A new species of Goniothalamus (Annonaceae) from New Caledonia, representing a significant range extension for the genus

A previously unknown Annonaceae species from the South Pacific island of New Caledonia is described as Goniothalamus dumontetii . This is the first Goniothalamus species reported from the island, and the easternmost record for the genus. It is easily distinguished from its congeners by the shape of the monocarp (flattened elongate with lateral triangular projections), which reflects the shape of the seeds (flattened rhombohedral). The conservation status of the species is evaluated as endangered (EN) using World Conservation Union (IUCN) red list categories, as it is known from only one relatively small population. The interpretation of geological and molecular data suggests that Goniothalamus dispersed to New Caledonia relatively recently, and does not represent a relict of the break-up of Gondwana.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 497–503.     

一种钒配合物LMC 抑制DNA 拓扑异构酶?的抗肿瘤作用

目的：探讨钒配合物LMc对拓扑异构酶Ⅰ、Ⅱ（Topo-Ⅰ、Topo-Ⅱ）的影响及其抗肿瘤活性。方法：采用DNA松弛实验观察LMC对Topo-Ⅰ、活性的影响并探讨其相关分子作用机制;采用MTT法、流式细胞术在细胞水平观察了IMC的抗肿瘤作用。结果：LMC可明显抑制Topo-Ⅰ活性,对Topo-Ⅱ无明显抑制作用,对多种肿瘤细胞株A549、Hela、BEL-7402具有明显抑制生长的作用,且可将细胞阻断在G2／M期,而对正常细胞株L-02生长无明显影响。结论：钒配合物LMC具有抑制Topo-Ⅰ活性而发挥抗肿瘤的作用。     

Interactions of neural glycosaminoglycans and proteoglycans with protein ligands: assessment of selectivity, heterogeneity and the participation of core proteins in binding

The method of affinity coelectrophoresis was used to study the binding of nine representative glycosaminoglycan (GAG)-binding proteins, all thought to play roles in nervous system development, to GAGs and proteoglycans isolated from developing rat brain. Binding to heparin and non-neural heparan and chondroitin sulfates was also measured. All nine proteins-laminin-1, fibronectin, thrombospondin-1, NCAM, L1, protease nexin-1, urokinase plasminogen activator, thrombin, and fibroblast growth factor-2-bound brain heparan sulfate less strongly than heparin, but the degree of difference in affinity varied considerably. Protease nexin-1 bound brain heparan sulfate only 1.8- fold less tightly than heparin (Kdvalues of 35 vs. 20 nM, respectively), whereas NCAM and L1 bound heparin well (Kd approximately 140 nM) but failed to bind detectably to brain heparan sulfate (Kd>3 microM). Four proteins bound brain chondroitin sulfate, with affinities equal to or a few fold stronger than the same proteins displayed toward cartilage chondroitin sulfate. Overall, the highest affinities were observed with intact heparan sulfate proteoglycans: laminin-1's affinities for the proteoglycans cerebroglycan (glypican-2), glypican-1 and syndecan-3 were 300- to 1800-fold stronger than its affinity for brain heparan sulfate. In contrast, the affinities of fibroblast growth factor-2 for cerebroglycan and for brain heparan sulfate were similar. Interestingly, partial proteolysis of cerebroglycan resulted in a >400- fold loss of laminin affinity. These data support the views that (1) GAG-binding proteins can be differentially sensitive to variations in GAG structure, and (2) core proteins can have dramatic, ligand-specific influences on protein-proteoglycan interactions.      

Quantitative Imaging of Preamyloid Oligomers,a Novel Structural Abnormality,in Human Atrial Samples

Abnormalities in atrial myocardium increase the likelihood of arrhythmias, including atrial fibrillation (AF). The deposition of misfolded protein, or amyloidosis, plays an important role in the pathophysiology of many diseases, including human cardiomyopathies. We have shown that genes implicated in amyloidosis are activated in a cellular model of AF, with the development of preamyloid oligomers (PAOs). PAOs are intermediates in the formation of amyloid fibrils, and they are now recognized to be the cytotoxic species during amyloidosis. To investigate the presence of PAOs in human atrium, we developed a microscopic imaging-based protocol to enable robust and reproducible quantitative analysis of PAO burden in atrial samples harvested at the time of elective cardiac surgery. Using PAO- and myocardial-specific antibodies, we found that PAO distribution was typically heterogeneous within a myocardial sample. Rigorous imaging and analysis protocols were developed to quantify the relative area of myocardium containing PAOs, termed the Green/Red ratio (G/R), for a given sample. Using these methods, reproducible G/R values were obtained when different sections of a sample were independently processed, imaged, and analyzed by different investigators. This robust technique will enable studies to investigate the role of this novel structural abnormality in the pathophysiology of and arrhythmia generation in human atrial tissue.     

Characterizing Penetration of Aminoethoxyvinylglycine (AVG) through Isolated Tomato Fruit Cuticles

Aminoethoxyvinylglycine (AVG) is an ethylene biosynthesis inhibitor that is commonly applied to apple trees prior to harvest to delay ripening and reduce fruit drop. To help understand how selected environmental factors and spray adjuvants affect AVG uptake, penetration of ¹⁴C-AVG through enzymatically isolated tomato (Solanum lycopersicon L.) fruit cuticular membranes (CM) was studied using a finite-dose diffusion system in which penetration is monitored from a drying spray droplet/deposit through an interfacing CM into a receiver solution. Penetration of AVG was initially rapid (4.1 % at 1 h after application), slow after droplet drying (12.5 % by 120 h after application), and averaged 20.7 % of the amount applied at 37 days after application. Rate and amount of AVG penetration were positively related to AVG concentration. Rewetting the dried droplet deposit with deionized water caused a transient increase in penetration that ceased when the droplet dried again. Increasing relative humidity from 50 to 100 % above the dried droplet deposit markedly increased penetration. Increasing temperature from 10 to 30 °C at constant water vapor pressure deficit (0.35 kPa) increased AVG penetration between 0 and 6 h after application but had little effect on penetration thereafter. LiCl, CaCl₂, and MgCl₂ at 100 mM increased AVG penetration at 120 h after application; lower concentrations had no effect. Our results indicate that AVG penetration was enhanced by increasing humidity above the droplet deposit or by the addition of hygroscopic salts to the spray solution, thereby maintaining the AVG mobility in the droplet deposit.