Absorption and structure of an LM unit isolated with sodium dodecyl sulfate from reaction centers of Rhodopseudomonas sphaeroides

Low-temperature absorption, circular dichroism and resonance Raman spectra of the LM units isolated with sodium dodecyl sulfate from wild-type Rhodopseudomonas sphaeroides reaction centers (Agalidis, I. and Reiss-Husson, F. (1983) Biochim. Biophys. Acta 724, 340–351) are described in comparison with those of intact reaction centers. In LM unit, the Q_y absorption band of P-870 at 77 K shifted from 890 nm (in reaction center) to 870 nm and was broadened by about 30%. In contrast, the 800 nm bacteriochlorophyll absorption band including the 810 species remained unmodified. It was concluded that the 810 nm transition is not the higher excitonic component of P-870. The Q_x band of P-870 shifted from 602 nm (in reaction center) to 598 nm in LM, whereas the Q_x band of the other bacteriochlorophylls was the same in reaction center and LM and had two components at about 605 and 598 nm. The Q_xII band of bacteriopheophytin was upshifted to 538 nm and a slight blue shift of the Q_y band of bacteriopheophytin was observed. Resonance Raman spectra of spheroidene in LM showed that its native cis-conformation was preserved. Resonance Raman spectroscopy also demonstrated that in LM the molecular interactions assumed by the conjugated carbonyls of bacteriochlorophyll molecules were altered, but not those assumed by the bacteriopheophytins carbonyls. In particular at least one Keto group of bacteriochlorophyll free in reaction center, becomes intermolecularly bounded in LM (possibly with extraneous water). This group may belong to the primary donor molecules.     

利用SSR定位籼稻品种Kaharamana中抗褐飞虱基因Bph9

褐飞虱是危害水稻生产最重要的害虫之一,利用寄主抗性被认为是防治褐飞虱最经济而有效的方法。斯里兰卡水稻品种Kaharamana对东亚和东南亚的褐飞虱种群均表现抗虫性,利用分子遗传学的方法对其携带的Bph9基因进行了SSR定位。所用的遗传群体为来源于Kaharamana和02428的含有180个单株的F2分离群体,每个F2单株套袋自交获得F2：3家系。利用苗期集团鉴定埘F2：3家系进行抗褐飞虱鉴定,以推测相应F2单株的基因型。连锁分析表明,Bph9位于第12染色体上的两个SSR标记RM463和RM5341之间,分别与之相距6．8cM和9．7cM。该标记有助十将Bph9用于分子标记辅助选择育种研究。     

Bph3在栽培稻和药用野生稻中的BAC-FISH比较物理定位(英)

用栽培稻 (OryzasativaL .)遗传图第四连锁群中与抗褐稻虱基因Bph3紧密连锁的RFLP标记RZ6 9及筛选出来的BAC克隆 38J9作探针 ,对药用野生稻 (O .officinalisWellexWatt)和栽培稻荧光原位杂交 ,供试标记RZ6 9及38J9均被定位于药用野生稻和栽培稻第 4染色体的短臂上 ,药用野生稻杂交信号的百分距分别为 2 2 .12± 3.4 4和2 0 .0 0± 5 .4 0 ,而栽培稻均为 0。在栽培稻中 ,信号检出率相应地为 6 .2 9%和 5 6 .10 % ,在药用野生稻中则为 6 .14 %和 5 0 .0 0 %。BAC克隆和RFLP标记探针杂交信号的百分距十分接近 ,说明在栽培稻和野生稻中RFLP标记RZ6 9都在同一BAC克隆的大插入片段中。由此推知 ,药用野生稻与抗性基因Bph3的同源顺序就在第 4染色体信号出现的相应位置。在未封阻的情况下 ,药用野生稻的BAC杂交在多条染色体上具有信号 ,这表明它和栽培稻的Cot_1DNA重复顺序也在一定程度上具有同源性。药用野生稻第 4染色体是根据栽培稻与药用野生稻的比较遗传图选用与Gm_6连锁的RG2 14通过FISH确定的。讨论了栽培稻BAC克隆对药用野生稻比较原位杂交物理作图的可行性问题。     

药用野生稻抗褐飞虱基因的RAPD标记研究

以药用野生稻1665(O.officinals)和栽培稻桂99远缘杂交的抗褐飞虱近等基因系B3F4分离群体为材料,利用随机引物对其抗褐飞虱基因进行了RAPD标记研究,获得3个与抗褐飞虱基因表现连锁的RAPD分子标记(S229703、S403783和S11591408)。采用MAPMAKER/EXP.Version 3.0分析,结果表明3个RAPD分子标记与抗褐飞虱基因属于同一连锁群,覆盖大小为18.1cm,标记间平均距离为4.53cm,为下一步水稻抗褐飞虱基因的精确定位和克隆奠定坚实的基础。