Isolation and identification of EG-VEGF/prokineticins as cognate ligands for two orphan G-protein-coupled receptors

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF, identical to prokineticin 1) is a novel peptide recently identified as a selective mitogen for endocrine gland endothelial cells. The present study demonstrates that EG-VEGF/prokineticin 1 and a peptide closely related to EG-VEGF, prokineticin 2, are cognate ligands of two orphan G-protein-coupled receptors designated ZAQ (=EG-VEGF/PK-R1) and I5E (=EG-VEGF/PK-R2). EG-VEGF/prokineticin 1 and prokineticin 2 induced a transient increase in intracellular calcium ion concentration ([Ca(2+)](i)) with nanomolar potency in Chinese hamster ovary (CHO) cells expressing EG-VEGF/PK-R1 and -R2 and bind to these cells with high affinity and with different receptor selectivity. EG-VEGF/prokineticins provoke rapid phosphorylation of p44/42 MAP kinase and DNA synthesis in the bovine adrenal capillary endothelial cells (BACE). The mRNAs of both EG-VEGF/PK-R1 and -R2 were expressed in BACE. The identification of the receptors for EG-VEGF/prokineticins may provide a novel molecular basis for the regulation of angiogenesis in endocrine glands.     

Changes in lignin content of leaf litters during mulching

Alkaline nitrobenzene oxidation, ozonation and methoxyl content determinations were applied to decomposing leaf litter of Ginkgo biloba L., Cinnamomum camphora sieb., Zelkova serrata Makino and Firmiana simplex W. F. Wight, respectively, during mulching to investigate the properties and estimate changes in lignin composition and content. Since the Klason lignin residue originated from components highly resistant to degradation by acid, the methoxyl content of Klason residue was used to estimate the lignin content of leaf litter. Quantitative analysis of presumed lignin-derived fragments, by use of alkaline nitrobenzene oxidation and ozonation methods, suggested that the estimated lignin content approximates that of the real lignin content of leaves, which is greatly overestimated by the Klason procedure. The estimated lignin contents ranged from 3.9 to 10.0% while the Klason lignan residue varied from 37.1 to 46.7% in un-mulched leaf litter. The absolute amounts of the measured lignin somewhat decreased during mulching, while the structure of lignin remaining in leaf litters after mulching was considered not to be very different from its original structure.     

Proteomic approach to apoptotic thymus maturation

Apoptosis is an essential process for selection of T lymphocytes specific for foreign antigen in the process of mammalian thymus maturation. Proteomics, a comprehensive study of proteins expressed in a cell, will facilitate the systematic analysis of protein molecules related to such a complicated biological system. Protein expression profiles including information about protein signatures, localization and their quantitative changes with extracellular stimulations are extremely useful to construct intracellular pathway models resulting in the apoptotic cell death.     

Interaction between leukemic-cell VLA-4 and stromal fibronectin is a decisive factor for minimal residual disease of acute myelogenous leukemia

Bone-marrow minimal residual disease (MRD) causes relapse after chemotherapy in patients with acute myelogenous leukemia (AML). We postulate that the drug resistance is induced by the attachment of very late antigen (VLA)-4 on leukemic cells to fibronectin on bone-marrow stromal cells. We found that VLA-4-positive cells acquired resistance to anoikis (loss of anchorage) or drug-induced apoptosis through the phosphatidylinositol-3-kinase (PI-3K)/AKT/Bcl-2 signaling pathway, which is activated by the interaction of VLA-4 and fibronectin. This resistance was negated by VLA-4-specific antibodies. In a mouse model of MRD, we achieved a 100% survival rate by combining VLA-4-specific antibodies and cytosine arabinoside (AraC), whereas AraC alone prolonged survival only slightly. In addition, overall survival at 5 years was 100% for 10 VLA-4-negative patients and 44.4% for 15 VLA-4-positive patients. Thus, the interaction between VLA-4 on leukemic cells and fibronectin on stromal cells may be crucial in bone marrow MRD and AML prognosis.     

Inhibition of recombinant dipeptidyl peptidase III by synthetic hemorphin-like peptides

In order to find the most effective antagonist for dipeptidyl peptidase III degrading enkephalin, we synthesized hemorphin-like pentapeptides with aliphatic or aromatic amino acids at the N-termini, such as VVYPW, LVYPW, IVYPW, YVYPW, FVYPW and WVYPW. Among those pentapeptides, IVYPW and WVYPW showed the strongest inhibitory activity toward rDPP III. The K(i) values of IVYPW and WVYPW were 0.100+/-0.011 and 0.126+/-0.015 microM (mean+/-S.E.), respectively. The order of K(i) values was Ile> or =Trp>Phe> or =Tyr>Leu>Ala>Val>Ser>Gly. rDPP III activity is inhibited in a non-competitive manner by these peptides. The peptide VYPW did not inhibit rDPP III activity, but the sequence is essential for the expression of inhibitory activity.     

Mother–young distance in Japanese Black cattle at pasture

Distance between dam and offspring (1–121 days old) in a herd of Japanese Black cattle (Bos taurus) grazing a tropical grass (Paspalum notatum) pasture (1.5 ha) was investigated during 7-h grazing periods over grazing seasons from May (spring) to October (autumn). The mother–young distance was not constant throughout the grazing period, repeatedly increasing and decreasing. Although significant periodicity was always detected in the mother–young distance, there was no consistent dominant cycle, indicating the complexity of the within-day pattern of mother–young distance. The mean mother–young distance over the grazing period increased as a calf aged, reaching a plateau at an age of about 33 days. The mean distance of a calf from its mother was usually shorter than that from a non-mother cow, with the difference between the mean distances decreasing sharply until a calf became about 35 days old. The results and literature show that mutual independence of mother and young rapidly develops in the first 30–50 days after parturition. Electronic Publication     

Community dynamic models of two dioecious tree species

The effects of dioecy on community dynamics were examined by using transition matrix models for two dioecious tree species, one a superior competitor with a narrow dispersal range and the other an inferior competitor with a wide dispersal range. The models are based on tree-by-tree replacements in each identical microsite occupied by either male or female canopy trees of the superior competitor and canopy trees of the inferior competitor. Coexistence of the two species is possible not only because of a trade-off between competitive and dispersal abilities but also because of the existence of a competitor gap, which the superior competitor cannot occupy. The competitor gap is created under the male trees of the superior competitor. The inferior competitor occupies the competitor gap because of its wide dispersal range. The relative abundance of the two species depends on the dispersal ability and sex ratios of the superior competitor. The decreasing dispersal ability and the female abundance of the superior competitor increase the competitor gap, which allows the regeneration of the inferior competitor.An erratum to this article can be found at     

Molecular Cloning and DNA Analysis of the Orotidine-5′-Phosphate Decarboxylase Gene from the Yeast Saccharomyces exiguus Yp74L-3

The orotidine-5′-phosphate decarboxylase gene of Saccharomyces exiguus Yp74L-3 was cloned as a DNA fragment complementing a ura4 mutation of this yeast. The coding region of the gene is 807 bp in length, and represents 68.7% similarity to the corresponding gene of S. cerevisiae (URA3). The cloned URA4 gene was shown to be located on the 790-kbp Chromosome (chr) VIII of S. exiguus Yp74L-3. The neighbor-joining phylogenetic tree based on the orotidine-5′-phosphate decarboxylase coding sequences indicates that S. exiguus Yp74L-3 is closely related to Kluyveromyces yeasts, as well as to a S. cerevisiae laboratory strain. Received: 4 February 2000 / Accepted: 3 July 2000     

Effect of Na+ on Ca2+-Binding on the Plasma Membrane of Barley Mesophyll Cells: an Electrophoretic Study

Characteristics of Ca²⁺-binding on the plasma membrane of barleymesophyll cells were studied by a microelec-trophoretic method.The results indicated that Na⁺ ions could cause nonspecificreduction but not specific reduction in the total amount ofCa²⁺ bound to the plasma membrane of (salt-tolerant) barleymesophyll cells. (Received October 13, 1997; Accepted January 23, 1998)     

Rho and Rab Small G Proteins Coordinately Reorganize Stress Fibers and Focal Adhesions in MDCK Cells

The Rho subfamily of the Rho small G protein family (Rho) regulates formation of stress fibers and focal adhesions in many types of cultured cells. In moving cells, dynamic and coordinate disassembly and reassembly of stress fibers and focal adhesions are observed, but the precise mechanisms in the regulation of these processes are poorly understood. We previously showed that 12-O-tetradecanoylphorbol-13-acetate (TPA) first induced disassembly of stress fibers and focal adhesions followed by their reassembly in MDCK cells. The reassembled stress fibers showed radial-like morphology that was apparently different from the original. We analyzed here the mechanisms of these TPA-induced processes. Rho inactivation and activation were necessary for the TPA-induced disassembly and reassembly, respectively, of stress fibers and focal adhesions. Both inactivation and activation of the Rac subfamily of the Rho family (Rac) inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly. Moreover, microinjection or transient expression of Rab GDI, a regulator of all the Rab small G protein family members, inhibited the TPA-induced reassembly of stress fibers and focal adhesions but not their TPA-induced disassembly, indicating that, furthermore, activation of some Rab family members is necessary for their TPA-induced reassembly. Of the Rab family members, at least Rab5 activation was necessary for the TPA-induced reassembly of stress fibers and focal adhesions. The TPA-induced, small G protein-mediated reorganization of stress fibers and focal adhesions was closely related to the TPA-induced cell motility. These results indicate that the Rho and Rab family members coordinately regulate the TPA-induced reorganization of stress fibers and focal adhesions that may cause cell motility.