水杉是北美红杉的一个亲本吗？

本文根据有关细胞学和形态学资料.不同意Schlarbaum等以红杉没有水杉的具长着丝点区域的标记染色体来否定水杉(属)是红杉的亲本,同时认为,他们提出某种杉木属植物为红杉提供了染色体组而是它的亲本的意见难以成立,从而支持Stebbins的假设,水杉(属)可能是北美红杉的一个亲本。而且,它或许还是一个父本。     

从形态学看北美红杉的亲本

本文通过形态性状的比较研究认为AAAABB的同源异源多倍体红杉可能由亲本水杉(属)和巨杉(属)杂交起源,它们分别为红杉提供了染色体组AA和染色体组B。这与根据核型等资料的分析结果相吻合。但跟Stebbins认为红杉除水杉(属)以外的另一个亲本已经灭绝并没有留下近缘的推论存在分歧。     

从杉木看一个新的高等植物核型类型

本文报道浙江丽水地区栽培杉木的核型为K(2n)=2x=22=20m(2SAT)+2sm,它的染色体长度比(最长/最短)大于2、小于4,没有臂比大于2的染色体,属Stebbins的“1B”核型。根据Stebbins的研究,后者在高等植物中尚未发现过,因此“1B”可能是一个新的高等植物核型类型。笔者还发现其他产地的杉木及德昌杉木、米德杉木、巨杉和红杉—B染色体组的核型也为“1B”类型。     

北美红杉的一个亲本是灭绝的吗?

本文作者对Stebbins的"水杉和红杉的染色体及亲缘关系"一文进行了评述, 认为红杉除水杉(属)以外的另一个二倍体亲本可能并没有灭绝, 它或许就是巨杉(属).     

巨杉可能是红杉的一个祖先吗?

世界闻名的珍稀植物红杉Sequoia sempervirens是裸子植物中唯一染色体倍性最高的自然多倍体(2n=6x=66),植物学工作者一直十分关注着它的起源问题。Hirayoshi &Nakamura认为巨杉Sequoiadendron giganteum可能为红杉提供了一个染色体组,但Stebbins在假设一个古代水杉属Metasequoia植物可能是同源异源多倍体(autoallopoly-     

杉科的细胞分类学和系统演化研究

根据杉科的核型资料,本文(1)提出“1B”可能是一个新的高等植物核型类型;(2)讨论了各属的有关分类学问题及相互亲缘关系,它们的进化顺序可能是柳杉属、水松属、落羽杉属、水杉属、巨杉属、红杉属、杉木属(密叶杉属与之近缘)、台湾杉属;(3)支持金松属分立成金松科,它可能比杉科各属原始;(4)红杉(AAAABB)的亲本可能是二个古代种水杉”和“巨杉”,它们的直接后裔或留下的近缘是水杉和巨杉;(5)杉科存在A和L两条进化路线,前者包括柳杉属、水松属、落羽杉属、台湾杉属,后者包括水杉属、巨杉属、红杉属、杉木属(密叶杉属);(6)提出一个杉科新系统(包括一个新亚科)：I．柳杉亚科(柳杉属),II．落羽杉亚科(水松属、落羽杉属),III．红杉亚科(冰杉属、巨杉属、红杉属),Ⅳ.杉木亚科(杉木属、密叶杉属),V．台湾杉亚科,新亚科(台湾杉属)。本文还对前人的杉科系统作了讨论。     

杉科的细胞分类学和系统演化研究

根据杉科的核型资料,本文(1)提出“1B”可能是一个新的高等植物核型类型;(2)讨论了各属的有关分类学问题及相互亲缘关系,它们的进化顺序可能是柳杉属、水松属、落羽杉属、水杉属、巨杉属、红杉属、杉木属(密叶杉属与之近缘)、台湾杉属;(3)支持金松属分立成金松科,它可能比杉科各属原始; (4)红杉(AAAABB)的亲本可能是二个古代种“水杉”和“巨杉”,它们的直接后裔或留下的近缘是水杉和巨杉;(5)杉科存在A和L两条进化路线,前者包括柳杉属、水松属、落羽杉属、台湾杉属;后者包括水杉属、巨杉属、红杉属、杉木属(密叶杉属);(6)提出一个杉科新系统(包括一个新亚科):Ⅰ.柳杉亚科(柳杉属),Ⅱ.落羽杉亚科(水松属、落羽杉属),Ⅲ.红杉亚科(水杉属、巨杉属、红杉属),Ⅳ.杉木亚科(杉木属、密叶杉属),Ⅴ.台湾杉亚科,新亚科(台湾杉属)。本文还对前人的杉科系统作了讨论。     

水氮组合对冬小麦干物质及氮素积累和产量的影响

于2015—2017年小麦生长季在山东省泰安市农业科学研究院肥城试验基地进行田间试验,供试材料为‘泰山28',在150(A₁)、300(A₂)、450(A₃)、600 m³·hm^-2(A₄)4个灌水量和90(B₁)、135(B₂)、180(B₃)、225 kg·hm^-2(B₄)4个施氮水平下,研究水氮组合对小麦生长发育过程中干物质积累、氮素积累、水分消耗利用、光合特性、籽粒产量等的影响。结果表明: A₃B₃条件下各生育阶段的干物质积累量和氮素积累量,成熟期籽粒干物质和氮素积累量均为最大,花前花后营养器官生产储藏干物质及氮素向籽粒的运输量最高,且与其他水氮组合处理差异显著。各氮素处理下,60~200 cm土层土壤耗水量均为A₃>A₄>A₂>A₁;A₃B₃处理下的水分利用效率和氮素利用效率高于A₃B₄、A₄B₃和A₄B₄。A₃B₃处理显著提高了开花后7~28 d的旗叶净光合速率、气孔导度和蒸腾速率,有利于小麦进行光合作用合成碳水化合物。水氮组合效应显著影响籽粒产量和产量构成,且A₃B₃处理下小麦产量最高,达到9400 kg·hm^-2。综上,450 m³·hm^-2和180 kg·hm^-2的水氮组合处理可以显著提高小麦干物质和氮素积累量,并促进干物质和氮素向籽粒运输,与高水肥处理相比,可以有效提高水分利用效率和氮素利用效率,有利于增强小麦旗叶的光合能力,产生更多的碳水化合物,增加籽粒产量。     

水杉的核型研究

本文观察了水杉的染色体,确定2n=22,核型公式为K(2n)=22m(2SAT),全具中着丝点,有一对随体。第8、10、11号染色体具“长着丝点区域”。属“1A”型,与北美红杉-AA的核型非常相近,可能是它的一个亲本种的直接后裔。     

不同种植模式对土壤氮素转化及酶活性的影响

采用两年大田试验,研究了小麦-大豆（A₁）、小麦-甘薯（A₂）、玉米（A₃）、小麦/玉米/大豆（A₄）和小麦/玉米/甘薯（A₅）5种种植模式下,小麦/玉米/大豆套作体系的土壤酶活性变化特征及其对土壤氮素转化的影响.结果表明：与A₁、A₂、A₃和A₅相比,A₄提高了各作物在开花期（或吐丝期）和成熟期的土壤总氮含量及脲酶和蛋白酶活性,处理间表现为套作＞单作、大豆茬口＞甘薯茬口、边行＞中行;降低了小麦、玉米土壤的NO₃^--N、NH₄⁺-N含量及小麦土壤的硝酸还原酶活性.玉米土壤的硝酸还原酶活性在玉米、大豆共生前的拔节期为单作＞套作,在玉米、大豆共生后的吐丝期和成熟期为套作＞单作、大豆茬口＞甘薯茬口;大豆土壤的NO₃^--N、NH₄⁺-N含量及硝酸还原酶活性在分枝期为单作＞套作,在开花期和成熟期为套作＞单作、大豆茬口＞甘薯茬口、中行＞边行.     

Adenosine receptor agonists: Synthesis and biological evaluation of the diastereoisomers of 2-(3-hydroxy-3-phenyl-1-propyn-1-yl)NECA

Among the recently reported 2-(ar)alkynyl derivatives of 5′-N-ethylcarboxamidoadenosine (NECA), the (R,S)-2-(3-hydroxy-3-phenyl-1-propyn-1-yl)NECA [(R,S)-PHPNECA or SCH 59761] was found to be a very potent agonist at A₁ and A_2A receptor subtypes, with a K_i of 2.5 nM and 0.9 nM, respectively. Furthermore, this compound showed an inhibitory activity on platelet aggregation 16-fold higher than NECA, being the most potent anti-aggregatory nucleoside reported so far. Since this compound bears a chiral carbon in the side chain, the diastereoisomer separation was undertaken both by chiral HPLC and by a stereospecific synthetic method. Binding assays have shown that the (S)-diastereomer is about fivefold more potent and selective than the (R)-diastereomer as agonist of the A_2A receptor subtype [(S)-PHPNECA, K_iA_2A = 0.5 nM; (R)-PHPNECA, K_iA_2A = 2.6 nM]. Functional studies indicated that (S)-PHPNECA possesses marked vasodilating activity and produces a relevant decrease in heart rate. Moreover, the (S)-diastereomer proved to be about ten times more potent than the (R)-diastereomer in inducing cardiovascular effects, in in vivo hemodynamic studies. However, the greatest difference between these two enantiomers resulted in the platelet aggregation test: in fact, the (R)-diastereomer displayed an inhibitory activity similar to that of NECA, whereas the (S)-diastereomer was 37-fold more active than NECA as an inhibitor of rabbit platelet aggregation, induced by ADP. These data suggest that (S)-PHPNECA could be a useful tool to investigate the mode of binding of agonists to the platelet adenosine receptor subtype.     

Optical difference spectrum of the electron acceptor Ao in photosystem I

Optical measurements were made during low temperature photoreduction of photosystem I acceptors, A₁ and A₀. In the presence of a significant amount ofA₁ (detected by EPR), no absorbance changes occurred between 750-350 nm, indicating that this species is not a chlorophyll or pheophytin molecule. Spectral changes in this region that may be correlated with the appearance of A⁻₀, suggest that this component is a chlorophyll a anion monomer. The species is present in reaction centres in a ratio of 0.94 A_o/P700.

Photosystem I Primary acceptor Optical difference spectrum Chlorophyll a monomer     

活性焦对晋北盐碱地土壤性质和两种植物生长的影响

固废基改良剂是盐碱地改良的有效手段之一.活性焦作为一种多孔废弃物,应用于盐碱地预期可以起到改善土壤性质、减缓植物盐碱胁迫的作用.为了阐明活性焦对晋北盐碱地的改良效应,本研究设置不同用量活性焦(CK,0g·kg-1;A10,10 g·kg-1;A20,20 g·kg-1;A50,50 g·kg-1),分析其对盐碱地土壤性...     

Synthesis of 4-amino-6-(hetero)arylalkylamino-1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives as potent A(2A) adenosine receptor antagonists

In previous papers (Colotta, V. et al. Arch. Pharm. Pharm. Med. Chem. 1999, 332, 39. Colotta, V. et al. J. Med. Chem. 2000, 43, 1158) we reported the synthesis and binding affinity at bovine (b) A₁ and A_2A and human (h) A₃ adenosine receptors (ARs) of the 4-amino-6-benzylamino-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-1-one (compound A) which resulted in a potent and selective A_2A AR antagonist. Compound A provided the lead compound of a series of 6- or 8-(hetero)arylalkylamino-4-amino-2-phenyl-1,2,4-triazolo[4,3-a]quinoxalin-1-one derivatives (compounds 1–20) which are the object of this paper. Most of the newly synthesized compounds are inactive at hA₃ ARs while they possess both nanomolar bA_2A affinities and different degrees of bA_2A versus bA₁ selectivity. The binding data show that hydrophilic substituents on the benzyl moiety are the most profitable for bA_2A receptor affinity. Furthermore, their steric hindrance seems to play an important role for the bA_2A AR interaction, thus suggesting that the 6-aralkylamino moiety of these ligands interacts with a size-limited binding pocket of this AR subtype. Thus, the SAR studies provided us some new insights about the structural requirements of the bA_2A AR recognition site.     

脉冲电场作用对植物释放负离子与气孔特征的关系

植物在自然状态下释放负离子的能力很弱,施加脉冲电场可激发其释放能力。在密闭的玻璃箱中,研究紫背竹芋(Stromanthe sanguinea)、绒叶肖竹芋(Calathea zebrina)和朱顶红(Hippeastrum rutilum)在常态、脉冲电场和光照刺激下释放负离子的浓度,并观察叶片气孔特征,结果表明:(1)不同参数脉冲电场对植物释放负离子的能力影响不同,每种植物均具有高效释放负离子的最佳脉冲电场,紫背竹芋为A3B3C3(A3,U=1.5×104 V;B3,T=1.5 s;C3,?=65 ms);绒叶肖竹芋为A3B4C1(A3,U=1.5×104 V;B4,T=2.0 s;C1,?=5 ms);朱顶红为A4B4C1(A4,U=2.0×104 V;B4,T=2.0 s;C1,?=5 ms)。(2)植物体上所储存的电压越大,其释放负离子的能力越强。(3)脉冲电场作用时,植物释放负离子的能力与光照度呈正相关;无电场刺激时两者差异不显著(P0.05)。(4)植物释放负离子的能力与叶片气孔特征关系密切,脉冲电场作用下叶片气孔的开合度和气孔密度越大,其释放能力越强。     

Ergosterol peroxides as phospholipase A2 inhibitors from the fungus Lactarius hatsudake

Four ergosterol derivatives (1–4) have been isolated for the first time from the fruiting bodies of a basidiomycete fungus, Lactarius hatsudake, through activity-guided fractionation. Their structures were determined, using spectroscopic analysis, as: (22E,24R)-ergosta-5,7,22-dien-3β-ol (ergosterol, 1); 5,8-epidioxy-(22E,24R)-ergosta-6,22-dien-3β-ol (ergosterol peroxide, 2); 5,8-epidioxy-(24S)-ergosta-6-en-3β-ol (3); and (22E,24R)-ergosta-7,22-dien-3β,5,6β-triol (cerevisterol, 4). Compounds 2 and 3 showed selective inhibitory activity against Crotalus adamenteus venom phospholipase A₂ (PLA₂) enzyme, but not against Apis mellifcra bee venom PLA₂. The antiphospholipase A₂ activity of compounds 2 and 3 are reported here for the first time.     

Antagonists of the human adenosine A2A receptor. Part 1: Discovery and synthesis of thieno[3,2-d]pyrimidine-4-methanone derivatives

The (−)-(11R,2′S)-enantiomer of the antimalarial drug mefloquine has been found to be a reasonably potent and moderately selective adenosine A_2A receptor antagonist. Further investigation of this compound has led to the discovery of a series of keto-aryl thieno[3,2-d]pyrimidine derivatives, which are potent and selective antagonists of the adenosine A_2A receptor. These derivatives show selectivity against the A₁ receptor. Furthermore, some of these compounds have been shown to have in vivo activity in a commonly used model, suggesting the potential for the treatment of Parkinson’s disease.     

Molecular forms of acetylcholinesterase in developing Torpedo embryos

We have studied the evolution of acetylcholinesterase molecular forms during the embryonic development of Torpedo marmorata, in the electric organs and in the electric lobes of the central nervous system. In the early stages of development (35 mm embryos, ‘myogenic phase’ of electric organ development), globular forms of acetylcholinesterase (G₄ and G₂) are abundant in both tissues and the collagen-tailed form A₁₂ is already present. In the electric organs, this form accumulates rapidly after the 55–60 mm stage (‘electrogenic phase’), when synapse formation first commences. Although the molecular characteristics of the collagen-tailed forms, and particularly their aggregation properties, do not appear to change during development, their solubilization requires higher concentrations of MgCl₂, as the electrocytes mature, suggesting that they become more tightly integrated in a better organized basal lamina. The smaller collagen-tailed form A₈ shows a transient increase which coincides approximately with the maximal accumulation of A₁₂, suggesting that it is an intermediate in its synthesis. The accumulation of the hydrophobic G₂, which eventually becomes predominent in the adult electric organs, lags behind that of A₁₂. The functional significance of this important fraction of acetylcholinesterase is therefore not that of a pool of precursor for the synthesis of A₁₂. In the electric lobes, the tetrameric form (G₄) is abundant during development, as well as G₂ and G₁ at certain stages, but the A₁₂ form is predominant in the adult.     

Expression of the A12 form of acetylcholinesterase by developing avian leg muscle cells in vivo and during differentiation in primary cell cultures

The accumulation of the molecular forms of acetylcholinesterase (AChE) has been studied in leg muscles during embryonic chick development and in cell cultures initiated with myoblasts obtained from embryos at different stages of development. The collagen-tailed, A₁₂ form appears in leg muscles as soon as day 5 in ovo. An early excision of the lumbar zone of the neural tube at day 2 1/2 in ovo severely delayed the morphological development. In leg muscles dissected at day 12 in ovo from operated embryos, we found that the total amount of AChE activity and particularly the proportion of A₁₂ form were dramatically reduced.

Muscle cells were grown in vitro in a medium supplemented with fetal calf serum. In these conditions, chick muscle cells unequivocally synthesize the A₁₂ form when they originated from muscles which accumulated this form in vivo. In contrast, myoblasts obtained from 5-day old embryo leg muscles did not produce the A₁₂ form either in aneural cultures or in the presence of nerve cells. In relation with previous observations concerning chick myogenesis, we discuss the possibility that this difference reflects the existence of two types of myoblasts. This hypothesis would also explain the results of cocultures performed with nerve cells and normal or demedullated leg muscle myoblasts.     

Involvement of phospholipase A2 in norepinephrine release from synaptosomes isolated from rat cerebral cortex

Phospholipase A₂ added directly to superfused [³H]norepinephrine-labeled synaptosomes could cause the release of neurotransmitter molecules. Chloroquine and quinacrine, which block the action of phospholipase A₂, inhibited either the phospholipase A₂-stimulated or the high potassium-stimulated release of [³H]norepinephrine from synaptosomes. Only quinacrine blocked the high potassium-stimulated influx of Ca²⁺. It appears that during stimulation of synaptosomes, Ca²⁺ influx leads to the activation of phospholipase A₂, which in turn, hydrolyzes membrane phospholipids in situ. The formation of lysophospholipids may alter the microenvironment and the physicochemical properties of membranes, resulting in the release of neurotransmitter through exocytosis.