OsCM regulates rice defence system in response to UV light supplemented with drought stress

Studies on plant responses to combined abiotic stresses are very limited, especially in major crop plants. The current study evaluated the response of chorismate mutase overexpressor (OxCM) rice line to combined UV light and drought stress. The experiments were conducted in pots in a growth chamber, and data were assessed for gene expression, antioxidant and hormone regulation, flavonoid accumulation, phenotypic variation, and amino acid accumulation. Wild-type (WT) rice had reduced the growth and vigour, while transgenic rice maintained growth and vigour under combined UV light and drought stress. ROS and lipid peroxidation analysis revealed that chorismate mutase (OsCM) reduced oxidative stress mediated by ROS scavenging and reduced lipid peroxidation. The combined stresses reduced biosynthesis of total flavonoids, kaempferol and quercetin in WT plants, but increased significantly in plants with OxCM. Phytohormone analysis showed that SA was reduced by 50% in WT and 73% in transgenic plants, while ABA was reduced by 22% in WT plants but increased to 129% in transgenic plants. Expression of chorismate mutase regulates phenylalanine biosynthesis, UV light and drought stress-responsive genes, e.g., phenylalanine ammonia lyase (OsPAL), dehydrin (OsDHN), dehydration-responsive element-binding (OsDREB), ras-related protein 7 (OsRab7), ultraviolet-B resistance 8 (OsUVR8), WRKY transcription factor 89 (OsWRKY89) and tryptophan synthase alpha chain (OsTSA). Moreover, OsCM also increases accumulation of free amino acids (aspartic acid, glutamic acid, leucine, tyrosine, phenylalanine and proline) and sodium (Na), potassium (K), and calcium (Ca) ions in response to the combined stresses. Together, these results suggest that chorismate mutase expression induces physiological, biochemical and molecular changes that enhance rice tolerance to combined UV light and drought stresses.

Size limit for particle-stabilized emulsion droplets under gravity

We demonstrate that emulsion droplets stabilized by interfacial particles become unstable beyond a size threshold set by gravity. This holds not only for colloids but also for supracolloidal glass beads, using which we directly observe the ejection of particles near the droplet base. The number of particles acting together in these ejection events decreases with time until a stable acornlike configuration is reached. Stability occurs when the weight of all remaining particles is less than the interfacial binding force of one particle. We also show the importance of the curvature of the droplet surface in promoting particle ejection.

Superconductivity in undoped single crystals of BaFe(2)As(2): field and current dependence

In previous work on undoped MFe(2)As(2), partial drops in the resistivity indicative of traces of superconductivity have been observed for some samples with M =  Ba (T(c)∼20 K, up to 25% drop in ρ) and M =  Ca (T(c)∼10 K, up to 45% drop in ρ). A complete drop in the resistivity to ρ = 0, along with a finite fraction of Meissner flux expulsion, has been observed for M  = Sr, T(c) = 22 K. Using In-flux grown single crystal samples of undoped BaFe(2)As(2), we find a complete drop in the resistivity to 0 for most samples beginning at T(c)(onset) = 22.5 K. However-in contrast to the SrFe(2)As(2) results-there is no measurable Meissner effect and no suppression of the resistive superconducting transition with annealing. The current sensitivity of the superconducting resistive transition in our samples of BaFe(2)As(2) is quite strong, with an increase in the current density of a factor of 15 to ∼1.5 A cm(-2) not changing T(c)(onset) but broadening the transition significantly and causing ρ to remain finite as [Formula: see text]. To investigate whether this unusually low critical current is indicative of filamentary conduction lacking the apparent anisotropy seen in the critical magnetic field, H(c2), measurements for, e.g., the bulk superconductor Co-doped BaFe(2)As(2), H(c2) was measured in both crystalline directions. These BaFe(2)As(2) samples show H(c2)(T) values in the ab-plane and along the c-axis comparable to those seen for BaFe(2-x)Co(x)As(2), which has a similar T(c). Since the lack of T(c) suppression after annealing argues against strain-induced superconductivity as proposed for the other undoped MFe(2)As(2) materials, another possible cause for the superconductivity in BaFe(2)As(2) is discussed.

Specific heat anomalies for [Formula: see text] in superconducting single crystal doped BaFe(2)As(2): comparison of different flux growth methods

One way to address the nature of the superconductivity in the new iron pnictides is to measure the low temperature specific heat in the superconducting state, where the temperature, field, and angular dependences of the specific heat each give important information. We report on an initial study of the specific heat down to 0.4 K in single crystals of Ba(0.6)K(0.4)Fe(2)As(2), T(c) = 32 K, prepared via Sn-flux and In-flux methods and compare to literature data for samples prepared using the self-flux method. We also report on the specific heat in zero and 1 T applied magnetic fields of Ba(Fe(0.926)Co(0.074))(2)As(2), T(c) = 22 K, prepared via the In-flux method. All samples show upturns in the specific heat divided by temperature below 2 K, with the upturn in the Sn-flux sample starting already at 4 K. These upturns, which are strongly dependent on the preparation method, impede determination of the intrinsic properties.

[Surgical strategy for wounds of the cervical part of the esophagus]

An analysis of results of treatment of 425 patients aged from 15 to 85 years with penetrating wounds of the neck was made. In 40 (8.1%) patients there were wounds of the cervical part of the esophagus, 29 of them had associated injuries. The proposed active surgical strategy consisted in a necessary thorough revision of the penetrating wounds of the neck using general anesthesia and then directly in the operation room using subsidiary methods of examination such as urgent x-ray analysis with a water-soluble contrast, esophagoscopy, larengotracheoscopy. This approach allowed detection of injuries of the cervical part of the esophagus, even in cases of the absence of clinical symptoms of esophagus injuries. In all the patients the wounds of the esophagus were sutured and followed by active aspiration drainage and antibacterial treatment with modern antimicrobial medicines.

c-Jun N-terminal kinase is involved in motility of endothelial cell

Cell motility is essential for a wide range of cellular activities including anigogenesis as well as metastasis of tumor cells. Ras has been implicated in cell migration and invasion, and functions at upstream of mitogen-activated protein kinase (MAPK) families, which include extracellular-signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK. In the present study, we examined the role of JNK in endothelial cell motility using stable transfectant (DAR-ECV) of ECV304 endothelial cells expressing previously established oncogenic H-Ras (leu 61). DAR-ECV cells showed an enhanced angiogenic potential and motility (approximately 2-fold) compared to ECV304 cells. Western blot analysis revealed constitutive activation of JNK in DAR-ECV cells. Pretreatment of JNK specific inhibitors, curcumin and all trans-retinoic acid, decreased the basal motility of DAR-ECV cells in a dose-dependent manner. These inhibitors also suppressed the motility stimulated by known JNK agonists such as TNFalpha and anisomycin. To further confirm the role of JNK, ECV304 cells expressing dominant active SEK1 (DAS-ECV) were generated. Basal non-stimulated levels of the cellular migration were greater in DAS-ECV clones than those in control ECV304 cells. These results suggest that Ras-SEK1-JNK pathway regulates motility of endothelial cells during angiogenesis.

Involvement of phospholipase D in oxidative stress-induced necrosis of vascular smooth muscle cells

Phospholipase D (PLD) has been associated with necrosis. However, it is not clear whether PLD plays a causative role in this cellular process. We investigated the role of PLD in oxidative stress-induced necrosis of vascular smooth muscle cells (VSMCs). Pervanadate (hydrogen peroxide plus orthovanadate) but not hydrogen peroxide alone activated PLD in a dose- and time-dependent manner. Exposure of VSMCs to pervanadate resulted in necrosis. Pretreatment with butan-1-ol, a PLD inhibitor, attenuated both pervanadate-induced necrosis and increase of intracellular Ca(2+). Removal of extracellular Ca(2+) inhibited pervanadate-induced necrosis by 50%. These results suggest that PLD activation mediates pervanadate-induced necrosis of VSMCs, which is at least partly due to Ca(2+) toxicity.

A clinical analysis of gasless endoscopic thyroidectomy

Gasless endoscopic surgery was applied to a thyroidectomy. Compared with the previous method of endoscopic thyroidectomy, this method is superior in obtaining hemostasis and minimizing the possible complications of gas-insufflating surgery, such as a hypercapnia or massive subcutaneous emphysema. We successfully removed 37 thyroid tumors in 35 patients by gasless endoscopic surgery without any significant complications. No scars remained in the neck, and all patients were satisfied with the cosmetic results. Gasless endoscopic thyroidectomy is a safe and technically feasible alternative to conventional thyroidectomy for cases of benign thyroid tumors and has good cosmetic results.

Production and characterization of monoclonal antibodies against amphiphysins

Amphiphysin I and II, proteins enriched in nerve terminals, form heterodimers and interact with dynamin and synaptojanin through their Src homology 3 (SH3) domain. In order to study the expression profile of Amphs in cells and tissues and the interaction state with other cellular molecules, we have prepared specific monoclonal antibodies (mAbs) designed to bait N-terminus, middle part, and C-terminus domains of Amph I, respectively by immunizing with the expressed smaller domain molecules using the GST gene fusion system. The expression of Amphs was found to be most abundant in PC12 cells, followed by B103 cells and vascular smooth muscle cells. Western blot analysis showed a relatively high level expression of Amphs that were found in both mouse and rat brain. There appeared to be some species difference in the expression pattern, i.e. Amphs are present more in the testis than in the lungs in rats, however, they are reversed in mice. Characterization of the mAbs revealed that clone 14-23 precipitated Amph I and II, whereas clone 8-2 could only precipitate Amph I. In addition, clathrin and dynamin in a complex with Amph were captured in the precipitate formed by mAbs and identified by the Western blot analysis. Cellular distribution of Amph was visualized with confocal immunofluorescence microscopy performed using the labeled-mAbs. Taken together, these results demonstrated that mAbs provided an excellent measure for studying Amphs' expression profile and their interacting proteins.

Cloning and expression pattern of a novel PEBP2 beta-binding protein (charged amino acid rich leucine zipper-1[Crl-1]) in the mouse

PEBP2 beta/Cbf beta is the beta subunit of PEBP2/Cbf, which has been demonstrated to have important biological activities in hematopoiesis and osteogenesis. However, PEBP2 beta is ubiquitously expressed, suggesting that PEBP2 has other additionally important physiological activities. In an effort to elucidate other possible functions for PEBP2, we have isolated a novel gene that encodes a PEBP2 beta-interacting protein from a mouse cDNA library. We have called this gene Crl-1 for charged amino acid rich leucine zipper-1 (Crl-1) because it is rich in charged amino acids and contains a putative leucine zipper region. Expression studies in a 17.5 days post-coitum mouse embryo demonstrated Crl-1 expression mainly in the olfactory bulb and cerebral cortex. Post-natally, Crl-1 expression was additionally observed in the cerebellar cortex with strong expression in the hippocampus. These findings show that this novel PEBP2 beta-interacting protein is expressed mainly in subsets of neuronal cells, suggesting that Crl-1 plays some role in the developing mouse brain.

Runx2 is a common target of transforming growth factor beta1 and bone morphogenetic protein 2, and cooperation between Runx2 and Smad5 induces osteoblast-specific gene expression in the pluripotent mesenchymal precursor cell line C2C12

When C2C12 pluripotent mesenchymal precursor cells are treated with transforming growth factor beta1 (TGF-beta1), terminal differentiation into myotubes is blocked. Treatment with bone morphogenetic protein 2 (BMP-2) not only blocks myogenic differentiation of C2C12 cells but also induces osteoblast differentiation. The molecular mechanisms governing the ability of TGF-beta1 and BMP-2 to both induce ligand-specific responses and inhibit myogenic differentiation are not known. We identified Runx2/PEBP2alphaA/Cbfa1, a global regulator of osteogenesis, as a major TGF-beta1-responsive element binding protein induced by TGF-beta1 and BMP-2 in C2C12 cells. Consistent with the observation that Runx2 can be induced by either TGF-beta1 or BMP-2, the exogenous expression of Runx2 mediated some of the effects of TGF-beta1 and BMP-2 but not osteoblast-specific gene expression. Runx2 mimicked common effects of TGF-beta1 and BMP-2 by inducing expression of matrix gene products (for example, collagen and fibronectin), suppressing MyoD expression, and inhibiting myotube formation of C2C12 cells. For osteoblast differentiation, an additional effector, BMP-specific Smad protein, was required. Our results indicate that Runx2 is a major target gene shared by TGF-beta and BMP signaling pathways and that the coordinated action of Runx2 and BMP-activated Smads leads to the induction of osteoblast-specific gene expression in C2C12 cells.

Up-regulation and co-expression of fibroblast growth factor receptors in human gastric cancer

Fibroblast growth factor (FGF), a key regulatory factor of cell growth and differentiation, is involved in embryonic development, angiogenesis, and tumorigenesis. To date, four different FGF receptors (FGFRs) have been cloned and characterized. We examined the expression of four FGFRs in human gastric cancer tissues and cell lines using Northern analysis, ribonuclease protection assay, and immunohistochemistry. The mRNAs of FGFR-1 (10/14), FGFR-2 (9/14), and FGFR-4 (9/14) were up-regulated in cancer compared with normal tissues. FGFR-3 mRNAs were barely detectable in both normal and cancer tissues. These FGFR mRNAs were co-expressed in various combinations of two or three in the same tissue. Immunohistochemistry confirmed specific staining of multiple FGFRs, except FGFR-3, in the cancer specimens. To investigate the functional significance of FGFR co-expression we examined the invasive property of SNU-16 cells, which exhibited gene amplification of FGFR-2, -3, and -4 as well as over-expression of keratinocyte growth factor receptor (KGFR), a splice variant of FGFR-2, and FGFR-4 mRNA. KGF plus acidic FGF (aFGF), KGF, and aFGF treatment enhanced the invasive potential of SNU-16 cells over the control by 100%, 107%, and 47%, respectively, indicating that neither additive nor synergistic effect was induced by stimulation with aFGF plus KGF. These results suggest that co-expression of FGFRs in various combinations may cause subtle changes in the progression of gastric cancer.

Down-regulation of phospholipase D during differentiation of mouse F9 teratocarcinoma cells

Phospholipase D has been recognized as playing an important role in signal transduction in many types of cells. We investigated the expression of phospholipase D during the differentiation of F9 embryonal teratocarcinoma cells. The ADP ribosylation factor-dependent phospholipase D activity, as measured by an in vitro assay, and H2O2-induced phospholipase D activity and phospholipase D protein content in whole cells were decreased during the differentiation of F9 cells induced by a combination of dibutyryl cyclic AMP and all-trans retinoic acid. In contrast, these changes were not observed when cells were induced by retinoic acid. These results suggest that down-regulation of phospholipase D protein is associated with differentiation of F9 cells to a parietal endoderm lineage.

Expression of SET is modulated as a function of cell proliferation

We explored a biological role of SET as it relates to cell proliferation and differentiation. Immunohistochemical staining demonstrated that the expression of SET was ubiquitous and diffuse over the whole embryo on gestational day 15. At a later stage of development, SET was expressed at relatively lower levels and localized to specific tissues and cells. On embryonic day 19, specific SET immunoreactivity was found in the epithelium of skin, respiratory tract, intestine, and retina as well as in muscle and cartilage. In these cells SET was stained mostly in the nucleus, which was supported indirectly by nuclear transport of enhanced green fluorescence protein-SET fusion proteins in ECV304 endothelial cells. Set mRNA expression was further confirmed in various cultured cells, including NIH 3T3 cells, L6 myoblast cells, human umbilical vein endothelial cells, and ECV304 cells. Using F9 teratocarcinoma cell lines, which were stimulated to differentiate into the two different cell lineages of parietal and visceral endoderm, we have further examined the role of SET. The expression of set mRNA and SET protein was diminished about three-fold in both differentiated endoderm cells compared to the undifferentiated F9 cells. However, when F9 cells were subjected to serum starvation, reduction of set mRNA abundance also took place at a similar level to that observed in response to differentiation. Consistent with this, quiescent L6 myoblast showed a marked downregulation of set mRNA compared to proliferating cells. These results suggest that SET is involved mainly in the regulation of cell proliferation rather than differentiation during embryonic development.

Overexpressed alpha3beta1 and constitutively activated extracellular signal-regulated kinase modulate the angiogenic properties of ECV304 cells

ECV304, a spontaneously transformed cell line derived from the human umbilical vein endothelial cell (HUVEC) (Takahashi et al., 1990), has been developed as an in vitro angiogenesis model. In the present study, we further characterized the angiogenic properties of this cell line. Compared to HUVEC, ECV304 cells showed distinct features including a higher activity of cellular adhesion, slower but reproducible progression of angiogenesis on Matrigel, and resistance to apoptosis. Thus, the expression of integrin and activation of extracellular-signal regulated kinase 1/2 (Erk1/2), a downstream effector of the integrin pathway, were examined. Flow cytometry revealed that alpha3beta1 integrin was markedly upregulated in ECV304 cells, while alpha(v)beta1 and alpha5beta1 integrins were slightly downregulated. Consistent with this, the binding activity to collagen type IV and laminin, major extracellular matrices of Matrigel, was increased 1.4- and 1.9-fold in ECV304 cells, respectively. This tight binding may retard the initial stage of sprouting and migration in the angiogenesis of ECV304 cells. It has been further demonstrated that Erk1/2 is constitutively active in ECV304 cells, rendering them resistent to the inhibitory effect of PD98059 on proliferation. However, migration of both HUVEC and ECV304 cells was inhibited to a similar extent by PD98059 in a dose-dependent manner. Up to 50 microM of PD98059, no significant changes in cell binding and tubulogenesis on Matrigel was observed in ECV304 cells. In contrast, the tubulogenesis of HUVEC was severely impaired by PD98059. Elevated Erk1/2 activity in ECV304 cells was suppressed by dominant negative H-Ras, but not by cytochalasin D. These results suggest that the overexpression of alpha3beta1 integrin and the constitutive activation of Erk1/2 play a key role in the alteration of the angiogenic properties of ECV304 cells.

H-Ras is a negative regulator of alpha3beta1 integrin expression in ECV304 endothelial cells

We have examined the role of Ras in integrin expression in ECV304 endothelial cells. Among the integrins examined in stable ECV304 transfectants expressing dominant active H-Ras (DAR-ECV), expression of alpha3beta1 integrin showed a prominent reduction in all the DAR-ECV clones when compared to the parental ECV304 cells. This implies that H-Ras negatively regulates the expression of alpha3beta1 integrin in ECV304 cells. When treated with inhibitors of the Ras downstream pathway (LY294002, PD98059, SB203580), the expression of alpha3beta1 integrin was up-regulated most significantly by LY294002, suggesting that among the downstream pathways of Ras, phosphatidylinositol 3-kinase is a major determinant. With the application of blocking antibody to alpha3beta1 integrin (2 - 2 x 10(4) nM), migration of ECV304 cells was enhanced to maximal (18%) at 20 nM. These results suggest that migration of endothelial cells could be modulated by H-Ras via alteration of the expression levels of alpha3beta1 integrin.

Involvement of tyrosine phosphorylation and protein kinase C in the activation of phospholipase D by H2O2 in Swiss 3T3 fibroblasts

We have investigated the mechanisms involved in H2O2-mediated phospholipase D (PLD) activation in Swiss 3T3 fibroblasts. In the presence of vanadate, H2O2 induced tyrosine phosphorylation of PLD as well as the platelet-derived growth (PDGF) factor receptor, protein kinase Calpha (PKCalpha), and a 62-kDa protein in rat brain PLD1 (rPLD1) immune complexes. PDGF also induced tyrosine phosphorylation of PLD, but this was abolished by catalase, indicating that it was mediated by H2O2 generation. Interestingly, PLD was found to be constitutively associated with the PDGF receptor and PKCalpha. Stimulation by H2O2 showed a concentration- and time-dependent tyrosine phosphorylation of the proteins in rPLD1 immunoprecipitates and activation of PLD in the cells. Pretreatment of the cells with the protein-tyrosine kinase inhibitors genistein and herbimycin A resulted in a concentration-dependent inhibition of H2O2-induced tyrosine phosphorylation and PLD activation. Activation of PLD by H2O2 was also inhibited dose-dependently by the PKC inhibitors Ro 31-8220 and calphostin C. Down-regulation of PKC by prolonged treatment with 4beta-phorbol 12-myristate 13-acetate also abolished H2O2-stimulated PLD activity. H2O2 or vanadate alone did not induce tyrosine phosphorylation of proteins in the rPLD1 immune complex or PLD activation. Reduction of intracellular H2O2 levels by pretreatment of the cells with catalase dramatically abrogated tyrosine phosphorylation of proteins in the rPLD1 immune complex and PLD activation, suggesting the potential role of intracellular H2O2 in H2O2-mediated PLD signaling. Taken together, these results suggest that both protein-tyrosine kinase(s) and protein kinase C participate in H2O2-induced PLD activation in Swiss 3T3 cells.

Expression of SET, an inhibitor of protein phosphatase 2A, in renal development and Wilms' tumor

The human gene set was originally identified as a component of the set-can fusion gene produced by a somatic translocation event in a case of acute undifferentiated leukemia. In the developing kidney, set was highly expressed in the zone of nephron morphogenesis. Recently, SET was shown to be a potent and specific inhibitor of protein phosphatase 2A, a family of major serine/threonine phosphatases involved in regulating cell proliferation and differentiation. The current study sought to define further the role of SET in the regulation of renal cell proliferation and tumorigenesis. The mRNA encoding SET was expressed at much higher levels in transformed human and rodent cell lines than in cultured renal epithelial and primary endothelial cells. Consistent with a role for SET in cell proliferation, set mRNA expression was markedly reduced in cells rendered quiescent by serum starvation, contact inhibition, or differentiation. Previous findings during renal development were extended by demonstrating that SET protein expression is also much greater in developing rat and human kidney than in fully differentiated, mature kidney. Finally, high levels of set mRNA and SET protein expression were found in Wilms' tumor, but not in renal cell carcinoma, adult polycystic kidney disease or in transitional cell carcinoma.

Spatially restricted expression of set mRNA in developing rat kidney

A somatic translocation event fusing the novel gene set to the putative oncogene can has been implicated in the development of acute nonlymphocytic leukemia in humans. In this study, full-length cDNAs highly homologous with human set were cloned from a rat neonatal kidney library. The expression pattern of set mRNA was then examined in developing rat kidney. Two groups of set cDNAs (alpha and beta) with different translation initiation sites and open reading frames of 867 and 831 bp, respectively, were found. The predicted protein products are 33,385 and 32,085 Da in size and contain approximately 30% acidic residues, over half of them clustered at the COOH terminal, thus forming a long acidic tail. No signal peptide or membrane-spanning domains were identified, suggesting an intracellular protein product. By ribonuclease protection assay, both alpha and beta variants of set were expressed in kidney. On Northern blots of total kidney RNA, 3.0- and 2.2-kb mRNAs hybridized with the labeled set cDNA probe. Expression of both transcripts was four- to eightfold greater in neonatal compared with adult rat kidney. When neonatal rat kidneys were examined for set mRNA expression by in situ hybridization with 35S-labeled riboprobe, expression was densely localized in the cortical region of morphogenesis over primitive nephron structures, including S-shaped bodies. Thus mRNA for Set, a putative intracellular protein involved in leukemogenesis, is expressed in kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Rat mesangial cell hypertrophy in response to transforming growth factor-beta 1

Central features of progressive glomerular sclerosis are initial glomerular hypertrophy and subsequent accumulation of extracellular matrix proteins. Since TGF-beta 1 may play a key role in this glomerular response to injury, the present study sought to explore further TGF-beta 1 actions and regulated expression of its receptor in rat mesangial cells. The rat TGF-beta type II receptor (TGF-beta RII) homolog was cloned by screening a rat kidney cDNA library with a human TGF-beta RII cDNA probe, and sequenced. Expression of this receptor subtype in rat mesangial cells was then demonstrated by RNase protection assay, and by Northern blot analysis of poly (A)+ RNA, TGF-beta RII expression was down-regulated in cells treated with exogenous TGF-beta 1. Affinity cross linking studies demonstrated presence of this receptor on cell surface. Rat mesangial cells also expressed TGF-beta 1 and autoinduction by TGF-beta 1 was observed in the same cells, suggesting that this polypeptide may act in an autocrine fashion on mesangial cells, and that it may stimulate a positive autoamplification loop. TGF-beta 1 inhibited mesangial cell proliferation and stimulated significant overall protein and collagen production. Furthermore, mesangial cell size increased in response to chronic TGF-beta 1 treatment. These findings demonstrate that rat mesangial cells express key components of the TGF-beta system and raise the intriguing possibility that in the glomerular mesangium, TGF-beta 1 may not only induce extracellular matrix synthesis, but may also participate in the process of glomerular hypertrophy in response to injury.

Expression of rat fibroblast growth factor receptor 1 as three splicing variants during kidney development

Fibroblast growth factors (FGF) are known to participate in the processes of embryogenesis and angiogenesis. This study was undertaken to examine the transcriptional and posttranscriptional regulation of the FGF receptor 1 (FGFR-1) subclass in the embryonic rat kidney. Two full-length FGF receptor cDNAs were cloned using low-stringency screening of a neonatal rat kidney library with a chicken FGFR-1 cDNA probe. Sequencing revealed these cloned cDNAs to be rat homologues of the FGFR-1 subtype, with the two clones representing splicing variants beta and gamma of the FGFR-1. Evidence for renal expression of a third splicing variant (alpha) was obtained by use of the polymerase chain reaction. Splicing variants alpha and beta of FGFR-1 are predicted to produce cell-surface FGF receptors with three and two immunoglobulin-like domains, respectively, whereas the gamma-isoform may represent an intracellular form of the receptor. Although all three splicing variants were expressed in the developing kidney at days 14, 17, and 20 of gestation, at neonatal days 1 and 7 and in mature rats the beta-isoform was present in vastly larger abundance than alpha- and gamma-isoforms at all stages studied. Northern blot analysis revealed enhanced expression of FGFR-1 in the neonatal compared with the mature kidney. It is concluded that FGFR-1 is expressed in the kidney predominantly as the beta-isoform splicing variant and that expression of this receptor is enhanced during kidney development.

Molecular cloning and characterization of catechol 2,3-dioxygenases from biphenyl/polychlorinated biphenyls-degrading bacteria

Catechol 2,3-dioxygenases were cloned from Alcaligenes sp. KF711, Pseudomonas putida KF715, and Achromobacter xylosoxidans KF701 which are biphenyl/polychlorinated biphenyls-degrading bacteria. All of the cloned enzymes were purified by preparative polyacrylamide gel electrophoresis (PAGE). The purified catechol 2,3-dioxygenases were significantly different from one another in ring-fission activities to catechol and its derivatives. The catechol 2,3-dioxygenase from Alcaligenes sp. KF711 exhibited higher ring-fission activity to 4-chlorocatechol than those from P. putida KF715 and A. xylosoxidans KF701. In electrophoretic mobilities, the three enzymes were different from one another on nondenaturing PAGE but the same on SDS-PAGE.