Gustatory synergism in ants mediates a species-specific symbiosis with lycaenid butterflies

Here we show that larvae of the lycaenid butterfly Niphanda fusca secrete droplets containing trehalose and glycine. These droplets attract the larva's host ants Camponotus japonicus, which collect and protect the larvae. We comparatively investigated gustatory preference for trehalose, glycine or a mixture of the two between host (C. japonicus) and non-host (Camponotus obscuripes) species of ants in behavioral and electrophysiological experiments. Glycine itself induced no taste sensation in either host or non-host ants. The mixture of trehalose plus glycine was chosen as much as pure trehalose by non-host ants. However, the host ants clearly preferred the mixture of trehalose plus glycine to trehalose alone. When we used sucrose instead of trehalose, the mixture of sucrose plus glycine was chosen as much as sucrose alone, in both species. These behavioral data are supported by the electrophysiological responsiveness to sugars and/or glycine in the sugar-taste receptor cells of the ants. Considering that lycaenid butterflies' secretions have species-specific compositions of sugar and amino acid; our results clearly showed that such species-specific compositions of larval secretions are precisely tuned to the feeding preferences of their host ant species, in which the feeding preferences are synergistically enhanced by amino acid.     

The Inhibition of Flowering by Non-Induced Cotyledons of Pharbitis nil

Inhibitory effects on flowering of a non-induced cotyledon havebeen examined in Pharbitis nil seedlings. The photoperiodicinduction of one cotyledon was accomplished by wrapping it inaluminium foil for 13 to 15 h while the seedling remained inthe light. The presence of the other cotyledon in the lightblocked this inductive stimulus. The timing of its inhibitoryeffect suggested that its action was to block the expressionof the inductive stimulus, presumably at the shoot apex. Byvarying the area of the non-induced cotyledon parallel inhibitoryeffects were shown on export of stimulus and of ¹⁴C-labelledassimilate to the apex from the induced cotyledon. Thus, partof the inhibition was by interference with assimilate/stimulusco-transport in the phloem. However, an additional inhibitoryeffect was also evident and for this second component therewas no relationship between assimilate and stimulus transport.This latter inhibition was generated by brief light interruptionsof darkness given to one cotyledon only whilst the other waswrapped. The control treatment, removal of the unwrapped cotyledon,did not alter flowering compared to seedlings with intact, darkenedcotyledons. Thus, these studies show that the brief night interruptionsacted to trigger a photoperiodically sensitive inhibitor notto block induction. The implications of these findings are discussedin relation to models of time measurement in the photoperiodiccontrol of flowering. (Received March 20, 1989; Accepted November 16, 1989)     

Chlorophyll and peptide compositions in the two photosystems of marine green algae.

The molar ratios of chlorophyll a to b in the thalli of marine green algae were between 1.5 and 2.2, being appreciably lower than the ratio between 2.8 and 3.4 found for the leaves of higher plants and the cells of fresh-water green algae. The ratio of chlorophylls to P-700 in these marine algae was also lower than that in higher plants. The a/b ratios in the pigment proteins of Photosystems 1 and 2 separated by polyacrylamide-gel electrophoresis from sodium dodecyl sulfate-solubilized chloroplasts of four species of marine green algae, Bryopsis maxima, Cheatomorpha spiralis, Enteromorpha compressa and Ulva conglobata, were approximately 5 and 1, which are considerably smaller than the ratios, 7 and 2, respectively, found for the pigment proteins of the two photosystems of higher plants separated by the same technique. The chloroplasts of Bryopsis maxima and Cheatomorpha spiralis lacked two of the peptides associated with Photosystem II, which are present in the chloroplasts of Spinacia oleracea and Taraxacum officinale.     

A case of dengue hemorrhagic fever in a Japanese child

A 6-year-old Japanese girl contracted a febrile illness with hemorrhagic manifestations when she traveled in Indonesia. A remarkable decrease in the numbers of platelets and white blood cells was observed in her acute-phase blood specimens. Her father, who accompanied her, showed dengue fever-like symptoms at almost the same time as her illness. It was determined by serological tests that they were infected with dengue virus type 1. Moreover, she showed a secondary antibody response to the flavivirus due to the pre-existing antibody to Japanese encephalitis virus. This is the first confirmed case of dengue hemorrhagic fever (DHF) in Japanese people.