The complete genome sequence of the gram-positive bacterium Bacillus subtilis

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large proportion of the genetic capacity is devoted to the utilization of a variety of carbon sources, including many plant-derived molecules. The identification of five signal peptidase genes, as well as several genes for components of the secretion apparatus, is important given the capacity of Bacillus strains to secrete large amounts of industrially important enzymes. Many of the genes are involved in the synthesis of secondary metabolites, including antibiotics, that are more typically associated with Streptomyces species. The genome contains at least ten prophages or remnants of prophages, indicating that bacteriophage infection has played an important evolutionary role in horizontal gene transfer, in particular in the propagation of bacterial pathogenesis.

Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Essential Bacillus subtilis genes

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

Axin, a negative regulator of the Wnt signaling pathway, forms a complex with GSK-3beta and beta-catenin and promotes GSK-3beta-dependent phosphorylation of beta-catenin

Glycogen synthase kinase-3 (GSK-3) mediates epidermal growth factor, insulin and Wnt signals to various downstream events such as glycogen metabolism, gene expression, proliferation and differentiation. We have isolated here a GSK-3beta-interacting protein from a rat brain cDNA library using a yeast two-hybrid method. This protein consists of 832 amino acids and possesses Regulators of G protein Signaling (RGS) and dishevelled (Dsh) homologous domains in its N- and C-terminal regions, respectively. The predicted amino acid sequence of this GSK-3beta-interacting protein shows 94% identity with mouse Axin, which recently has been identified as a negative regulator of the Wnt signaling pathway; therefore, we termed this protein rAxin (rat Axin). rAxin interacted directly with, and was phosphorylated by, GSK-3beta. rAxin also interacted directly with the armadillo repeats of beta-catenin. The binding site of rAxin for GSK-3beta was distinct from the beta-catenin-binding site, and these three proteins formed a ternary complex. Furthermore, rAxin promoted GSK-3beta-dependent phosphorylation of beta-catenin. These results suggest that rAxin negatively regulates the Wnt signaling pathway by interacting with GSK-3beta and beta-catenin and mediating the signal from GSK-3beta to beta-catenin.

Somatic frameshift mutations in the BAX gene in colon cancers of the microsatellite mutator phenotype

Cancers of the microsatellite mutator phenotype (MMP) show exaggerated genomic instability at simple repeat sequences. More than 50 percent (21 out of 41) of human MMP+ colon adenocarcinomas examined were found to have frameshift mutations in a tract of eight deoxyguanosines [(G)8] within BAX, a gene that promotes apoptosis. These mutations were absent in MMP- tumors and were significantly less frequent in (G)8 repeats from other genes. Frameshift mutations were present in both BAX alleles in some MMP+ colon tumor cell lines and in primary tumors. These results suggest that inactivating BAX mutations are selected for during the progression of colorectal MMP+ tumors and that the wild-type BAX gene plays a suppressor role in a p53-independent pathway for colorectal carcinogenesis.

GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4}  years. We infer the component masses of the binary to be between 0.86 and 2.26  M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60  M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28  deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8}  Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.

Total enteroscopy with a nonsurgical steerable double-balloon method

BACKGROUND

Deep insertion of an enteroscope by use of a push technique is difficult. A new method of enteroscopy was developed, a double-balloon method, to improve the access to the small intestine.

METHODS

The new method uses 2 balloons, one attached to the tip of the endoscope and another at the distal end of an overtube. By using these balloons to grip the intestinal wall, the endoscope can be inserted further without forming redundant loops in the small intestine. This method was tried with a standard upper endoscope in 3 patients and with a longer enteroscope in 1 patient.

RESULTS

Despite its short length the upper endoscope was successfully inserted as far as 30 to 50 cm beyond the ligament of Treitz in the 3 patients. In the fourth patient the longer enteroscope was successfully inserted beyond the ileo-cecal valve.

CONCLUSIONS

The double-balloon method facilitates endoscopic access to the small intestine.

The reeler gene-associated antigen on Cajal-Retzius neurons is a crucial molecule for laminar organization of cortical neurons

In the neurological mutant mouse reeler, the histological organization of the neocortex develops abnormally and essentially results in an inversion of the relative positions of the cortical layers. The reeler mutation, therefore, provides an insight into the molecular mechanisms underlying the formation of the cortical layers. We have generated a monoclonal antibody (CR-50) that probes a distinct allelic antigen present in wild-type but not in reeler mutant mice. CR-50 reacted specifically with Cajal-Retzius neurons, one of the first cortical neurons to differentiate in the neocortex, but whose functional role is not known. When dissociated cerebral cortical cells were incubated with CR-50 in reaggregation culture, the genotype-dependent histogenetic assembly of wild-type cortical cells resembled that of reeler mutants. These findings revealed that the selective expression of a distinct molecule on Cajal-Retzius neurons is critical for the normal lamination of cortical neurons in the mammalian neocortex.

Proposals of Sphingomonas paucimobilis gen. nov. and comb. nov., Sphingomonas parapaucimobilis sp. nov., Sphingomonas yanoikuyae sp. nov., Sphingomonas adhaesiva sp. nov., Sphingomonas capsulata comb. nov., and two genospecies of the genus Sphingomonas

Based on the partial nucleotide sequence analysis of 16S ribosomal ribonucleic acid (rRNA), presence of unique sphingoglycolipids in cellular lipid, and the major type of ubiquinone (Q10), we propose Sphingomonas gen. nov. with the type species Sphingomonas paucimobilis (Holmes et al, 1977) comb. nov. From the homology values of deoxyribonucleic acid-deoxyribonucleic acid hybridization and the phenotypic characteristics, three new species, Sphingomonas parapaucimobilis, Sphingomonas yanoikuyae, Sphingomonas adhaesiva, and one new combination, Sphingomonas capsulata, are described. S. parapaucimobilis JCM 7510 (= GIFU 11387), S. yanoikuyae JCM 7371 (= GIFU 9882), and S. adhaesiva JCM 7370 (= GIFU 11458) are designated as the type strains of the three new species. Emended description of the type strain of S. capsulata is presented.

A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction

Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing a perpendicular magnetic easy axis are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. To attain perpendicular anisotropy, a number of material systems have been explored as electrodes, which include rare-earth/transition-metal alloys, L1(0)-ordered (Co, Fe)-Pt alloys and Co/(Pd, Pt) multilayers. However, none of them so far satisfy high thermal stability at reduced dimension, low-current current-induced magnetization switching and high tunnel magnetoresistance ratio all at the same time. Here, we use interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane anisotropy. This approach requires no material other than those used in conventional in-plane-anisotropy MTJs. The perpendicular MTJs consisting of Ta/CoFeB/MgO/CoFeB/Ta show a high tunnel magnetoresistance ratio, over 120%, high thermal stability at dimension as low as 40 nm diameter and a low switching current of 49 microA.

Impaired muscarinic endothelium-dependent relaxation and cyclic guanosine 5'-monophosphate formation in atherosclerotic human coronary artery and rabbit aorta

The dependence of vascular relaxation on an intact endothelium and the relationship between relaxation and cyclic GMP accumulation were determined in coronary arteries isolated from cardiac transplantation patients with or without coronary atherosclerosis. In nonatherosclerotic arteries, the endothelium-dependent agent acetylcholine produced concentration-related relaxations. In atherosclerotic arteries, endothelium-dependent relaxations were abolished with acetylcholine, partly suppressed with substance P and histamine, and completely preserved with the ionophore A23187. In these arteries, the endothelium-independent agent nitroglycerin remained fully active. Accumulation of cyclic GMP in atherosclerotic strips was suppressed with acetylcholine but unattenuated with A23187 and nitroglycerin. In aortas from rabbits with diet-induced atherosclerosis, there was likewise an impaired cholinergic relaxation and cyclic GMP accumulation in the presence of preserved responses to A23187 and nitroglycerin. The results demonstrate that impaired cholinergic responses in atherosclerotic arteries reflect a muscarinic defect and not an inability of endothelium to release endothelial factor or smooth muscle to respond to it.

A vitamin D receptor gene polymorphism in the translation initiation codon: effect on protein activity and relation to bone mineral density in Japanese women

The effect of a T-C transition polymorphism at the translation initiation codon of the human vitamin D receptor (VDR) gene on the biological function of the encoded protein was investigated. Of 239 Japanese women volunteers subjected to genotype analysis for this polymorphism, 32 (13%) were genotype MM (the M allele is ATG at the putative translation start site), 75 (31%) were genotype mm (the m allele is ACG at the putative translation start site), and 132 (55%) were genotype Mm. The bone mineral density (BMD) in the lumbar spine (L2-L4) was determined for 110 healthy premenopausal women from the volunteers and was shown to be 12.0% greater (p < 0.05) for mm homozygotes than for MM homozygotes. Synthesis of the proteins by the M and m alleles from the cloned cDNAs in vitro and in transfected COS-7 cells revealed them to have a size of 50 and 49.5 kD, respectively, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. This size difference is consistent with initiation of translation of the M allele-encoded protein from an ATG codon located at nucleotides +10 to +12 in the conventional open reading frame. The extent of vitamin D-dependent transcriptional activation of a reporter construct under the control of a vitamin D response element in transfected HeLa cells was approximately 1.7-fold greater for the m type VDR than for the M type protein. These results suggest that the polymorphism at the translation start site of the VDR gene may modulate BMD in premenopausal Japanese women.

The different courses of early- and late-onset idiopathic and alcoholic chronic pancreatitis

BACKGROUND/AIMS

Compared with alcoholic pancreatitis, little is known about the natural history of idiopathic pancreatitis. Two hundred forty-nine patients with alcoholic pancreatitis and 66 patients with idiopathic chronic pancreatitis seen at our institution between 1976 and 1982 were investigated.

METHODS

Records were analyzed retrospectively from the onset of symptomatic disease, and patients were followed up prospectively until 1985. Patients with early-onset (n = 25) and late-onset (n = 41) idiopathic chronic pancreatitis had a median age at onset of symptoms of 19 and 56 years, respectively.

RESULTS

The gender distribution was nearly equal in idiopathic chronic pancreatitis, but 72% of patients with alcoholic pancreatitis were men (P = 0.001 vs. idiopathic). In early-onset idiopathic pancreatitis, calcification and exocrine and endocrine insufficiency developed more slowly than in late-onset idiopathic and alcoholic pancreatitis (P = 0.03). However, in early idiopathic chronic pancreatitis, pain frequently occurred initially (P = 0.003 vs. late and alcoholic) and was more severe (P = 0.04 vs. late and alcoholic). In late-onset idiopathic pancreatitis, pain was absent in nearly 50% of patients.

CONCLUSIONS

There are two distinct forms of idiopathic chronic pancreatitis. Patients with early-onset pancreatitis have initially and thereafter a long course of severe pain but slowly develop morphological and functional pancreatic damage, whereas patients with late-onset pancreatitis have a mild and often a painless course. Both forms differ from alcoholic pancreatitis in their equal gender distribution and a much slower rate of calcification.

Exosomal microRNA in serum is a novel biomarker of recurrence in human colorectal cancer

Background:

Functional microRNAs (miRNAs) in exosomes have been recognised as potential stable biomarkers in cancers. The aim of this study is to identify specific miRNAs in exosome as serum biomarkers for the early detection of recurrence in human colorectal cancer (CRC).

Methods:

Serum samples were sequentially obtained from six patients with and without recurrent CRC. The miRNAs were purified from exosomes, and miRNA microarray analysis was performed. The miRNA expression profiles and copy number aberrations were explored using microarray and array CGH analyses in 124 CRC tissues. Then, we validated exosomal miRNAs in 2 serum sample sets (90 and 209 CRC patients) by quantitative real-time RT–PCR.

Results:

Exosomal miR-17-92a cluster expression level in serum was correlated with the recurrence of CRC. Exosomal miR-19a expression levels in serum were significantly increased in patients with CRC as compared with healthy individuals with gene amplification. The CRC patients with high exosomal miR-19a expression showed poorer prognoses than the low expression group (P<0.001).

Conclusions:

Abundant expression of exosomal miR-19a in serum was identified as a prognostic biomarker for recurrence in CRC patients.

Axin, a negative regulator of the wnt signaling pathway, directly interacts with adenomatous polyposis coli and regulates the stabilization of beta-catenin

The regulators of G protein signaling (RGS) domain of Axin, a negative regulator of the Wnt signaling pathway, made a complex with full-length adenomatous polyposis coli (APC) in COS, 293, and L cells but not with truncated APC in SW480 or DLD-1 cells. The RGS domain directly interacted with the region containing the 20-amino acid repeats but not with that containing the 15-amino acid repeats of APC, although both regions are known to bind to beta-catenin. In the region containing seven 20-amino acid repeats, the region containing the latter five repeats bound to the RGS domain of Axin. Axin and beta-catenin simultaneously interacted with APC. Furthermore, Axin stimulated the degradation of beta-catenin in COS cells. Taken together with our recent observations that Axin directly interacts with glycogen synthase kinase-3beta (GSK-3beta) and beta-catenin and that it promotes GSK-3beta-dependent phosphorylation of beta-catenin, these results suggest that Axin, APC, GSK-3beta, and beta-catenin make a tetrameric complex, resulting in the regulation of the stabilization of beta-catenin.

Anti-oncogenic and oncogenic potentials of interferon regulatory factors-1 and -2

Interferon regulatory factor-1 (IRF-1), a transcriptional activator, and IRF-2, its antagonistic repressor, have been identified as regulators of type I interferon and interferon-inducible genes. The IRF-1 gene is itself interferon-inducible and hence may be one of the target genes critical for interferon action. When the IRF-2 gene was overexpressed in NIH 3T3 cells, the cells became transformed and displayed enhanced tumorigenicity in nude mice. This transformed phenotype was reversed by concomitant overexpression of the IRF-1 gene. Thus, restrained cell growth depends on a balance between these two mutually antagonistic transcription factors.

Phosphorylation and regulation of glutamate receptors by calcium/calmodulin-dependent protein kinase II

The major postsynaptic density (PSD) protein at glutaminergic synapses is calcium/calmodulin-dependent protein kinase II (CaM-K II), but its function in the PSD is not known. We have examined glutamate receptors (GluRs) as substrates for CaM-K II because (1) they are colocalized in the PSD, (2) cloned GluRs contain consensus phosphorylation sites for protein kinases including CaM-K II, and (3) several GluRs are regulated by other protein kinases. Regulation of GluRs, which are involved in excitatory synaptic transmission and in mechanisms of learning and memory, by CaM-K II is of interest because of the postulated role of CaM-K II in synaptic plasticity and its known involvement in induction of long-term potentiation. Furthermore, mice lacking the major neural isoform of CaM-K II exhibit deficits in models of learning and memory that require hippocampal input. We report here that CaM-K II phosphorylates GluR in several in vitro systems, including the PSD, and that activated CaM-K II enhances kainate-induced ion current three- to fourfold in cultured hippocampal neurons. These results are consistent with a role for PSD CaM-K II in strengthening postsynaptic GluR responses in synaptic plasticity.

Mutations in the dystrophin-associated protein gamma-sarcoglycan in chromosome 13 muscular dystrophy

Severe childhood autosomal recessive muscular dystrophy (SCARMD) is a progressive muscle-wasting disorder common in North Africa that segregates with microsatellite markers at chromosome 13q12. Here, it is shown that a mutation in the gene encoding the 35-kilodalton dystrophin-associated glycoprotein, gamma-sarcoglycan, is likely to be the primary genetic defect in this disorder. The human gamma-sarcoglycan gene was mapped to chromosome 13q12, and deletions that alter its reading frame were identified in three families and one of four sporadic cases of SCARMD. These mutations not only affect gamma-sarcoglycan but also disrupt the integrity of the entire sarcoglycan complex.

Development and prevention of advanced diabetic nephropathy in RAGE-overexpressing mice

Vascular complications arising from multiple environmental and genetic factors are responsible for many of the disabilities and short life expectancy associated with diabetes mellitus. Here we provide the first direct in vivo evidence that interactions between advanced glycation end products (AGEs; nonenzymatically glycosylated protein derivatives formed during prolonged hyperglycemic exposure) and their receptor, RAGE, lead to diabetic vascular derangement. We created transgenic mice that overexpress human RAGE in vascular cells and crossbred them with another transgenic line that develops insulin-dependent diabetes shortly after birth. The resultant double transgenic mice exhibited increased hemoglobin A(1c) and serum AGE levels, as did the diabetic controls. The double transgenic mice demonstrated enlargement of the kidney, glomerular hypertrophy, increased albuminuria, mesangial expansion, advanced glomerulosclerosis, and increased serum creatinine compared with diabetic littermates lacking the RAGE transgene. To our knowledge, the development of this double transgenic mouse provides the first animal model that exhibits the renal changes seen in humans. Furthermore, the phenotypes of advanced diabetic nephropathy were prevented by administering an AGE inhibitor, (+/-)-2-isopropylidenehydrazono-4-oxo-thiazolidin-5-ylacetanilide (OPB-9195), thus establishing the AGE-RAGE system as a promising target for overcoming this aspect of diabetic pathogenesis.

Enlargement of spontaneous intracerebral hemorrhage. Incidence and time course

BACKGROUND AND PURPOSE

Standard radiographic criteria for hematoma enlargement have not been established. We undertook this investigation to assess the incidence and time course of hematoma growth using objective cutoff values.

METHODS

We reviewed the clinical records of 204 patients with spontaneous intracerebral hemorrhage treated nonsurgically who underwent initial computed tomography (CT) within 48 hours and repeat CT within 120 hours of the onset of symptoms. The consensus of five observers reading the CT films was considered the "gold standard" for hematoma enlargement. The discriminant values of the difference (V2-V1) or the ratio (V2/V1) of the hematoma volume on the initial (V1) and second (V2) CT scans were determined by use of receiver operating characteristic curves. We chose the cutpoint that had the highest sensitivity and specificity for identifying hematoma expansion.

RESULTS

The cutpoint for hematoma enlargement was determined as V2-V1 = 12.5 cm3 or V2/V1 = 1.4 (sensitivity = 94.4%, specificity = 95.8%). Forty-one patients (20%) had changes that exceeded these criteria. Frequency of hematoma expansion was greatest among those who underwent the initial CT scan early (27 [36%] of 74 patients at < or = 3 hours) and progressively declined as the time to initial scan was prolonged (7 [16%] of 45 patients at 3 to 6 hours; 5 [15%] of 33 patients at 6 to 12 hours; 2 [6%] of 34 patients at 12 to 24 hours; and 0 [0%] of 18 patients at 24 to 48 hours).

CONCLUSIONS

The enlargement of hematoma was defined radiographically as the increase of its volume by > or = 12.5 cm3 or by > or = 1.4 times. Although expansion of intracerebral hemorrhage on CT scan was common in the hyperacute stage, 17% of hematoma expansion occurred even after 6 hours of onset. Enlargement after 24 hours of onset seems extremely rare. Early CT scanning appears to increase the rate of detection of enlarging hematomas.

Mucoadhesive nanoparticulate systems for peptide drug delivery

This chapter describes the preparation of and methods for evaluating mucoadhesive nanoparticulate systems, including liposomes and polymeric nanoparticles. Mucoadhesive ability is conferred on the particulate systems by coating their surface with mucoadhesive polymers such as chitosan and Carbopol. The feasibility of this surface modification was confirmed by measuring the zeta potential. Several methods of evaluating the mucoadhesive properties of particulate systems have been reported in the literature. We have also developed some novel evaluation procedures including a particle counting method using a Coulter counter for polymer-coated liposomes. The mucoadhesive properties of the polymer-coated liposomes and polymeric nanoparticles were confirmed by means of these mucoadhesion tests. In applying these mucoadhesive nanoparticles to the oral and pulmonary administration of peptide drugs, more effective and prolonged action was observed in comparison with non-coated systems, thereby confirming the usefulness of mucoadhesive nanoparticulate systems for the delivery of peptide drugs.

The receptor for advanced glycation end products is induced by the glycation products themselves and tumor necrosis factor-alpha through nuclear factor-kappa B, and by 17beta-estradiol through Sp-1 in human vascular endothelial cells

The binding of advanced glycation end products (AGE) to the receptor for AGE (RAGE) is known to deteriorate various cell functions and is implicated in the pathogenesis of diabetic vascular complications. Here we show that AGE, tumor necrosis factor-alpha (TNF-alpha), and 17beta-estradiol (E(2)) up-regulated RAGE mRNA and protein levels in human microvascular endothelial cells and ECV304 cells, with the mRNA stability being essentially invariant. Transient transfection experiments with human RAGE promoter-luciferase chimeras revealed that the region from nucleotide number -751 to -629 and the region from -239 to -89 in the RAGE 5'-flanking sequence exhibited the AGE/TNF-alpha and E(2) responsiveness, respectively. Site-directed mutation of an nuclear factor-kappaB (NF-kappaB) site at -671 or of Sp-1 sites at -189 and -172 residing in those regions resulted in an abrogation of the AGE/TNF-alpha- or E(2)-mediated transcriptional activation. Electrophoretic mobility shift assays revealed that ECV304 cell nuclear extracts contained factors which retarded the NF-kappaB and Sp-1 elements, and that the DNA-protein complexes were supershifted by anti-p65/p50 NF-kappaB and anti-Sp-1/estrogen receptor alpha antibodies, respectively. These results suggest that AGE, TNF-alpha, and E(2) can activate the RAGE gene through NF-kappaB and Sp-1, causing enhanced AGE-RAGE interactions, which would lead to an exacerbation of diabetic microvasculopathy.

Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes

PURPOSE

The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs.

METHODS

Multilamellar liposomes consisting of dipalmitoylphosphati-dylcholine (DPPC)and dicetyl phosphate (DCP) (DPPC: DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored.

RESULTS

The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats.

DIX domains of Dvl and axin are necessary for protein interactions and their ability to regulate beta-catenin stability

The N-terminal region of Dvl-1 (a mammalian Dishevelled homolog) shares 37% identity with the C-terminal region of Axin, and this related region is named the DIX domain. The functions of the DIX domains of Dvl-1 and Axin were investigated. By yeast two-hybrid screening, the DIX domain of Dvl-1 was found to interact with Dvl-3, a second mammalian Dishevelled relative. The DIX domains of Dvl-1 and Dvl-3 directly bound one another. Furthermore, Dvl-1 formed a homo-oligomer. Axin also formed a homo-oligomer, and its DIX domain was necessary. The N-terminal region of Dvl-1, including its DIX domain, bound to Axin directly. Dvl-1 inhibited Axin-promoted glycogen synthase kinase 3beta-dependent phosphorylation of beta-catenin, and the DIX domain of Dvl-1 was required for this inhibitory activity. Expression of Dvl-1 in L cells induced the nuclear accumulation of beta-catenin, and deletion of the DIX domain abolished this activity. Although expression of Axin in SW480 cells caused the degradation of beta-catenin and reduced the cell growth rate, expression of an Axin mutant that lacks the DIX domain did not affect the level of beta-catenin or the growth rate. These results indicate that the DIX domains of Dvl-1 and Axin are important for protein-protein interactions and that they are necessary for the ability of Dvl-1 and Axin to regulate the stability of beta-catenin.