifugal chloroplasts in bundle sheath cells and is designatedan NAD-ME(F) species, while the male parent was Makarikari grass,which has centripetal chloroplasts in the bundle sheath cellsand is designated an NAD-ME(P) species. Suberin lamellae arepresent in Kabulabula grass but are lacking in Makarikari grass.Both F₁hybrids had the same chromosome number (2n =36) as theparents but exhibited both univalent (about 45%) and bivalent(about 55%) chromosome pairing which was the major basis forthe identification of F₁hybrids. In F₁-1, elongated bundle sheathcell chloroplasts are arranged mainly in a centripetal position,similar to those in the male parent, Makarikari grass. In contrast,most of the bundle sheath cells in F₁-2 are packed with starch-containingchloroplasts, although in some cells chloroplasts tended tobe centripetally arranged. In both F₁hybrids, suberin lamellaewere found in the bundle sheath cell walls, similar to the femaleparent, Kabulabula grass. The ¹³C values of both F₁hybrids were-11.4 to -11.7, almost the same as those of Kabulabula grass(-11.4), but significantly higher than those of Makarikari grass(-12.7). These results indicate that the chloroplast orientationin the bundle sheath cells and the presence of suberin lamellaeare not obligatorily linked in their expression and suggestthat suberin lamellae may play an important role in discriminationagainst¹³C. Panicum ; NAD-malic enzyme species; hybrid; chloroplast position; ¹³C discrimination; suberin lamellae     

CHANGES IN EMISSION SPECTRA OF PHOTOSYNTHETIC PIGMENTS IN VIVO

1. The effects of 3-(4'-chlorophenyl)-1, 1-dimethylurea (CMU)onthe fluorescence of photosynthetic pigments in vivo wereinvestigatedin blue-green, red and brown algae and in isolatedspinach chloroplasts.CMU caused an increase in steady statelevel of fluorescenceof chlorophyll a, but did not influencethe fluorescence ofphycobilins. The spectrum of the fluorescenceincrement hada peak at 685 m/µ and a shoulder at 730–740mµ.These two bands probably arise from chlorophyll a(C_f684) belongingto pigment system II.
2. On excitation of chlorophylla in a red alga, Porphyra yezoensis,a fluorescence band witha peak at 720 mµ was observedbesides a shoulder at 685mµ. The 720 m band is inferredto arise from chlorophylla (probably, C_f-1) in pigment systemI.
3. On addition of CMUto the algal cells, the induction of fluorescencewas modifiedto take a simple time course. The induction wasobserved onlywith respect to the fluorescence of chlorophylla, but not inthe fluorescence of phycobilins. The spectrumof the "transient"fluorescence showed two emission bands ofchlorophyll a at 685mµ and 740 mµ, and was quitesimilar in form tothe spectrum of the CMU-caused increase insteady state fluorescence.
4. These facts were interpreted in terms of the correlation offluorescence of chlorophyll a and the photochemical reactionsof photosynthesis

(Received July 20, 1967; )     

Genetic modification of the fatty acid unsaturation of phosphatidylglycerol in chloroplasts alters the sensitivity of tobacco plants to cold stress

The cis‐unsaturated molecular species of phosphatidylglycerol (PG) in chloroplasts have been implicated in the chilling sensitivity of plants. Homozygous lines of transgenic tobacco (Nicotiana tabacum) that overexpressed the cDNA for glycerol‐3‐phosphate acyltransferase, a key enzyme in the determination of the extent of cis‐unsaturation of PG, were established from a chilling‐sensitive squash (Cucurbita moschata). In transgenic plants, the proportion of saturated plus trans‐monounsaturated molecular species of PG increased from 24 to 65%. However, this change did not affect the architecture of the chloroplasts. Chilling stress decreased the growth and biomass production of young seedlings of transgenic plants more severely than those of wild‐type plants, and this observation suggests that the changes in the proportion of cis‐unsaturated PG affected not only leaves but also developing plants. Chilling stress also damaged inflorescences. In particular, the abscission of flower buds and inflorescence meristems from transgenic plants occurred more frequently than that from wild‐type plants. Thus, it is likely that decreases in the proportion of cis‐unsaturated PG enhanced the sensitivity to chilling of reproductive organs.     

Isolation and characterization of microsatellites in the sea hibiscus (Hibiscus tiliaceus L., Malvaceae) and related hibiscus species

Microsatellite loci were isolated from the sea hibiscus (Hibiscus tiliaceus L., Malvaceae), a pantropical plant with sea‐drifted seeds. This study describes six dinucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with different levels of variability (between three and nine alleles). Six markers were amplified in four other species of hibiscus, greatly increasing the utility of these markers.