Immunolocalization of Drosophila eye-specific diacylgylcerol kinase, rdgA, which is essential for the maintenance of the photoreceptor

The Drosophila retinal degeneration A (rdgA) mutant has photoreceptor cells that degenerate within a week after eclosion. The degeneration starts with the disruption of the subrhabdomeric cisternae (SRC), which are the organelles essential for the transport of phospholipids to the photoreceptive membranes. Our previous biochemical and molecular studies suggested that the rdgA gene encodes an eye-specific diacylglycerol kinase (DGK). In this study, we show that retinal degeneration is prevented by the introduction of the eye-DGK gene in the rdgA mutant genome, suggesting that the DGK activity is crucial for the maintenance of the photoreceptor. Furthermore, by immunohistochemical analysis, we have demonstrated that the rdgA protein is predominantly associated with the SRC, suggesting that the conversion from diacylglycerol (DG) to phosphatidic acid (PA) most actively occurs in SRC. The analysis of the eyes of mutants homozygous for rdgA and eye-protein kinase C mutations indicates that retinal degeneration is caused by the deficiency of PA rather than excessive accumulation of DG. From these data, we conclude that the production of PA in the SRC membranes is essential for the maintenance of the photoreceptor.

A monoclonal antibody directed to terminal residue of beta-galactofuranose of a glycolipid antigen isolated from Paracoccidioides brasiliensis: cross-reactivity with Leishmania major and Trypanosoma cruzi

A mouse monoclonal antibody, MEST-1, was produced against Band 1 glycolipid antigen of Paracoccidioides brasiliensis. The glycan structure of Band 1 antigen was recently elucidated and the monosaccharides sequence was defined as: Galf beta 1-->6(Manp alpha 1-->3)Manp beta 1-->2Ins. The reactivity of MEST-1 MAb was determined by solid-phase radioimmunoassay and high performance thin layer chromatography immunostaining. Selective oxidation of galactofuranose residues and inhibition assays with different methyl-glycosides, revealed that MAb MEST-1 is directed against the terminal residue of beta-D-galactofuranose of Band 1, a phosphoglyceroglycolipid antigen of P. brasiliensis. By indirect immunofluorescence, it was observed that the epitope recognized by MEST-1 is accessible to the antibody in yeast forms of this fungus. Reactivity of MEST-1 with parasites known to express galactofuranose containing glycoconjugates was also analyzed by indirect immunofluorescence. A positive fluorescence was observed with promastigotes of Leishmania major and epimastigotes of Trypanosoma cruzi. GIPL-1 was identified as the antigen recognized by MEST-1 in Leishmania major, indicating that the MAb MEST-1 recognizes terminal galactofuranose residue in either beta 1-->6 or beta 1-->3 linkage to the mannose.

[Clinical features of postinfectious chronic cough]

Postinfectious cough has been drawing attention as a factor involved in the etiology of chronic cough in the United States. In Japan, clinical features of postinfectious chronic cough (PICC) have not been described in detail. We investigated 22 patients with PICC diagnosed by the established criteria (Jpn. J. Allergol. 1995; 44: 1418). All patients were nonsmokers and none received ACE inhibitors. None had a history of atopy or sinus diseases. There were four men and 18 women with a median age of 65 years. These 22 patients underwent clinical examinations including chest roentgenograms, respiratory function tests, eosinophil counts in venous blood, serum IgE titers, antibody titers to Mycoplasma pneumoniae, sputum cytologic findings taken from ten patients, and histological features of bronchial biopsy specimens obtained from two patients; all findings were within normal limits. Clinical course of cough in 20 of the patients with PICC was evaluated using a cough diary. One patient did not keep a cough diary. Ten patients improved with dextromethorphan hydrobromide (D) and oxatomide (O). Three of the remaining 9 patients improved with Bakumondo-to (B) only, 4 with D+O+B, and 2 with D+O+B+ozagrel hydrochloride. The duration of cough before treatment showed a significant correlation with the time from the start of treatment to recovery (r = 0.47, p < 0.05). These results indicate that PICC tends to occur in elderly women and to improve with treatment combining with D, O, and B. We hope to establish a standard therapy for postinfectious chronic cough.

[Bronchiolitis obliterans and no radiographic abnormalities in a patient with rheumatoid arthritis]

A 53-year-old woman was given a diagnosis of rheumatoid arthritis in 1988, and begun treatment with D-penicillamine in September 1992. She noticed dry coughing and exertional dyspnea that began in April 1993. Chest X-ray and CT films revealed no abnormal opacities. However, bronchiolitis obliterans was suspected because of a low FEV1% (23%). Examination of specimens obtained by thoracoscopic lung biopsy revealed constrictive obliteration by granulation tissue in proximal bronchioles and follicular bronchiolitis. Alveoli and respiratory bronchioles were intact. After corticosteroid and cyclophosphamide pulse therapy, FEV1% increased to 35%. At the time of this writing she was alive 2.5 years after hospitalization.

Alteration of fatty acid composition in a pgsA3 mutant of Escherichia coli

We examined the fatty acid composition in an Escherichia coli pgsA3 mutant lacking the potential to synthesize phosphatidylglycerolphosphate, a precursor of phosphatidylglycerol. The contents of C18:1cis-9 (oleic acid) and C18:1cis-11 (cis-vaccenic acid) in the total phospholipids extracted from the pgsA3 mutant growing at 37 degrees C were higher and that of C14:0 was lower than the wild type cells, resulting in a higher level of unsaturation of fatty acids (ratio of unsaturated fatty acids to saturated ones) in the mutant. The higher level of the unsaturated fatty acids in the pgsA3 mutant was more obvious in cardiolipin than in phosphatidylethanolamine. On the other hand, at 28 degrees C, at which the pgsA3 mutant shows limited cell growth, the content of unsaturated fatty acids in cardiolipin decreased in the pgsA3 mutant compared with the wild type. We consider that the pgsA3 mutant maintains cellular homeostasis by altering the level of unsaturated fatty acids in cardiolipin, and the mechanism is influenced by temperature.

Improved separation and determination of phospholipids in animal tissues employing solid phase extraction

Separation of five glycerophospholipids having different polar groups, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylglycerol (PG) and cardiolipin (CL), was investigated by means of solid-phase extraction (SPE) cartridges. First, the phospholipids were retained in an aminopropyl-bonded phase (NH2) cartridge and subsequently eluted as neutral (PC and PE) and acidic (PS, PG and CL) glycerophospholipid fractions. Secondly, a combination of silica gel (SI) cartridge and NH2 cartridge was employed to separate five glycerophospholipids. The polarity of the eluent was responsible for neutral glycerophospholipid separation. Concerning acidic glycerophospholipids, the separation of PG and CL from PS depended mainly on the pH of the eluents, and the separation of PG and CL was affected by the solvent, depending on eluent polarities. Favorable recovery (not less than 95%, for five authentic phospholipids, 10-100 micrograms each) and repeatability (sigma = 2.3 for 10 micrograms ranges) were attained by the present method. This method of separation was applicable to the analysis of phospholipids in biological samples.

Tertiary structural models for human interleukin-6 and evaluation by a sequence-structure compatibility method and NMR experimental information

Tertiary structure models of Interleukin-6 were constructed using a routine prediction method based on the X-ray crystal structures of granulocyte colony-stimulating factor (GCSF) and leukemia inhibitory factor (LIF). The models were evaluated with the aid of the sequence-structure compatibility (3D-1D) method program compass and NMR experimental information. The model constructed from GCSF gained higher scores on compass examination than did that from LIF, and the NOE data [Nishimura et al. (1996) Biochemistry 35, 273-281] also turned to be more consistent with the former model.

Dexamethasone and nitric oxide synthase gene expression in brain

Systemic administration of lipopolysaccharide (LPS), which causes endotoxemia and systemic inflammation, has been reported to induce expression of the gene for type II inducible nitric oxide synthase (iNOS) in peripheral organs. This study was carried out to examine whether intraperitoneally injected LPS elicits the expression of iNOS messenger ribonucleic acid (mRNA) in the rat brain. We also investigated whether intraperitoneal treatment with dexamethasone (DEX) prevents this induction. To determine levels of iNOS mRNA, a quantitative reverse transcription-polymerase chain reaction (RT-PCR) method was employed. Treatment with LPS induced the expression of iNOS mRNA in various brain regions, accounting for approximately 1 x 10(5) to 4 x 10(5) molecules per micrograms of poly A+ RNA, and these inductions were markedly suppressed by DEX. The results suggest that, during systemic inflammation, iNOS mRNA induction occurs in brain through a DEX-sensitive mechanism.

Glycosphingolipid antigens from Leishmania (L.) amazonensis amastigotes. Binding of anti-glycosphingolipid monoclonal antibodies in vitro and in vivo

Specific glycosphingolipid antigens of Leishmania (L.) amazonensis amastigotes reactive with the monoclonal antibodies (MoAbs) ST-3, ST-4 and ST-5 were isolated, and their structure was partially elucidated by negative ion fast atom bombardment mass spectrometry. The glycan moieties of five antigens presented linear sequences of hexoses and N-acetylhexosamines ranging from four to six sugar residues, and the ceramide moieties were found to be composed by a sphingosine d18:1 and fatty acids 24:1 or 16:0. Affinities of the three monoclonal antibodies to amastigote glycosphingolipid antigens were also analyzed by ELISA. MoAb ST-3 reacted equally well with all glycosphingolipid antigens tested, whereas ST-4 and ST-5 presented higher affinities to glycosphingolipids with longer carbohydrate chains, with five or more sugar units (slow migrating bands on HPTLC). Macrophages isolated from footpad lesions of BALB/c mice infected with Leishmania (L.) amazonensis were incubated with MoAb ST-3 and, by indirect immunofluorescence, labeling was only detected on the parasite, whereas no fluorescence was observed on the surface of the infected macrophages, indicating that these glycosphingolipid antigens are not acquired from the host cell but synthesized by the amastigote. Intravenous administration of 125I-labeled ST-3 antibody to infected BALB/c mice showed that MoAb ST-3 accumulated significantly in the footpad lesions in comparison to blood and other tissues.

Measuring unilateral spatial neglect during stepping

OBJECTIVE

To examine the diaschisis of faultless conventional neuropsychological tests of unilateral spatial neglect (USN) and defects of activities of daily living (ADL) functions.

DESIGN

The evaluations of USN by assessments now in wide use were compared with newly developed assessments using a dual-task methodology in which a stepping activity was used as a "distracter" during USN assessment.

SETTING

A rehabilitation unit in a medical school hospital.

PATIENTS

Subjects consisted of 31 patients who suffered from stroke (right hemisphere lesions, 19; left hemisphere lesions, 12).

MAIN OUTCOME MEASURES

Observation of behavior of hemi-inattention, ADL evaluation (transfer and gait), and conventional tests of USN (line bisection, line cancellation, copying of flowers) were conducted. USN test during stepping was performed by stepping on two force plates connected to a microprocessor and to videocassette player so that the subject was required to step continuously.

RESULTS

Most of the subjects who had exhibited USN in the written tests on admission showed no defects in the test after about 60 days even if hemi-inattention was observed in behavior. In the test during stepping, subjects with hemi-inattention behavior neglected some visual stimulations applied from the direction contralateral to the hemisphere lesion.

CONCLUSIONS

Combined tests of visual attention and distracter activity (stepping) can more effectively reflect the ADL functions of USN patients than conventional tests.

Still life, a protein in synaptic terminals of Drosophila homologous to GDP-GTP exchangers

The morphology of axon terminals changes with differentiation into mature synapses. A molecule that might regulate this process was identified by a screen of Drosophila mutants for abnormal motor activities. The still life (sif) gene encodes a protein homologous to guanine nucleotide exchange factors, which convert Rho-like guanosine triphosphatases (GTPases) from a guanosine diphosphate-bound inactive state to a guanosine triphosphate-bound active state. The SIF proteins are found adjacent to the plasma membrane of synaptic terminals. Expression of a truncated SIF protein resulted in defects in neuronal morphology and induced membrane ruffling with altered actin localization in human KB cells. Thus, SIF proteins may regulate synaptic differentiation through the organization of the actin cytoskeleton by activating Rho-like GTPases.

Corneal lens secretion in newly emerged Drosophila melanogaster examined by electron microscope autoradiography

Drosophila corneal lens secretion was studied by electron microscope autoradiography of [3H]amino acids (leucine, lysine, phenylalanine, proline and tyrosine) and [3H]sugars (glucosamine and mannose) in newly emerged flies. Ommatidial lenses were homogeneously labelled with both tracers at low levels, suggesting that lens materials turn over continuously after lens formation is completed. In contrast, ocellar lenses were heavily labelled, indicating that deposition of ocellar lens cuticle is still active at this stage. [3H]amino acids and [3H]sugars were deposited in distinct patterns in ocelli. Although over 90% of [3H] sugars remained, even after 3 h after application, within 1 micron of the apices of corneagenous cells associated with lens bases, [3H]amino acids distributed diffusely. There was an obvious gradient of [3H]sugars from center to periphery of the lens base, suggesting that structure of the corneal lens in dorsal ocelli is determined by spatially regulated secretion of chitin by corneagenous cells.

Receptor subtype for vasopressin-induced release of nitric oxide from rat kidney

The vasopressin receptor subtype that causes nitric oxide (NO) release remains controversial. To elucidate this receptor-ligand interaction, we examined the effects of vasopressin receptor antagonists on vasopressin-induced release of NO from isolated perfused rat kidneys by using a sensitive chemiluminescence assay. Vasopressin increased renal perfusion pressure and NO signals in the perfusate in a dose-dependent manner. N omega-Monomethyl-L-arginine abolished this increase in NO release; however, a similar increase in renal perfusion pressure induced by prostaglandin F2 alpha was not associated with the increase in NO release. OPC-21268, a V1 receptor antagonist, significantly reduced the vasopressin-evoked renal vasoconstriction and NO release, whereas OPC-31260, a V2 receptor antagonist, had no effects. Moreover, desmopressin, a selective V2 receptor agonist, did not increase the NO signal. NO release by vasopressin was markedly attenuated in deoxycorticosterone acetate (DOCA)-salt hypertensive rat kidneys compared with control kidneys (10(-10) mol/L vasopressin: +0.8 +/- 0.3 versus +6.9 +/- 1.4 fmol/min per gram kidney, DOCA versus control; P < .001). Histochemical analysis for renal NO synthase revealed a substantial attenuation of the staining of endothelial NO synthase in DOCA-salt rats. These results directly demonstrate that vasopressin stimulates NO release via the endothelial V1 receptor in the rat kidney.

Gene identification in 1.6-Mb region of the Down syndrome region on chromosome 21

The Down syndrome (DS) region has been defined by analyses of partial trisomy 21. The 2.5-Mb region between D21S17 and ERG is reportedly responsible for the main features of DS. Within this 2.5-Mb region, we focused previously on a distal 1.6-Mb region from an analysis of Japanese DS patients with partial trisomy 21. Previously we also performed exon-trapping and direct cDNA library screening of a fetal brain cDNA library and identified a novel gene TPRD. Further screening of a fetal heart cDNA library was performed and a total of 44 possible exons and 97 cDNA clones were obtained and mapped on a BamH1 map. By rescreening other cDNA libraries and a RACE reaction, we isolated nearly full-length cDNAs of three additional genes [holocarboxylase synthetase (HCS), G protein-coupled inward rectifier potassium channel 2 (GIRK2), and a human homolog of Drosophila minibrain gene (MNB)] and a coding sequence of a novel inward rectifier potassium channel-like gene (IRKK). The gene distribution and direction of transcription were determined by mapping both ends of the cDNA sequences. We found that these genes, except IRKK, are expressed ubiquitously and are relatively large, extending from 100 kb to 300 kb on the genome. These nearly full-length cDNA sequences should facilitate understanding of the detailed genome structure of the DS region and help to elucidate their role in the etiology of DS.

The human GATA-6 gene: structure, chromosomal location, and regulation of expression by tissue-specific and mitogen-responsive signals

GATA factors constitute a family of transcriptional regulatory proteins expressed with distinct developmental and tissue-specific profiles and thought to regulate cell-restricted programs of gene expression. Here we describe the molecular cloning, chromosomal location, and transcription of the human GATA-6 gene. The GATA-6 cDNA encodes a predicted 449-amino-acid protein, which is highly conserved among vertebrates, and includes the two adjacent zinc-finger/basic domains characteristic of the GATA factor family. GATA-6 maps to human chromosome 18q11.1-q11.2 by fluorescence in situ hybridization. The gene is transcribed in a pattern overlapping that of GATA-4. Transcripts for both of these genes are prominent in heart, pancreas, and ovary, but only GATA-6 mRNA is found in lung and liver. GATA-6 transcripts are also detected in cultures of human and rat vascular smooth muscle cells (VSMCs). In VSMCs, GATA-6 transcripts are down- regulated when quiescent cultures are stimulated to proliferate in response to mitogen activation. These data demonstrate that GATA-6 is subject to both tissue-specific and mitogen-responsive regulatory signals. GATA-6 is a prime candidate for a gene that might regulate the differentiative state of VSMCs.

Open sandwich ELISA: a novel immunoassay based on the interchain interaction of antibody variable region

We describe an immunoassay that is based on the interchain interaction of separated VL and VH chains from a single chain antibody variable region. In the presence of antigen, the chains reassociate. VL fragments of anti-hen egg lysozyme (HEL) antibody HyHEL-10 were immobilized on microtiter plates. Samples were coincubated with an M13-displayed VH chain, and assayed with peroxidase-labeled anti-M13 antibody. Signal was detected in direct proportion to the amount of HEL in the sample. Wide dynamic range with < 15 ng/ml sensitivity was attained.

Cytokines involving gp130 in signal transduction suppressed growth of a mouse hybridoma cell line and enhanced its antibody production

Three cytokines, interleukin 6 (IL-6), leukaemia inhibitory factor (LIF), and oncostatin M (OSM), that bind to composite receptors including a common signal transducer gp130 suppressed proliferation of a mouse B-cell hybridoma cell line 2E3-O cultured in serum-free medium, while they enhanced antibody production of the cells. The specific growth rate of the cells reduced from 1.0/day for control to 0.6/day for the cultures supplemented with IL-6, LIF, or OSM at 1, 4, or 2 ng/ml, respectively. The antibody productivity increased five-fold when the cells were cultured with IL-6, LIF, or OSM at 1, 25, or 20 ng/ml, respectively. Transforming growth factor beta1(TGF-beta1) similarly suppressed growth of the cells at the concentration of 5 ng/ml, while it did not enhance the antibody production. Cell cycle analysis revealed that IL-6 induced the cells to be arrested at G1 phase of the cell cycle more intensively than TGF-beta1, indicating that IL-6 and TGF-beta1 suppressed the growth through mutually different mechanisms. As a whole, this work suggests that gp130, which is commonly involved in each receptor for IL-6, LIF, and OSM, transduces signals for suppressing proliferation and possibly for enhancing antibody production in the hybridoma cells.

Temperature dependence of crystal structure of NaK0.72(NH4)0.28(+)-C4H4O6.4H2O in the paraelectric phase

The crystal structures of the ferroelectric NaK0.72 (NH4)0.28(+)-C4H4O6.4H2O (RS0.72ARS0.28) have been studied in the paraelectric phase [Mr = 276.32, orthorhombic, P21212,° Z = 4, F(000) = 575.04, λ(Mo Kα1) = 0.70926 Å]; T = 213 (1), 253 (1) and 293 (1) K. The crystal data are as follows: (I) at T = 213 (1) K: R = 0.0424, wR = 0.0399, number of reflections = 3414, a = 11.899 (2), b = 14.273 (2), c = 6.211 (1) Å, V = 1054.9 (2) Å3, Dx = 1.740 g cm−3; (II) at T = 253 (1) K: R = 0.0498, wR = 0.0442, number of reflections = 3284, a = 11.929 (1), b = 14.297 (1), c = 6.221 (1) Å, V = 1061.0 (2) Å3, Dx = 1.730 g cm−3; (III) at T = 293 (1) K: R = 0.0473, wR = 0.0392, number of reflections = 3179, a = 11.955 (1), b = 14.317 (1), c = 6.231 (1) Å, V = 1066.5 (1) Å3, Dx = 1.721 g cm−3. X-ray investigations reveal details of structural change with temperature in the paraelectric phase. The carboxylate anion O(3)—C(4)—O(4) in the tartrate molecule is displaced along the a axis as the temperature decreases; moreover, the O(8) atom is displaced in the opposite direction against the shift of the carboxylate anion. The temperature dependence of the thermal motions of O(8) shows different behavior from the other O atoms of the water molecules. The amplitude of the thermal motion of O(8) does not tend to zero at T = 0 K, while the other O atoms of the water molecules tend to zero.

Method of obtaining mutants defective in immunoglobulin mu transcription factors

A method of obtaining mutants defective in the regulatory function of Ig mu gene expression was developed. Such mutants are useful for discovering the functions of transcription factors and isolating their genes, especially those of DNA-unbinding factors. Cells expressing Ig mu and Eco-GPT simultaneously under control of each mu enhancer were prepared as follows: myeloma X63Ag8.653 cells were transfected with pSV-V mu Me delta CH1 encoding a mu gene modified for cell surface mu expression without light chains, selected by neomycin resistance, transfected with Eco-GPT gene connected to the mu enhancer, and selected with mycophenolic acid in a medium containing xanthine. The mu(m)/Eco-GPT cells were mutated with ethane methyl sulfonate (EMS), and selected with toxin-conjugated anti-mu antibody, and then with 6-thioguanine. The mu(M)-/Eco-GPT- mutants obtained were fused with X63Ag8.653 cells. Fusion caused the mutant to recover mu(M) expression, suggesting that some trans-acting transcription factor other than the mu-encoding gene itself was probably mutated.