Occurrence of 2n gametes in the F1 hybrids of Oriental × Asiatic lilies (Lilium): Relevance to intergenomic recombination and backcrossing     

R. Barba-Gonzalez  K.-B. Lim  M. S. Ramanna  R. G. F. Visser  J. M. Van Tuyl 《Euphytica》2005,143(1-2):67-73

Cytological modes of the origin of 2n gametes were investigated in six different genotypes of F₁ hybrids between Oriental and Asiatic (OA) lilies (Lilium, 2n = 2x = 24). Chromosome pairing between the parental genomes was very low, the average frequency range from 0.3 to 1.2 bivalents per cell among the genotypes. Within a genotype the frequency of bivalents varied from 0 to 6 in some cases. The normally occurring haploid pollen grains were totally sterile. In contrast, in different genotypes, variable percentages of 2n pollen were found and shown to be fertile as estimated from pollen germination. A cytological analysis of Metaphase I and subsequent stages of meiosis using genomic in situ hybridization (GISH) revealed that there was intergenomic recombination between the alien genomes. Following Metaphase I stage, three different types of abnormal cytological events led to the formation of 2n pollen: (i) Post-Metaphase I division (PMI), (ii) Post-Metaphase II division (PMII) and (iii) Asymmetric Cytokinesis of the pollen mother cell followed by chromosome division. All three cytological events led to first division restitution (FDR) gametes. Based on in vitro pollen germination it was proved for two genotypes that 2n pollen was viable only during the first day of anthesis. It was possible to use 2n pollen successfully for backcrossing. Implications of 2n pollen for intergenomic recombination in BC₁ progenies are discussed.  相似文献   

Anti-inflammatory inhibition of endothelial cell adhesion molecule expression by flavone derivatives     

Kwon HM  Choi YJ  Jeong YJ  Kang SW  Kang IJ  Lim SS  Kang YH 《Journal of agricultural and food chemistry》2005,53(13):5150-5157

Endothelial expression of cell adhesion molecules (CAM) including VCAM-1, E-selectin, and PECAM-1 plays a leading role in atherosclerosis. Phenolic flavones have been shown to have an anti-inflammatory property. This study examines whether 3',4'-dimethoxy-7-hydroxyflavone (methoxyflavone) and 2',3',7-trihydroxyflavone (hydroxyflavone) inhibited monocyte adhesion to TNF-alpha-activated endothelium via reduction of CAM expression in human umbilical vein endothelial cells (HUVEC). In stimulated HUVEC the expression of VCAM-1 and E-selectin was enhanced with increasing mRNA levels. Methoxyflavone markedly interfered with the THP-1 monocyte adhesion to TNF-alpha-stimulated HUVEC. At concentrations of > or =25 microM, methoxyflavone blocked the induction of VCAM-1 but not that of E-selectin on the activated HUVEC. Immunocytochemical staining showed that methoxyflavone modestly inhibited PECAM-1 expression induced by TNF-alpha. In contrast, hydroxyflavone minimally inhibited TNF-alpha-stimulated E-selectin expression without affecting VCAM-1 level. The inhibitory effect of methoxyflavone on THP-1 adhesion to HUVEC appears to be greater than that of hydroxyflavone, most likely due to a greater inhibition of CAM expression. Thus, some flavone derivatives containing methoxy groups may have therapeutic potential attenuating inflammatory response-related atherosclerosis.  相似文献   

Lowland rainforest avifauna and human disturbance: persistence of primary forest birds in selectively logged forests and mixed-rural habitats of southern Peninsular Malaysia     

Kelvin S.-H. Peh  Navjot S. Sodhi  Susan L.-H. Lim 《Biological conservation》2005,123(4):489-505

We compared the composition and structure of primary forest avifauna among primary forests, selectively logged forests and mixed-rural areas (e.g. villages and agricultural areas) of Peninsular Malaysia. We found that forests that were selectively logged at least 30 years ago contained only 73-75% of the 159 species of extant primary forest birds, with an increased proportion of dominant species. We estimated that only 28-32% of the primary forest species utilized the mixed-rural habitat, and that the number of species that bred in the agricultural landscapes might be even lower. The microhabitat of different species most affected their vulnerability to disturbance. Most small, arboreal frugivores and omnivores, and insectivores that fed from tree trunks, showed greater persistence in the mixed-rural habitat than ground dwelling bird species, which were affected most by disturbance. Resource abundance and variables that were closely related to forest disturbance such as the density of large trees, density of dead trees, canopy cover density and shrub volume influenced the distribution of the primary forest birds. Large primary forest reserves and a revision of short-cycle logging regimes (ca. 30 years) are needed if we are to conserve the lowland rainforest avifauna of Peninsular Malaysia and other parts of Southeast Asia.  相似文献   

A method for selection of restriction enzymes for sdCAPS marker construction     

YeSol Jeong  SunYoung Lee  InHye Choi  YongPyo Lim  YoonKang Hur  Jack E. Staub  SangMin Chung 《Plant Breeding》2011,130(3):401-403

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Specific lipopolysaccharide found in cystic fibrosis airway Pseudomonas aeruginosa     

Ernst RK  Yi EC  Guo L  Lim KB  Burns JL  Hackett M  Miller SI 《Science (New York, N.Y.)》1999,286(5444):1561-1565

Cystic fibrosis (CF) patients develop chronic airway infections with Pseudomonas aeruginosa (PA). Pseudomonas aeruginosa synthesized lipopolysaccharide (LPS) with a variety of penta- and hexa-acylated lipid A structures under different environmental conditions. CF patient PA synthesized LPS with specific lipid A structures indicating unique recognition of the CF airway environment. CF-specific lipid A forms containing palmitate and aminoarabinose were associated with resistance to cationic antimicrobial peptides and increased inflammatory responses, indicating that they are likely to be involved in airway disease.  相似文献   

Conservation with sense     

Lim ML  Sodhi NS  Endler JA 《Science (New York, N.Y.)》2008,319(5861):281

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Comment on " 'Stemness': transcriptional profiling of embryonic and adult stem cells" and "a stem cell molecular signature"     

Fortunel NO  Otu HH  Ng HH  Chen J  Mu X  Chevassut T  Li X  Joseph M  Bailey C  Hatzfeld JA  Hatzfeld A  Usta F  Vega VB  Long PM  Libermann TA  Lim B 《Science (New York, N.Y.)》2003,302(5644):393; author reply 393

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家蚕茧层练减率的遗传和育种学的研究     

林中芬  钟生泉 《华南农业大学学报》1992,13(4):154-161

本试验对家蚕茧层练减率进行了遗传及育种学的研究,结果表明,不同化性间、不同系统间,不同品种间以及品种内雌雄性间的茧层练减率均有很显著差异,茧层练减率与全茧量,茧层量,茧层率的相关关系没有一致倾向,按海曼(Hayman)模型估算出茧层练减率的遗传参数为: D=1.8341、H_1=0.2793、H_2=0.2690、F=-0.0798;在茧层练减率的遗传成分中,以加性成分为主,茧层练减率显性效应由一个或一组不完全显性的主效基因控制;茧层练减率的广义遗传力为91.16％狭义遗传力为82.21％。茧层练减率的一般配合力间以及特殊配合力间差异很显著。茧层练减率一般情况下表现为负向杂种优势,通过用系统育种法和杂交育种法对茧层练减率进行选择试验,表明选择有效,但以杂交育种法更为理想。  相似文献   

Differences between tight and loose cultures: a 33-nation study     

Gelfand MJ  Raver JL  Nishii L  Leslie LM  Lun J  Lim BC  Duan L  Almaliach A  Ang S  Arnadottir J  Aycan Z  Boehnke K  Boski P  Cabecinhas R  Chan D  Chhokar J  D'Amato A  Ferrer M  Fischlmayr IC  Fischer R  Fülöp M  Georgas J  Kashima ES  Kashima Y  Kim K  Lempereur A  Marquez P  Othman R  Overlaet B  Panagiotopoulou P  Peltzer K  Perez-Florizno LR  Ponomarenko L  Realo A  Schei V  Schmitt M  Smith PB  Soomro N  Szabo E  Taveesin N  Toyama M  Van de Vliert E  Vohra N  Ward C  Yamaguchi S 《Science (New York, N.Y.)》2011,332(6033):1100-1104

With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.  相似文献   

Influence of land use on water quality in a tropical landscape: a multi-scale analysis     

María Uriarte  Charles B. Yackulic  Yili Lim  Javier A. Arce-Nazario 《Landscape Ecology》2011,26(8):1151-1164

There is a pressing need to understand the consequences of human activities, such as land transformations, on watershed ecosystem services. This is a challenging task because different indicators of water quality and yield are expected to vary in their responsiveness to large versus local-scale heterogeneity in land use and land cover (LUC). Here we rely on water quality data collected between 1977 and 2000 from dozens of gauge stations in Puerto Rico together with precipitation data and land cover maps to (1) quantify impacts of spatial heterogeneity in LUC on several water quality indicators; (2) determine the spatial scale at which this heterogeneity influences water quality; and (3) examine how antecedent precipitation modulates these impacts. Our models explained 30–58% of observed variance in water quality metrics. Temporal variation in antecedent precipitation and changes in LUC between measurements periods rather than spatial variation in LUC accounted for the majority of variation in water quality. Urbanization and pasture development generally degraded water quality while agriculture and secondary forest re-growth had mixed impacts. The spatial scale over which LUC influenced water quality differed across indicators. Turbidity and dissolved oxygen (DO) responded to LUC in large-scale watersheds, in-stream nitrogen concentrations to LUC in riparian buffers of large watersheds, and fecal matter content and in-stream phosphorus concentration to LUC at the sub-watershed scale. Stream discharge modulated impacts of LUC on water quality for most of the metrics. Our findings highlight the importance of considering multiple spatial scales for understanding the impacts of human activities on watershed ecosystem services.  相似文献