Spectroscopic characterization of plastocyanin from hornwort

Plastocyanin isolated from an aquatic higher plant, Ceratophyllum demersum L. (hornwort), has been characterized by electronic absorption, circular dichroism (CD), and electron paramagnetic resonance (EPR) spectroscopies. The visible absorption, CD, and EPR spectra of hornwort plastocyanin indicated a complete similarity of blue copper center to those of terrestrial higher plants and algae. However, the ultraviolet absorption spectrum of hornwort plastocyanin exhibited a lower tyrosine (Tyr) and a higher phenylalanine (Phe) content of the protein comparing with other plastocyanins. The ratio of Phe/Tyr residues was estimated to be 9 by amino acid analysis. The hornwort plastocyanin resembles in amino acid composition terrestrial higher plant plastocyanins rather than alga plastocyanins but is peculiar in the content of Phe and Tyr residues.     

Structural basis for actin assembly, activation of ATP hydrolysis, and delayed phosphate release

Assembled actin filaments support cellular signaling, intracellular trafficking, and cytokinesis. ATP hydrolysis triggered by actin assembly provides the structural cues for filament turnover in vivo. Here, we present the cryo-electron microscopic (cryo-EM) structure of filamentous actin (F-actin) in the presence of phosphate, with the visualization of some α-helical backbones and large side chains. A complete atomic model based on the EM map identified intermolecular interactions mediated by bound magnesium and phosphate ions. Comparison of the F-actin model with G-actin monomer crystal structures reveals a critical role for bending of the conserved proline-rich loop in triggering phosphate release following ATP hydrolysis. Crystal structures of G-actin show that mutations in this loop trap the catalytic site in two intermediate states of the ATPase cycle. The combined structural information allows us to propose a detailed molecular mechanism for the biochemical events, including actin polymerization and ATPase activation, critical for actin filament dynamics.     

Prostatic acid phosphomonoesterase of the Japanese monkey (Macaca f. fuscata)

Possible immunological differences between monkey and human prostate gland proteins and also between seminal vesicle proteins of these species were investigated by agarose gel electrophoresis, agarose gel immunoelectrophoresis and by the agar gel immunodiffusion method, using anti-sera against human plasma, human seminal plasma and human prostatic acid phosphomonoesterase (PMEase). At the same time, the electrophoretic mobility of these prostatic acid PMEases was compared by means of starch gel electrophoresis.Each of these two tissues, monkey and human, was found to contain antigenic proteins with immunological identity. Though antigenic similarity of monkey and human prostatic acid PMEase was demonstrated by immunological methods, a clear difference was observed in the electrophoretic mobility of these enzymes when examined by starch gel electrophoresis.     

Protein N-myristoylation is required for cellular morphological changes induced by two formin family proteins, FMNL2 and FMNL3

The subcellular localization of 13 recently identified N-myristoylated proteins and the effects of overexpression of these proteins on cellular morphology were examined with the aim of understanding the physiological roles of the protein N-myristoylation that occurs on these proteins. Immunofluorescence staining of HEK293T cells transfected with cDNAs coding for the proteins revealed that most of them were associated with the plasma membrane or the membranes of intracellular compartments, and did not affect cellular morphology. However, two proteins, formin-like2 (FMNL2) and formin-like3 (FMNL3), both of them are members of the formin family of proteins, were associated mainly with the plasma membrane and induced significant cellular morphological changes. Inhibition of protein N-myristoylation by replacement of Gly2 with Ala or by the use of N-myristoylation inhibitor significantly inhibited membrane localization and the induction of cellular morphological changes, indicating that protein N-myristoylation plays critical roles in the cellular morphological changes induced by FMNL2 and FMNL3.     

Galectin-4, a Novel Predictor for Lymph Node Metastasis in Lung Adenocarcinoma

Metastasis is still a major issue in cancer, and the discovery of biomarkers predicting metastatic capacity is essential for the development of better therapeutic strategies for treating lung adenocarcinoma. By using a proteomic approach, we aimed to identify novel predictors for lymph node metastasis in lung adenocarcinoma. Two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis showed 6 spots differentially expressed between lymph node metastasis-positive and lymph node metastasis-negative groups in a discovery set. Subsequent mass spectrometry showed that 2 of these spots were derived from galectin-4, and western blot analysis confirmed the overexpression of galectin-4 in metastatic samples. The predictive value of galectin-4 was confirmed by immunohistochemical analysis for a validation set consisting of 707 surgically resected specimens of lung adenocarcinomas (stages I to IV). We observed that 148 lung adenocarcinomas (20.9%) expressed galectin-4, which was significantly associated with variables of disease progression such as tumor size (p<0.0001), pleural invasion (p = 0.0071), venous invasion (p = 0.0178), nodal status (p = 0.0007), and TNM stage (p<0.0001). By the multivariate analysis, Galectin-4 expression was revealed as one of the independent predictor for lymph node metastasis, together with solid predominant and micropapillary histologic pattern. Furthermore, galectin-4 expression was revealed to be an independent predictor for lymph node metastasis and an adverse survival factor in patients with lung adenocarcinoma of acinar predominant type. Galectin-4 plays an important role in metastatic process of lung adenocarcinoma. Immunohistochemical testing for galectin-4 expression may be useful together with the detection of specific histology to predict the metastatic potential of lung adenocarcinoma.     

Studies on the Amylases of Paecilomyces subglobosus

Two strains of molds, which had a very close similarity with each other, and the acid-stable α-amylase activity of which was very high, were isolated from the air. Studies on the morphology of these strains revealed that, although they were fairly close to Paecilomyces varioti, they had some peculiar characteristics, and that their existence had not been reported hitherto. Therefore the authors concluded that the strains must belong to a new species in the genus Paecilomyces, and named them Paecilomyces subglobosus sp. nov. TPR-3810 and -3811, respectively, after their characteristic shape of the conidiospores.     

Identification of xanthine dehydrogenase/xanthine oxidase as a rat Paneth cell zinc-binding protein

Paneth cells are zinc-containing cells localized in small intestinal crypts, but their function has not been fully elucidated. Previously, we showed that an intravenous injection of diphenylthiocarbazone (dithizone), a zinc chelator, induced selective killing of Paneth cells, and purified a zinc-binding protein in Paneth cells. In the present study, we further characterized one of these proteins, named zinc-binding protein of Paneth cells (ZBPP)-1. Partial amino acid sequences of ZBPP-1 showed identity with rat xanthine dehydrogenase (XD)/xanthine oxidase (XO). Anti-rat XD antibody (Ab) recognized ZBPP-1, and conversely anti ZBPP-1 Ab recognized 85 kDa fragment of rat XD in Western blotting. Messenger RNA and protein levels of XD were consistent with our previous data on the fluctuation of Paneth cell population after dithizone injection. Thus, ZBPP-1 is an 85 kDa fragment of XD/XO in Paneth cells. XD/XO in Paneth cells may play important roles in intestinal function.     

Periplasmic location of dissimilatory nitrate and nitrite reductases in a denitrifying phototrophic bacterium, Rhodopseudomonas sphaeroides forma sp. denitrificans

The localization of dissimilatory nitrate and nitrite reductasesof a denitrifying phototrophic bacterium, Rhodopseudomonas sphaeroidesforma sp. denitrificans, was investigated. Nitrate and nitritereductases were located in the periplasmic space of the bacteriumgrown anaerobically in the presence of nitrate either in lightor in darkness. Chromatophores showed nitrate and nitrite reductaseactivities when dithionite-reduced benzyl viologen was an electrondonor; this suggests that the enzymes were trapped inside thevesicles. ¹Present address: Japanese Red Cross Central Blood Center, Hiroo4-1-31, Shibuyaku, Tokyo 150, Japan. ²Present address: Plant Growth Laboratory, University of California,Davis, California 95616, U.S.A. (Received November 7, 1979; )     

The effects of acebutolol alone and in combination with furosemide or hydralazine in experimentally induced hypertensive G-minipigs

Experimentally induced hypertensive G-minipigs were used for assessing the antihypertensive effects of acebutolol, a cardioselective beta-adrenergic blocking agent. In the acute experiment, six females were used. Acebutolol (3 mg/kg, i.v.) alone or in combination with furosemide (1 mg/kg, i.v.) or hydralazine (1 mg/kg, i.v.) was administered through an implanted catheter. In the chronic experiments, five females received oral acebutolol (100-200 mg/day). The blood pressure, heart rate, plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were used as parameters. In the acute experiment, there were no marked changes in the blood pressure or heart rate during the nondosing period. Acebutolol alone caused a marked decrease in the blood pressure and heart rate. In the two combination tests, combined administration with acebutolol and furosemide had a greater effect on the blood pressure and heart rate than did acebutolol alone. A combined acebutolol and hydralazine regimen caused a slight reduction not only in the blood pressure, but also in the heart rate compared with acebutolol alone. PRA and PAC remained essentially constant, with minor fluctuations, throughout the nondosing period. Following the injection of acebutolol alone, PRA showed an elevation with a significant rise after three hours and PAC showed a tendency to increase. PRA and PAC generally tended to increase in the case of combined administration with furosemide or hydralazine, but these tendencies were less conspicuous than with acebutolol alone. On the other hand, chronic treatment with acebutolol produced a significant decrease in the heart rate from two weeks after the administration and in the blood pressure from four weeks.(ABSTRACT TRUNCATED AT 250 WORDS)