Photoprotective Effects of D1 Protein Turnover and the Lutein Cycle on Three Ephemeral Plants under Heat Stress

To clarify the characteristics of photoinhibition and the primary defense mechanisms of ephemeral plant leaves against photodestruction under high temperature stress,inhibitors and the technology to determine chlorophyll fluorescence were used to explore the protective effects of D1 protein turnover and the lutein cycle in the high temperature stress of the leaves of three ephemeral plants.The results showed that the maximum light conversion efficiency(Fv/Fm)of the ephemeral plant leaves decreased,and the initial fluorescence(Fo)increased under 35℃±1℃ heat stress for 1-4 h or on sunny days in the summer.Both Fv/Fm and Fo could be recovered after 8 h of darkness or afternoon weakening of the external temperature.Streptomycin sulfate(SM)or dithiothreitol(DTT)accelerated the decrease of Fv/Fm and the photochemical quenching coefficient(qP)in the leaves of three ephemeral plants at high temperature,and the decrease was greater in the SM than in the DTT treatment.When the high temperature stress was prolonged,the Y(II)values of light energy distribution parameters of PSII decreased,and the Y(NPQ)and Y(NO)values increased gradually in all the treatment groups of the three ephemeral plants.The results showed that the leaves of the three ephemeral plants had their own highly advanced mechanisms to protect against photodamage,which inhibited the turnover of D1 protein and xanthophyll cycle.This can damage the PSII reaction center in the leaves of the three ephemeral plants under high temperature.The protective effect of D1 protein turnover on heat stress in Erodium oxyrrhynchum and Senecio subdentatus was greater than that of the lutein cycle,while the protective effect of lutein cycle was greater than that of D1 protein turnover in Heliotropium acutiflorum subjected to heat damage.

小麦waxy蛋白亚基1D-SDS-PAGE分离方法改良

对小麦waxy蛋白的提取技术和电泳后胶片的银染方法进行了改良∶将无胚的半粒种子研磨成粉 ,用洗液浸泡 2h代替蒸馏水浸泡过夜 ,并且去掉了用洗液反复洗涤和离心的程序 ;电泳后胶片的染色采用快速银染法代替常用的银染法 .改良后的单向十二烷基硫酸钠聚丙烯酰胺凝胶电泳方法 (1D SDS PAGE)具有省时、方便、经济和有效的特点 ,可适用于大批小麦材料的waxy蛋白亚基的分析 .图 1参

Correlation Analysis of Differences of Photoinhibitory Sensitivity of D1 Proteins in Oryza sativa ssp. japonica and indica and Structural Features of the Sequences of the Coding Genes

Oryza sativa L. ssp. japonica and indica exhibit different sensitivity to photoinhibition and they show different stability of their core proteins D1 in the chloroplast photosystem Ⅱ. Using in situ hybridization, psbA, the gene encoding D1 protein of O. sativa ssp. japonica cv. 9516, and that of O. sativa ssp. indica cv. Shanyou 63 was cloned. As revealed by homology comparison of their sequences, the sequences are identical in the regions of promoter and 5′-UTR; differences are found in individual bases in the coding region all of which, being in the third position of respective codons, however, do not affect the amino acids coded finally; a difference is noted in the length of the oligo-U sequence in the region of 3′-UTR. It is thus apparent that, rather than a result of any difference in the amino acid sequences, the differences in the sensitivity to photoinhibition of D1 proteins between japonica and indica rice may be related to the upstream factors that regulate expression of psbA or to differences of photoprotective mechanisms.

A型口蹄疫病毒1D蛋白在大肠埃希菌中的可溶性表达、纯化及电子显微镜检测

目的本实验旨在表达出高可溶性的A型口蹄疫病毒1D蛋白,并通过电子显微镜检测,以期望形成纳米样颗粒。方法根据A型口蹄疫病毒核酸序列,得到FMDV A/GDMM/CHA/2013株的1D蛋白基因,并进行截短和优化,共132个氨基酸;同时,从结肠弯曲杆菌(Campylobacter coli)中分离得到135个氨基酸的铁蛋白(Fn)基因片段,将A型口蹄疫病毒1D蛋白与铁蛋白串联,设计并合成了口蹄疫病毒1D蛋白-铁蛋白片段,命名为CcFnt166AS。构建了CcFnt166AS融合Grifin、GST、MBP、Sumo、Thioredoxin、γ-crystallin、ArsC、PpiB、CeHSP17等9种不同可溶性标签的表达重组载体。分别转化至大肠埃希菌BL21(DE3)中,异丙基硫代半乳糖苷(IPTG)诱导,SDSPAGE电泳对融合蛋白的可溶性表达进行检测,筛选出高可溶性表达的CcFnt166AS融合蛋白。重组蛋白通过NiNTA Agarose亲和纯化,进行电子显微镜检测。结果成功构建9种CcFnt166AS表达载体;9个标签中,MBP与CcFnt166AS蛋白相融合的可溶表达效果最好,并获得了高纯度的MBP-CcFnt166AS重组蛋白质;电子显微镜结果显示,MBP-CcFnt166AS形成了纳米样颗粒。结论本实验建立了稳定获得CcFnt166AS重组蛋白质的方法。

Bcl-1 Rearrangement and Cyclin D1 Protein Expression in Multiple Myeloma Precursor Cells

The rearrangement of Bcl-1 gene (Bcl-1/IgH rearrangement) and expression of cyclin D1 in multiple myeloma (MM) precursor cells were studied and the role of cyclin D1 in the pathogenesis of MM was investigated. The BCL-1 rearrangement and cyclin D1 protein expression in 15 cases of MM were detected. By using hemi-nested polymerase chain reaction (PCR) the genomic DNA from fresh peripheral blood and bone marrow was amplified and the expression of cyclin D1 in the smears was detected by using immunohistochemical method. Ten volunteer with normal bone marrow served as control group. The results showed Bcl-1 rearrangement was detectable in 3/15 (20 %) MM patients and cyclin D, expression in 4/15 (27 % ) MM patients. BeLl-1 rearrangement and cyclin D1 protein expression were also detected in MM precursor cells. No overexpression of cyclin D1 or the rearrangement of the BeL-1 gene was found in the 10 volunteers. It was concluded that Bel-1 rearrangement and cyclin D1 protein overexpression were detected in MM precursor cells, speculating that overexpression of cyclin D1 protein may play an initial (critical) role in the pathogenesis of MM.

EXPRESSION OF p16,CYCLIN D1 AND RB PROTEIN IN GASTRIC CARCINOMA AND PREMALIGNANT LESIONS

Objective: To investigate the expression of p16, cyclin D1 and Rb protein in gastric carcinoma and premalignant lesions including dysplastic gastric mucosa and intestinal metaplasia gastric mucosa. Methods: Using SP immunohistochemical methods, the expression of pl6, cyclin D1 and Rb proteins was detected in 10 specimens of normal gastric mucosa, 15 specimens of dysplastic gastric mucosa, 15 specimens of intestinal metaplasia gastric mucosa, 30 specimens of gastric carcinoma. The clinical characteristics of the 30 patients with gastric carcinoma were analysed to explore the relationship between the parameter detected and biological action of gastric cancer. Results: Expression of p16 protein was detected in 90% of normal gastric mucosa, 86.67% of dysplastic gastric mucosa, 86.67% of intestinal metaplasia gastric mucosa, 36.67% of gastric carcinoma. The positive rate of p16 protein expression in gastric carcinoma is significantly lower than that in normal gastric mucosa and gastric premalignant lesions mucosa (P<0.01). Expression of cyclin D1 protein was detected in 10% of normal gastric mucosa, 20% of dysplastic gastric mucosa, 20% of intestinal metaplasia gastric mucosa, 53.33% of gastric carcinoma. The positive rate of cyclin D1, protein expression in gastric carcinoma is significantly higher than that in normal gastric mucosa and gastric premalignant lesions mucosa (P<0.05). Expression of Rb protein was detected in 90% of normal gastric mucosa, 80% of dysplastic gastric mucosa, 80% of intestinal metaplasia gastric mucosa, 50% of gastric carcinoma. The positive rate of Rb protein expression in gastric carcinoma is significantly lower than that in normal gastric mucosa (P<0.05). The expression of p16, cyclin D1 gene were associated with the degree of differentiation of gastric carcinoma, lymphnodes metastasis and distant metastasis. Conclusion: p16, Cyclin D1 and Rb gene play important role in gastric carcinoma genesis. The expression of p16, cyclin D1 and Rb gene have some value to the diagnosis at earlier stage of gastric cancer. Detection of expression of p16, cyclin D1 gene would be helpful to judge the prognosis of gastric cancer.

Photochemical Efficiency of PSⅡ and Membrane Lipid Peroxidation in Leaves of indica and japonica Rice (Oryza sativa) Under Chilling Temperature and Strong Light Stress Conditions

Relationships between fluorescence parameters and membrane lipid peroxidation in leaves of indica and japonica rice (Oryza sativa L.) during later growth stage were studied under chilling temperature and strong light stress conditions. Results showed that D1 protein contents of PSⅡ in photosynthetic apparatus dropped, the generation of antheraxanthin (A) and zeaxanthin (Z) of xanthophyll cycle were inhibited partly, PSⅡ photochemical efficiency (F v/F m)and non-photochemical quenching (q N) were also decreased obviously. In addition, endogenous active oxygen scavenger—superoxide dismutase (SOD) reduced, superoxide anion radical (O -· 2) and malondialdehyde (MDA) accumulated, as a result, photooxidation of leaves occurred under chilling temperature and strong light stress conditions. Obvious differences in the changes of the above mentioned physiological parameters between indica and japonica rice were observed. Experiments in leaves treated with inhibitors under chilling temperature and strong light conditions showed that indica rice was more sensitive to chilling temperature with strong light and subjected to photooxidation more than japonica rice. Notable positive correlation between D1 protein contents and F v/F m or (A+Z)/(A+Z+V), and a marked negative correlation between F v/F m and MDA contents were obtained by regression analysis in indica and japonica rice during chilling temperature and strong light conditions. According to the facts mentioned above, it was inferred that PSⅡ photochemical efficiency(F v/F m) was the key index to forecast for the prediction of photooxidation under stress circumstances and the physiological basis were the synthetic capacity of D1 protein and the protection of xanthophyll cycle.

Photoinhibition and Photooxidation in Leaves of indica and japonica Rice Under Different Temperatures and Light Intensities

Physiological indices related to the efficiency (F-v/F-m) of light energy conversion in PS II and the peroxidation of membrane lipid were measured in leaves of Oryza sativa L. sp. indica rice cv. 'Shanyou 63' and sp. japonica rice cv. '9516'' under different temperatures and fight intensities for 4 days. No changes in F-v/F-m and membrane lipid peroxidation product (MDA) were observed, so neither photoinhibition nor photooxidation happened in both rice cultivars under moderate temperature and medium light intensity. However, F-v/F-m dropped obviously with no change in MDA contents, and photoinhibition appeared in indica rice cv. 'Shanyou 63' under medium temperature and strong light intensity. Furthermore, both photoinhibition and photooxidation were observed in two rice cultivars under chilling temperature and strong light intensity. Experiments with inhibitors under chilling temperature and strong light intensity showed that indica rice had a decrease in DI protein content and SOD activity, and the extent of inhibition of xanthophyll. cycle and nonphotochemical quenching (qN) was larger, and a higher level of MDA was observed. The photoinhibition and photooxidation in indica rice were more distinct as compared with japonica rice. The authors suggested that PS II light energy conversion efficiency (F-v/F-m) and membrane lipid peroxidation were the key indices for the detection of photooxidation.

中国大麦种质资源Wx蛋白分析及糯大麦分子标记验证

为了鉴定中国大麦种质资源Wx蛋白类型以及对已有的糯性分子标记进行验证,利用1D-SDS-PAGE分析了中国167份不同直链淀粉含量类型的大麦种质资源的Wx蛋白类型,发现在低直糯大麦和无直糯大麦两种类型中,可能存在四种生化遗传变异类型。其中有两种与无直糯大麦有关,一种是Wx基因可以正常转录,但转录产生的Wx蛋白无活性,不能催化直链淀粉合成;另一种是Wx基因不能正常转录,既无Wx蛋白产生,也无直链淀粉合成。另外两种与低直糯大麦有关,一种是Wx基因可以正常转录,但转录产生的Wx蛋白活性有限,催化直链淀粉合成的功能降低;另一种是Wx基因不完全正常转录,产生的Wx蛋白数量有限,影响直链淀粉合成。利用4个大麦与小麦的STS标记和2个大麦与小麦的SSR标记对不同Wx蛋白类型进行糯性鉴定,结果表明,迄今利用的Wx基因的STS引物P1可能只适合用于与CDC Candle遗传类型相同的糯大麦品种或基因型的鉴定;其他标记均不能用于鉴定大麦糯性胚乳表型。因此当前对于糯大麦育种及Wx分子鉴定研究而言,还有待于开发新的分子标记。

The expressions of Pin1, β-catenin and cyclin D1 in elderly lung carcinomas and their significance

Objective： To investigate the expressions and correlations of Pin1, β-catenin and cyclin D1 in elderly lung carcinomas. Methods： The expressions of Pin1, β-catenin and cyclin D1 were examined in the specimens of 92 elderly lung carcinomas and 10 normal lung tissues by immunohistochemistry and explored the relationship between the expression levels and clinicopathological factors. Results： （1） The overexpression of Pin1 and cyclin D1 in lung carcinomas was 46 （50%） cases and 60 （65.22%） cases respectively and 56 （60.82%） cases showed positive immunoreactivity for 13-catenin in the nuclear and （or） cytoplasmic fraction in tumor tissues. In normal tissue, the expressions of Pin1 and cyclin D1 were negative, the expression of β-catenin was lied in cell membrane. （2） In lung carcinomas the expressions of Pin1, β-catenin and cyclin D1 correlated with tumor differentiation （P 〈 0.05）. The pesitive expression rate and intensity of Pin1 correlated with tumor stage （P = 0.032） and lymph node positive disease （P = 0.041）. The expression of β-catenin correlated with lymph node positive disease （P = 0.012）. （3） High expression levels of Pin1 correlated with aberrant I]-catenin expression （P = 0.000） but did not show a correlation with cyclin D1 （P = 0.157）. Conclusion： In elderly lung carcinomas, the positive expression of Pin1 causes abnormal accumulation of β-catenin and actives its target gene, however, this target gene was not cyclin DI. The detection of Pin1 expression had some clinical significance in estimating prognosis of elderly patient with lung carcinomas.

Traits Related to Chilling-Induced Photoinhibition in Leaves of indica and japonica Rice (Oryza sativa)

Physiological indices related to PS II photochemical efficiency (Fv/Fm) and membrane lipid peroxidation were measured in leaves of indica rice cv Shanyou 63 and japonica rice 9516 at different temperatures and light intensities for four days. No obvious changes in Fv/Fm and MDA were observed in both indica and japonica rice at moderate temperature and medium PFD, implying neither photoinhibition nor photooxidation happened in these cases. In indica rice either at medium temperature with higher PFD or at lower temperature with medium PFD Fv/Fm dropped obviously with no changes in MDA contents, and photoinhibition appeared while photooxidation did not occur. However, D1 protein, Fv/Fm, (A+Z)/(A+Z+V), and SOD activities dropped, and O2 - production and MDA content increased accordingly, as well as both photoinhibition and photooxidation appeared in two rice varieties at lower temperature and higher PFD. Experiment with inhibitors at lower temperature and higher PFD showed that as compared with japonica rice the decrements appeared in D1 protein contents, SOD activities, and (A+Z)/(A+Z+V) ratios, the xanthophyll cycle and non-photochemical quench (qN) were inhibited in a more degree, as well as increments of MDA content were greater, thus exhibiting more distinct photoinhibition and photooxidation in indica rice. It is suggested that Fv/Fm and membrane lipid peroxidation product-MDA were the key indices to predict and diagnose photooxidation.

BCL-1 Rearrangement in Acute Lymphocytic Leukemia and Its Clinical Significance

BCL 1 rearrangement (BCL 1/IgH gene rearrangement) in acute lymphocytic leukemia and its clinical significance was investigated. In 38 patients with acute lymphocytic leukemia (ALL), the genomic DNA of mononuclear cells isolated from peripheral blood and bone marrow was amplified by using hemi nested polymerase chain reaction (PCR) technique and the expression of cycline D1 protein of mononuclear cells was detected by using immunohistochemical method. Ten patients with acute granulocytic leukemia, 2 with chronic granulocytic leukemia and 10 with normal bone marrow served as control group. The results showed that BCL 1 rearrangement was detectable in 3 of 38 ALL patients (7.9 %) and cyclin D1 protein positive expression was detected in 4 ALL patients (10 5 %). Three ALL patients with BCL 1 rearrangement were all B cell leukemia (B ALL) and accompanied by cyclin D1 protein expression. No BCL 1/IgH rearrangement or cyclin D1 protein expression was detected in 12 patients with granulocytic leukemia and 10 cases of normal bone marrow. Leukocyte counts in peripheral blood of B ALL patients with BCL 1 rearrangement and(or) cyclin D1 protein expression were significantly increased and the patients had bad reaction to chemotherapy. It was concluded that: 1) BCL 1/IgH gene rearrangement were detected in acute B lymphocytic leukemia; 2) B ALL patients with BCL 1 rearrangement and(or) cyclin D1 protein expression had poor prognosis.

THE OVEREXPRESSION AND SIGNIFICANCE OF CYCLIN D1 AND P53 IN CERVICAL SQUAMOUS CELL CARCINOMAS

Objective To investigate the significance of overexpresson of cyclin D1 and P53 protein in cervical squamous cell carcinomas.Methods Fifty cases of invasive cervical squamous cell carcinomas and 10 cases of normal cervical squamous epithelia were investigated with immunihistochemical technique. Results The overexpression of cyclin D1 and P53 in invasive cervical carcinomas was 70% and 50%, respectively. There was no overexpression of them in the control group. The overexpression of cyclin D1 in grade Ⅱ and Ⅲ was much higher than that in gradeⅠ(P<0.05). The overexpresson of cyclin D1 in stage Ⅲ of cervical carcinoma was significantly higher than that in stage Ⅱ (P<0.05). The overexpression of P53 in grade Ⅱ and grade Ⅲ of cervical carcinoma was remarkably higher than that in grade Ⅰ (P<0.05).Conclusion The action point of both cyclin D1 and P53 may be at G1/S transition. The overexpression of them was associated with development and progression of cervical carcinoma probably in different mechanisms and different pathways.

Effect of Exogenous bFGF on the Proliferation of Human Adenoid Cystic Carcinoma ACC-2 Cells

To observe the effects of basic fibroblast growth factor （bFGF） on human adenoid cystic carcinoma ACC-2 cell line proliferation and ERK, cyclin D1/p21^waf/cip1 signaling pathways, human adenoid cystic carcinoma cells （ACC-2） were cultured and the influence of bFGF of different concentrations on cell proliferation was determined by MTT. Protein was detected by immuno-precipitation and ERK activity by using ERK agent kit. p-ERK1/2 and down-stream cyclin D1, p21^waf/cip1 expression were detected by Western blotting and the interfering role of mitogen protein-activated kinase （MEK） suppressor U0126 in the afore-mentioned indicators was examined. MTT demonstrated ACC-2 cell proliferation was substantially enhanced by bFGF, immuo-precipitation displayed ERK activity was up-regulated by bFGF, and immuno-imprinting also showed p-ERK1/2, cyclin D1 expression was greatly enhanced and p21^waf/cip1 expression was inhibited by bFGE U0126 suppressed the effect of bFGF. It is concluded that bFGF can promote the proliferation of human adenoid cystic carcinoma ACC-2 cells, and its pathways are associated with the up-regulated activity and expression of p-ERK1/2, inhibited p21waf/cip1 expression and enhanced cyclin D1 expression.

Wip1在炎症反应中的研究进展

炎症反应是具有血管系统的活体组织对各种损伤因子的刺激所发生的以防御反应为主的病理生理过程。野生型p53诱导的磷酸酶1(wild-type p53-induced phosphatase 1,Wip1)是一种由镁离子/锰离子依赖性蛋白激酶1D(protein phosphatase,Mg^(2+)/Mn^(2+)dependent 1D,PPM1D)编码的丝氨酸/苏氨酸磷酸酶,属PP2C家族。Wip1通过去磷酸化p38 MAPK、p53和共济失调毛细血管扩张突变(ataxia telangiectasia-mutated,ATM)激酶等多种重要的信号分子调控细胞核的DNA损伤修复和炎症细胞的增殖、衰老、凋亡及自噬。越来越多的研究证实,Wip1对许多炎症细胞起着关键性的调节作用,文章就Wip1的结构特点、Wip1与炎症细胞的关系以及在炎症性疾病中的作用等研究进展展开综述。

Calcium contributes to photoprotection and repair of photosystem II in peanut leaves during heat and high irradiance

In this study, we investigated the effects of exogenous calcium nitrate on photoinhibition and thylakoid protein level in peanut plants under heat （40 ℃） and high irradiance （HI） （1,200 mmol/m2 per s） stress. Compared with control seedlings （cultivated in 0 mmol/L Ca（NO3）2 medium）, the maximal photochemical efficiency of photosystem II （PSII） in Ca2t‐treated plants showed a slight decrease after 5 h stress, accompanied by lower degree of PSII closure （1‐qP）, higher non‐photochemical quenching, and lower level of membrane damage. Ca2t inhibitors were used to analyze the varieties of antioxidant enzymes activity and PSII proteins. These results indicated that Ca2t could protect the subunits of PSII reaction centers from photoinhibition by reducing the generation of reactive oxygen species. In the presence of both ethyleneglycol‐bis（2‐aminoethylether）‐tetraacetic acid and ascorbic acid （AsA）, the net degradation of the damaged D1 protein was faster than that only treated with AsA. Our previous study showed that either the transcriptional or the translational level of calmodulin was obviously higher in Ca2t‐treated plants. These results suggested that, under＆amp;nbsp;heat and HI stress, the Ca2t signal transduction pathway can al eviate the photoinhibition through regulating the protein repair process besides an enhanced capacity for scavenging reactive oxygen species.

Relationships between Phosphatidylglycerol Molecular Species of Thylakoid Membrane Lipids and Sensitivities to Chilling-induced Photoinhibition in Rice

In an attempt to explore the relationships between phosphatidylglycerol （PG） molecular species of thylakoid membrane lipids and sensitivities to chilling-induced photoinhibition, PG molecular species, D1 protein, electron transport activities of thylakoid membrane and the potential quantum yield （FvlFm） in rice treated under middle and low photon flux density （PFD） at 11℃ were analyzed by high performance liquid chromatography, enzyme hydrolysis, gas phase chromatography （GC） and so on. Results showed that the major molecular species of PGs in rice thylakoid membrane were 18：3/16：0, 18：3/16：1（3t）, 18：2/16：0, 18：2/16：1（3t）, 18：1/16：0, 18：1/16：1（3t）, 16：0/16：0, 16：0/16：1（3t）. There were large differences in the contents of unsaturated PG molecular species such as 18：1-3/16：0-16：1（3t） and saturated PG molecular species like 16：0/16：0-16：1（3t） among japonica cv 9516 0-9516）, japonica-indica hybrid F1 j-9516/i-SY63 （ji-95SY） and indica cv Shanyou 63 （i-SY63）. J-9516 containing higher contents of unsaturated PG molecular species was manifest in stable D1 protein contents under chill and tolerant to chill-induced photoinhibition. In contrast to j-9516, i-SY63 with lower contents of unsaturated PG molecular species, exhibited unstable D1 protein contents under chill and was sensitive to chill-induced photoinhibition, ji-95SY containing middle contents of unsaturated PG molecular species between those of j-9516 and i-SY63, exhibited mid extent of sensitivity to chill-induced photoinhibition. The losses in D1 protein also account for the inhibition in electron transport activity of thylakoid membrane and the observed decline in FvlFm. The PG molecular species that is efficient in raising chilling-resistant capacity were those containing unsaturated fatty acids, namely, unsaturated PG molecular species. These results implied that the substrate selectivity of the glycerol-3-phosphate acyltransferase in chloroplasts towards 16：0 or 18：1 displayed greatly the difference between japonica and indica rice. Itwas possible to enhance the capacity of resistance to chilling-induced photoinhibition by improving or modifying the GPAT gene.

Xanthophyll Cycle and Inactivation of Photosystem Ⅱ Reaction Centers Alleviating Reducing Pressure to Photosystem Ⅰ in Morning Glory Leaves under Short-term High Irradiance

Under 30-min high irradiance （1500μmol m^-2 s^-1）, the roles of the xanthophyll cycle and D1 protein turnover were investigated through chlorophyll fluorescence parameters in morning glory （Ipomoea setosa） leaves, which were dipped into water, dithiothreitol （DTT） and lincomycin （LM）, respectively. During the stress, both the xanthophyll cycle and D1 protein turnover could protect PSI from photoinhibition. In DTT leaves, non-photochemical quenching （NPQ） was inhibited greatly and the oxidation level of P700 （P700^＋） was the lowest one. However, the maximal photochemical efficiency of PSII （Fv/Fm） in DTT leaves was higher than that of LM leaves and was lower than that of control leaves. These results suggested that PSI was more sensitive to the loss of the xanthophyll cycle than PSII under high irradiance. In LM leaves, NPQ was partly inhibited, Fv/Fm was the lowest one among three treatments under high irradiance and P700^＋ was at a similar level as that of control leaves. These results implied that inactivation of PSII reaction centers could protect PSI from further photoinhibition. Additionally, the lowest of the number of active reaction centers to one inactive reaction center for a PSII cross-section （RC/CSo）, maximal trapping rate in a PSll cross-section （TRo/CSo）, electron transport in a PSll cross-section （ETo/CSo） and the highest of 1-qP in LM leaves further indicated that severe photoinhibition of PSII in LM leaves was mainly induced by inactivation of PSII reaction centers, which limited electrons transporting to PSh However, relative to the LM leaves the higher level of RC/CSo, TRo/CSo, Fv/Fm and the lower level of 1-qP in DTT leaves indicated that PSI photoinhibition was mainly induced by the electron accumulation at the PSI acceptor side, which induced the decrease of P700^＋ under high irradiance.

Changes in Unsaturated Levels of Fatty Acids in Thylakoid PSII Membrane Lipids During Chilling-induced Resistance in Rice

Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cultivars of rice （Oryza sativa L.）, japonica cv. 9516 （j-9516）, the two parental lines of superhigh-yield hybrid rice between subspecies, Peiai/E32 （ji-PE）, and the traditional indica hybrid rice Shanyou 63 （i-SY63）. Leaves of chill-treated rice showed chilling-induced resistance, as an increase of their low-temperature tolerance was measured using chlorophyll fluorescence measurements, revealing a change in photosystem II （PSII） efficiency. After 5 d of exposure to 11 ~C under low light （100 pmol·m^-2·s^-1）, levels of unsaturated fatty acids in PSII thylakoid membrane lipids decreased during the initial 1-2 d, then increased slowly and reached 99.2%, 95.3% and 90.1% of the initial value （0 d） in j-9516, ji-PE and i-SY63, respectively, on the fifth day. However, under medium light （600 μmol·m^-2·s^-1）, all cultivars experienced similar substantial photoinhibition, which approached steady state levels after a decline in levels of unsaturated fatty acids in PSII thylakoid membrane lipids to about 57.1%, 53.8% and 44.5% of the initial values （0 d） in j-9516, ji-PE and i-SY63 on the fifth day. Under either chilling-induced resistance （the former） or low temperature photoinhibition （the latter） conditions, the changes of other physiological parameters such as D1 protein contents, electron transport activities of PSII （ETA）, Fv/Fm, xanthophyl cycle activities expressed by DES （deepoxide state） were consistent with that of levels of unsaturated fatty acids in PSII thylakoid membrane lipids. So there were negative correlations between saturated levels of fatty acids （16：1（3t）, 16：0, 18：0）, especially the 16：1（3t） fatty acid on thylakoid membrane and other physiological parameters, such as D1 protein contents, ETA and （A＋Z）/（A＋V＋Z）. A specific role of desaturation of fatty acids and the photoprotective pigments of the xanthophyl cycle, leading to an acclimation response in thylakoid membrane lipids may be involved. We conclude that chilling-induced resistance is accelerated by the unsaturation of thylakoid membranes, and the ability of rice plants to cold-harden can be enhanced by genetic engineering.

Disruption of dopamine D1 receptor phosphorylation at serine 421 attenuates cocaine-induced behaviors in mice

Dopamine D1 receptors（D1Rs） play a key role in cocaine addiction, and multiple protein kinases such as GRKs, PKA, and PKC are involved in their phosphorylation. Recently, we reported that protein kinase D1 phosphorylates the D1 R at S421 and promotes its membrane localization. Moreover, this phosphorylation of S421 is required for cocaineinduced behaviors in rats. In the present study, we generated transgenic mice over-expressing S421A-D1 R in the forebrain. These transgenic mice showed reduced phospho-D1R（S421） and its membrane localization, and reduced downstream ERK1/2 activation in the striatum. Importantly, acute and chronic cocaine-induced locomotor hyperactivity and conditioned place preference were significantly attenuated in these mice. These findings provide in vivo evidence for the critical role of S421 phosphorylation of the D1 R in its membrane localization and in cocaine-induced behaviors. Thus, S421 on the D1 R represents a potential pharmacotherapeutic target for cocaine addiction and other drug-abuse disorders.