土壤中嗜酸性氧化亚铁硫杆菌的分离鉴定及其性能研究

采用改进型Leathen培养基直接从辽宁省抚顺市红透山铜矿附近的土壤中分离到了一株高度嗜酸的氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)菌株(暂命名为R2).鉴定表明,该菌株为革兰氏阴性细菌,在扫描电镜下观察该菌株为短杆状,菌体大小为(0.4±0.2)μm×(1.6±0.4)μm.最适pH值2.0,化能自养型,能利用亚铁、单质硫和硫代硫酸钠生长,不能利用葡萄糖、蛋白胨生长.并且以16S rDNA序列同源性为基础构建了17株已报道菌种在内的系统发育树,将16S rDNA测序结果输入Genebank以Blast软件进行序列同源性比较,结果显示与氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)的多株细菌具有较高的同源性(>99%),其中与Acidithiobacillus.ferrooxidans strain TGS的相似性达到100%,与标准株Acidithiobacillus ferrooxidans strain ATCC33020相似性为99.3%,结合其生理生化特性可以确定该菌为氧化亚铁硫杆菌种.序批式试验法研究表明.接种该株菌可有效溶出土壤中重金属,经过5 d的生物淋滤,Cu、Cr、Zn、Cd的最高去除率分别达到30.6%、16.3%、58.4%和72%.     

氧化亚铁硫杆菌的磁性及铁源种类对磁小体合成的影响

氧化亚铁硫杆菌,通过氧化二价铁或还原态无机硫化物获得能量,在细胞内能合成磁性纳米颗粒。通过扫描电镜和透射电镜对氧化亚铁硫杆菌菌体进行分析。探讨了该菌的趋磁性以及不同铁源对菌体生长和磁小体合成的影响。结果表明:生长于9K培养基的细菌能够合成磁小体,单个细胞的磁小体数目大概为2个;干燥菌体和湿菌体都能被磁铁吸附;当有外加磁场时,细菌在半固体平板和光学显微镜下均可见趋磁性;氧化亚铁硫杆菌生长和磁小体合成的最佳铁源均为硫酸亚铁。     

一株嗜酸性氧化亚铁硫杆菌的分离及其氧化活性的研究

本研究从铜陵新桥矿区的高硫矿堆废水中分离一株嗜酸菌S t1,经生理生化特征及16S rDNA分子鉴定,确定其为嗜酸性氧化亚铁硫杆菌。该菌株分别在含有FeSO4·7H2O、S0、黄铁矿石颗粒（FeS2）的9K无机盐液体培养基中获得生长所需要的能量。结果嗜酸菌S t1对Fe2＋氧化速率最快,培养到36h时溶液中44.1g·L-1 FeSO4·7H2O有95%被氧化;S0为能量底物的培养体系中,培养到26d时培养液中SO42-浓度达到2.2412 mg· mL-1,pH值降至1.18;黄铁矿石颗粒（FeS2）为能量底物的培养体系中,SO42-平均生成速率为1.3602 mmol·L-1·d-1,黄铁矿石颗粒氧化速率达到0.068mmol·d-1·g-1。     

Control of crystal size and lattice formation by starmaker in otolith biomineralization

The stone-like otoliths from the ears of teleost fishes are involved in balance and hearing and consist of calcium carbonate crystallites embedded in a protein framework. We report that a previously unknown gene, starmaker, is required in zebrafish for otolith morphogenesis. Reduction of starmaker activity by injection of modified antisense oligonucleotides causes a change in the crystal lattice structure and thus a change in otolith morphology. The expression pattern of starmaker, along with the presence of the protein on the growing otolith, suggest that the expression levels of starmaker control the shape of the otoliths.     

钾对棉籽成分与品质的影响

研究了不同钾水平处理下的棉籽成分与品质．结果表明：施钾能促进光合产物向棉籽运输,增加棉籽的百粒重,从而大大提高棉花种子的活力和发芽率;钾能显著提高棉籽仁中粗脂肪含量和不饱和脂肪酸的比例,降低蛋白质含量,有利于油脂品质的提高;但施钾可明显提高棉籽中有毒物质棉酚的含量,这对棉籽的综合利用是个不利因素．     

Inhibition of cholesterol crystal formation by apolipoproteins in supersaturated model bile

Apolipoproteins A-1 and A-2 were purified from human plasma. At concentrations present in human bile these proteins prolonged the nucleation time of cholesterol monohydrate crystals when added to model systems of supersaturated bile. In contrast, apolipoprotein C-3 and other serum proteins did not have this effect. Also, when human gallbladder bile was fractionated by gel filtration chromatography, apolipoproteins A-1 and A-2 were among the proteins present in a fraction of bile enriched in potent inhibitors of cholesterol crystal nucleation. These findings suggest that apolipoproteins A-1 and A-2 in supersaturated human gallbladder bile could inhibit the rate of formation of solid cholesterol crystals and thus help to prevent spontaneous cholesterol gallstone formation in humans.     

夏蜡梅的双受精和种子形成

夏蜡梅传粉后,花粉管８ｄ到达胚囊,１０－１３ｄ实现双受精,为珠孔受精。胚乳为核型胚乳。初生胚乳核经短暂休眠进行分裂,１８ｄ胚完全细胞化,呈单鲁细胞,随后细胞分裂成多列,并不断消耗珠心组织及珠被。合子经过近１周的休眠后开始分裂,为柳叶菜型。３９ｄ 形成后,以一个方向包绕胚乳,与胚周边胚民中胚乳存在形态上的差异,表现出为胚输送养料的一种结构,并保留至种子成熟。胚乳发育存在特殊性,具营养和吸器的功能。     

水稻籽粒发育和胚乳淀粉粒形成的研究

水稻籽粒长、宽快速增长期为花后０－６天,粒型（长／宽）形成期为花后１５天;抽穗后０－３天粒重发育缓慢,之后迅速增长,至第１８天粒重发育基本完成;受季节影响,水稻晚季粒型值大于早季,尤其是灿稻品种其早、晚季粒型值的差异达极显著水平;淀粉粒在胚乳中形成的时间为子房受粉后２－３天,并于边缘的胚乳细胞中最先出现。     

Effect of seed priming with different concentrations of potassium nitrate on the pattern of seed imbibition and germination of rice(Oryza sativa L.)

Low germination and vigor of rice seed associated with dry-seed broadcasting are common problems encountered by rice growers.The objectives of this study were to evaluate the role of potassium nitrate(KNO_3)on the pattern of seed imbibition and to determine the effect of seed priming with KNO_3 on the germination percentage,speed and uniformity of germination in rice seed.Experiment 1 compared the patterns of seed imbibition of six concentrations of KNO_3(0,0.25,0.50,1.00,1.50,and 2.00%)in two rice cultivars-KDML105 and RD15.The results showed that soaking rice seed in KNO_3 at higher concentrations could delay the imbibition time.The higher concentrations of KNO_3 delayed the imbibition time of rice seed and took a longer time to reach the end of phases 1 and 2 compared to the lower concentrations.The patterns of seed imbibition using distilled water of both rice cultivars(KDML105 and RD15)were quite similar,but with different concentrations of KNO_3,the imbibition time taken to reach the end of phases 1 and 2 was slightly postponed in KDML105 suggesting that different rice cultivars may need different imbibition times for soaking seed in the priming process.Experiment 2 evaluated the effects of seed priming with 1.0 and 2.0%KNO_3 at different imbibition times.It was found that priming with 1.0%KNO_3 showed better seed germination than priming with 2.0%KNO_3 and seed priming with 1.0%KNO_3 at the imbibition time of early phase 2(or 28 h for KDML105)improved seed germination and increased both the speed and uniformity of seed germination.The results of this study show promise for the use of priming with 1.0%KNO_3 soaked until early phase 2 of seed imbibition for improving the seed germination and vigor of rice in dry seed broadcasting.     

盐预处理对大麦种子萌发和小孢子愈伤形成的影响

为探究盐预处理对大麦种子萌发和小孢子培养的影响,以大麦耐盐品种花11和盐敏感品种花30为材料,比较了它们在不同盐浓度预处理下,种子萌发过程中的发芽率、主根长以及小孢子培养过程中的愈伤组织产量差异,同时对2个品种在小孢子时期响应盐胁迫的4个关键基因的表达进行了研究。结果显示:花30的种子和小孢子在无NaCl和低浓度NaCl预处理时,对盐胁迫的耐受性均低于花11,但经高浓度NaCl (萌发期为15 g/L,小孢子时期为300 mg/L)预处理后,花30的种子和小孢子对高浓度盐胁迫的耐受性均显著增强,且发芽率、主根长和愈伤产量均显著高于花11;通过对2个品种在盐预处理下的发芽率、主根长以及愈伤产量相对值的相关性分析发现,2个品种在种子萌发期和小孢子时期响应盐预处理的相对值呈显著正相关。同时,在小孢子培养阶段,经过300 mg/L NaCl预处理后,花30中小热激蛋白基因HvsHSP1和翻译起始因子1基因HveIF1A的表达量在高浓度盐胁迫下较花11显著上调。因此,供试品种间在种子萌发过程和小孢子培养过程对盐预处理的响应差异在某种程度上可能具有一致性,HvsHSP1和HveIF1A基因可能与盐...     

不同类型玉米品种籽粒胚乳细胞增殖与籽粒建成的关系

【目的】研究不同类型玉米品种籽粒胚乳细胞增殖与籽粒充实期相关性状的关系。【方法】以紧凑型玉米品种(先玉335和郑单958)和平展型玉米品种(长城799和农大364)为试验材料,于授粉后3,5,7,10,15,20,25,30,35,40,45,50,55,60 d取果穗中部籽粒,观测胚乳细胞数目、单粒质量、灌浆速率、淀粉含量、籽粒淀粉磷酸化酶和蔗糖转化酶活性等指标的变化动态,并分析不同玉米品种籽粒胚乳细胞增殖动态与籽粒灌浆期相关生理指标的关系。【结果】随着灌浆期的延长,不同玉米品种籽粒胚乳细胞数、单粒质量、淀粉含量均呈"S"型曲线增长,籽粒胚乳细胞数在授粉后20 d基本稳定。胚乳细胞数与单粒质量、淀粉含量和灌浆速率均呈极显著正相关;籽粒充实期的生理状态影响着籽粒灌浆,淀粉磷酸化酶和蔗糖转化酶活性在灌浆期呈现单峰曲线,但峰值出现时间因品种而异,紧凑型玉米酶活性最高点出现时间要晚于平展型玉米;籽粒胚乳细胞数与这两种酶活性均呈显著相关。【结论】玉米籽粒中胚乳细胞数与胚乳细胞的充实状态、籽粒单粒质量、灌浆速率、淀粉含量、淀粉磷酸化酶蔗糖转化酶活性均呈显著正相关;要提高玉米产量,应在灌浆前期提高胚乳细胞增殖速率和灌浆速率,保证光合产物快速充分地运送到籽粒中去,使籽粒淀粉积累达到最佳状态,进而达到高产。