Coordination of flagella on filamentous cells of Escherichia coli.

Video techniques were used to study the coordination of different flagella on single filamentous cells of Escherichia coli. Filamentous, nonseptate cells were produced by introducing a cell division mutation into a strain that was polyhook but otherwise wild type for chemotaxis. Markers for its flagellar motors (ordinary polyhook cells that had been fixed with glutaraldehyde) were attached with antihook antibodies. The markers were driven alternately clockwise and counterclockwise, at angular velocities comparable to those observed when wild-type cells are tethered to glass. The directions of rotation of different markers on the same cell were not correlated; reversals of the flagellar motors occurred asynchronously. The bias of the motors (the fraction of time spent spinning counterclockwise) changed with time. Variations in bias were correlated, provided that the motors were within a few micrometers of one another. Thus, although the directions of rotation of flagellar motors are not controlled by a common intracellular signal, their biases are. This signal appears to have a limited range.     

Roles of epidermal growth factor (EGF) in the growth and differentiation of human endometrium

Endometrial tissues undergo drastic changes during menstrual cycle. After menstruation, they proliferate and differentiate into cells with secretory activity in the preparation for egg implantation. Although sex steroids play an important role in the development of endometrial tissues, sequential events occurring in the endometrium can not be fully explained by the direct actions of sex steroids. In this study, we offer evidences that EGF is released from endometrial cells and they possess the receptor for EGF. These findings prompted us to explore the biological roles of EGF in endometrial tissues. Here we clearly demonstrate that EGF is involved in the proliferation of endometrial cells. Moreover, EGF is found to enhance both glycogenesis and glycogenolysis, thus increasing the supply of glucose for blastocysts. We further set forth that EGF augments the capacity of progestin receptor and release of prostaglandins in endometrial cells. In summary, this study emphasizes that EGF may participate in the development of human endometrial tissues in concert with sex steroids, thus contributing to the acquisition of receptivity of eggs in the endometrium.     

Elastase-1-secreting acinar cell carcinoma of the pancreas. A cytologic, electron microscopic and histochemical study

A case of acinar cell carcinoma of the pancreas was diagnosed by fine needle aspiration cytology during surgery. The cytologic characteristics of this neoplasm are described. Electron microscopy disclosed numerous zymogen granules in the tumor while histochemistry demonstrated the presence of elastase-1. Serum elastase-1 levels were markedly elevated. The cytologic differential diagnosis of pancreatic tumors is discussed.     

A cell-based assay for evaluating the interaction of heparin-like molecules and basic fibroblast growth factor.

A simple panning procedure that allows for the evaluation of interactions between various heparin-like molecules and basic FGF has been developed. This assay measures the ability of compounds to inhibit the interaction of transfected human lymphoblastoid cells, UC 729-6 (UC cells), expressing hamster syndecan and basic FGF-coated plastic plates. The transfected cells bind rapidly to basic FGF-coated plates while the control cells do not bind well. Binding of the transfected cells to basic FGF was inhibited by heparin and heparin sulfate (HS), but not by chondroitin sulfate, dermatan sulfate, keratan sulfate, and hyaluronic acid. There was little inhibition of binding by chemically modified heparin such as completely desulfated, N-acetylated heparin, completely desulfated, N-sulfated heparin, and N-desulfated, N-acetylated heparin. These results suggested that both the N-sulfate and O-sulfate groups of heparin are required for binding to basic FGF. In addition, inhibition by oligosaccharides derived from depolymerized heparin increased with fragment size; partial inhibition was observed with oligosaccharides as small as hexamers. The biochemical basis for the binding of transfected cells to basic FGF was established by showing a significant increase of 35SO4 incorporation into HS. In particular, the level of 35SO4-HS in the trypsin-releasable (cell surface) pool increased fivefold. This increase was accounted for by demonstration of the presence of HS on immunoprecipitated syndecan from the transfected cells.     

Deletion of C-terminal 12 amino acids of GLUT1 protein does not abolish the transport activity.

We engineered the GLUT1 cDNA to delete C-terminal 12 amino acids of encoded GLUT1 protein. This mutated GLUT1 protein expressed in CHO cells by transfection of its cDNA was demonstrated to reside on the plasma membrane by cell surface labeling technique, and retain the transport activity, similar to that of the wild-type GLUT1. In addition, metabolic labeling of the intact cells with 35S indicated that the half-life of the mutated GLUT1 was not significantly different from that of the wild-type GLUT1. These results suggest that C-terminal 12 amino acids of GLUT1 are not important for the transport activity and the stability of the protein. Taken together with our previous results on the mutant without C-terminal 37 amino acids, the amino acids between the 37th and the 13th from the C-terminus appear to be essential for the transport activity.     

Contagious egg-distribution on host pods and avoidance of pods received eggs in a wild bruchidKytorhinus sharpianus

The present study investigated the way a wild bruchid, Kytorhinus sharpianus, distributes its eggs on host pods. First, we counted the number of eggs per pod on the host plant (Sophola flavescens) in the field. The egg-distributions by the overwintered-generation adults in July and by the second-generation adults in mid October did not deviate from Poisson distribution because of small numbers of eggs laid. However, the egg-distribution in late August when many first-generation adults emerged was significantly contagious. The deposition of eggs was determined for three types of pods: (A) clean pods, (B) pods with eggs, and (C) those which eggs had been laid on but were removed from later. The numbers of eggs laid newly on three types of pods were significantly different; A>C>B, suggesting that an oviposition marker pheromone (O.M.P.) caused females to avoid pods on which eggs were deposited. Egg-shells reinforced that response. Monte Carlo simulations for the egg-distribution on pods predicted that even if females avoid pods with heavy egg-load through O.M.P., the egg-distribution becomes contagious when there is a large heterogeneity in quality of the pods.     

Bi- and trivoltine complex life cycles in a Kanto (Japan) population of a wild bruchid Kytorhinus sharpianus

The partial trivoltinism and overwintering of Kytorhinus sharpianus Bridwell (Coleoptera: Bruchidae) was studied in the Kanto district, Japan. The later in the summer eggs were laid by the first-generation adults, the higher was the incidence of larval diapause in the second generation. The incidence of diapause also fluctuated between years, influencing the abundance of third-generation larvae. A relatively large proportion of third-generation larvae did not attain the diapause stage by the beginning of winter. The diapause development of larvae in diapause was completed by mid-January. Immature larvae of the third generation also overwintered and emerged as adults in the spring.