藜科盐生植物的形态特征与耐盐分子机理研究进展

在非生物环境胁迫因子中,盐胁迫是造成农作物减产的主要因素之一.从藜科植物耐盐的形态生理学机制和分子生物学角度入手,讨论了藜科植物耐盐基因工程的新进展,探讨藜科盐生植物的盐胁迫机理,为利用基因工程手段培育耐盐植物奠定基础.     

The Micronesia Challenge: Assessing the Relative Contribution of Stressors on Coral Reefs to Facilitate Science-to-Management Feedback

Fishing and pollution are chronic stressors that can prolong recovery of coral reefs and contribute to ecosystem decline. While this premise is generally accepted, management interventions are complicated because the contributions from individual stressors are difficult to distinguish. The present study examined the extent to which fishing pressure and pollution predicted progress towards the Micronesia Challenge, an international conservation strategy initiated by the political leaders of 6 nations to conserve at least 30% of marine resources by 2020. The analyses were rooted in a defined measure of coral-reef-ecosystem condition, comprised of biological metrics that described functional processes on coral reefs. We report that only 42% of the major reef habitats exceeded the ecosystem-condition threshold established by the Micronesia Challenge. Fishing pressure acting alone on outer reefs, or in combination with pollution in some lagoons, best predicted both the decline and variance in ecosystem condition. High variances among ecosystem-condition scores reflected the large gaps between the best and worst reefs, and suggested that the current scores were unlikely to remain stable through time because of low redundancy. Accounting for the presence of marine protected area (MPA) networks in statistical models did little to improve the models’ predictive capabilities, suggesting limited efficacy of MPAs when grouped together across the region. Yet, localized benefits of MPAs existed and are expected to increase over time. Sensitivity analyses suggested that (i) grazing by large herbivores, (ii) high functional diversity of herbivores, and (iii) high predator biomass were most sensitive to fishing pressure, and were required for high ecosystem-condition scores. Linking comprehensive fisheries management policies with these sensitive metrics, and targeting the management of pollution, will strengthen the Micronesia Challenge and preserve ecosystem services that coral reefs provide to societies in the face of climate change.     

水稻生殖突变体的外观形态特征研究

通过对3种水稻生殖突变体材料的外观形态进行观察后发现,FM1突变体植株不能由营养生长转入生殖生长,一直保持营养生长状态;FM2突变体植株不能分化发育出小穗,只能在进入生殖生长后分化出穗枝梗;FM3突变体植株在生殖生长过程中不能分化出正常小穗,其疑花内部的雌蕊和雄蕊明显退化。已经证实这3种生殖突变性体植株都不能产生有性生殖后代,只能通过群体内的显性杂合体分离出隐性突变体植株。     

Relative Importance of Modularity and Other Morphological Attributes on Different Types of Lithic Point Weapons: Assessing Functional Variations

The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point''s contour. Klingenberg''s covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as “near decomposable units” in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric attributes, and evolving on a modular way.     

泰山虫草子实体形态特征与rDNA变异位点分析

用光学显微镜和扫描电镜对采自泰山的虫草子实体可孕部分进行形态观察,结果表明泰山虫草在子实体形态、子囊的排列方式、子囊的包埋方式、子囊壳的形态等与九州虫草完全一致。对虫草核糖体DNA的18S、28S、ITS区克隆测序,并进行序列比对后发现两种虫草的碱基差异较小,其同源性高达99%,符合种内遗传特性。结合形态学和分子生物学两方面的特征,初步推断两者可能都是九州虫草。     

锥状施克里普藻孢囊的多种形态特征

休眠孢囊是某些甲藻生活史的重要阶段,它被认为是甲藻赤潮爆发的种源。通过观察我国沿海海域采集的锥状施克里普藻（Scrippsiella trochoidea（Stein）Loeblich）休眠孢囊的类型以及形态特征,并将实验条件下形成的休眠孢囊与海区沉积物中休眠孢囊的形态特征进行比较,结果表明,锥状施克里普藻细胞在20°C、12小时光照/12小时黑暗、f/2培养基和f/2-N培养基中分别培养至第14天和第8天,可以观察到休眠孢囊的产生。培养30天后,培养液中有大量休眠孢囊,将藻液避光保存90天后,观察到培养基中有4种类型的休眠孢囊产生：（1）球形到椭球形（长25-39μm）,钙质外壁,稀疏或密被钙质附属物（长1-4μm）;（2）球形（直径为29-35μm）,钙质外壁,附属物非钙质（长0.5-1.5μm）;（3）球形到椭球形（长29-35μm）,钙质,表面光滑,无附属物;（4）球形（直径24-35μm）,有机外壁,无附属物。第1种类型的孢囊最为常见,分别占到2种培养条件下所得全部孢囊的77.70%和95.18%。从沉积物中所得的孢囊多属于第1种类型。分析了实验条件下形成不同类型休眠孢囊的原因和比例,同时探讨了海区沉积物中形成多种孢囊形态特征的原因,为锥状施克里普藻孢囊的生态研究提供了依据。     

Congruence of Morphological and Molecular Phylogenies

When phylogenetic trees constructed from morphological and molecular evidence disagree (i.e. are incongruent) it has been suggested that the differences are spurious or that the molecular results should be preferred a priori. Comparing trees can increase confidence (congruence), or demonstrate that at least one tree is incorrect (incongruence). Statistical analyses of 181 molecular and 49 morphological trees shows that incongruence is greater between than within the morphological and molecular partitions, and this difference is significant for the molecular partition. Because the level of incongruence between a pair of trees gives a minimum bound on how much error is present in the two trees, our results indicate that the level of error may be underestimated by congruence within partitions. Thus comparisons between morphological and molecular trees are particularly useful for detecting this incongruence (spurious or otherwise). Molecular trees have higher average congruence than morphological trees, but the difference is not significant, and both within- and between-partition incongruence is much lower than expected by chance alone. Our results suggest that both molecular and morphological trees are, in general, useful approximations of a common underlying phylogeny and thus, when molecules and morphology clash, molecular phylogenies should not be considered more reliable a priori.     

Phylogenetic Relationships of Extinct Cetartiodactyls: Results of Simultaneous Analyses of Molecular, Morphological, and Stratigraphic Data

Although some recent morphological and molecular studies agree that Cetacea is closely related to Hippopotamidae, there is little consensus on the phylogeny within Cetartiodactyla. We addressed this problem by conducting two analyses: (1) a simultaneous cladistic analysis of intrinsic data (morphology and molecules) and (2) a stratocladistic analysis, which included morphological, molecular, and stratigraphic data. Unlike previous simultaneous analyses, we had the opportunity to include data from the recently described hindlimbs of protocetid and pakicetid cetaceans. Our intrinsic dataset includes 73 taxa scored for 8,229 informative characters, of which 208 are morphological and 8,021 molecular. Both analyses supported the exclusion of Mesonychia from Cetartiodactyla and a close phylogenetic relationship between Hippopotamidae and Cetacea. Many polytomies in the strict consensus of the most parsimonious trees for the intrinsic dataset can be attributed to differing positions for Raoellidae, which in some trees is the sister-group to Cetacea. Pruning Raoellidae and 18 other taxa from all most parsimonious produced a fully resolved agreement subtree, which indicates that the Old World taxa Cebochoerus and Mixtotherium are successive stem taxa to Whippomorpha (i.e., Cetacea + Hippopotamidae). The main result of adding stratigraphic information to the intrinsic dataset was that we found fewer most parsimonious trees, which in most respects were congruent with a subset of the shortest trees for the intrinsic dataset. Our stratocladistic analysis supports species of Diacodexis as the most basal cetartiodactyls, a clade of suiform cetartiodactyls, a monophyletic Tylopoda that includes Protoceratidae, and a monophyletic Carnivora. We were unable to identify any pre-Miocene stem taxa to Hippopotamidae, thus its ghost lineage is still 39 million years long. The relatively low Bremer support for many nodes in our trees indicates that our phylogenetic hypotheses should be subjected to further testing.     

Inhibition of Platelet Activation and Thrombus Formation by Adenosine and Inosine: Studies on Their Relative Contribution and Molecular Modeling

Background

The inhibitory effect of adenosine on platelet aggregation is abrogated after the addition of adenosine-deaminase. Inosine is a naturally occurring nucleoside degraded from adenosine.

Objectives

The mechanisms of antiplatelet action of adenosine and inosine in vitro and in vivo, and their differential biological effects by molecular modeling were investigated.

Results

Adenosine (0.5, 1 and 2 mmol/L) inhibited phosphatidylserine exposure from 52±4% in the control group to 44±4 (p<0.05), 29±2 (p<0.01) and 20±3% (p<0.001). P-selectin expression in the presence of adenosine 0.5, 1 and 2 mmol/L was inhibited from 32±4 to 27±2 (p<0.05), 14±3 (p<0.01) and 9±3% (p<0.001), respectively. At the concentrations tested, only inosine to 4 mmol/L had effect on platelet P-selectin expression (p<0.05). Adenosine and inosine inhibited platelet aggregation and ATP release stimulated by ADP and collagen. Adenosine and inosine reduced collagen-induced platelet adhesion and aggregate formation under flow. At the same concentrations adenosine inhibited platelet aggregation, decreased the levels of sCD40L and increased intraplatelet cAMP. In addition, SQ22536 (an adenylate cyclase inhibitor) and ZM241385 (a potent adenosine receptor A_2A antagonist) attenuated the effect of adenosine on platelet aggregation induced by ADP and intraplatelet level of cAMP. Adenosine and inosine significantly inhibited thrombosis formation in vivo (62±2% occlusion at 60 min [n = 6, p<0.01] and 72±1.9% occlusion at 60 min, [n = 6, p<0.05], respectively) compared with the control (98±2% occlusion at 60 min, n = 6). A_2A is the adenosine receptor present in platelets; it is known that inosine is not an A_2A ligand. Docking of adenosine and inosine inside A_2A showed that the main difference is the formation by adenosine of an additional hydrogen bond between the NH₂ of the adenine group and the residues Asn253 in H6 and Glu169 in EL2 of the A_2A receptor.

Conclusion

Therefore, adenosine and inosine may represent novel agents lowering the risk of arterial thrombosis.     

横斑锦蛇的形态学性状初探

横斑锦蛇Euprepiophis perlacea是中国西部特有种,《中国濒危动物红皮书》极危物种,研究成果相对匮乏。本研究采用样带法和样方法在横斑锦蛇分布区内采集到标本20号,测量其鳞片特征、体长、尾长等形态学性状,结合文献资料中已有的5号标本数据,进行统计分析。结果表明,鳞片特征是有效的分类依据,尤其背鳞(19-19-17行)、左上唇鳞数(7)和右上唇鳞数(7)在所有标本中无任何变化,是鉴定该物种的最重要特征。对尾下鳞、体长、尾长、头长、头宽、头高、眼间距共7个形态学性状数据进行方差分析,性别间的差异均无统计学意义,未发现蛇类中普遍存在的两性异形现象。横斑锦蛇体色靓丽、无毒、性情温和、行动迟缓、分布区狭窄、种群数量稀少,分布区内人口密度高,人为干扰严重,急需加强科学研究、法制宣传和科普教育,以保障该物种种群延续。     

Relative Impacts of Elephant and Fire on Large Trees in a Savanna Ecosystem

Elephant and fire are considered to be among the most important agents that can modify the African savanna ecosystem. Although the synergistic relationship between these two key ecological drivers is well documented, it has proved much more difficult to establish the relative effects they have on savanna vegetation structure at a fine-scale over time. In this study, we explore the comparative impacts of fire and elephant on 2,522 individually identified large trees (≥5 m in height) in the Kruger National Park, South Africa. Data were collected from 21 transects first surveyed in April 2006 and resurveyed in November 2008, to determine the relative importance of past damage by these agents on subsequent impacts and mortality. The occurrence of fire or elephant damage in 2006 affected the amount of tree volume subsequently removed by both these agents; elephant removed more tree volume from previously burned trees and the impact of subsequent fire was higher on previously burned or elephant-utilized trees than on undamaged trees. Mortality was also affected by an interaction between previous and recent damage, as the probability of mortality was highest for trees that suffered from fire or elephant utilization after being pushed over. Subsequent fire damage, but not elephant utilization, on debarked trees also increased the probability of mortality. Mortality was twice (4.6% per annum) that of trees progressing into the ≥5 m height class, suggesting an overall decline in large tree density during the 30-month study period. The responses of large trees were species and landscape-specific in terms of sensitivity to elephant and fire impacts, as well as for levels of mortality and progression into the ≥5 m height class. These results emphasize the need for fine-scale site-specific knowledge for effective landscape level understanding of savanna dynamics.     

Morphological and Molecular Analysis Calls for a Reappraisal of the Red Rain Cells of Kerala

Early studies on the coloured particles that fell as red rain over southern India identified them as unicellular eukaryotes such as members of the red algae or fungi; however, the results of the present investigation are not consistent with this designation. Using transmission electron microscopy, we have demonstrated significant differences in the ultrastructure when compared with representative species from these other groups. Most notably, the red rain cells show no evidence of typical eukaryotic internal structures such as mitochondria or endoplasmic reticulum. Furthermore, comparisons based on elemental composition using energy-dispersive X-ray analysis, as well as Raman spectral signatures demonstrate significant dissimilarities in their molecular composition. The identity and origins of the red rain cells remain an enigma; however, our findings are more consistent with an unidentified prokaryote, and thus suggest that previous attempts at their identification should be reappraised.     

自噬的形态特征及分子调控

自噬过程是生物进化过程中保留下来的一种细胞蛋白和细胞器的循环利用机制,一般认为自噬过程对于细胞在恶劣环境下生存具有重要意义.而细胞的发育和凋亡与自噬有着密切的关系.本文通过自噬体的形成方式综述了三种自噬形式的形态特征以及自噬的分子调控对细胞的影响.     

Morphological and Molecular Variation of Morus laevigata in India

Morus spp., commonly known as mulberry, is significantly associated with human civilization and spread of silk-culture from Asia to Europe, Africa and Latin America. One of its species, Morus laevigata, traditionally well known for its timber value, forage use and silkworm's feed, is widely distributed in India extending from Himalayan foothill to Andaman islands. The variability occurring for 12 morpho-biochemical parameters and RAPD profiles, generated with 13 selected RAPD primers, for M. laevigata accessions from six different zones were investigated. Analyses revealed high degree of genotypic similarity of collection from Himalayan foothill (West Bengal) with those from Andaman Islands. Specific accessions from central India and south India also revealed genotypic similarities with specific accessions from north-east India. These observations are discussed in the context of clonal propagation of mulberry and evolutionary perspective of dispersal of this species, through human activities     

Relative Importance of Rootstock and Scion in Determining Growth and Fruiting in Young Apple Trees

Principal component analysis has been used on annual measuresof vegetative and reproductive activity of young apple trees.The trial consisted of four clones (M.2, M.4, M.9, and M.16)used as both rootstock and scion in all possible combinationsto give 16 tree types. The results have suggested that theseannual records can best be summarized by their sum and lineartrend with time. Further analyses using these new measures ofsum and trend have enabled the effects of rootstock and scionto be partitioned. Increase in stem dry weight is largely rootstock-controlledbut trend with time is mainly scion-controlled. The reverseoccurs with fruit number where total fruit is largely scion-controlledbut the trend is dominated by the rootstock. Measures of leadergrowth are intermediate between stem growth and fruiting intheir responses. Statistical interactions are greatest withfruiting records which suggests that this activity is less harmoniouslycontrolled by rootstock and scion than other activities. Use of sum and linear trend is recommended for future analysesof apple tree trials without recourse to further multivariateanalyses.     

Simultaneous Molecular and Morphological Analysis of Braconid Relationships (Insecta: Hymenoptera: Braconidae) Indicates Independent mt-tRNA Gene Inversions Within a Single Wasp Family

We investigated the phylogeny of the Braconidae (Insecta: Hymenoptera) with a much expanded data set compared with that of previous attempts, employing 16S and 28S rDNA gene fragments, together with a suite of morphological characters, from 74 ingroup taxa. Most notably, parsimony analyses under a range of models recovered the Aphidiinae as sister group to the cyclostomes and the Ichneutinae as sister group to the microgastroids. The cyclostomes were recovered as a natural group only if certain, putatively misplaced genera (Mesostoa, Aspilodemon) were excluded from them. Further, mapping of rearrangement characters onto this phylogeny of the Braconidae indicated parallel inversions of the mt-tRNA^D gene, with the two instances of inversion distinguishable by the presence or absence of an additional tRNA gene (tRNA^H). This is the first report of a parallel inversion of a mt-tRNA gene and makes the Braconidae the first metazoan family to display both parallel inversions and translocations. Received: 6 April 2001 / Accepted: 9 July 2001     

Diplazium subsinuatum and Di. tomitaroanum should be Moved to Deparia According to Molecular, Morphological, and Cytological Characters

rbcL sequence data revealed that the putative intergeneric hybrid, Diplazium tomitaroanum Masam. belongs in Deparia, as also does Diplazium subsinuatum (Wall, ex Hook, et Grev.) Tagawa, one of the putative parents. An examination of rachis, scale and spore morphology, and chromosome data provide support for this placement. We propose a new taxonomic treatment of the two Diplazium species as Deparia. Received 7 December 1999/ Accepted in revised form 15 February 2000     

Relative Contribution of Terminal Oxidases to the Respiration of Isolated Cells

The relative contributions of cytochrome (Cyt) oxidase, cyanide-insensitiveoxidase and residual oxidase to the total respiration of isolatedleaf cells were determined in order to integrate them into amathematical model. During cell incubation, the contributionof cyanide-insensitive oxidase decreased whereas the latentactivity of the enzyme increased. Carbonyl cyanide m-chlorophenyl-hydrazonemainly stimulated the Cyt oxidase activity but did not releasethe latent activity of cyanide-insemitive oxidase. (Received May 10, 1983; Accepted September 21, 1983)