采后荔枝果皮色素、总酚及有关酶活性的变化

成熟度约八成的“淮枝”在采收后2天内,色素的合成代谢仍相当活跃,类胡萝卜素,花色素苷的含量增高,多酚氧化酶和苯丙氨酸解氨酶的活性增大,总酚保持原有水平,叶绿素降解,反映了果实达到完全成熟的特征,随后,上述各项参数因果实的衰老而下降,与采收当天相比,7天后花色素苷为90％,类黄酮为59％,总酚为71％,苯丙氨酸解氨酶活性为46％,讨论了酚类,花色素苷及两种酶活性之间的关系及对荔枝果实在成熟,衰老褐变中的作用。     

采后荔枝果皮色素、总酚及有关酶活性的变化

成熟度约八成的“淮枝”在采收后2天内,色素的合成代谢仍相当活跃,类胡萝卜素,花色素苷的含量增高,多酚氧化酶和苯丙氨酸解氨酶的活性增大,总酚保持原有水平,叶绿素降解,反映了果实达到完全成熟的特征,随后,上述各项参数因果实的衰老而下降,与采收当天相比,7天后花色素苷为90％,类黄酮为59％,总酚为71％,苯丙氨酸解氨酶活性为46％,讨论了酚类,花色素苷及两种酶活性之间的关系及对荔枝果实在成熟,衰老褐变中的作用。     

高浓度臭氧对蒙古栎叶片酚类物质含量和总抗氧化能力的影响

采用开顶箱(OTC)法,研究了高浓度臭氧(80±8 nmol·mol^-1)熏蒸处理对蒙古栎叶片 中总酚、类黄酮、单宁及丙二醛(MDA)含量的影响,使用1,1-二苯基苦基苯肼(DPPH) 法测定了蒙古栎叶片的总抗氧化能力.结果表明:蒙古栎叶片中总酚、类黄酮、缩合单宁和MDA的含量都有所增加,其中总酚和缩合单宁含量分别增加了48.17%和26.77%,差异显著（P<0.05）;类黄酮和MDA含量分别增加了24.66%和5.26%,差异不显著(P＞0.05);蒙古栎叶片总抗氧化能力显著增强(P<0.05),且与叶片中总酚和缩合单宁含量呈显著的正相关关系.     

栗瘿蜂幼虫期虫瘿与寄主植物部分营养和防御物质含量或活性的比较

为验证营养假说,本研究首次利用分光光度计测定了栗瘿蜂(Dryocosmus kuriphilus)幼虫期虫瘿及其着生枝条的部分营养和防御物质的含量或活性。研究结果表明:虫瘿中单宁和类黄酮的含量及苯丙氨酸解氨酶和多酚氧化酶的活性显著低于枝条的含量或活性,符合营养假说;虫瘿蛋白质和还原糖含量显著低于枝条的含量,淀粉的含量与枝条的含量差异不显著,不符合营养假说。     

β-氨基丁酸对拟南芥叶片花色素苷的影响

研究发现β-氨基丁酸（BABA）处理减少了拟南芥（Arabidopsis thaliana）叶片花色素苷的积累,而且BABA处理降低了花色素苷合成基因（CHS,LDOX,UF3GT）的表达,却上调了苯丙氨酸解氨酶（PAL）的表达,同时促进了花色素苷降解酶多酚氧化酶（PPO）的活性。叶片对DPPH（1,1-二苯基-2-苦基苯肼）的清除能力、总酚和类黄酮含量以及电导率和细胞死亡率的测定表明BABA降低了叶片的抗氧化能力、电导率及细胞死亡率。结果表明BABA处理抑制了花色素苷在叶片中的积累。     

不同灰霉病抗性苹果果实中酚类物质代谢特征

以‘秦冠’、‘富士’、‘金冠’苹果果实为材料,通过对损伤接种灰葡萄孢菌(Botrytis cinerea Pers)后果肉组织酚类代谢主要产物和相关酶活性变化的分析测定,揭示苹果采后酚类物质代谢与灰霉病抗性的关系,为苹果灰霉病抗性鉴定和筛选抗灰霉病苹果资源提供理论指导。结果表明:(1)接种灰葡萄孢菌后,3个苹果品种的果实灰霉病发病率和病斑直径大小均为‘秦冠’‘富士’‘金冠’,而且3个品种间的发病率和病斑直径均差异显著,各品种对灰霉病的抗性由强到弱依次为‘秦冠’‘富士’‘金冠’。(2)抗病品种‘秦冠’果肉组织中类黄酮、木质素含量及苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)活性均显著高于感病品种‘富士’和‘金冠’,但总酚含量为‘秦冠’‘金冠’‘富士’,且3品种间总酚含量差异显著。研究表明,抗病苹果品种通过调节果肉内酚类物质代谢,增强次生代谢能力,其中类黄酮和木质素含量的增加强化了果实的抗性反应,进而提高对灰霉病的抗性,但总酚含量与植物抗病性关系不大。     

诱抗菌激发子诱导黄瓜产生对炭疽病的抗性

用细胞壁提取法从诱抗菌中提取出激发子,经点滴法测定发现该激发子与活菌一样能诱导黄瓜产生对炭疽病的抗性反应。黄瓜经激发子处理后,体内与抗病反应有关的过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶活性显著增强;过氧化物酶同功酶酶带增多,着色加深;酚类物质和木质素含量也明显提高。     

诱抗菌激发子诱导黄瓜产生对炭疽病的抗性

用细胞壁提取法从诱抗菌中提取出激发子,经点滴法测定发现该激发子与活菌一样能诱导黄瓜产生对炭疽病的抗性反应。黄瓜经激发子处理后,体内与抗病反应有关的过氧化物酶、多酚氧化酶和苯丙氨酸解氨酶活性显著增强;过氧化物酶同功酶酶带增多,着色加深;酚类物质和木质素含量也明显提高。     

红树植物秋茄类黄酮代谢及其抗氧化活性对高盐胁迫的响应

以红树植物秋茄为试验材料,设置不同浓度NaCl(0、200和500mmol·L-1)处理的砂培实验,应用qRTPCR分析秋茄叶片中类黄酮物质合成上游的4个关键酶基因——苯丙氨酸解氨酶基因(PAL)、肉桂酸羟化酶基因(C4 H)、4-香豆酰辅酶A连接酶基因(4CL)和查尔酮合成酶基因(CHS)的转录水平,并对关键酶活性进行了分析,同时测定了幼苗生物量、钾钠离子含量、类黄酮含量及其抗氧化活性,以探讨秋茄耐盐性与类黄酮物质的关系,为揭示木本植物耐盐机制奠定基础。结果显示:(1)在盐处理条件下,秋茄叶片中PAL、4CL、C4 H和CHS4个关键酶基因的转录水平显著上调,PAL、4CL、C4H酶活性和CHS含量随着盐浓度的增加而明显上升。(2)与对照相比,秋茄根、茎、叶干重在盐处理3d和15d后均无显著变化,而秋茄株高仅在200mmol·L-1盐处理15d后显著增加,其余浓度和时间均未发现有显著性变化。(3)随着盐浓度的升高,秋茄叶片类黄酮含量显著增加,K+/Na+明显下降,丙二醛含量显著降低,活性氧自由基清除率显著增加。研究表明,盐处理加强了秋茄叶片中类黄酮代谢过程中相关酶基因的表达,类黄酮物质的累积有助于其抗氧化能力的提高,进而提高秋茄的抗盐性,维持盐胁迫下秋茄的正常生长。     

黑斑病对甘薯叶酚类物质含量、PPO及PAL活性的影响

选用对甘薯黑斑病抗性不同的品种南京-92(高抗)和烟台-252(高感)的叶片为材料,研究黑斑病对甘薯叶总酚含量、绿原酸含量、类黄酮含量以及苯丙氨酸解氨酶(PAL)活性和酚氧化酶(PPO)活性的影响。结果表明:在未受黑斑病侵染时,南京-92叶片中类黄酮含量、绿原酸含量、PAL活性显著或极显著高于烟台-252,可以作为选育和鉴定抗黑斑病品种的生理指标,但总酚含量和PPO活性差异不显著。接种后2～8d内,南京-92叶片内总酚含量和PPO活性增加迅速,与烟台-252达到显著或极显著差异,总酚含量和PPO活性的上升速度快、保持时间长,有利于提高对黑斑病的抵抗能力。     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Analysis of twin of eyeless regulation during early embryogenesis in Drosophila melanogaster

The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.     

Host plants of someRhinanthoideae (Scrophulariaceae) of eastern North America

Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.     

Apoptotic Regulation of Caspase Activity

Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.     

广西青藓科分类学修订

通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

New species of Peruvian Orchidaceae III

Sixteen new species are proposed in the generaAckermania, Dressleria, Epidendrum, Maxillaria, Oncidium, Rodriguezia, Sigmatostalix, andTrigonidium. All new species are illustrated.Maxillaria vittariifolia L. O. Williams is newly recorded for Peru. A key is provided forTrigonidium of Peru.Trigonidium loretoense Schltr. andT. peruvianum Schltr. are lectotypified.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.