凤眼莲根分泌物氨基酸对根际肠杆菌属F2细菌降酚的影响

研究2种有代表性的凤眼莲(Eichhornia crassipes)根分泌物Met、Lys对其根际肠杆菌属F₂细菌(Enterobacter sp.F₂)降酚的影响.结果表明,具有正趋化作用的Met的不同浓度对细菌的生长动态、细菌降酚酶活性、细菌降酚效率基本没有影响;而具有负趋化作用的Lys在高浓度(10^-2、10^-3mol·L^-1)下延滞细菌的生长,抑制细菌的降酚酶活性,随着Lys浓度的降低各种抑制作用相应减弱,凤眼莲根分泌物氨基酸作为根际微生态系统的信息流,影响着该系统的降酚功能.     

凤眼莲根分泌物氨基酸组分对根际肠杆菌属F_2细菌的趋化作用

凤眼莲（Ｅｉｃｈｈｏｒｎｉａｃｒａｓｓｉｐｅｓ）的根分泌物中含有Ｍｅｔ等多种氨基酸,其中Ｍｅｔ、ＧＡＢＡ、Ｇｌｙ、Ａｌａ、Ａｓｐ、Ｓｅｒ、Ｖａｌ和Ｌｅｕ（１０－７～１０－２ｍｏｌ·Ｌ－１）均对凤眼莲的根际肠杆菌属Ｆ２（Ｅｎｔｅｒｏｂａｃｔｅｒｓｐ．Ｆ２）细菌有强烈的正趋化作用;Ｇｌｕ、Ｔｈｒ和Ｈｉｓ（１０－７～１０－３ｍｏｌ·Ｌ－１）也对该菌有一定的正趋化作用;而Ｌｙｓ、Ｃｙｓ、Ａｒｇ、Ｔｙｒ、Ｐｒｏ、Ａｓｎ、Ｇｌｎ、Ｉｌｅ、Ｐｈｅ和Ｔｙｐ则对该菌表现出一定的负趋化作用．对细菌的正趋化作用存在一个趋化物的最适浓度范围．具有正趋化作用的氨基酸在凤眼莲根际的浓度都较高,而具有负趋化作用的浓度则较低,这正是凤眼莲与该根际细菌结合为根际微生态系统的原因之一．     

凤眼莲根分泌物氨基酸对根际肠杆菌属F2细菌降酚的影响

研究２种有代表性的凤眼莲（Ｅｉｃｈｈｏｒｎｉａｃｒａｓｓｉｐｅｓ）根分泌物Ｍｅｔ、Ｌｙｓ对其根际肠杆菌属Ｆ２细菌（Ｅｎｔｅｒｏｂａｃｔｅｒｓｐ．Ｆ２）降酚的影响．结果表明,具有正趋化作用的Ｍｅｔ的不同浓度对细菌的生长动态、细菌降酚酶活性、细菌降酚效率基本没有影响;而具有负趋化作用的Ｌｙｓ在高浓度（１０－２、１０－３ｍｏｌ·Ｌ－１）下延滞细菌的生长,抑制细菌的降酚酶活性,随着Ｌｙｓ浓度的降低各种抑制作用相应减弱,凤眼莲根分泌物氨基酸作为根际微生态系统的信息流,影响着该系统的降酚功能     

施氮水平对蚕豆枯萎病和根际微生物代谢功能多样性的影响

研究不同氮肥用量对蚕豆根际微生物功能多样性的影响及其与蚕豆枯萎病发生的关系.通过田间小区试验,采用Biolog微平板分析法研究了4个施氮水平N₀(0 kg·hm-2)、N₁(56.25 kg·hm^-2)、N₂(112.5 kg·hm^-2)和N₃(168.75 kg·hm^-2)对蚕豆枯萎病危害和根际微生物代谢功能多样性的影响.结果表明： 施氮(N₁、N₂、N₃)处理显著降低了蚕豆枯萎病的病情指数和根际镰刀菌的数量,显著增加了蚕豆根际的细菌、放线菌数量、细菌/真菌和放线菌/真菌.其中N₂处理蚕豆枯萎病病情指数和镰刀菌数量最低,而细菌、放线菌数量、细菌/真菌和放线菌/真菌最高.与N₀处理相比,N₁、N₂、N₃处理均提高了根际微生物群落碳源利用率(AWCD),但对6类碳源的利用存在一定的差异.不同施氮水平下根际微生物群落对糖类、羧酸类和氨基酸类碳源利用程度较高.主成分分析表明,施氮明显改变了蚕豆根际微生物群落结构,糖类、羧酸类和氨基酸类碳源是区分施氮导致土壤微生物群落变化的敏感碳源.施氮抑制了根际微生物对部分糖类和羧酸类碳源的利用,而提高了对氨基酸和酚酸类碳源的利用,这可能是施氮减轻蚕豆枯萎病危害的重要原因之一.适量施氮能增加根际细菌、放线菌数量,改变微生物代谢功能,降低病原菌数量,是抑制蚕豆枯萎病发生的有效措施.     

根际CO2浓度升高对网纹甜瓜光合特性及产量和品质的影响

采用雾培植株根际通CO₂处理方式,研究了开花结果期根际CO₂浓度升高对网纹甜瓜光合作用及产量和品质的影响.结果表明：在网纹甜瓜果实发育期间,与350 μL·L^-1（对照）处理相比,根际2500和5000 μL CO₂·L^-1处理的叶片光合色素含量、净光合速率（P_n）、气孔导度（g_s）、胞间CO₂浓度（C_i）及PSⅡ最大光化学效率（F_v/F_m）均不同程度降低,而气孔限制值（L_s）显著提高,且5000 μL CO₂·L^-1处理的变化幅度高于2500 μL CO₂·L^-1处理;单株产量、果实中维生素C和可溶性糖含量显著降低,有机酸含量显著提高.可见,网纹甜瓜果实发育期间根际CO₂浓度超过2500 μL·L^-1时,其光合作用及果实发育会受到显著抑制,从而导致产量和品质降低.
     

根际CO2浓度升高对网纹甜瓜光合特性及产量和品质的影响

采用雾培植株根际通CO₂处理方式,研究了开花结果期根际CO₂浓度升高对网纹甜瓜光合作用及产量和品质的影响.结果表明：在网纹甜瓜果实发育期间,与350 μL·L^-1（对照）处理相比,根际2500和5000 μL CO₂·L^-1处理的叶片光合色素含量、净光合速率（P_n）、气孔导度（g_s）、胞间CO₂浓度（C_i）及PSⅡ最大光化学效率（F_v/F_m）均不同程度降低,而气孔限制值（L_s）显著提高,且5000 μL CO₂·L^-1处理的变化幅度高于2500 μL CO₂·L^-1处理;单株产量、果实中维生素C和可溶性糖含量显著降低,有机酸含量显著提高.可见,网纹甜瓜果实发育期间根际CO₂浓度超过2500 μL·L^-1时,其光合作用及果实发育会受到显著抑制,从而导致产量和品质降低.
     

短期CO2浓度升高和干旱胁迫对白羊草土壤碳氮和微生物根际效应的影响

采用人工气候室和盆栽控水试验研究黄土丘陵区典型草本植物白羊草在倍增CO₂浓度(800 μmol·mol^-1)下和充分供水(75%～80%的田间持水量)、轻度干旱胁迫(55%～60%的田间持水量)和重度干旱胁迫(35%～40%的田间持水量)下根际和非根际土壤碳氮含量和微生物群落结构及其根际效应.结果表明: CO₂浓度升高和干旱胁迫对白羊草根际和非根际土壤有机碳、全氮和水溶性有机碳(DOC)含量及其根际效应均无显著影响.轻度干旱胁迫下CO₂浓度升高显著促进了根际土壤水溶性有机氮(DON)的消耗,导致DOC/DON升高,提高了DON的负根际效应和DOC/DON的正根际效应.干旱胁迫和CO₂浓度升高对土壤总磷脂脂肪酸(总PLFA)和细菌PLFA的根际效应无显著影响.CO₂浓度升高条件下干旱胁迫显著提高了根际土壤G⁺/G^- PLFA,降低了非根际土壤G⁺/G^- PLFA,导致其根际效应显著提高,表明根际微生物群落由自养微生物群落向异养微生物群落的转变.     

短期CO2浓度升高和干旱胁迫对白羊草土壤碳氮和微生物根际效应的影响

采用人工气候室和盆栽控水试验研究黄土丘陵区典型草本植物白羊草在倍增CO₂浓度(800 μmol·mol^-1)下和充分供水(75%～80%的田间持水量)、轻度干旱胁迫(55%～60%的田间持水量)和重度干旱胁迫(35%～40%的田间持水量)下根际和非根际土壤碳氮含量和微生物群落结构及其根际效应.结果表明: CO₂浓度升高和干旱胁迫对白羊草根际和非根际土壤有机碳、全氮和水溶性有机碳(DOC)含量及其根际效应均无显著影响.轻度干旱胁迫下CO₂浓度升高显著促进了根际土壤水溶性有机氮(DON)的消耗,导致DOC/DON升高,提高了DON的负根际效应和DOC/DON的正根际效应.干旱胁迫和CO₂浓度升高对土壤总磷脂脂肪酸(总PLFA)和细菌PLFA的根际效应无显著影响.CO₂浓度升高条件下干旱胁迫显著提高了根际土壤G⁺/G^- PLFA,降低了非根际土壤G⁺/G^- PLFA,导致其根际效应显著提高,表明根际微生物群落由自养微生物群落向异养微生物群落的转变.     

杉木解酚菌的研究

从杉木林土壤中筛选到5株高效解酚菌(F₂、F₃、F₄、F₇、F₁₅),结果表明,F₄、Fd,F₂、F₁₅5d能将600rng·L^-1的阿魏酸降解完,F₇的降解率为91.3%;F₄、F₃、F₂、F₇d,F₁₅、4d能将600mg·L^-1的对羟基苯甲酸完全降解;5株解酚菌对邻香草醛的降解能力较弱,除F₂5d能将300mg·L^-1的邻香草醛完全降解外,其余4株5d的降解率为83%～96%.同时发现,F₄能抑制杉苗生长,而其余4株则能在不同条件下促进杉苗生长,将5种菌按等比例混合使用,在土壤添加酚酸的情况下,仍能促进菌根苗Z和非菌根苗生长,杉木苗干重增长率为8.9%～168%.     

不同二氧化碳浓度条件下红松和长白赤松幼苗根际土壤微生物数量研究

以连续5年不同CO₂浓度(开顶箱700μmol·mol^-1、500μmol·mol^-1、对照箱和裸地)处理的长白赤松和红松幼苗为研究对象,在2003年7～9月分别对幼苗根际土壤细菌、真菌、放线菌数量进行比较研究.结果表明,高浓度CO₂处理对长白赤松幼苗根际土壤细菌数量起显著的(P≤0.001)促进作用,对根际真菌和放线菌数量的促进作用却不明显;对红松来说,除8月份700μmol·mol^-1CO₂处理和7月份500μmol·mol^-1CO₂处理之外,在各月份中受高浓度CO₂处理的根际土壤细菌数量均较对照箱和裸地显著增多(P≤0.001),而根际土壤真菌数量变化除9月份(P≤0.001)外均不明显,放线菌数量受高浓度CO₂的影响亦不明显.     

Characterization and Separation of Some of the Coordination Compounds of Chromium and Aluminon

Chromic nitrate and aluminon (ATA) react to form highly colored lakes. Examination of these lakes by the Vosburgh and Cooper method has led to the identification of a pigment [(ATA)Cr(H₂O)_x] which is insoluble in water and absolute alcohol, a deep red anionic component [(ATA)_BCr(H₂O)_x]^-y, and a purplish-red cationic component [(ATA)Cr₄(H₂O)_x]^+y. These components of the lake have been isolated and separated in the dry form. The anionic compound is apparently a simple coordination compound and can be used as a cytoplasmic stain while the cationic component is a chelate and can be used as a rather selective nuclear stain. In addition to these components, a number of other components were also found. Not only the ratio between chromium and aluminon but also the concentration of the reactants influences the formation of these different components. The amount of pigment formed is maximal with a molar ratio of 1 and a concentration of 10^-2 M or 10^-1 M. The anionic component is maximal with a molar ratio of 1 Cr to 6 aluminon at the 10^-1 M concentration, the cationic component is maximal with a molar ratio of 4 chromium to 1 aluminon at the 10^-1 M concentration. None of these are formed at the 10^-4 M concentration but only a deep redpurple soluble compound at the 1 : 1 ratio, which was not further investigated.     

灌溉施肥水平对盐渍化农田水盐分布及玉米产量的影响

水资源缺乏和过量施肥影响着干旱半干旱盐渍化地区农业的发展.研究不同灌溉和施肥量对土壤水盐分布和青贮玉米产量的影响,可为该区确定适宜的灌溉和施肥量提供依据.试验于2015和2016年在大同盆地的盐渍化农田进行,设3种灌溉水平:土壤水分上限分别为田间持水率(θ_f)的100%(W₁)、90%(W₂)和80%(W₃),根据各处理灌溉前的土壤平均实际含水率计算灌水量;2015年设4种施肥水平:900(F₁)、750(F₂)、600(F₃)和450 kg·hm^-2(F₄),2016年设F₁、F₂和F₃共3种.试验用化肥为缓释复合肥,总养分含量48%,其中N:P₂O₅:K₂O的比例为30:12:6.结果表明: 土壤表层电导率随施肥量的增加而增大,施肥水平对平均电导率(EC)和含水率的影响在0～10 cm土层显著,与F₁相比,F₂的0～10 cm土层平均EC在2015年和2016年分别降低25.6%～42.7%和6.4%～7.7%.20～80 cm土层的水分含量随施肥量的增加而降低,与F₁相比,2015年F₂、F₃和F₄处理20～80 cm土层平均土壤含水率分别增加5.9%、16.7%和16.7%,2016年F₂和F₃分别增加13.3%和16.7%.产量在两年中均表现为F₁和F₂高于F₃和F₄,W₃低于W₁和W₂; F₁和F₂的产量差异不明显;与W₁相比,W₂的产量减少低于15 %.因此,施复合肥600～750 kg·hm^-2(氮肥含量180～270 kg·hm^-2),且灌溉水平为W₁和W₂时,可以保证该地区盐渍化土壤种植玉米获得较高的产量,并且不会造成根系层的盐分积累.     

The number and localisation of adenine nucleotide-binding sites in beef-heart mitochondrial ATPase (F1) determined by photolabelling with 8-azido-ATP and 8-azido-ADP

1. When irradiated 8-azido-ATP becomes covalently bound (as the nitreno compound) to beef-heart mitochondrial ATPase (F₁) as the triphosphate, either in the absence or presence of Mg²⁺, label covalently bound is not hydrolysed.

2. In the presence of Mg²⁺ the nitreno-ATP is bound to both the and β subunits, mainly (63%) to the subunits.

3. After successive photolabelling of F₁ with 8-azido-ATP (no Mg²⁺) and 8-azido-ADP (with Mg²⁺) 4 mol label is bound to F₁, 2 mol to the and 2 mol to the β subunits.

4. When the order of photolabelling is reversed, much less 8-nitreno-ATP is bound to F₁ previously labelled with 8-nitreno-ADP. It is concluded that binding to the -subunits hinders binding to the β subunits.

5. F₁ that has been photolabelled with up to 4 mol label still contains 2 mol firmly bound adenine nucleotides per mol F₁.

6. It is concluded that at least 6 sites for adenine nucleotides are present in isolated F₁.     

Enzymatic synthesis of new aromatic and aliphatic esters of flavonoids using Candida antarctica lipase as biocatalyst

Enzymatic acylation of rutin and esculin with aromatic, aliphatic and aryl-aliphatic acids using Candida antarctica lipase in tert amyl alcohol as solvent was investigated under low water content. Whatever the acyl donor used, the conversion yields and initial rates for esculin were higher than for rutin. For a given flavonoid, the performance of these reactions depended on the acyl donor structures. For aliphatic acids, conversion yields and initial rates of both flavonoids were respectively in the ranges of 68-90% and of 9.5×10^-2-72×10^-2 mmol l^-1 h^-1. For aromatic acids, the reaction occurred only with the aryl subgroup (cinnamic, hydrocinnamic, 3,4-dihydroxyhydrocinnamic and 4-hydroxyphenyl acetic acids) and was drastically influenced by the presence of side chain and substitution patterns of the aromatic ring. Except for hydrocinnamic acid (75%, 23.4×10^-2 mmol l^-1 h^-1), with these acids the conversion yields and initial rates were lower and in the range of 10-45% and of 0.7×10^-2 to 12.1×10^-2 mmol l^-1 h^-1. Unsaturation of the side chain of the hydrocinnamic acid decreased the esculin conversion rate from 75 to 13% and initial rate from 23.4 to 1.76×10^-2 mmol l^-1 h^-1. The presence of hydroxyl or nitro-groups on the aromatic ring of the aryl aliphatic acid also reduced conversion yields and initial rates. Even without a spacer, the non-phenolic ring acid (quinic acid) was reactive and lead to conversion yields of about 20 and 23% respectively for rutin and esculin.     

斑马鱼tbx2b调控心脏房室间隔发育的功能研究*

tbx2是早期心脏发育的关键基因。为进一步探究其对房室间隔(AVC)发育的影响,研究利用CRISPR/Cas9介导的基因敲除技术,成功构建了斑马鱼tbx2b突变体。通过T7E1酶切对其F₀进行敲除效率检测,结果显示平均敲除效率约为57.5%。F₁进一步筛选获得tbx2b杂合突变体,测序结果显示突变类型为11 bp碱基缺失的移码突变。tbx2b杂合子内交获得纯合子,tbx2b纯合突变体在5 dpf死亡并出现早期心脏环化异常表型。斑马鱼整胚原位杂交实验显示在3 dpf tbx2b纯合突变体中, 心脏腔室分化特异性标志基因nppa、nppb表达上调并异位表达在AVC,而AVC发育关键基因has2的表达消失。高效构建tbx2b突变体并初探其对下游基因的影响,为后续深入研究tbx2b对心脏AVC发育的作用奠定了基础,同时加深了人们对早期心脏调控网络的认识。     

Spring Time and Autumn Time Toxic Effects of Copper (II), 3-(2-Furyl) Prop-2-Enal Semicarbazone and [CuCl2(FASC)2] Complex in Mice

In vitro, 3-(2-furyl) prop-2-enal semicarbazone-copper (II) complex [CuCl₂(FASC)₂] presents antimitotic effects. In this work we studied the in vivo seasonal toxic effects in male Swiss mice of CuCl₂, and FASC and the [CuCl₂(FASC)₂] complex. In spring, one injection of CuCl₂8.10^-2 mmol killed 16% of animals after 24 h. Cupric chloride lethal dose was up to 64.10^-2 mmol with 100% mice dead after 24 h. FASC was well tolerated from 0.65 to 1.3 mmol. The complex was 100% lethal with 48.10^-2 mmol. In autumn, mice were more sensitive to CuCl₂ and to the complex with lethal doses up to 32.10^-2 mmol and 8.10^-2 mmol, respectively. On the other hand, FASC was well tolerated. It is concluded that the in vivo toxic effects of CuCl₂ and [CuCl₂(FASC)₂] complex are quite different in spring and autumn.     

Uncoupler-reversible inhibition of mitochondrial ATPase by metal chelates of bathophenanthroline. II. comparison with other inhibitors

(1) Trisbathophenanthroline-Fe²⁺(BPh₃Fe²⁺) alters the hyperbolic relationship between concentration of ATP and reaction velocity of F₁-ATPase to sigmoidal, with a simultaneous decrease in maximal velocity. (2) BPh₃Fe²⁺ binds to the β-subunit of F₁ and competes with the binding of aurovertin. The reversal of this effect by uncouplers in enhanced by ADP and diminished by ATP. BPh₃Fe²⁺ also changes the hyperbolic concentration dependence of aurovertin binding to sigmoidal. (3) BPh₃Fe²⁺ stabilizes F₁ against cold inactivation and cold dissociation in an uncoupler-reversible manner. (4) BPh₃Fe²⁺ efficiently protects F₁ against the light-induced inactivation occurring in the presence of Rose Bengal, and the effect is reversed by uncouplers. (5) The results are discussed in relation to the reaction mechanism of F₁-ATPase and other enzymes catalyzing the reversible hydrolysis of pyrophosphate bonds.     

Uncoupler-reversible inhibition of mitochondrial ATPase by metal chelates of bathophenanthroline. I. General features

(1) Certain metal chelates of 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline, BPh) are potent inhibitors of soluble mitochondrial F₁-ATPase. (2) The BPh-metal chelate inhibition of soluble mitochondrial F₁-ATPase is relieved by uncouplers of oxidative phosphorylation. (3) The uncouplers appear to interact directly with the inhibitory chelates, forming stoichiometric adducts. (4) A complex between F₁ and bPh₃Fe²⁺, containing 3 mol BPh₃Fe²⁺/mol F₁, has been isolated. The enzymically inactive F₁-BPh₃Fe²⁺ complex binds uncouplers, yielding an enzymically active F₁-BPh₃Fe²⁺-uncoupler complex.