Field survey and resin casting of <Emphasis Type="Italic">Gymnogobius macrognathos</Emphasis> spawning nests in the Tatara River,Fukuoka Prefecture,Japan

We investigated the spawning nests of Gymnogobius macrognathos on a tidal flat in the Tatara River, Fukuoka Prefecture, Japan. Digging uncovered 19 spawning nests. The number of eggs and the standard length of the guarding male were positively correlated. Nine spawning nests were examined using in situ resin casting. All casts had structures characteristic of callianassid shrimp burrows and were most likely those of Nihonotrypaea japonica. Spawning nests had significantly greater average diameters than shrimp burrow openings and may have been widened by G. macrognathos.     

Partial Sequences of Large Subunit Ribosomal DNA of a New Yeast Species,Trichosporon domesticum and Related Species

We determined the partial sequences of large subunit rDNA of a new yeast species, Trichosporon domesticum, which was isolated from the house of a summer-type hypersensitivity pneumonitis patient. Phylogenetically, T. domesticum was positioned in the taxonomic group containing T. montevideense and T. brassicae, which indicated an identical serotype. A phylogenetic relationship among all species of the genus Trichosporon which belong to the basidiomycetous yeast is clarified.     

Phytochrome Participation in Induction of Haustoria in Cuscuta japonica, a Holoparasitic Flowering Plant

Seedlings of Cuscuta japonica pasted on an acrylic plate developedmany haustoria in response to far-red light after pre-irradiationwith white light. The effect of far-red light was cancelledcompletely by red light irradiated immediately after the far-redlight. In order to elucidate the photoreceptor(s) for photocontrolin the induction of haustoria, action spectra for the photo-inductionand its reversion were determined in the wavelength region from340 nm to 800 nm using the Okazaki Large Spectrograph. The action spectrum for the induction of haustoria had a pronouncedpeak at 740 nm and a small peak at 420 nm, while the actionspectrum for reversal of the induction had a pronounced peakat 660 nm and a small peak at 380 nm. These results indicatethat phytochrome is involved in the photocontrol of inductionof haustoria in Cuscuta japonica. Considering the far-red /redreversibility, it was suggested that phytochrome B is the photorecepter.This is the first reliable evidence of phytochome participationon development of haustoria in parasitic plants. ⁴Present address: Graduate School of Science Division of BiologicalScience, Nagoya University, Nagoya, 464-01 Japan.     

Effect of deuterium oxide on the thermodynamic quantities associated with phase transitions of phosphatidylcholine bilayer membranes

The bilayer phase transitions of three kinds of phospholipids, dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC) and dihexadecylphosphatidylcholine (DHPC), in deuterium oxide (D₂O) and hydrogen oxide (H₂O) were observed by differential scanning calorimetry (DSC) under ambient pressure and light-transmittance measurements under high pressure. The DSC measurements showed that the substitution of H₂O by D₂O affected the pretransition temperatures and the main-transition enthalpies of all PC bilayers. The temperature-pressure phase diagrams for these PC bilayer membranes in both solvents were constructed by use of the data of light-transmittance measurements. Regarding the main transition of all PC bilayer membranes, there was no appreciable difference between the transition temperatures in D₂O and H₂O under high pressure. On the other hand, the phase transitions among the gel phases including the pretransition were significantly affected by the solvent substitution. The thermodynamic quantities of phase transitions for the PC bilayer membranes were evaluated and the differences in thermodynamic properties by the water substitution were considered from the difference of interfacial-free energy per molecule in the bilayer in both solvents. It was proved that the substitution of H₂O by D₂O causes shrinkage of the molecular area of phospholipid at bilayer interface due to the difference in bond strength between deuterium and hydrogen bonds and produces the great influence on the bilayer phase with the smaller area. Further, the induction of bilayer interdigitation in D₂O turned out to need higher pressures than in H₂O.     

Identification and genomic structure of chemosensory proteins (CSP) and odorant binding proteins (OBP) genes expressed in foreleg tarsi of the swallowtail butterfly Papilio xuthus

Chemoreception is a key feature for selection of host plants by phytophagous insects. Female swallowtail butterflies recognize their host plants using chemosensilla present on foreleg tarsi. We constructed a cDNA library of female tarsi and a genome library of Papilio xuthus. We identified 11 chemosensory protein (CSP) genes and three odorant binding proteins (OBP) genes from the cDNA library and eight additional CSP genes from the genome library using the ESTs as probes. A sequence similarity tree of insect CSPs showed that lepidopteran CSPs constructed big branches of the order. Small numbers of CSPs have been identified from the whole genomes of several insect orders which belong to branches separated from those of Lepidoptera. The CSP gene family of Lepidoptera may have diverged in at least two steps, the first on a small scale and the second on a large scale before and after the diversification of insect orders, respectively. Seventeen of 19 CSP genes of P. xuthus clustered in a specific region of the genome, suggesting that they were diversified by gene duplication from a common ancestral gene.