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Antimicrobial peptides, named tachystatins A, B, and C, were identified from hemocytes of the horseshoe crab Tachypleus tridentatus. Tachystatins exhibited a broad spectrum of antimicrobial activity against Gram-negative and Gram-positive bacteria and fungi. Of these tachystatins, tachystatin C was most effective. Tachystatin A is homologous to tachystatin B, but tachystatin C has no significant sequence similarity to tachystatins A and B. Tachystatins A and B showed sequence similarity to omega-agatoxin-IVA of funnel web spider venom, a potent blocker of voltage-dependent calcium channels. However, they exhibited no blocking activity of the P-type calcium channel in rat Purkinje cells. Tachystatin C also showed sequence similarity to several insecticidal neurotoxins of spider venoms. Tachystatins A, B, and C bound significantly to chitin. A causal relationship was observed between chitin binding activity and antifungal activity. Tachystatins caused morphological changes against a budding yeast, and tachystatin C had a strong cell lysis activity. The septum between mother cell and bud, a chitin-rich region, was stained by fluorescence-labeled tachystatin C, suggesting that the primary recognizing substance on the cell wall is chitin. As horseshoe crab is a close relative of the spider, tachystatins and spider neurotoxins may have evolved from a common ancestral peptide, with adaptive functions.

In order to develop additional surface functions such as excellent corrosion resistance and decorative colours on stainless steels, plasma-assisted coating processes utilizing sputtering, ion plating and plasma chemical vapour deposition (CVD) have been assessed. In this study, the process parameters controlling corrosion-resistant and chromatic properties were investigated. Guidelines for selecting suitable processes and coating conditions were established.

AN amino acid, 3,5-dihydroxyphenylglycine (DHPG) induced current responses in Xenopusoocytes expressing a metabotropic glutamate receptor clone mGluRl. Apparent EC50of DHPG for mGluRl was slightly lower than that of (±)-l-aminocyclopentane-trans-l,3-dicarboxylic acid (ACPD). DHPG responses were partially inhibited by 2-amino-3-phosphonopropionic acid (AP-3). DHPG had no effect on ionotropic glutamate receptors whose expression was induced in the oocytes following injection of poly(A)+mRNA of rat brains. In hippocampal slices, DHPG produced slow excitation of pyramidal cells, resulting from a depression of Ca2+-dependent K+current and a voltage-dependent K+current. These results indicate that DHPG is a specific and potent agonist of mGluRs.

The effects of catechol on various ionic channels of isolated primary afferent neurones of the bull‐frog were examined by a single‐suction‐electrode clamp system, which combined internal perfusion and current or voltage clamp using an electronic switching circuit. Catechol was found to inhibit rather specifically the fast K+ current as does 4‐aminopyridine (4‐AP). Ca2+, Na+ and slow K+ currents were not affected. Although both 4‐AP and catechol were inhibitors of the fast K+ channels, their sites of action were quite different. Catechol was effective when applied on the external surface of the cell membrane whereas 4‐AP acted preferably internally. We assumed that a single fast K+ channel has two distinct sites for blockers: the catechol site is exposed to the external medium or situated at the outer orifice of the pore, and the 4‐AP site is located within the same channel but is more easily accessible from inside the nerve cell than outside. The 4‐AP and catechol sites were not, however, completely separate and independent of each other since a synergistic interaction was observed between catechol and 4‐AP.

A 4-year-old Holstein cow developed a large neoplastic mass, which was formed in the deep soft tissue of the neck and removed surgically. The neoplasm was shown to be a smooth muscle tumour by the presence of alpha smooth muscle actin and fine intracytoplasmic filaments with focal densities. This malignant neoplasm showed extensive areas of necrosis and haemorrhage, high cellularity, marked pleomorphism, atypical giant cells and numerous mitoses with occasional abnormal figures.

Stainless steels are widely used for architecture, vehicles, etc. because of their good corrosion resistance and surface aesthetics. In order to provide additional surface functions, such as decorative colors, we have developed a continuous dry coating process, which can provide stainless steel strip with a multilayer ceramic or metallic coating. In this paper, the role of the environment will be discussed from two different points of view. The first is the performance of these coated stainless steels in corrosive and mechanically stressed environments. The second is the influence of the plasma environment used to synthesize the coating materials on the quality of thin films.

Effects of 5-hydroxytryptamine (serotonin; 5-HT) on the anterior aorta and ventricle muscle of the marine gastropod Aplysia are characterized. Bath-applied 5-HT depolarizes muscle fibers and causes tension increases in both the anterior aorta and ventricle above ca. 10(-9) M. Iontophoretically applied 5-HT caused localized depolarizations of anterior aorta muscle fibers. 5-HT increases the levels of adenosine-3',5'-cyclic monophosphate (cAMP) markedly in the anterior aorta of A. kurodai and A. californica and in the ventricle of A. kurodai. Effects of 5-HT on the contractility of and cAMP synthesis in the anterior aorta and ventricle are both blocked by methysergide. 5-HT and cAMP analogs stimulate 45Ca2+ efflux from the ventricle, implying that the effects of cAMP on contractility involve intracellular Ca2+ movements.

1. The intracellular reaction mechanism underlying electrophysiological responses evoked by neurotensin (NT) was studied using Xenopus laevis oocytes injected with poly (A)+ messenger ribonucleic acid (mRNA) isolated from rat brains. 2. A few days after the injection of mRNA, oocytes were found to acquire sensitivity to NT and substance P. 3. Under voltage‐clamp conditions (‐60 mV), application of NT to mRNA‐injected oocytes produced transient and oscillatory inward currents which began after a delay of several tens of seconds. These inward currents were accompanied by an increase in membrane conductance. 4. NT receptors on mRNA‐injected oocytes showed essentially the same pharmacological properties as those of native NT receptors. 5. The NT response showed desensitization and was not readily recovered even after extensive washing of cells for more than 30 min. 6. NT response was suppressed when the muscarinic acetylcholine (ACh) response of the same cell, which was also induced by the same mRNA, was desensitized by a large dose of ACh. 7. NT response and ACh response showed many similarities: they were both inhibited by pertussis toxin and intracellular ethyleneglycol‐bis‐(beta‐aminoethylether) N, N'‐tetraacetic acid (EGTA), mimicked by intracellularly injected inositol 1, 4, 5‐trisphosphate (InsP3), and suppressed when cell response to InsP3 was desensitized by a large dose of InsP3. Reversal‐potential analyses indicated that both responses were mediated by an increase in membrane permeability to Cl‐. 8. It is concluded that NT responses and muscarinic ACh responses of Xenopus oocytes induced by rat brain mRNA may most likely share a common reaction mechanism. The reaction sequence includes the activation of receptors, activation of inhibitory guanine nucleotide‐binding regulatory protein, production of InsP3, intracellular Ca2+ mobilization, and increased membrane permeability to Cl‐.

We describe the prevalence of community-acquired M. pneumoniae pneumonia diagnosed by culture methods in a single institute in Japan from January 1979 to December 1999. Cultures were performed in 2971 pneumonia cases and yielded M. Pneumoniae in 508 cases. The epidemic peaks recurred regularly at 4-year intervals (1980, 84, 88 and 91–2). Although a large epidemic has not occurred since 1992, traces of epidemic periodicity have still persisted from 1992 to 1999 at 3-year intervals.