The presence of neighbors affects waving display frequency by Scopimera globosa (Decapoda, Ocypodidae)

Scopimera globosa, a small ocypodid crab, rhythmically raises and lowers its body and both chelae in a waving display when it is not interacting directly with another individual. To determine whether waving is a social signal and to deduce its possible function, we manipulated the sex and density of crabs in a field enclosure and recorded the waving frequency of males. Males with abundant female neighbors waved significantly more often than when the same males were caged with abundant male neighbors. Males caged with fewer neighbors of either sex seldom waved. Thus, males waved most in the presence of females, especially at high density, and least in the presence of other males, suggesting that waving may function in female acquisition. Received: August 18, 1998 / Accepted: October 2, 1999     

Two onygenalean fungi from Russian Far East soil

Two onygenalean fungi isolated from forest soil in the Sikhote-Alin reserve, Russian Far East (east Siberia), are described and illustrated:Gymnostellatospora parvula as a new species andAphanoascus canadensis as a new record.Gymnostellatospora parvula is characterized by psychrophilic growth, pale yellow to pale cinnamon ascomata with a hyphal peridium, small, hyaline discoid ascospores with an equatorial rim and more or less longitudinally ridged wall.     

Intermolecular association of the p185neu protein and EGF receptor modulates EGF receptor function

We have used cross-linking reagents on cell lines expressing both p185neu and EGFR. The lysates of the cells were precipitated with anti-p185neu or anti-EGFR antibodies. These precipitates included a high molecular weight complex that was identified as an EGFR-p185neu heterodimer. Heterodimerization was found to be induced by exposure to EGR. The EGFR of these cells displayed three affinity states for EGF: low (Kd, approximately 10(-9) M), high (Kd, 10(-9) to 10(-10) M), and very high (Kd, 10(-11) M), as determined by Scatchard analyses. Relatively small levels of EGF had a dramatic biological effect on cells expressing very high affinity EGFR. The very high affinity EGFR disappeared after the cells were treated with anti-p185neu monoclonal antibodies that selectively down-regulated p185neu. EGF and TPA had differential effects on down-modulation of the EGFR in cells that express either one or both species of receptor proteins.     

Purification of protein phosphatase from hen oviduct

Two protein phosphatases of 103 and 29 kDa as determined by gel filtration, were purified from hen oviducts. The 103 -kDa phosphatase was purified 7300-fold to near homogeneity and dissociated into two polypeptides in the presence of SDS. Molecular masses of these polypeptides were estimated to be 60 and 38 kDa by SDS-polyacrylamide slab gel electrophoresis using the buffer system of Laemmli, but 68 and 35 kDa using the buffer system of Weber and Osborn. The stoichiometry of these polypeptides was approx 1:1 according to the densitometric analysis of gels at 550 nm. The 29 -kDa phosphatase was purified 2900-fold. Both phosphatases dephosphorylated the alpha-subunit of phosphorylase kinase more rapidly than the beta-subunit.     

On the Mechanisms of Diurnal Vertical Migration Behavior of Heterosigma akashiwo (Raphidophyceae)

The marine raphidophycean biflagellate, Heterosigma akashiwo,clearly showed diurnal vertical migration under a 12 h light-12h dark photoperiod appearing at the surface of the culture mediumduring the light period and at the bottom during the dark period.The upward migration commenced a few hours before the lightwas turned on and the downward migration a few hours beforeit was turned off. The diuranal vertical migration behaviorwas closely correlated with diurnal changes in the specificgravity of the cells, those near the surface of the culturemedium had a smaller specific gravity than those at the bottom.The migration behavior was also correlated with the directionof cell swimming. More cells had flagella furrow facing upwardthan downward in the light phase, and vice versa in the darkphase. Phototaxis was not the main factor inducing the verticalmigration, though the cells did show a tactic respose to light.Chemotactic responses to O₂, N₂ or CO₂ gas did not occur. (Received August 9, 1984; Accepted January 9, 1985)     

Amphipathic antigen from Actinomyces viscosus

Abstract Amphipathic antigen (AcA) was extracted with phenol solution from whole cells of Actinomyces viscosus , and purified by gel filtration on Sepharose 6B. From the results of the gel diffusion test and passive hemagglutination assay, AcA was shown to be present as the cell-surface antigen.     

Velocity of chloroplast avoidance movement is fluence rate dependent.

In Arabidopsis leaves, chloroplast movement is fluence rate dependent. At optimal, lower light fluences, chloroplasts accumulate at the cell surface to maximize photosynthetic potential. Under high fluence rates, chloroplasts avoid incident light to escape photodamage. In this paper, we examine the phenomenon of chloroplast avoidance movement in greater detail and demonstrate a proportional relationship between fluence rate and the velocity of chloroplast avoidance. In addition we show that the amount of light-activated phototropin2, the photoreceptor for the avoidance response, likely plays a role in this phenomenon, as heterozygous mutant plants show a reduced avoidance velocity compared to that of homozygous wild type plants.     

Single-molecule Study on the Decay Process of the Football-shaped GroEL-GroES Complex Using Zero-mode Waveguides

It has been widely believed that an asymmetric GroEL-GroES complex (termed the bullet-shaped complex) is formed solely throughout the chaperonin reaction cycle, whereas we have recently revealed that a symmetric GroEL-(GroES)₂ complex (the football-shaped complex) can form in the presence of denatured proteins. However, the dynamics of the GroEL-GroES interaction, including the football-shaped complex, is unclear. We investigated the decay process of the football-shaped complex at a single-molecule level. Because submicromolar concentrations of fluorescent GroES are required in solution to form saturated amounts of the football-shaped complex, single-molecule fluorescence imaging was carried out using zero-mode waveguides. The single-molecule study revealed two insights into the GroEL-GroES reaction. First, the first GroES to interact with GroEL does not always dissociate from the football-shaped complex prior to the dissociation of a second GroES. Second, there are two cycles, the “football cycle ” and the “bullet cycle,” in the chaperonin reaction, and the lifetimes of the football-shaped and the bullet-shaped complexes were determined to be 3–5 s and about 6 s, respectively. These findings shed new light on the molecular mechanism of protein folding mediated by the GroEL-GroES chaperonin system.     

Plectranthias ryukyuensis,a new species of perchlet from the Ryukyu Islands,Japan, with a key to the Japanese species of Plectranthias (Serranidae: Anthiadinae)

A new perchlet, Plectranthias ryukyuensis, is described on the basis of four specimens (41.2–61.6 mm standard length: SL) from the Okinawa Islands, Japan. Plectranthias ryukyuensis can be distinguished from all congeners by the following combination of characters: X, 15 or 16 dorsal-fin rays; 14 pectoral-fin rays, all unbranched; lateral line complete, with 29 or 30 pored scales; 3 scale rows above lateral line; 5 or 6 diagonal rows of large scales on cheek between eye and corner of preopercle; preopercle with two antrorse spines on ventral margin, 20–29 serrae on posterior margin; margins of subopercle and interopercle with a few serrae (weak in large individuals); minute flaps at tips of first to ninth dorsal-fin spines; caudal fin shallowly emarginate, with some ray branches distinctively elongated past fin margin; fourth dorsal-fin spine longest, its length 110.6–128.6% that of third spine; body pinkish-white with two longitudinal rows of irregular orange-red blotches on upper half of lateral surface when fresh (rows close together in smaller than ca. 50 mm SL), blotches interconnecting anteriorly on upper and lower rows, and posterior half of lower row; four faint orange-red vertical bands below lateral line on posterior half of body and two distinct yellow blotches on cheek in fresh specimens; body uniformly yellowish-brown with two longitudinal rows of irregular dark blotches on upper half of lateral surface in preserved specimens (faint in small specimens). A key to the Japanese species of Plectranthias is given.