Aneuploid neurons are functionally active and integrated into brain circuitry

The existence of aneuploid cells within the mammalian brain has suggested the influence of genetic mosaicism on normal neural circuitry. However, aneuploid cells might instead be glia, nonneural, or dying cells, which are irrelevant to direct neuronal signaling. Combining retrograde labeling with FISH for chromosome-specific loci, distantly labeled aneuploid neurons were observed in expected anatomical projection areas. Coincident labeling for immediate early gene expression indicated that these aneuploid neurons were functionally active. These results demonstrate that functioning neurons with aneuploid genomes form genetically mosaic neural circuitries as part of the normal organization of the mammalian brain.

Glucagon does not affect catecholamine release in primary cultures of bovine adrenal chromaffin cells

OBJECTIVE

Human pheochromocytoma tumor cells express glucagon receptors, and bolus i.v. glucagon injection rapidly increases plasma epinephrine levels, suggesting that glucagon can directly stimulate adrenomedullary secretion. In this study, we tested whether the catecholamine secretory response to glucagon was present in bovine chromaffin cells or exclusive to the tumor cells.

DESIGN AND METHODS

Adrenomedullary cells were cultured in 24-well plates (10(6) cells per well). After 48-72 hours, wells were incubated for 1-20 minutes with (1) incubation medium (control), (2) catecholamine secretagogues (nicotine or potassium ion), or (3) glucagon (10(-8) to 10(-5) M). After incubation, catecholamine contents in medium and cells were assayed by high-pressure liquid chromatography with electrochemical detection. Fractional release rates of epinephrine, norepinephrine, and dopamine were calculated and compared to controls. Reverse-transcriptase PCR was performed to compare expression of mRNA of the glucagon receptor in chromaffin cells and pheochromocytoma cells.

RESULTS

Nicotine and potassium evoked time-dependent release of epinephrine, norepinephrine, and dopamine. Glucagon did not affect catecholamine secretion at any concentration. Reverse-transcriptase PCR failed to detect mRNA for glucagon receptor in bovine adrenomedullary cells, but did detect it in human pheochromocytoma cells.

CONCLUSIONS

In contrast to pheochromocytoma tumor cells, bovine adrenomedullary chromaffin cells do not express the glucagon receptor, and therefore do not secrete catecholamines in response to glucagon.

The use of a fibrin tissue sealant during laparoscopic partial nephrectomy

OBJECTIVE

To assess the feasibility and efficacy of commercially available fibrin tissue sealant as a haemostatic agent and collecting-system sealant during hand-assisted laparoscopic partial nephrectomy (LPN).

PATIENTS AND METHODS

Fifteen consecutive patients underwent LPN for enhancing renal masses suspicious for renal cell carcinoma via a transperitoneal approach and with the use of a hand-assistance device. Monopolar electrocauterization and argon-beam coagulation were initially used to slow bleeding from the resection site. Through a laparoscopic applicator, Tisseel(TM) fibrin sealant (Baxter Inc., Deerfield, IL) was applied to the transected partial nephrectomy bed while the surgeon's hand maintained adequate compression and partial haemostasis. No further haemostatic measures were required in any patient; the patients were evaluated for acute and delayed bleeding or urinary extravasation.

RESULTS

In all cases electrocauterization and argon-beam coagulation followed by the application of Tisseel was successful in obtaining strict haemostasis of the surgical bed, with no evidence of bleeding during or after surgery on immediate and extended follow-up. In addition, there was no evidence during or after surgery of any urinary leak. There were no immediate or delayed complications in any of the patients; a short-term outpatient follow-up (12-60 weeks) revealed no additional problems.

CONCLUSIONS

Conventional haemostatic measures of electrocauteriztion and argon-beam coagulation combined with commercial fibrin sealant allows successful haemostasis during LPN. In addition to haemostatic properties, fibrin sealants appear to have sealing properties that may help to prevent complications of urinary leakage by helping to seal or close the small defects in the urinary collecting system. The use of this compound may facilitate the ability of the urological laparoscopist during LPN.

Genetics and cell biology of lysophosphatidic acid receptor-mediated signaling during cortical neurogenesis

Lysophosphatidic acid (LPA) is a small lysophospholipid that signals through G-protein coupled receptors (GPCRs) to mediate diverse cellular responses. Two LPA receptors, LPA(1) and LPA(2), show gene expression profiles in mouse embryonic cerebral cortex, suggesting roles for LPA signaling in cerebral cortical development. Here, we review loss-of-function and gain-of-function models that have been used to examine LPA signaling. Genetic deletion of lpa(1) or both lpa(1) and lpa(2) in mice results in 50-65% neonatal lethality, but not obvious cortical phenotypes in survivors, suggesting that compensatory signaling systems exist for regulating cortical development. A gain-of-function model, approached by increasing receptor activation through exogenous delivery of LPA, shows that LPA signaling regulates cerebral cortical growth and anatomy by affecting proliferation, differentiation and cell survival during embryonic development.

Novel ceramide analogues display selective cytotoxicity in drug-resistant breast tumor cell lines compared to normal breast epithelial cells

The sphingolipid ceramide is involved in diverse cell signaling pathways related to proliferation and differentiation. Elevated ceramide also triggers apoptosis. Synthetic ceramide derivatives have been shown to be cytotoxic to tumors, yet few studies have evaluated whether cytotoxicity of synthetic ceramides is selective for tumor cells. We have evaluated the cytotoxic potency of several novel ceramide analogues in the drug-resistant breast tumor cell lines, SKBr3 and MCF-7/Adr, and compared their cytotoxicity in normal breast epithelial cells. Cytotoxicity was assessed using release of lactate dehydrogenase into the culture medium. (2S, 3S)-3-(6'-Dodecylpyridin-2'-yl)-2-butanoylamidopropane-1,3-diol (pyridine-C4-ceramide) produced non-selective cytotoxicity across the three cell types (EC50= 12.8-16.7 microM, at 24 hr). However, 2S,5R-2-(octanoylamido-(3E))-octadecene-1,5-diol (5R-OH-3E-C8-ceramide), (2S,3R)-2-(N-adamantoyl)-(4E)-octadecen-1,3-diol (adamantyl-ceramide), and (2S,3R)-3-(3'-dodecylphenyl)-2-butanoylamidopropane-1,3-diol (benzene-C4-ceramide) exhibited increased cytotoxicity in the tumor cell lines compared to the normal breast epithelial cells. The EC50 values (microM) at 24 hr for these compounds in SKBr3 cells, MCF-7/Adr cells, and normal breast epithelial cells, respectively, were as follows: 5R-OH-3E-C8-ceramide, 18.3, 21.2 and 58.7; adamantyl-ceramide, 10.9, 24.9 and >100; benzene-C4-ceramide, 18.9, 45.5 and >100. At a concentration of 30 microM, the fold increase in cytotoxicity in breast tumor cell lines compared with normal breast epithelial cells was as follows: 5R-OH-3E-C8-ceramide, 23.7 and 19; adamantyl-ceramide, 11.2 and 10.3 and benzene-C4-ceramide, 79.3 and 77.2, for SKBr3 and MCF-7/Adr cells, respectively. Possible mechanisms accounting for selectivity are discussed. Ceramide analogues with relatively selective toxicity against tumor cells may have potential as therapeutic agents. Elucidating the mechanisms of selective cytotoxicity could identify novel targets that may lead to development of anti-neoplastic agents with a higher therapeutic index.

Prolonged procoagulant activity on overstretch-injured coronary arteries in pigs

This study was designed to assess the time course and nature of the vascular procoagulant response after 1.5-fold balloon overstretch injury of the coronary arteries in pigs. Arteries were excised for chromogenic assay of bound factor (F)Xa and thrombin at 24 h, 3 days, 1 week, or 2 weeks after injury. FXa at the site of injury remained elevated for 1 week (4.9 +/- 5.9 microg cm(-2), n = 10), compared with non-injured control arteries (0.4 +/- 0.2 microg cm(-2), n = 18, P = 0.00025), while thrombin was increased only at 24 h. Tissue factor protein was abundant in non-injured coronaries (10 +/- 6 ng microg(-1) total protein, n = 9) and levels were unchanged by injury (13 +/- 11 ng microg(-1), n = 6) or 24-h administration of tissue factor pathway inhibitor (16 +/- 6 ng microg(-1), n = 6). Persistent tissue factor-mediated procoagulant activity may explain the need for prolonged anticoagulation to attenuate neointimal formation after balloon-induced coronary injury.

Chromosomal variation in neurons of the developing and adult mammalian nervous system

A basic assumption about the normal nervous system is that its neurons possess identical genomes. Here we present direct evidence for genomic variability, manifested as chromosomal aneuploidy, among developing and mature neurons. Analysis of mouse embryonic cerebral cortical neuroblasts in situ detected lagging chromosomes during mitosis, suggesting the normal generation of aneuploidy in these somatic cells. Spectral karyotype analysis identified approximately 33% of neuroblasts as aneuploid. Most cells lacked one chromosome, whereas others showed hyperploidy, monosomy, and/or trisomy. The prevalence of aneuploidy was reduced by culturing cortical explants in medium containing fibroblast growth factor 2. Interphase fluorescence in situ hybridization on embryonic cortical cells supported the rate of aneuploidy observed by spectral karyotyping and detected aneuploidy in adult neurons. Our results demonstrate that genomes of developing and adult neurons can be different at the level of whole chromosomes.

Arenibacter gen. nov., new genus of the family flavobacteriaceae and description of a new species, Arenibacter latericius sp. nov

Five dark-orange-pigmented, Gram-negative, rod-shaped, non-motile, aerobic bacterial strains were isolated from sandy sediment samples collected in the South China Sea in the Indian Ocean, from a holothurian, Apostichopus japonicus, in the Sea of Japan and from a brown alga, Chorda filum, from the Sea of Okhotsk in the Pacific Ocean. Phenotypic data were collected, demonstrating that the bacteria are chemo-organotrophic and require seawater-based media for growth. Polar lipids were analysed and 27% of the total extract comprised phosphatidylethanolamine as the major component. The predominant cellular fatty acids were branched-chain saturated and unsaturated [i-C15:0, i-C15:1, a-C15:0, C15:0, C16:1(n-7)]. The DNA base composition was 37.5-38.2 mol % G+C. The level of DNA homology of the five isolates was 83-94%, indicating that these isolates belong to the same species. A 16S rDNA sequence of the type strain KMM 426T was determined and phylogenetic analysis, based on neighbour-joining and Fitch-Margoliash methods, revealed that the type strain formed a distinct phyletic line in a clade corresponding to the family Flavobacteriaceae and represented a new genus. From the results of this polyphasic taxonomic analysis, it is proposed that the bacterial strains be classified in a new genus, Arenibacter gen. nov., and species, Arenibacter latericius sp. nov. The type strain is KMM 426T (VKM B 2137DT = LMG 19694T = CIP 106861T).

Regulation of Schwann cell morphology and adhesion by receptor-mediated lysophosphatidic acid signaling

In peripheral nerves, Schwann cells (SCs) form contacts with axons, other SCs, and extracellular matrix components that are critical for their migration, differentiation, and response to injury. Here, we report that lysophosphatidic acid (LPA), an extracellular signaling phospholipid, regulates the morphology and adhesion of cultured SCs. Treatment with LPA induces f-actin rearrangements resulting in a "wreath"-like structure, with actin loops bundled peripherally by short orthogonal filaments. The latter appear to anchor the SC to a laminin substrate, because they colocalize with the focal adhesion proteins, paxillin and vinculin. SCs also respond to LPA treatment by forming extensive cell-cell junctions containing N-cadherin, resulting in cell clustering. Pharmacological blocking experiments indicate that LPA-induced actin rearrangements and focal adhesion assembly involve Rho pathway activation via a pertussis toxin-insensitive G-protein. The transcript encoding LP(A1), the canonical G-protein-coupled receptor for LPA, is upregulated after sciatic nerve transection, and SCs cultured from lp(A1)-null mice exhibit greatly diminished morphological responses to LPA. Cultured SCs can release an LPA-like factor implicating SCs as a potential source of endogenous, signaling LPA. These data, together with the previous demonstration of LPA-mediated SC survival, implicate endogenous receptor-mediated LPA signaling in the control of SC development and function.

Selective loss of sphingosine 1-phosphate signaling with no obvious phenotypic abnormality in mice lacking its G protein-coupled receptor, LP(B3)/EDG-3

Sphingosine 1-phosphate (S1P) exerts diverse physiological actions by activating its cognate G protein-coupled receptors. Five S1P receptors have been identified in mammals: LP(B1)/EDG-1, LP(B2)/H218/AGR16/EDG-5, LP(B3)/EDG-3, LP(B4)/NRG-1/EDG-8, and LP(C1)/EDG-6. One of these receptors, LP(B1), has recently been shown to be essential for mouse embryonic development. Here we disrupted the lp(B3) gene in mice, resulting in the complete absence of lp(B3) gene, transcript, and LP(B3) protein. LP(B3)-null mice were viable and fertile and developed normally with no obvious phenotypic abnormality. We prepared mouse embryonic fibroblast (MEF) cells to examine effects of LP(B3) deletion on S1P-induced signal transduction pathways. Wild-type MEF cells expressed lp(B1), lp(B2), and lp(B3) but neither lp(B4) nor lp(C1), and they were highly responsive to S1P in phospholipase C (PLC) activation, adenylyl cyclase inhibition, and Rho activation. Identically prepared LP(B3)-null MEF cells showed significant decreases in PLC activation, slight decreases in adenylyl cyclase inhibition, and no change in Rho activation. Retrovirus-mediated rescue of the LP(B3) receptor in LP(B3)-null MEF cells restored S1P-dependent PLC activation and adenylyl cyclase inhibition. These results indicate a nonessential role for LP(B3) in normal development of mouse but show nonredundant cellular signaling mediated by a single type of S1P receptor.

Metschnikowia koreensis sp. nov., a novel yeast species isolated from flowers in Korea

A novel ascomycetous yeast was isolated from flowers of Lilium sp. and Ipomoea sp. in Korea. The name Metschnikowia koreensis sp. nov. (type strain SG99-34T = CBS 8854T = KCTC 7998T) is proposed for this novel species based on comparative sequence analyses of the D1/D2 domain of 26S rDNA and phenotypic characteristics.

Angiotensin II-responsive element is the insulin-responsive element in the adipocyte fatty acid synthase gene: role of adipocyte determination and differentiation factor 1/sterol-regulatory-element-binding protein 1c

We have previously shown that angiotensin II (Ang II) increases the expression of the gene encoding adipocyte fatty acid synthase (FAS). Here we investigate the mechanism responsible for increased FAS gene transcription by Ang II. We demonstrate that Ang II increased luciferase activity by 3-fold in 3T3-L1 adipocytes transfected with fusion constructs linking the FAS promoter to the luciferase reporter gene. Interestingly, we mapped the Ang II regulatory sequences to the insulin-responsive region (E box) in the proximal FAS promoter. The E box alone was able to mediate Ang II responsiveness when linked to a heterologous promoter. However, this response was lost when mutations that abolished the binding of the E box to its transcription factors were introduced. Using adenoviral overexpression of a dominant-negative form of adipocyte determination and differentiation factor 1 (ADD1), a transcription factor that binds to the insulin-responsive E box, we demonstrated that ADD1 was required for Ang II regulation of the FAS gene in 3T3-L1 adipocytes. Furthermore, ADD1 expression was also up-regulated by Ang II. With the use of transfections as well as glucose transport assays, we further demonstrated that Ang II stimulation of the FAS gene was dependent on glucose. In conclusion, this is the first report that Ang II regulates adipocyte FAS gene transcription via insulin response sequences in a glucose-dependent manner and that this regulation is mediated at least in part via the ADD1 transcription factor.

Expression and function of lysophosphatidic acid receptors in cultured rodent microglial cells

Microglia are the resident tissue macrophages of the central nervous system. They are rapidly activated by a variety of insults; and recently, receptors linked to cytoplasmic Ca(2+) signals have been implicated in such events. One potential class of receptors are those recognizing lysophosphatidic acid (LPA). LPA is a phospholipid signaling molecule that has been shown to cause multiple cellular responses, including increases in cytoplasmic calcium. We examined whether any of the known LPA receptor genes (lp(A1)/Edg2, lp(A2)/Edg4, and lp(A3)/Edg7) are expressed by cultured mouse or rat microglia. Reverse transcriptase-polymerase chain reaction indicated that mouse microglia predominantly expressed the lp(A1) gene, whereas rat microglia predominantly expressed lp(A3). Although LPA induced increases in the cytoplasmic Ca(2+) concentration in both microglial preparations, the responses differed substantially. The Ca(2+) signal in rat microglia occurred primarily through Ca(2+) influx via the plasma membrane, whereas the Ca(2+) signal in mouse microglia was due to release from intracellular stores. Only at high concentrations was an additional influx component recruited. Additionally, LPA induced increased metabolic activity in mouse (but not rat) microglial cells. Our findings provide evidence for functional LPA receptors on microglia. Thus, LPA might play an important role as a mediator of microglial activation in response to central nervous system injury.

Lysophospholipid receptors

Lysophospholipids (LPs), including lysophosphatidic acid and sphingosine 1-phosphate, produce many cellular effects. However, the prolonged absence of any cloned and identified LP receptor has left open the question of how these lipids actually bring about these effects. The cloning and functional identification of the first LP receptor, lp(A1)/vzg-1, has led rapidly to the identification and classification of multiple orphan receptors/expression sequence tags known by many names (e.g. edg, mrec1.3, gpcr26, H218, AGR16, nrg-1) as members of a common cognate G protein-coupled receptor family. We review features of the LP receptor family, including molecular characteristics, genomics, signaling properties, and gene expression. A major question for which only partial answers are available concerns the biological significance of receptor-mediated LP signaling. Recent studies that demonstrate the role of receptor-mediated LP signaling in the nervous system, cardiovascular system, and other organ systems indicate the importance of this signaling in development, function, and pathophysiology and portend an exciting time ahead for this growing field.

Genotypes associated with virulence in environmental isolates of Vibrio cholerae

Vibrio cholerae is an autochthonous inhabitant of riverine and estuarine environments and also is a facultative pathogen for humans. Genotyping can be useful in assessing the risk of contracting cholera, intestinal, or extraintestinal infections via drinking water and/or seafood. In this study, environmental isolates of V. cholerae were examined for the presence of ctxA, hlyA, ompU, stn/sto, tcpA, tcpI, toxR, and zot genes, using multiplex PCR. Based on tcpA and hlyA gene comparisons, the strains could be grouped into Classical and El Tor biotypes. The toxR, hlyA, and ompU genes were present in 100, 98.6, and 87.0% of the V. cholerae isolates, respectively. The CTX genetic element and toxin-coregulated pilus El Tor (tcpA ET) gene were present in all toxigenic V. cholerae O1 and V. cholerae O139 strains examined in this study. Three of four nontoxigenic V. cholerae O1 strains contained tcpA ET. Interestingly, among the isolates of V. cholerae non-O1/non-O139, two had tcpA Classical, nine contained tcpA El Tor, three showed homology with both biotype genes, and four carried the ctxA gene. The stn/sto genes were present in 28.2% of the non-O1/non-O139 strains, in 10.5% of the toxigenic V. cholerae O1, and in 14.3% of the O139 serogroups. Except for stn/sto genes, all of the other genes studied occurred with high frequency in toxigenic V. cholerae O1 and O139 strains. Based on results of this study, surveillance of non-O1/non-O139 V. cholerae in the aquatic environment, combined with genotype monitoring using ctxA, stn/sto, and tcpA ET genes, could be valuable in human health risk assessment.

Two novel Xenopus homologs of mammalian LP(A1)/EDG-2 function as lysophosphatidic acid receptors in Xenopus oocytes and mammalian cells

Lysophosphatidic acid (LPA) induces diverse biological responses in many types of cells and tissues by activating its specific G protein-coupled receptors (GPCRs). Previously, three cognate LPA GPCRs (LP(A1)/VZG-1/EDG-2, LP(A2)/EDG-4, and LP(A3)/EDG-7) were identified in mammals. By contrast, an unrelated GPCR, PSP24, was reported to be a high affinity LPA receptor in Xenopus laevis oocytes, raising the possibility that Xenopus uses a very different form of LPA signaling. Toward addressing this issue, we report two novel Xenopus genes, xlp(A1)-1 and xlp(A1)-2, encoding LP(A1) homologs (approximately 90% amino acid sequence identity with mammalian LP(A1)). Both xlp(A1)-1 and xlp(A1)-2 are expressed in oocytes and the nervous system. Overexpression of either gene in oocytes potentiated LPA-induced oscillatory chloride ion currents through a pertussis toxin-insensitive pathway. Injection of antisense oligonucleotides designed to inhibit xlp(A1)-1 and xlp(A1)-2 expression in oocytes eliminated their endogenous response to LPA. Furthermore, retrovirus-mediated heterologous expression of xlp(A1)-1 or xlp(A1)-2 in B103 rat neuroblastoma cells that are unresponsive to LPA conferred LPA-induced cell rounding and adenylyl cyclase inhibition. These results indicate that XLP(A1)-1 and XLP(A1)-2 are functional Xenopus LPA receptors and demonstrate the evolutionary conservation of LPA signaling over a range of vertebrate phylogeny.

Physician-patient dialogue and clinical evaluation of erectile dysfunction

Erectile dysfunction affects 31% to 52% of all men. Although considerable advances have been made in the diagnosis and management of erectile dysfunction, the inadequate knowledge of erectile dysfunction by health care providers still precludes them from initiating candid discussions with their patients. This article provides the health care professional with the ability to establish comfortable doctor-patient dialogue and to clinically evaluate erectile dysfunction in a goal-directed manner. The goal of evaluation is to find the appropriate treatment for the individual, dictated primarily by factors like the patients' preferences, comfort, cost, and the availability of treatment modalities.

The mouse lp(A3)/Edg7 lysophosphatidic acid receptor gene: genomic structure, chromosomal localization, and expression pattern

The extracellular signaling molecule, lysophosphatidic acid (LPA), mediates proliferative and morphological effects on cells and has been proposed to be involved in several biological processes including neuronal development, wound healing, and cancer progression. Three mammalian G protein-coupled receptors, encoded by genes designated lp (lysophospholipid) receptor or edg (endothelial differentiation gene), mediate the effects of LPA, activating similar (e.g. Ca(2+) release) as well as distinct (neurite retraction) responses. To understand the evolution and function of LPA receptor genes, we characterized lp(A3)/Edg7 in mouse and human and compared the expression pattern with the other two known LPA receptor genes (lp(A1)/Edg2 and lp(A2)/Edg4non-mutant). We found mouse and human lp(A3) to have nearly identical three-exon genomic structures, with introns upstream of the coding region for transmembrane domain (TMD) I and within the coding region for TMD VI. This structure is similar to lp(A1) and lp(A2), indicating a common ancestral gene with two introns. We localized mouse lp(A3) to distal Chromosome 3 near the varitint waddler (Va) gene, in a region syntenic with the human lp(A3) chromosomal location (1p22.3-31.1). We found highest expression levels of each of the three LPA receptor genes in adult mouse testes, relatively high expression levels of lp(A2) and lp(A3) in kidney, and moderate expression of lp(A2) and lp(A3) in lung. All lp(A) transcripts were expressed during brain development, with lp(A1) and lp(A2) transcripts expressed during the embryonic neurogenic period, and lp(A3) transcript during the early postnatal period. Our results indicate both overlapping as well as distinct functions of lp(A1), lp(A2), and lp(A3).

The LPA receptors

Lysophosphatidic acid (LPA) is a growth factor-like lipid that produces many cellular responses. These responses, including actin cytoskeletal rearrangements, cell proliferation and inhibition of gap junction communication, have been documented in many cell types over the last 2 decades. Both non-receptor and receptor-mediated mechanisms had been implicated to explain these responses. A clear advance in this field was the cloning and functional identification of LPA receptors, and there are currently three high-affinity members, LPA1, LPA2 and LPA3 (synonymous with orphan receptor names edg-2, edg-4 and edg-7, respectively). Here we review the gene structure, expression and functions of LPA receptors. We also discuss the in vivo roles mediated by a single LPA receptor type, based on studies of the nervous system, a major locus of LPA receptor expression.

Hahella chejuensis gen. nov., sp. nov., an extracellular-polysaccharide-producing marine bacterium

A bacterial strain, designated 96CJ10356T, which produced abundant extracellular polysaccharides and red pigment was isolated from marine sediment collected from Marado, Cheju Island, Republic of Korea. The organism is Gram-negative, aerobic, rod-shaped and motile. Growth was not observed in the absence of NaCl, and was optimal at an NaCl concentration of 2%. The strain contained oxidase and catalase, and was able to hydrolyse aesculin and gelatin. The major cellular fatty acids were saturated or monounsaturated straight-chain fatty acids. An almost complete 16S rDNA sequence of the test strain was determined. Phylogenetic analysis based on the neighbour-joining and Fitch-Margoliash methods indicated that the organism formed a distinct phyletic line within the gamma Proteobacteria. This relationship was also supported by sequence comparison, as no valid bacterial species showed more than 90% sequence homology with the isolate. It is clear from polyphasic evidence that the isolate merits the status of genus in the gamma subclass of the Proteobacteria, and the name Hahella chejuensis gen. nov., sp. nov. is proposed for the marine isolate 96CJ10356T (= KCTC 2396T = IMSNU 11157T).

Arthrobacter siderocapsulatus Dubinina and Zhdanov 1975AL is a later subjective synonym of Pseudomonas putida (Trevisan 1889) Migula 1895AL

The taxonomic position of Arthrobacter siderocapsulatus Dubinina and Zhdanov 1975AL was investigated using 16S rDNA, fatty acid and phenotypic analyses. The type strain (NCIMB 11286T) showed 99.85% 16S rDNA similarity to the type strain of Pseudomonas putida. Phenotypic properties of the two strains were compared using API 20NE and BIOLOG kits. Identical reactions were recorded for all tests, except for assimilation of malonic acid. The two strains also showed almost identical cellular fatty acid profiles. On the basis of evidence presented in this and earlier studies, it is proposed that Arthrobacter siderocapsulatus is a later subjective synonym of Pseudomonas putida (Trevisan 1889) Migula 1895AL.

Pancreatic endocrine tumors

Pancreatic endocrine tumors are rare but have long held a fascination for clinicians because of the physiologic derangements that they can cause, and the dramatic corrections that can be achieved by appropriate management. In the year reviewed in this article, the literature again demonstrated the ongoing interest and research in this area. In particular, the areas of gastrinoma, insulinoma, and multiple endocrine neoplasia type 1 have received careful attention.

Lysophosphatidic acid (LPA) is a novel extracellular regulator of cortical neuroblast morphology

During cerebral cortical neurogenesis, neuroblasts in the ventricular zone (VZ) undergo a shape change termed "interkinetic nuclear migration" whereby cells alternate between fusiform and rounded morphologies. We previously identified lp(A1), the first receptor gene for a signaling phospholipid called lysophosphatidic acid (LPA) and showed its enriched expression in the VZ. Here we report that LPA induces changes in neuroblast morphology from fusiform to round in primary culture, accompanied by nuclear movements, and formation of f-actin retraction fibers. These changes are mediated by the activation of the small GTPase, Rho. In explant cultures, where the cerebral cortical architecture remains intact, LPA not only induces cellular and nuclear rounding in the VZ, but also produces an accumulation of rounded nuclei at the ventricular surface. Consistent with a biological role for these responses, utilization of a sensitive and specific bioassay indicates that postmitotic neurons can produce extracellular LPA. These results implicate LPA as a novel factor in cortical neurogenesis and further implicate LPA as an extracellular signal from postmitotic neurons to proliferating neuroblasts.

Lysophosphatidic acid receptors

Lysophosphatidic acid (LPA) is a simple bioactive phospholipid with diverse physiological actions on many cell types. LPA induces proliferative and/or morphological effects and has been proposed to be involved in biologically important processes including neurogenesis, myelination, angiogenesis, wound healing, and cancer progression. LPA acts through specific G protein-coupled, seven-transmembrane domain receptors. To date, three mammalian cognate receptor genes, lp(A1)/vzg-1/Edg2, lp(A2)/Edg4, and lp(A3)/Edg7, have been identified that encode high-affinity LPA receptors. Here, we review current knowledge on these LPA receptors, including their isolation, function, expression pattern, gene structure, chromosomal location, and possible physiological or pathological roles.

Requirement for the lpA1 lysophosphatidic acid receptor gene in normal suckling behavior

Although extracellular application of lysophosphatidic acid (LPA) has been extensively documented to produce a variety of cellular responses through a family of specific G protein-coupled receptors, the in vivo organismal role of LPA signaling remains largely unknown. The first identified LPA receptor gene, lp(A1)/vzg-1/edg-2, was previously shown to have remarkably enriched embryonic expression in the cerebral cortex and dorsal olfactory bulb and postnatal expression in myelinating glia including Schwann cells. Here, we show that targeted deletion of lp(A1) results in approximately 50% neonatal lethality, impaired suckling in neonatal pups, and loss of LPA responsivity in embryonic cerebral cortical neuroblasts with survivors showing reduced size, craniofacial dysmorphism, and increased apoptosis in sciatic nerve Schwann cells. The suckling defect was responsible for the death among lp(A1)((-/-)) neonates and the stunted growth of survivors. Impaired suckling behavior was attributable to defective olfaction, which is likely related to developmental abnormalities in olfactory bulb and/or cerebral cortex. Our results provide evidence that endogenous lysophospholipid signaling requires an lp receptor gene and indicate that LPA signaling through the LP(A1) receptor is required for normal development of an inborn, neonatal behavior.

Synthesis of ceramide analogues having the C(4)-C(5) bond of the long-chain base as part of an aromatic or heteroaromatic system

Two efficient and stereoselective methods are described for the preparation of aryl and heteroaryl ceramide analogues 2 and 3. The first route involves the addition of an aryllithium or a heteroaryllithium reagent (7a or 25a, respectively) to the L-serine-derived aldehyde 4, followed by hydrolysis of the oxazolidine, liberation of the amino group, and N-acylation. The second route, which was used to prepare arylceramide analogue 2 in eight steps and 28% overall yield starting with 3-bromobenzaldehyde, utilizes a Heck reaction to afford (E)-alpha,beta-unsaturated ester 16, then osmium-catalyzed asymmetric dihydroxylation for the introduction of the desired chirality at C-2 and C-3. Regioselective alpha-azidation of alpha-O-nosyl-beta-hydroxyester 18 with sodium azide, followed by LiAlH(4) reduction of the azido and ester groups and N-acylation, complete the synthesis of arylceramide analogue 2.

Glypican-4 is an FGF2-binding heparan sulfate proteoglycan expressed in neural precursor cells

FGF2 is a crucial mitogen for neural precursor cells in the developing cerebral cortex. Heparan sulfate proteoglycans (HSPGs) are thought to play a role in cortical neurogenesis by regulating the action of FGF2 on neural precursor cells. In this article, we present data indicating that glypican-4 (K-glypican), a GPI-anchored cell surface HSPG, is involved in these processes. In the developing mouse brain, glypican-4 mRNA is expressed predominantly in the ventricular zone of the telencephalon. Neither the outer layers of the telencephalic wall nor the ventricular zone of other parts of the developing brain express significant levels of glypican-4, with the exception of the ventricular zone of the tectum. In cultures of E13 rat cortical precursor cells, glypican-4 is expressed in cells immunoreactive for nestin and the D1.1 antigen, markers of neural precursor cells. Glypican-4 expression was not detected in early postmitotic or fully differentiated neurons. Recombinant glypican-4 produced in immortalized neural precursor cells binds FGF2 through its heparan sulfate chains and suppressed the mitogenic effect of FGF2 on E13 cortical precursor cells. The spatiotemporal expression pattern of glypican-4 in the developing cerebral wall significantly overlaps with that of FGF2. These results suggest that glypican-4 plays a critical role in the regulation of FGF2 action during cortical neurogenesis.

Functional comparisons of the lysophosphatidic acid receptors, LP(A1)/VZG-1/EDG-2, LP(A2)/EDG-4, and LP(A3)/EDG-7 in neuronal cell lines using a retrovirus expression system

Lysophosphatidic acid (LPA) is a potent lipid mediator with diverse physiological actions on a wide variety of cells and tissues. Three cognate G-protein-coupled receptors have been identified as mammalian LPA receptors: LP(A1)/VZG-1/EDG-2, LP(A2)/EDG-4, and LP(A3)/EDG-7. The mouse forms of these genes were analyzed in rodent cell lines derived from nervous system cells that can express these receptors functionally. An efficient retrovirus expression system was used, and each receptor was heterologously expressed in B103 rat neuroblastoma cells that neither express these receptors nor respond to LPA in all assays tested. Comparative analyses of signaling pathways that are activated within minutes of ligand delivery were carried out. LPA induced cell rounding in LP(A1)- and LP(A2)-expressing cells. By contrast, LP(A3) expression resulted in neurite elongation in B103 cells and inhibited LPA-dependent cell rounding in TR mouse neuroblast cells that endogenously express LP(A1) and LP(A2) but not LP(A3). Each of the receptors could couple to multiple G-proteins and induced LPA-dependent inositol phosphate production, mitogen-activated protein kinase activation, and arachidonic acid release while inhibiting forskolin-induced cAMP accumulation, although the efficacy and potency of LPA varied from receptor to receptor. These results indicate both shared and distinct functions among the three mammalian LPA receptors. The retroviruses developed in this study should provide tools for addressing these functions in vivo.

Use of a chiA probe for detection of chitinase genes in bacteria from the Chesapeake Bay(1)

PCR primers specific for the chiA gene were designed by alignment and selection of highly conserved regions of chiA sequences from Serratia marcescens, Alteromonas sp., Bacillus circulans and Aeromonas caviae. These primers were used to amplify a 225 bp fragment of the chiA gene from Vibrio harveyi to produce a chiA gene probe. The chiA PCR primers and probe were used to detect the presence of the chiA gene in an assemblage of 53 reference strains and gave consistent results. Selected chiA fragments amplified by PCR were cloned and sequenced from nine known strains and from Chesapeake Bay isolates 6d and 11d. This confirmed the specificity and utility of the primers for detection of chiA-positive environmental strains. Over 1000 bacterial isolates from Chesapeake Bay water samples were tested for the presence of the chiA gene which was found to be present in 5-41% (average 21%) of the culturable bacterial community. The approach developed in this study was valuable for isolation and enumeration of chiA-positive bacteria in environmental samples.

Transcriptional regulation of the adipocyte fatty acid synthase gene by agouti: interaction with insulin

Mice carrying dominant mutations at the agouti locus exhibit ectopic expression of agouti gene transcripts, obesity, and type II diabetes through unknown mechanisms. To gain insight into the role of agouti protein in modulating adiposity, we investigated regulation of a key lipogenic gene, fatty acid synthase (FAS) by agouti alone and in combination with insulin. Both agouti and insulin increase FAS activity in 3T3-L1 and in human adipocytes. Agouti and insulin independently and additively increase FAS activity in 3T3-L1 adipocytes. We further investigated the mechanism responsible for the agouti-induced FAS expression in these cells and demonstrated that both insulin (3-fold increase) and agouti (2-fold) increased FAS gene expression at the transcriptional level. Furthermore, insulin and agouti together exerted additive effects (5-fold increase) on FAS gene transcription. Transfection assays of FAS promoter-luciferase fusion gene constructs into 3T3-L1 adipocytes indicated that the agouti response element(s) is (are) located in the -435 to -415 region (-435/-415) of the FAS promoter. Nuclear proteins binding to this novel sequence are adipocyte specific. Thus the agouti response sequences mapped to a region upstream of the insulin-responsive element (which we previously reported to be located at -67/-52), consistent with additive effects of these two factors on FAS gene transcription.

Nocardiopsis kunsanensis sp. nov., a moderately halophilic actinomycete isolated from a saltern

A moderately halophilic actinomycete, designated HA-9T, was isolated from a saltern in Kunsan, Republic of Korea, and was the subject of polyphasic identification. Analysis of 16S rDNA indicated that the isolate belonged to the genus Nocardiopsis, but differed genetically from other Nocardiopsis species. Strain HA-9T contained meso-diaminopimelic acid, no diagnostic sugars, hexa- or octa-hydrogenated menaquinones with 10 isoprene units, straight-chain saturated or monounsaturated, iso-, anteiso-, 10-methyl branched fatty acids with 13-18 carbons and type III phospholipids. All of these characters consistently assign the isolate to the genus Nocardiopsis. All of the validly described Nocardiopsis species, including moderately halophilic Nocardiopsis halophila, can be differentiated from the saltern isolate using morphological and physiological traits. On the basis of polyphasic evidence, the name Nocardiopsis kunsanensis sp. nov. is proposed for strain HA-9T (= KCTC 9831T), which is designated the type strain.

Leuconostoc kimchii sp. nov., a new species from kimchi

A Gram-positive, catalase-negative, facultatively anaerobic, coccus-shaped bacterium, designated IH25T, was isolated from kimchi, a traditional Korean vegetable product. Phylogenetic analysis based on almost complete 16S rDNA sequences placed the isolate in a monophyletic clade corresponding to the genus Leuconostoc. All validly described species in the genus Leuconostoc, with the exception of Leuconostoc fallax, showed high sequence identity of over 97%. The 16S rDNA sequence of strain IH25T showed the highest homology to those of Leuconostoc gelidum DSM 5578T (98.9%) and Leuconostoc citreum KCTC 3526T (98.3 %). However, DNA-DNA hybridization experiments indicated that the organism represents a novel genomic species in the genus, since the previously known leuconostocs share DNA homology with strain IH25T of less than 70%. In this work, it is proposed that isolate IH25T be classified in the genus Leuconostoc as Leuconostoc kimchii sp. nov. The type strain of Leuconostoc kimchii is IH25T (= KCTC 2386T = IMSNU 11154T).

Phylogenetic analysis of Bacillus subtilis and related taxa based on partial gyrA gene sequences

Partial gyrA sequences were determined for twelve strains belonging to Bacillus amyloliquefaciens, B. atrophaeus, B. licheniformis, B. mojavensis, B. subtilis subsp. subtilis, B. subtilis subsp. spizizenii and B. vallismortis. The average nucleotide and translated amino acid similarities for the seven type strains were 83.7 and 95.1%, respectively, whereas the corresponding value for the 16S rRNA sequences was 99.1%. All of the type strains were sharply separated; the closest relationship was found between B. atrophaeus and B. mojavensis which shared a nucleotide similarity of 95.8%. Phylogenetic trees were inferred from gyrA nucleotide sequences using the neighbor-joining, Fitch-Margoliash and maximum parsimony algorithms. The test strains were divided into four groups, which generally reflected results previously reported in restriction digest and DNA-DNA hybridization studies. It is concluded from the comparative sequence analysis that the gyrA sequences provide a firm framework for the rapid and accurate classification and identification of Bacillus subtilis and related taxa.

Mechanism-based inactivation of cytochromes P450 2B1 and P450 2B6 by 2-phenyl-2-(1-piperidinyl)propane

2-Phenyl-2-(1-piperidinyl)propane (PPP), an analog of phencyclidine, was tested for its ability to inactivate cytochrome P450s (P450s) 2B1 and 2B6. PPP inactivated the 7-(benzyloxy)resorufin O-dealkylation activity of liver microsomes obtained from phenobarbital-induced rats with a K(I) of 11 microM. The 7-ethoxy-4-(trifluoromethyl)coumarin O-deethylation activity of purified rat liver P450 2B1 and expressed human P450 2B6 was inactivated by PPP in a reconstituted system containing NADPH-cytochrome P450 reductase and lipid. In the presence of NADPH, the loss of activity was time- and concentration-dependent, and followed pseudo first order kinetics. The rate of inactivation for P450 2B1 was 0.3 min(-1), and the concentration of PPP required to achieve half-maximal inactivation was 12 microM. The time for 50% of the P450 2B1 to become inactivated at saturating concentrations of PPP was 2.5 min. P450 2B6 was inactivated with a k(inact) of 0.07 min(-1), a K(I) of 1.2 microM, and a t(1/2) of 9.5 min. The inactivated P450s 2B1 and 2B6 lost about 25 and 15%, respectively, of their ability to form a CO-reduced complex, suggesting that the loss of activity was caused by a PPP modification of the apoprotein rather than the heme. The estimated partition ratio for P450s 2B1 and 2B6 with PPP was 31 and 15, respectively. The inactivation was not reversible and reductase activity was not affected. Coincubation of P450 2B1 and 2B6 with PPP and NADPH in the presence of an alternate substrate protected both enzymes from inactivation. The exogenous nucleophile GSH did not affect the rate of inactivation. PPP-inactivated P450s 2B1 and 2B6 were recognized on Western blots by an antibody generated to phencyclidine that had been conjugated to BSA. Stoichiometries of 1.4:1 and 0.7:1 were determined for the binding of a [3H]PPP metabolite to P450 2B1 and 2B6, respectively.

Decreased apoptosis in proliferative and postmitotic regions of the Caspase 3-deficient embryonic central nervous system

Caspase 3 (CPP32/Yama/apopain), a mammalian homolog of the Caenorhabditis elegans pro-cell death gene ced-3, is required for normal programmed cell death (PCD) in the nematode. Its prior deletion by homologous recombination in mice resulted in embryonic/early postnatal lethality associated with dramatic central nervous system (CNS) hyperplasia, yet a reported subtle decrease in cell death (Kuida et al. [1996] Nature 384:368-372). By comparison, the magnitude and distribution of dying cells identified using a DNA end-labeling technique, in situ end-labeling plus (ISEL+) (Blaschke et al. [1996] Development 122:1165-1174; Blaschke et al. [1998] J. Comp. Neurol. 396:39-50), supported an alternative explanation where the loss of caspase 3 function produces a more pervasive block in cell death, particularly among neuroblasts. To determine the relationship between loss of caspase 3 and dying cells identified by ISEL+, we analyzed caspase 3 +/+, +/-, and -/- embryos for normal caspase 3 expression and ISEL+ labeling. Both caspase 3 mRNA and active caspase 3 protein are present throughout the +/+ embryonic CNS, and both are absent from -/- embryonic cortices. Quantitation of dying cells identified by ISEL+ reveals a 30% reduction of labeled cells throughout the caspase 3 -/- embryonic cortices relative to +/+ littermates. Associated with this decrease is marked expansion of the total population of actively proliferating neuroblasts identified by 5-bromo-2;-deoxyuridine incorporation that nevertheless appears to maintain histological features of normal neurogenesis rather than dysregulated, neoplastic growth. These data indicate that caspase 3 deficiency results in a pervasive, albeit partial, decrease in embryonic neuroblast apoptosis that can account for the observed phenotypic hyperplasia in -/- embryos, and support the additional operation of caspase 3-independent PCD mechanisms during embryonic CNS development.

Polyphasic assignment of an aromatic-degrading Pseudomonas sp., strain DJ77, in the genus Sphingomonas as Sphingomonas chungbukensis sp. nov

Pseudomonas sp. strain DJ77, which was described as an aromatic-degrading bacterium, was investigated to clarify its taxonomic position. Phylogenetic analysis based on 16S rDNA sequences indicated that the strain belonged to the genus Sphingomonas and formed a monophyletic clade with the type strains of Sphingomonas chlorophenolica, Sphingomonas herbicidovorans and Sphingomonas yanoikuyae with sequence similarity values of 98.1, 96.1 and 95.6%, respectively. Genomic relatedness based on DNA-DNA hybridization of strain DJ77 to these strains is 7-14%. Strain DJ77 contained ubiquinone 10 as the main respiratory quinone, and the G+C content of DNA was 63 mol%. The organism contained octadecenoic acid (67%) as major cellular fatty acid. Strain DJ77 can be readily differentiated from representative members of the genus Sphingomonas using a battery of biochemical tests. On the basis of polyphasic evidence, it is proposed that strain DJ77, previously known as Pseudomonas sp., be reclassified in the genus Sphingomonas as Sphingomonas chungbukensis sp. nov. The type strain is strain DJ77T (= KCTC 2955T = IMSNU 11152T).

Paenibacillus koreensis sp. nov., a new species that produces an iturin-like antifungal compound

A bacterial strain, YC300T, that produces an iturin-like antifungal antibiotic was isolated from compost and identified as member of the genus Paenibacillus. Gram reaction of the strain was variable depending upon growth stages and culture media. Three different types of colonies were developed on tryptic soy agar. The organism was facultatively anaerobic and grew at 50 degrees C. The DNA G+C content was 54 mol % and anteiso-C15:0 was the major fatty acid. A 0.9 kb fragment was produced by PCR amplification of strain YC300T DNA using primers PAEN515F and 1377R. Levels of 16S rDNA similarity between strain YC300T and other Paenibacillus species were between 89.8 and 94.8%. Phylogenetically, strain YC300T formed a significant monophyletic clade with Paenibacillus validus. It is clear from polyphasic evidence that the isolate should be classified as Paenibacillus koreensis sp. nov., the type strain of which is YC300T (= KCTC 2393T, KCCM 40903T).

Systematic analysis of xanthomonads (Xanthomonas spp.) associated with pepper and tomato lesions

The taxonomy and evolutionary relationships among members of the genus Xanthomonas associated with tomato and pepper have been a matter of considerable controversy since their original description in 1921. These bacteria, which are a major affliction of tomato and pepper crops in warm and humid regions, were originally described as a single species, but subsequent research has shown the existence of at least two genetic groups differentiated by physiological, biochemical and pathological characteristics. This work synthesizes the findings from several approaches, including pathogenicity tests, enzymic activity, restriction fragment analysis of the entire genome, DNA-DNA hybridization and RNA sequence comparisons based on a 2097 base sequence comprising the 16S rRNA gene, the intergenic spacer located between the 16S and 23S rRNA genes and a small region of the 23S rRNA gene. Within the group of xanthomonads pathogenic on pepper and tomato four distinct phenotypic groups exist, of which three form distinct genomic species. These include Xanthomonas axonopodis pv. vesicatoria (A and C group), Xanthomonas vesicatoria (B group) and Xanthomonas gardneri (D group). On the basis of phenotypic and genotypic differences between A- and C-group strains, the C strains should be considered as a subspecies within Xanthomonas axonopodis pv. vesicatoria.

Neurobiology of receptor-mediated lysophospholipid signaling. From the first lysophospholipid receptor to roles in nervous system function and development

Identification of the first lysophospholipid receptor, LPA1/Vzg-1, cloned by way of neurobiological analyses on the embryonic cerebral cortex, has led to the realization and demonstration that there exist multiple, homologous LP receptors, including those encoded by a number of orphan receptor genes known as "Edg," all of which are members of the G-protein-coupled receptor (GPCR) superfamily. These receptors interact with apparent high affinity for lysophosphatidic acid (LPA) or sphingosine-1-phosphate (S1P or SPP), and are referred to based upon their functional identity as lysophospholipid receptors: LPA and LPB receptors, respectively, with the expectation that additional subgroups will be identified (i.e., LPC, etc.). Here an update is provided on insights gained from analyses of these receptor genes as they relate to the nervous system, particularly the cerebral cortex, and myelinating cells (oligodendrocytes and Schwann cells).