Maintenance of pair bond during the non-reproductive season in a monogamous pipefish <Emphasis Type="Italic">Corythoichthys haematopterus</Emphasis>

During the non-reproductive season, male and female Corythoichthys haematopterus came to a particular site every early morning and performed a series of displays, called greetings, for a few minutes. After exchanging greetings, they had no further interactions during the daytime. This behavioural pattern was basically the same as that observed during the reproductive season. All greeting pairs bred in the following reproductive season if both members were present. These results indicate that mate fidelity of this pipefish is very high and that daily greetings lasting only a few minutes were enough to maintain pair bond all year around.     

The core oligosaccharide in LPS of the Ter-15 mutant after the transformation of F'-lac episome

Ribosomes from stationary phase $\text{Bacillus stearothermophilus}$ have a diminished activity in protein synthesis due to the presence of a bound protein (association factor I, AF_I). This factor inhibits the binding of fmet-tRNA to ribosomes. The inhibition of protein synthesis can be reversed in systems directed by viral mRNA by the addition of an excess of high salt ribosomal wash obtained from mid-log cells. Under this condition AF_I is released from ribosomes.     

Mate acquisition by a solitary crabZebrida adamsii,a symbiont of the sea urchin

A small crabZebrida adamsii, an obligate symbiont of the sea urchin, lives solitary on a host from the earliest stage of its benthic life. In the breeding season males frequently move between hosts to search for mates. Analysis of daily positional changes of individually marked crabs indicates that males often land on the substrate to migrate between separate hosts. Females also change hosts before they copulate, but after oviposition they stay on the same hosts for a long time, similarly to crabs in the nonbreeding season.     

A simple method for in planta tomato transformation by inoculating floral buds with a sticky Agrobacterium tumefaciens suspension

Tomato transformation is conventionally performed using Agrobacterium tumefaciens-infected cotyledons. Here, we propose a simple procedure for tomato transformation, by which A. tumefaciens cells were smeared onto floral buds of a tomato plant using a paintbrush. Sufficient numbers of fruits were obtained from them, although the smearing of an excess number of A. tumefaciens cells led to an adverse effect on the plant growth. Progeny plants were screened by growth on a kanamycin-containing selection medium plate. The nptII gene was detected in 10 plants among 1,599 progenies. These transformants were derived from fruits other than those obtained from the smeared buds. This suggested that A. tumefaciens cells moved to the buds located near the smeared buds and caused the transformation event. Our findings suggest that this procedure can be used for the introduction of a foreign gene into plant cells.     

An Improved Method for Determining the Ionic Conductance and Capacitance of the Membrane of Chara corallina

The assumption of a single exponential change for the voltageresponse caused by a square current of subthreshold intensityis not necessarily an adequate explanation of the situationin the Chara membrane. By improving the speed of electronicsfor current clamping and the accuracy of data simulation, itwas found that an additional process, which can be generallysimulated with another exponential function, was superimposedon the voltage response. Such an additional exponential processmay be partly atributed to the response of the tonoplast, ifthe internal potential measuring microelectrode is in the vacuole.However, this additional process still remained in the voltageresponse of the plasmalemma of the Chara internode when thetonoplast and a large amount of endoplasm were removed by internalperfusion with an glycol ether diaminetetraacetic acid solution.The additional exponential component arose from the change ofthe electromotive force of the single membrane during applicationof the test current pulse. The increase of the conductance of the plasmalemma alone waslarge during excitation, while that of the elecrostatic capacitancewas negligible. On the other hand, the conductance and capacitancewhich reflect an additional exponential ionic process duringthe test pulse both increased greatly around the peak of excitation.This rise is the main reason for an apparent large increaseof membrane capacitance which was deduced from a simple approximationof the membrane with a single time constant model. (Received January 6, 1982; Accepted June 23, 1982)     

Further Clonal Expansion of T Cells upon Rechallenge of Superantigen Staphylococcal Enterotoxin A

Superantigens are known to induce clonal anergy and/or deletion in reactive T cells peripherally. This study was undertaken to investigate the T-cell status early after exposure to staphylococcal enterotoxin A (SEA) in vivo and in vitro. At the peak of clonal expansion following the administration of 5 μg SEA (i.e., 2 days after the injection), C57BL/6 mice were rechallenged with the same dose of SEA in vivo. The secondary stimulation augmented clonal expansion of the T cells bearing Vβ3 and Vβ11 in both CD4⁺ and CD8⁺ populations. In vitro restimulation of the spleen cells taken from the SEA-primed mice also induced further expansion of the Vβ3⁺ T cells during 2 days of culturing, whereas without restimulation, a marked reduction of Vβ3⁺ T cells occurred. The spleen cells from the SEA-primed mice were hyper-reactive to in vitro restimulation with SEA as measured by ³H-TdR uptake on day 1 of culturing, but augmented proliferation leveled off thereafter. By day 3, the values of ³H-TdR uptake were less than 20% of those of the controls in which spleen cells from native mice were stimulated with SEA in vitro. These results suggest that T cells exposed to SEA in vivo are still capable of proliferating upon SEA rechallenge, but subsequently, the proliferation starts to wane.