Female recognition of trills in the male calling song of the field cricket,<Emphasis Type="Italic"> Teleogryllus taiwanemma</Emphasis>

The calling song of the field cricket, Teleogryllus taiwanemma, is usually considered to consist of sequences of separate chirps. However, sometimes it comprises a phrase of several chirps in a row, with one long chirp (chirp) and a few short chirps (trills). In this study, I compared the phrase containing only chirps with that containing both chirps and trills by analyzing male songs and conducting playback experiments of male songs to females. The song analyses showed significant differences between chirps and trills for all song parameters except bandwidth. To test whether female preference differed with respect to the two phrases, I performed two-speaker playback experiments. When the same numbers of phrases were presented per unit time, females preferred the song with trills to that without trills. This result may reflect female preference for songs with greater sound density. In subsequent playback experiments, I equalized the total sound duration per unit time (duty cycle) in songs with and without trills. The numbers of females that preferred songs with and without trills did not differ significantly. This suggests that trills can attract females like chirps do, even though the two sounds have different components.     

Temperature and nutrient availability control growth rate and fatty acid composition of facultatively psychrophilic <Emphasis Type="Italic">Cobetia marina</Emphasis> strain L-2

A facultative psychrophilic bacterium, strain L-2, that grows at 0 and 5°C as minimum growth temperatures in complex and defined media, respectively, was isolated. On the basis of taxonomic studies, strain L-2 was identified as Cobetia marina. The adaptability of strain L-2 to cold temperature was higher than that of the type strain and of other reported strains of the same species. When the bacterium was grown at 5–15°C in a defined medium, it produced a high amount of trans-unsaturated fatty acids. By contrast, in a complex medium in the same temperature range it produced a low amount of trans-unsaturated fatty acids. In the complex medium at 5°C, the bacterium exhibited a three-fold higher growth rate than that obtained in the defined medium. Following a temperature shift from 11 to 5°C, strain L-2 grew better in complex than in defined medium. Furthermore, when the growth temperature was shifted from 0 to 5°C both the growth rate and the yield of strain L-2 growing in complex medium was markedly enhanced. These phenomena suggest that an upshift of the growth temperature had a positive effect on metabolism. The effects of adding complex medium components to the defined medium on bacterial growth rate and fatty acid composition at 5°C were also studied. The addition of yeast extract followed by peptone was effective in promoting rapid growth, while glutamate addition was less effective, resulting in a cis-unsaturated fatty acid ratio similar to that of cells grown in the complex medium. These results suggest that the rapid growth of strain L-2 at low temperatures requires a high content of various amino acids rather than the presence of a high ratio of cis-unsaturated fatty acids in the cell membrane.     

Functional characterization of contractile vacuole isolated from Amoeba proteus

Contractile vacuoles (CVs) released from cells of Amoeba proteus were used to analyze its function in vitro. When CV was transferred to a hypertonic medium, its volume decreased within 10 sec. When it was subsequently returned to its original medium, it quickly started swelling. However, it ruptured before recovering its initial volume. These results suggested that the CV membrane is semi-permeable and that the fluid is collected by the osmotic gradient in vivo. The water permeability of membrane of isolated CV was calculated from the rate of osmotic volume change to be 0.94 microm/sec . OsM. This high value suggested that CV membrane is equipped with water channel. CV contracted (or burst) quickly upon addition of 1 mM ATP. Contraction was induced by ATP, but not by other nucleotides, GTP, ITP, ADP, or the analogues of ATP, AMP-PNP and ATPgammaS. It was suggested that the contraction of isolated CV was caused by increase in the tension of its membrane by ATP.     

Complementary expression patterns of retinoid acid-synthesizing and -metabolizing enzymes in pre-natal mouse inner ear structures

Retinoic acid (RA) plays a pivotal role in patterning and differentiation of the embryonic inner ear. Despite its documented effects during embryonic development, the cellular sites that synthesize or metabolize RA in the inner ear have yet to be determined. Here we describe the distribution of three synthesizing enzymes, retinaldehyde dehydrogenases 1, 2 and 3 (RALDH1, RALDH2 and RALDH3) and two catabolizing enzymes (CYP26A1 and CYP26B1) in the mouse inner ear at embryonic day 18.5 when active cell differentiation is underway. Two detection methods, radioactive and non-radioactive in situ hybridization, were employed to elucidate the tissue distribution and cellular localization of these enzymes, respectively. All of the five enzymes examined, with the exception of CYP26A1, were expressed in both vestibular and cochlear end organs. While expression of the three RALDHs was observed in various cell types, CYP26B1 expression was found only in supporting cells of the vestibular and cochlear end organs. In the cochlea, expression domains of RALDH1-3 and CYP26B1 were complementary to one another. These results reveal specific tissue- and cellular expression patterns of RA synthesizing and catabolizing enzymes in the pre-natal inner ear, and suggest that a precise control of RA concentrations in various cell types of the inner ear is achieved by the balance between RALDHs and CYP26B1 activities.     

Uniaxial drawing and mechanical properties of poly[(R)-3-hydroxybutyrate]/poly(L-lactic acid) blends

Blends of poly(L-lactic acid) (PLLA) with two kinds of poly[(R)-3-hydroxybutyrate] (PHB) having different molecular weights, commercial-grade bacterial PHB (bacterial-PHB) and ultrahigh molecular weight PHB (UHMW-PHB), were prepared by the solvent-casting method and uniaxially drawn at two drawing temperatures, around PHB's T(g) (2 degrees C) for PHB-rich blends and around PLLA's T(g) (60 degrees C) for PLLA-rich blends. Differential scanning calorimetry analysis showed that this system was immiscible over the entire composition range. Mechanical properties of all of the samples were improved in proportion to the draw ratio. Although PLLA domains in bacterial-PHB-rich blends remained almost unstretched during cold drawing, a good interfacial adhesion between two polymers and the reinforcing role of PLLA components led to enhanced mechanical properties proportionally to the PLLA content at the same draw ratio. On the contrary, in the case of UHMW-PHB-rich blends, the minor component PLLA was found to be also oriented by cold drawing in ice water due to an increase in the interfacial entanglements caused by the very long chain length of the matrix polymer. As a result, their mechanical properties were considerably improved with increasing PLLA content compared with the bacterial-PHB system. Scanning electron microscopy observations on the surface and cross-section revealed that a layered structure with uniformly oriented microporous in the interior was obtained by selectively removal of PLLA component after simple alkaline treatment.     

Free oxygen radicals are generated at the time of aspiration of oocytes from ovaries that have been stored for a long time

In ischaemic tissues, reperfusion induces acute injury and functional changes. In this work, ovaries were stored for various times, and superoxide dismutase (SOD) and dimethylthiourea (DTMU) were used at the time of oocyte aspiration. We then attempted to determine whether free oxygen radicals are generated at oocyte aspiration and whether they impair the developmental competence of oocytes. Over 2 mM of DMTU and 1000 U/ml of SOD significantly improved the rate of blastulation 8 days after insemination. For ovaries that were preserved for 3 and 7 h, using antioxidants also significantly improved the rate of blastulation 8 days after insemination. However, no effect was observed on oocytes from ovaries preserved for 1 h. We examined how the antioxidants affected the presence of germinal vesicles, chromatin configuration, and polar body extrusion 6 or 21 h after culture. Chromatin configuration was classified into three groups according to the amount of chromatin condensation (group 1, strong condensation; group 2, moderate; group 3, slight). Storing ovaries for a long time decreased the frequency of occurrence of group 2, but increased groups 1 and 3. However, using antioxidants at oocyte aspiration decreased the frequency of group 3 and increased group 1. Moreover, there was no difference in the rate of germinal vesicle breakdown and polar body extrusion. Our results show that preserving ovaries for a long time induces the generation of free oxygen radicals and that these chemicals impair oocyte viability. Using antioxidants at oocyte aspiration was beneficial for embryo production.     

Identification of the sea urchin 350-kDa sperm-binding protein as a new sialic acid-binding lectin that belongs to the heat shock protein 110 family: implication of its binding to gangliosides in sperm lipid rafts in fertilization

The 350-kDa sperm-binding protein (SBP), a species-specific sperm-binding protein, is localized in the vitelline layer of sea urchin eggs. In this study, we have shown for the first time that sperm gangliosides are ligands for the intact glycosylated SBP. Using recombinant fragments of the SBP, the N-terminal heat shock protein 110-like domain was shown to be responsible for the binding. The intact SBP could bind various gangliosides, and the binding was sialidase-sensitive and inhibited by sialyllactose, thus indicating that it is the sialic acid-binding protein. Calcium and magnesium ions were not required but they did enhance the binding activity of SBP. The observation that bacterially expressed recombinant SBP and the sialidase-treated intact glycosylated SBP lost divalent cation-dependent enhancement of binding activity suggests that the sialylated carbohydrate moieties of the SBP may be involved in this property. Furthermore, the SBP was shown to bind sperm lipid rafts, in which gangliosides are enriched, and this binding was lost upon sialidase treatment of the lipid rafts. Finally, liposomes containing the ganglioside specifically inhibited fertilization. Taken together, these results allow us to identify SBP as a member of a new class of sialic acid-binding lectin belonging to the Hsp110 family, and indicate that SBP may be involved in interaction of sperm with the vitelline layer of the egg.     

A consensus linkage map for sugi (Cryptomeria japonica) from two pedigrees, based on microsatellites and expressed sequence tags

A consensus map for sugi (Cryptomeria japonica) was constructed by integrating linkage data from two unrelated third-generation pedigrees, one derived from a full-sib cross and the other by self-pollination of F1 individuals. The progeny segregation data of the first pedigree were derived from cleaved amplified polymorphic sequences, microsatellites, restriction fragment length polymorphisms, and single nucleotide polymorphisms. The data of the second pedigree were derived from cleaved amplified polymorphic sequences, isozyme markers, morphological traits, random amplified polymorphic DNA markers, and restriction fragment length polymorphisms. Linkage analyses were done for the first pedigree with JoinMap 3.0, using its parameter set for progeny derived by cross-pollination, and for the second pedigree with the parameter set for progeny derived from selfing of F1 individuals. The 11 chromosomes of C. japonica are represented in the consensus map. A total of 438 markers were assigned to 11 large linkage groups, 1 small linkage group, and 1 nonintegrated linkage group from the second pedigree; their total length was 1372.2 cM. On average, the consensus map showed 1 marker every 3.0 cM. PCR-based codominant DNA markers such as cleaved amplified polymorphic sequences and microsatellite markers were distributed in all linkage groups and occupied about half of mapped loci. These markers are very useful for integration of different linkage maps, QTL mapping, and comparative mapping for evolutional study, especially for species with a large genome size such as conifers.