藻胆体的光谱特性光能传递

1．对嗜热蓝藻层理鞭枝藻(Mastigocladus laminosus)藻胆体的光谱特性和光能传递进行了研究。其完整藻胆体的吸收峰位于622 nm，室温荧光发射峰位于673 nm。在77K荧光发射光谱中，完整藻胆体的荧光峰只有一个，位于685 nm，是末端发射体1的荧光。在低浓度磷酸缓冲液中发生严重解离的藻胆体，其77K荧光发射光谱中有二个发射峰和一个发射肩。两个荧光发射峰分别位于644 nm和683 nm。前者为主峰，属于C-藻蓝蛋白的荧光，后者是次峰，属于末端发射体2的荧光。荧光发射肩位于660 nm附近，属于别藻蓝蛋白的荧光。据此，提出层理鞭枝藻藻胆体光能传递途径如下： 藻红蓝蛋白→c—藻蓝蛋白→别藻蓝蛋白→端发射体l、末端发射体2： 2．对嗜热蓝藻层理鞭枝藻藻胆体—类囊体膜的光谱特性和光能传递进行了研究。在吸收光谱中，其藻胆体——类囊体膜在可见光区域有5个峰，它们分别位于420 nm、438 nm、490 nm、624 nm和678 nm。420 nm、438 nm和678 nm为叶绿素a的吸收峰位置。490 nm是类胡罗卜素的吸收峰，624 nm是藻胆体的吸收峰。对藻胆体——类囊体膜用580 nm波长的光激发藻胆蛋白时，在室温荧光发射光谱中有一个发射峰和一个发射肩，分别位于657 nm和690 nm，前者属于藻胆蛋白的荧光，后者属于叶绿素a的荧光。这说明藻胆蛋白能将捕获的光能传递给类囊体膜上的叶绿素a。在77K荧光发射光谱中有4个峰，它们分别位于649 nm、660 nm、688 nm和730 nm。前二者属于藻胆蛋白的荧光，后二者属于叶绿素a的荧光。这同样说明藻胆蛋白能将捕获的光能传递给类囊体膜上的叶绿素a。当用436 nm波长光激发叶绿素a时，藻胆体——类囊体膜的室温荧光发射光谱中有两个荧光峰出现，位于685 nm的峰来源于光系统Ⅱ，位于713 nm的峰来源于系统I。这说明叶绿素a捕获的光能不能逆传递给藻胆体中的藻胆蛋白。在77K荧光发射光谱中也只有叶绿素a的荧光峰，位于695 nm的峰来源于光系统Ⅱ，位于730 nm的峰来源于光系统l。此结果同样说明叶绿素a捕获的光能不能逆传递给藻胆蛋白． 3．我们以多变鱼腥藻(Anabaena variabilis)为材料，对其藻胆体核心和藻蓝蛋白进行了重组实验，得到了具有光能传递效率的藻胆体核心——藻蓝蛋白复合物。在吸收光谱中，藻胆体核心有一吸收峰和一个吸收肩，分别位于654 nm和600 nm。藻蓝蛋白的吸收光谱中只有一个峰，位于620 nm．重组样品的吸收光谱有一吸收峰和一吸收肩，分别位于654 nm和620 nm．由于620 nm与654 nm的吸收比远大于核心的600 nm与654 nm的吸收比，因此，可以认为部分藻蓝蛋白已与核心重组。在室温荧光发射光谱中，藻胆体核心只有一个峰，位于676 nm。藻蓝蛋白只有一个峰，位于653 nm。重组样品有一荧光发射峰和一荧光发射肩，分别在669 nm和650 nm附近。669 nm荧光来源于核心，650 nm荧光来源于藻蓝蛋白。重组后的核心的650 nm荧光显著大于未重组的核心，这也说明部分藻蓝蛋白与核心已重组．在77K荧光发射光谱中，藻蓝蛋白只有一个峰，位于655 nm。藻胆体核心有二个峰，分别位于666 nm和686 nm。重组样品有两个荧光发射峰和一荧光发射肩，分别位于666 nm、683 nm和648 nm附近．重组的核心的别藻蓝蛋白的荧光(F666)和藻蓝蛋白的荧光(F648)都强于未重组的核心。这一结果同样说明有藻胆体——藻蓝蛋白复合物生成。 除以上研究工作之外，我们还对多变鱼腥藻藻胆体在解离过程中的光谱特性及光能传递、藻胆体——类囊体膜的光谱特性及光能传递、藻胆体解离重组、藻胆体核心在低浓度磷酸缓冲液中的光谱特性、以及温度对藻胆体核心的影响等进行了研究。研究结果有待整理。 本文编写：PBS：藻胆体;PEB：藻红胆素;PE：藻红蛋白;PUB:藻尿胆素;PEC：藻红蓝蛋白;PCB:藻蓝胆素;PC：藻蓝蛋白;PSⅡ：光系统Ⅱ;APC:别藻蓝蛋白;PS I：光系统I;TE:末端发射体

A markov chain Monte Carlo method for estimating population mixing using Y-chromosome markers: Mixing of the Han people in China

We present a new approach for estimating mixing between populations based on non-recombining markers, specifically Y-chromosome microsatellites. A Markov chain Monte Carlo (MCMC) Bayesian statistical approach is used to calculate the posterior probability

A de novo originated gene depresses budding yeast mating pathway and is repressed by the protein encoded by its antisense strand

Recent transcription profiling studies have revealed an unexpectedly large proportion of antisense transcripts in eukaryotic genomes. These antisense genes seem to regulate gene expression by interacting with sense genes. Previous studies have focused on the non-coding antisense genes, but the possible regulatory role of the antisense protein is poorly understood. In this study, we found that a protein encoded by the antisense gene ADF1 acts as a transcription suppressor, regulating the expression of sense gene MDF1 in Saccharomyces cerevisiae. Based on the evolutionary, genetic, cytological and biochemical evidence, we show that the protein-coding sense gene MDF1 most likely originated de novo from a previously non-coding sequence and can significantly suppress the mating efficiency of baker's yeast in rich medium by binding MAT alpha 2 and thus promote vegetative growth. These results shed new light on several important issues, including a new sense-antisense interaction mechanism, the de novo origination of a functional gene, and the regulation of yeast mating pathway.

Feeder layer- and serum-free culture of rhesus monkey embryonic stem cells

The common culture system of rhesus monkey embryonic stem (rES) cells depends largely on feeder cells and serum, which limits the research and application of rES cells. This study reports a feeder layer-free and serum-free system for culture of rES cells.

中国灵猫科的支序系统学分析

选取分布于中国境内的8属9种灵猫科动物的88个骨骼性状、31个外部形态性状和1个行为性状,运用替代外群法分别以赤狐(犬科狐属)和青鼬(鼬科貂属)共同或单独作为外群进行支序分析,得出10个支序图(其步长(TL)为106--136,一致性指数(CI)为0.581--0.660,保留指数(RI)为0.610--0.714。经合意分析得到4个相似的支序图,其TL为41--136,CI为0.581--0.732,RI为0.610--0.818,结果支持:(1)斑灵狸、大灵猫、小灵猫构成一个单系群,与传统分类一致(均属灵猫亚科);(2)椰子狸、花面狸、熊狸构成一个单系群,与传统分类一致(均属长尾狸亚科);(3)红颊meng、食蟹meng与灵猫科其他种为姐妹关系(Bootstrap检验支持率100%),建议meng类为一亚科;(4)长颌带狸拥有较多自近裔性状如三个门齿孔,是一个高度特化的种类,其系统地位有待进一步研究。

Taxonomic review of the genus Sinocrossocheilus Wu (Teleostei : Cyprinidae), with a description of four new species

All Sinocrossocheilus species, except S. microstomatus, are reviewed. Four new species, S. labiata, S. papillolabra, S. nigrovittata, and S. longibulla, are described. The genus Sinocrossocheilus differs from other genera of Cyprinidae by the last simple dorsal fin ray being unserrated and unossified, the last unbranched anal fin ray being unserrated and unossified, the 5-branched anal fin rays, the mouth gap being inferior, the rostral cap covering the lower jaw and connecting directly with the lower lip, a row of fleshy lobes on the lower jaw, and a cloudy black spot above the pectoral fin. Sinocrossocheilus labiata is small and has 22 predorsal scales; S. longibulla has a very large air bladder; S. papillolabra possesses a well-developed ventral fin and a wide band covered by fleshy papillae on the lower lip; and S. nigrovittata possesses black longitudinal stripes along the lateral line. Crossocheilus bamaensis and Crossocheilus liuchengensis are transferred to the genus Sinocrossocheilus. Sinocrossocheilus species are endemic to the central and eastern Yunnan-Guizhou Plateau of China, where river systems are anfractuous, including seasonal rivers, cave rivers, underground rivers, and streamlets between mountains. These separated rivers probably provide conditions for the allopatric speciation of the Sinocrossocheilus.