Molecular cloning and characterization of the platelet-activating factor receptor gene expressed in the human heart.

PAF decreases cardiac contractility and blood pressure. To characterize the cardiac PAF receptor, we screened a human ventricular cDNA library in a low stringency condition, using a PCR product derived from guinea pig lung PAF receptor as a probe. Four clones were obtained and named HV1-4. In Xenopus oocytes injected with cRNA derived from HV3 or 4 but not from HV1 or 2, PAF elicited a Ca(2+)-activated Cl- current. HV3 and HV4 were duplicate clones, encoding a 342 amino-acid polypeptide which was identical to that of the human leukocyte PAF receptor. However, a portion of the 5' untranslated region of HV3 (or 4) was different from that of the leukocyte receptor cDNA. Northern blotting of human ventricles and atria using the HV3 insert showed a single band of approximately 4 kb. These results suggest a tissue-specific translational mechanism responsible for regulation of the expression of the PAF receptor mRNA in these tissues.     

Proliferation and Teratogenicity of Aino Virus in Chick Embryos

Aino virus (AIV; JaNAr 28 strain) 10³ TCID₅₀/0.2 ml was inoculated in the yolk sac of 8-day-old chick embryos. Recovery and titration of the virus from various organs including the central nervous system (CNS) and skeletal muscle were performed at 2, 4, 7, 10 and 13 days after inoculation (PI). AIV was systemically disseminated and proliferated even 2 days PI. The titers of the recovered virus from the CNS and from skeletal muscle was the highest at 4 days PI and declined with time, whereas hydranencephaly, arthrogryposis and cerebellar hypoplasia developed at 7 days PI and gradually progressed until 13 days PI.     

Genetic Mapping of Four Mouse bHLH Genes Related toDrosophilaProneural Geneatonal

It has been shown that mammalian neurogenesis is partly controlled by multiple basic helix–loop–helix (bHLH) genes, as inDrosophila.Recently, mouse homologs ofDrosophila atonal,a proneural gene encoding a bHLH protein required for chordotonal organ and photoreceptor development, have been characterized to obtain further insights into the molecular nature of mammalian neurogenesis. Here, to assess their potential involvement in genetic neural disorders, we have determined genetic map positions for four mouseatonal-related genes,Atoh1, Atoh2, Atoh3,andNdrf,which encode MATH-1, MATH-2, MATH-3, and NDRF, respectively. Interspecific backcross analysis indicated thatAtoh1andAtoh2were located in separate positions of Chr 6 and thatAtoh3andNdrfwere mapped to Chr 10 and Chr 11, respectively. Thus, these structurally related genes are located separately on multiple chromosomes.     

Radular mechanosensory neuron in the buccal ganglia of the terrestrial slug,Incilaria fruhstorferi

A radular mechanosensory neuron, RM, was identified in the buccal ganglia of Incilaria fruhstorferi. Fine neurites ramified bilaterally in the buccal ganglia, and main neurites entered the subradular epithelium via buccal nerve 3 (n3). When the radula was distorted by bending, RM produced an afferent spike which was preceded by an axonic spike recorded at n3. The response of RM to radular distortion was observed even in the absence of Ca²⁺, which drastically suppressed chemical synaptic interactions. Therefore, RM was concluded to be a primary radular mechanoreceptor.During rhythmic buccal motor activity induced by food or electrical stimulation of the cerebrobuccal connective, RM received excitatory input during the radular retraction phase. In the isolated buccal ganglia connected to the radula via n3s, the afferent spike, which had been evoked by electrical stimulation of the subradular epithelium, was broadened with the phasic excitatory input. Since the afferent spike was also broadened by current injection into the soma, depolarization due to the phasic input may have produced the spike broadening.Spike broadening was also observed during repetitive firing evoked by current injection. The amplitude of the excitatory postsynaptic potential in a follower neuron increased depending on the spike broadening of RM.Abbreviations CBC cerebrobuccal connective - EPSP excitatory postsynaptic potential - n1,n3 buccal nerves 1 and 3 - RBMA rhythmic buccal motor activity - RM radular mechanosensory neuron - SMT supramedian radular tensor neuron     

Growth characteristics of the diatoms Pseudonitzschia pungens and P. fraudulenta exposed to ultraviolet radiation

Interest in the biology of planktonic, chain-forming Pseudonitzschia species has grown recently after the discovery of toxin production in Pseudonitzschia pungens and related taxa, following the outbreak of shellfish toxicity in Canada in 1987. As part of a broader study on the effects of enhanced ultraviolet light on the growth of bloom-forming phytoplankton, we have examined the growth rates and production of the toxin domoic acid and two additional chemicals [bacillariolides I and II] by Pseudonitzschia pungens varieties and Pseudonitzschia fraudulenta from Narragansett Bay, Rhode Island. Growth of P. fraudulenta is significantly inhibited by enhanced UV, P. pungens var. pungens shows slight inhibition, and P. pungens var. multiseries is unaffected. Production of bacillariolides I and II by P. pungens var. multiseries is similar in enhanced and deleted UV light. Tolerance of UV light by P. pungens var. multiseries appears to be acquired, and persistent. If ambient UV light continues to increase as a result of global ozone depletion, one may expect UV-resistant taxa such as P. pungens var. multiseries to become more prominent in coastal phytoplankton communities.     

Some properties and occurrence of cytochrome c-552 in the aerobic photosynthetic bacterium Roseobacter denitrificans

Characteristics and occurrence of cytochrome c-552 from an aerobic photosynthetic bacterium, Roseobacter denitrificans, were described.Relative molecular mass of the cytrochrome was 13.5 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 15,000 by gel filtration. This cytochrome was a acidic protein having a pI of 5.6 and E_m was +215 mV at pH 7.0. Absorption peaks were at 278, 408 and 524 nm in the oxidized form and 416, 523 and 552 nm in the reduced form.Amino acid composition and N-terminal amino acid sequence of cytochrome c-552 determined for 24 residues had low similarities to those of cytochrome c-551 of this bacterium, which is homologous to cytochrome c ₂, although the physico-chemical properties of these two cytochromes were similar to each other.Cytochrome c-552 was maximally synthesized in the light under aerobic conditions but not in the dark. The synthesis also occurred in the presence of alternative acceptors such as trimethylamine N-oxide (TMAO) and nitrate under anaerobic conditions. Our results suggest that cytochrome c-552 is involved in TMAO respiration and denitrification in R. denitrificans, although the effect of light remains to be solved.Abbreviations E_m Midpoint redox potential - PAGE Polyacrylamide ge electrophoresis - SDS-PAGE Sodium dodecyl sulfate polyacrylamide gel electrophoresis - TMAO Trimethylamine N-oxide     

Purification and properties of thiamine-binding proteins from sesame seed

Three thiamine-binding proteins of 17-19 kDa (STBP-I, II, and III) were purified from sesame seed (Sesamum indicum L.). Each of the proteins was composed of two subunits of equal molecular mass and each subunit consisted of a large polypeptide and a small polypeptide linked by a disulfide bond(s). They were rich in glutamic acid (or glutamine) and arginine. Their binding activities were optimal at neutral pH. They bound specifically free thiamine but not thiamine phosphates. STBP-I had higher affinity for thiamine than STBP-II or STBP-III. STBP-II and STBP-III bound one molecule of thiamine per molecule, and STBP-I bound 0.5 molecule. The amino acid composition and structure of the STPBs were similar to those of 2S storage proteins.     

On-line state recognition in a yeast fed-batch culture using error vectors

The physiological states with respect to cell growth and ethanol production in a yeast fed-batch culture expressed in linguistic form could be recognized on-line by fuzzy inferencing based on error vectors. The error vector was newly defined here in a macroscopic elemental balance equation. The physiological states for cell growth and ethanol production were characterized by error vectors using many experimental data from fed-batch cultures. Fuzzy membership functions were constructed from the frequency distributions of the error vectors and state recognition was performed by fuzzy inferencing. In particular, an unusual physiological state for a yeast cultivation, in which aerobic ethanol production was accompanied by very low cell growth, could be recognized accurately. According to the results of the state recognition, an energy parameter, the P/O ratio in the metabolic reaction model was adaptively estimated, and the cell growth was successfully evaluated with the estimated P/O. (c) 1995 John Wiley & Sons, Inc.     

Localization of immuno-analogues of erythrocyte protein 4.1 and spectrin in epidermis of psoriasis vulgaris

The presence and localization of immuno-analogues of human erythrocyte protein 4.1 and spectrin were examined in the epidermis of psoriasis vulgaris. Immunoblot analysis with antibodies against human erythrocyte protein 4.1 revealed that psoriatic epidermis contains a 4.1-like protein of 80 kDa, and also minor immunoreactive polypeptides, including a 45-kDa polypeptide. The 45-kDa band was not detected in non-lesional epidermis. Lesional epidermis of psoriasis contains spectrin-like proteins of 240 kDa. Analysis with immunofluorescence microscopy revealed that 4.1-like proteins were detected mainly in the cytoplasm of the suprabasal cells in lesional epidermis and in the peripheral cytoplasm of the basal cells in non-lesional epidermis. On the other hand, spectrin-like proteins were localized to the peripheral cytoplasm of basal keratinocytes in both lesional and non-lesional psoriatic epidermis. The present results indicate that proteins related to protein 4.1 and spectrin are consistently detected within epidermal cells of psoriasis, a chronic skin disease characterized by epidermal hyperplasia; the expression and distribution of protein 4.1 in lesional epidermis of psoriasis differs from that in non-lesional epidermis. These membrane skeletal proteins may be of significance in the hyperproliferative epidermis of psoriasis.