AMMONIUM ION-INDUCED CHANGES IN FORM AND HYDROXYPROLINE CONTENT OF WALL PROTEIN IN THE LIVERWORT,GYMNOCOLEA INFLATA

Ammonium ion induces phenovariation in Gymnocolea inflata (Huds.) Dum. (Lophoziaceae) similar in nature to that induced in representatives of four other families of leafy liverworts by antagonists of hydroxyproline-protein metabolism. That is, in the presence of ammonium ion, ventral leaves developed and the lateral leaf morphology and the branching pattern of the plants changed. These changes, which reflect altered patterns of morphogenesis, were correlated with statistically significant (P ≥ 0.01) differences in peptidyl-hydroxyproline between normal and NH₄⁺-induced phenovariant plants. The results support the hypothesis that cell wall-associated hydroxyproline-protein plays a morphoregulatory role and that any of a number of factors, genetic, epigenetic or environmental, that could alter the synthesis/distribution of this moiety could cause changes in form.     

Synthesis and characterization of new copper(I) complexes containing 4-(diphenylphosphane)benzoic acid and "scorpionate" ligands with "in vitro" superoxide scavenging activity

New copper(I) complexes have been synthesised from the reaction of CuCl with 4-(diphenylphosphane)benzoic acid and lithium tris(1H-pyrazol-1-yl)methanesulfonate, Li(SO(3))C(pz)(3), sodium hydrotris(3-trifluoromethyl-1H-pyrazol-1-yl)borate, NaHB[3-(CF(3))pz](3), potassium dihydrobis(1H-1,2,4-triazol-1-yl)borate, KH(2)B(tz)(2), hydrotris(1H-1,2,4-triazol-1-yl)borate, KHB(tz)(3), sodium hydrotris(1H-pyrazol-1-yl)borate, NaHB(pz)(3), potassium hydrotris(3,5-dimethyl-1H-pyrazol-1-yl)borate KHB(3,5-Me(2)Pz)(3) or potassium hydrotris(4-bromo-1H-pyrazol-1-yl)borate KHB(4-Brpz)(3). The complexes obtained have been characterized by elemental analyses and FT-IR in the solid state, and by NMR (1H and 31P[(1)H]) spectroscopy and conductivity measurements in solution. The solution data are consistent with partial dissociation of the sterically hindered complexes by way of breaking of Cu-P and Cu-N bonds. Electrospray mass spectrometry has been used to investigate the relative properties of the 4-(diphenylphosphane)benzoic acid and of the "scorpionate" ligands towards copper(I) ions. Chemiluminescence technique was used to evaluate the superoxide scavenging activity of these new copper complexes.     

Lymphatic Endothelial Tumors Induced by Intraperitoneal Injection of Incomplete Freund's Adjuvant

Endothelial cells form the inner lining of blood and lymphatic vessels. In mice, only tumors of the blood vessel endothelium (haemangiomas) have been thus far reported. Here we describe a highly reproducible method for the induction of benign tumors of the lymphatic endothelial cells (lymphangiomas) in mice by intraperitoneal injection of incomplete Freund's adjuvant. Morphological and histopathological studies of the lesions revealed the presence of cells at various levels of vascular development. The lymphangiomas developed in the peritoneal cavity and expressed the endothelial markers CD31/PECAM (platelet endothelial cell adhesion molecule), CD54/ICAM-1 (InterCellular Adhesion Molecule-1), and CD102/ICAM-2, as well as the vascular endothelial growth factor (VEGF) receptor Flk-1, the endothelial cell specific receptors Tie-1 and Tie-2 and the lymphatic endothelial cell specific Flt4 receptor as shown byin situhybridization. The Flk-1 and Flt4 receptors were also identified in immunoblots of the tumors and in cells cultured from them. When induced in β-galactosidase knock-in Flt4^+/−mice, the tumor endothelia could be stained blue in a number of tumor cells although the staining was of lower intensity than in normal lymphatic vessels. The tumor-derived cells could be propagatedin vitroand they spontaneously differentiated, forming vessel-like structures. Murine lymphangiomas thus represent a highly reproducible and convenient source of lymphatic endothelial cells.     

Hypoxia-inducible Factor-1-mediated Regulation of Semaphorin 4D Affects Tumor Growth and Vascularity

Tumor progression and metastasis depend on the ability of cancer cells to initiate angiogenesis to ensure delivery of oxygen, nutrients, and growth factors to tumor cells and provide access to the systemic circulation. Hypoxia-inducible factor-1 (HIF-1) can activate expression of a broad range of genes that mediate many of the adaptive responses to decreased oxygen concentration, such as enhanced glucose uptake and formation of new blood vessels. Acting through Plexin-B1 on endothelial cells, Semaphorin 4D (Sema4D) has been shown to promote angiogenesis and enhance invasive growth and proliferation in some tumors. Here we show that the gene for Sema4D, the product of which is elevated in head and neck squamous cell carcinoma (HNSCC) cells, contains upstream hypoxia response elements (HRE) and is strongly induced in hypoxia in a HIF-1-dependent manner. Knocking down Sema4D expression with short hairpin (sh) RNA reduces in vitro endothelial cell migration and growth and vascularity of HNSCC xenografts expressing a degradation resistant HIF-1α subunit. We also demonstrate a correlation between HIF-1 activity and Sema4D expression in HNSCC specimens. These findings indicate that Sema4D is induced by hypoxia in a HIF-1-dependent manner and influences endothelial cell migration and tumor vascularity. Expression of Sema4D may be a strategy by which carcinomas promote angiogenesis and therefore could represent a therapeutic target for these malignancies.     

Parametric scaling from species to growth-form diversity: an interesting analogy with multifractal functions

We propose a measure of divergence from species to life-form diversity aimed at summarizing the ecological similarity among different plant communities without losing information on traditional taxonomic diversity. First, species and life-form relative abundances within a given plant community are determined. Next, using Rényi's generalized entropy, the diversity profiles of the analyzed community are computed both from species and life-form relative abundances. Finally, the speed of decrease from species to life-form diversity is obtained by combining the outcome of both profiles. Interestingly, the proposed measure shows some formal analogies with multifractal functions developed in statistical physics for the analysis of spatial patterns. As an application for demonstration, a small data set from a plant community sampled in the archaeological site of Paestum (southern Italy) is used.