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排序方式: 共有392条查询结果,搜索用时 15 毫秒
1.
Abstract

Several aroma hops (Humulus lupulus L.) were recently introduced in Northern Italy as a small-scale production of excellence. In this preliminary study, the American cultivar Cascade was investigated in a combined morphological and phytochemical survey. Morphological investigation on trichome structure, density and distribution was performed by scanning electron microscopy and light microscopy. Essential oil composition, α/β-acid and polyphenol profiles over 3 years were determined by GC-MS and HPLC analyses. Two types of non-glandular (simple and cystolithic) and glandular (peltate and bulbous) trichomes were observed on leaves and female inflorescences. The peltate trichomes resulted as the main sites of terpene production and accumulation. The essential oil profiles showed myrcene, β-caryophyllene, (E)-β-farnesene and humulene epoxide II as the dominant compounds over the three collection times, although with different relative abundances. The presence of two exclusive compounds, γ-muurolene and trans-γ-cadinene, characterized the investigated cv. Cascade, potentially enhancing herbal, woody and spicy aroma traits of this cultivation in Northern Italy. The bitter acid composition showed quantitative values consistent with literature data only for the second and third monitoring year. Qualitative differences in polyphenol content were also recorded, for the presence of quercetin-3-O-malonylglucoside and kaempferol-3-O-rutinoside, which may characterize this peculiar Italian cultivation.  相似文献   
2.
Summary The idea of trade-offs among antiherbivore defences in plants is examined using data from a South American blackberry (Rubus bogotensis). Two distinct morphs of R. bogotensis, one with glandular trichomes and one without, were compared with respect to leaf toughness, number of prickles and prickle length. The two morphs were sympatric and grew under similar environmental conditions. The morph lacking trichomes had significantly tougher leaves and also tended to have more and longer prickles. Bioassay showed that Ithomiid larvae fed to a lesser extent on tough leaves than on more tender ones. Correlations between antiherbivore defences within each phenotype revealed three significant or almost significant negative relationships. The comparisons support the hypothesis that trade-offs exist among antiherbivore defences.  相似文献   
3.
Escalation (macroevolutionary increase) or divergence (disparity between relatives) in trait values are two frequent outcomes of the plant‐herbivore arms race. We studied the defences and caterpillars associated with 21 sympatric New Guinean figs. Herbivore generalists were concentrated on hosts with low protease and oxidative activity. The distribution of specialists correlated with phylogeny, protease and trichomes. Additionally, highly specialised Asota moths used alkaloid rich plants. The evolution of proteases was conserved, alkaloid diversity has escalated across the studied species, oxidative activity has escalated within one clade, and trichomes have diverged across the phylogeny. Herbivore specificity correlated with their response to host defences: escalating traits largely affected generalists and divergent traits specialists; but the effect of escalating traits on extreme specialists was positive. In turn, the evolution of defences in Ficus can be driven towards both escalation and divergence in individual traits, in combination providing protection against a broad spectrum of herbivores.  相似文献   
4.
Endometriosis is a chronic inflammatory syndrome and nearly 6%‐10% of women are affected by it during the reproductive period. Previous studies have proved that microRNAs (miRNAs) are implicated in the pathogenesis of ovarian endometriosis. In this study, we aimed to investigate that restored miR‐488 would effectively inhibit the development of endometriosis. The microarray‐based data analysis was performed to screen endometriosis‐related differentially expressed genes (DEGs). The mouse model in endometriosis syndrome was established by being subcutaneously injected with Estradiol benzoate, and the ectopic endometrial tissues and normal endometrial tissues were collected. Additionally, the endometrial glandular epithelial cells were extracted from the endometrial glandular epithelial tissues from normal and endometriosis mice. In order to examine the role of miR‐488 in mice with endometriosis, we measured miR‐488 expression and expression levels of Frizzled‐7 (FZD7), cyclinD1, β‐catenin, and c‐Myc in vivo and in vitro. Finally, we detected the effect of miR‐488 on cell proliferation, apoptosis, migration and invasion in vitro. FZD7 was upregulated in human endometriosis. The data showed higher expression levels of FZD7, β‐catenin, c‐Myc and cyclinD1, and lower miR‐488 expression in mouse endometrial tissues. FZD7 was the target gene of miR‐488. Furthermore, elevated miR‐488 in isolated mouse endometrial glandular endometrial cells inhibited FZD7, the translocation of β‐catenin to nucleus, the activation of Wnt pathway, and the cell proliferation, migration and invasion. Collectively, these findings indicated that up‐regulated miR‐488 may reduce the proliferation, migration and invasion of endometrial glandular epithelial cells through inhibiting the activation of Wnt pathway by down‐regulating FZD7.  相似文献   
5.
The ultrastructure of the labellar epidermis of 13 species of Maxillaria and one hybrid was examined using low-vacuum scanning electron microscopy (SEM). The labellum may be homogeneous and glabrous or papillose, comprising one type of cell only, or heterogeneous with papillae, uniseriate trichomes and/or glands in various combinations. The trichomes are unbranched and multicellular with pointed or truncated tips. Moreover, in some taxa, moniliform trichomes occur, and these are thought to fragment with the formation of pseudopollen. Homogeneous and heterogeneous labellar organization may represent separate evolutionary lines. Preliminary results suggest that labellar features may provide additional taxonomic characters allowing determination of intrageneric affinities.  相似文献   
6.
K. Chummun, M. Fitzpatrick, P. Lenehan, P. Boylan, E. Mooney and G. Flannelly
Diagnostic and therapeutic dilemma associated with atypical glandular cells on liquid‐based cervical cytology Background: In 2008, the management of women in Ireland with atypical glandular cells changed to immediate referral to colposcopy. The optimal management of these women is unclear. A balance between the detection of occult disease and overtreatment is required. Methods: Our study aim was to document the experience of this policy at the National Maternity Hospital, Dublin. Information from the computerized data management system was analysed with the statistical package SPSS. Results: In 2009, 156 women attended colposcopy following a single atypical glandular cell diagnosis on liquid‐based cytology. The mean age was 41 years. Thirty (19.2%) women had abnormal vaginal bleeding, 31 (19.9%) were smokers and 34 (21.8%) had received previous treatment. The colposcopy was satisfactory in 125 (80.1%) and unsatisfactory in 31 (19.9%). Cervical histology was available for 146 (93.6%) women: 57 excisional procedures and 89 diagnostic biopsies. Abnormal histology was detected in 46 women (31.5%). Four women (2.7%) had invasive cancer, five (3.4%) had adenocarcinoma in situ, 21 (14.4%) had cervical intraepithelial neoplasia (CIN) grade 2 or 3 and 16 (11.0%) had CIN1. No abnormality was detected in 100 women (68.5%), including 35 (61.4%) of those who had undergone excisional procedures. The colposcopic impression in this group was unsatisfactory in 10 women (28.6%), glandular abnormalities in six (17.1%), high‐ and low‐grade changes in 12 (34.2%) and six (17.1%) women, respectively, and normal in one (2.9%). The findings were essentially negative in the remaining 10 women: overall, 30 (19.2%) of the 156 women referred to colposcopy had at least CIN2. Conclusion: This study confirmed significant levels of high‐grade disease in women referred to colposcopy with atypical glandular cells on cytology. Concerns about undetected endocervical disease resulted in high levels of negative excisional biopsies. Alternative strategies, including endometrial sampling, human papillomavirus testing and discussion at clinicopathological meeting, should be considered.  相似文献   
7.
Abstract.  1. Nutrient resource availability and host-plant foliar pubescence both influence arthropod food webs, but multifactor studies are needed to understand their interdependence and relative importance. Arthropods were sampled by clipping foliage from Metrosideros polymorpha (Myrtaceae) trees of pubescent, glabrous, and intermediate leaf forms on fertilised and unfertilised plots.
2. Fertilisation decreased leaf mass per area (LMA) but did not change the relative mass of pubescence within leaf morphological classes.
3. Fertilisation increased densities of individuals in four taxonomic orders, densities of individuals and species of all trophic levels, and the biomass of Collembola and Homoptera. Herbivore relative diversity (Shannon H ') also increased with fertilisation, but detritivore diversity declined due to increasing dominance of Salina celebensis (Schaeffer) (Collembola).
4. Detritivore density, driven again by S. celebensis , increased with decreasing leaf pubescence, but Heteroptera and Acari were most abundant on the intermediate pubescence class, and Psocoptera density and biomass increased with increasing pubescence. Trophic-level species density did not change with leaf morphological class, but relative diversity of all arthropods and of detritivores increased with increasing pubescence.
5. Both resource availability and leaf pubescence affected Metrosideros arthropod communities. However, the pervasive positive influence of fertilisation did not translate to compositional shifts, and there were no interactions with leaf morphological class. In contrast, the effects of leaf pubescence on arthropod density, biomass, and diversity were more restricted taxonomically, and non-parametric manova and redundancy analyses demonstrated significant differentiation in community composition on the pubescent morphology.  相似文献   
8.
Summary Foliar pubescence in the mexican madrone (Arbutus xalapensis H.B.K.) is an extremely variable character. Leaf specimens of pilose and glabrous madrones showed a similar composition of major secondary compounds. On the other hand, sympatric pilose and glabrous individuals were found to support significantly different insect guilds. Insect preference was strongly associated to mouthpart anatomy. Chewing and gall-forming insects were significantly more abundant on glabrous trees while sucking insects were more common on pilose trees. Additionally, parasitation of sucking insects was lower on pilose trees, possibly because the plant trichomes provide protection against parasitoids.  相似文献   
9.
The leaves of 52 species of Lithocarpus in China were studied. The adaxial leaf epidermis was investigated by light microscopy. Epidermal cells of the adaxial surface were classified into three types on the basis of the outline of their anticlinal walls, i.e. sinuate, straight and curved. The abaxial leaf epidermis was investigated by light microscopy and scanning electron microscopy. The following types of trichome were observed: appressed parallel tuft, stellate, fused stellate, papillae, stipitate fasciculate, solitary unicellular, appressed laterally attached unicellular, curly thin‐walled unicellular, bulbous and thin‐walled peltate. The fused stellate, appressed laterally attached unicellular and curly thin‐walled unicellular trichomes were reported in Lithocarpus for the first time. The appressed parallel tuft trichome, which is recognized as a salient characteristic of Lithocarpus, was not found in 15 species. A cladistic analysis was performed on the basis of the leaf epidermal features. According to the leaf epidermal features and several morphological characteristics, 26 of the 52 species could be divided into seven groups. Similar groups can be found in Barnett's and Camus' systems. The trichomes of four genera in Fagaceae are listed and compared. Lithocarpus had 14 types of trichome, 11 of which were identical to types found in Quercus, more than in Castanopsis and Cyclobalanopsis. The evolutionary trends of trichomes in Fagaceae are discussed and a new point of view is raised. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 216–228.  相似文献   
10.
Leaf architecture and epidermal characters in Zelkova, Ulmaceae   总被引:4,自引:0,他引:4  
Zelkova , with six extant species in Eurasia - three in East Asia (Z. schneideriana, Z. serrata, Z. sinica) , one in south-western Asia (Z. carpinifolia) and two in southern Europe (Z. abelicea, Z. sicula) - was investigated with respect to leaf architecture and epidermal characters by LM and SEM. The leaf venation of Zelkova is relatively uniform, while leaf size and shape are highly variable. Characters such as teeth and epidermal cells, trichomes and stomata provide useful specific distinctions. Beginning in the Miocene, increasing aridity in Central Asia would appear to have been responsible for isolating the eastern Asiatic species from their European/western Asiatic counterparts. The European range underwent further changes in response to Quaternary climatic oscillations.  相似文献   
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