A molecular assessment of species diversity in Tympanopleura and Ageneiosus catfishes (Auchenipteridae: Siluriformes)

In order to test the congruence of genetic data to the morphologically defined Neotropical catfish genera Tympanopleura and Ageneiosus and explore species diversity, we generated 17 DNA barcodes from five of six species of Tympanopleura and 12 of 13 species of Ageneiosus. To discriminate limits between species, an automatic barcode gap discovery (ABGD), a generalised mixed yule-coalescent model (GYMC) and fixed distance thresholds Kimura two-parameter (K2P; 3%) were used to discriminate putative species limits from the DNA barcodes. The ABGD, GMYC and K2P methods agreed by each generating 13 clusters: six in Tympanopleura (five nominal plus one undescribed species) and seven in Ageneiosus. These clusters corresponded broadly to the described species, except in the case of the Ageneiosus ucayalensis group (A. akamai, A. dentatus, A. intrusus, A. ucayalensis, A. uranophthalmus and A. vittatus). Haplotype sharing and low divergences may have prevented molecular methods from distinguishing these species. We hypothesise that this is the result of a recent radiation of a sympatric species group distributed throughout the Amazon Basin. One putative new species of Tympanopleura was also supported by the molecular data. These results taken together highlight the utility of molecular methods such as DNA barcoding in understanding patterns of diversification across large geographic areas and in recognising overlooked diversity.     

Unique features of the motility and structures in the flagellate polar region of Campylobacter jejuni and other species: an electron microscopic study

Similarly to Helicobacter pylori but unlike Vibrio cholerae O1/O139, Campylobacter jejuni is non‐motile at 20°C but highly motile at ≥37°C. The bacterium C. jejuni has one of the highest swimming speeds reported (>100 μm/s), especially at 42°C. Straight and spiral bacterial shapes share the same motility. C. jejuni has a unique structure in the flagellate polar region, which is characterized by a cup‐like structure (beneath the inner membrane), a funnel shape (opening onto the polar surface) and less dense space (cytoplasm). Other Campylobacter species (coli, fetus, and lari) have similar motility and flagellate polar structures, albeit with slight differences. This is especially true for Campylobacter fetus, which has a flagellum only at one pole and a cup‐like structure composed of two membranes.     

Transmission ratio distortion of molecular markers in a doubled haploid population originated from a natural hybrid between Osmunda japonica and O. lancea

In ferns, intra-gametophytic selfing occurs as a mode of reproduction where two gametes from the same gametophyte form a completely homozygous sporophyte. Intra-gametophytic selfing is considered to be prevented by lethal or deleterious recessive genes in several diploid species. In order to investigate the modes and tempo of selection acting different developmental stages, doubled haploids obtained from intra-gametophytic selfing within isolated gametophytes of a putative F1 hybrid between Osmunda japonica and O. lancea were analyzed with EST_derived molecular markers, and the distribution pattern of transmission ratio distortion (TRD) along linkage map was clarified. As the results, the markers with skewness were clustered in two linkage groups. For the two highly distorted regions, gametophytes and F2 population were also examined. The markers skewed towards O. japonica on a linkage group (LG_2) showed skewness also in gametophytes, and the TRD was generated in the process of spore formation or growth of gametophytes. Also, selection appeared to be operating in the gametophytic stage. The markers on other linkage group (LG_11) showed highest skewness towards O. lancea in doubled haploids, and it was suggested that the segregation of LG_11 were influenced by zygotic lethality or genotypic evaluation and that some deleterious recessive genes exist in LG_11 and reduce the viability of homozygotes with O. japonica alleles. It is very likely that a region of LG_11were responsible for the low frequencies of intra-gametophytic selfing in O. japonica.     

Long-Duration Carbon Dioxide Anesthesia of Fish Using Ultra Fine (Nano-Scale) Bubbles

Introduction: We investigated whether adding ultrafine (nano-scale) oxygen-carrying bubbles to water concurrently with dissolved carbon-dioxide (CO₂) could result in safe, long-duration anesthesia for fish. Results: To confirm the lethal effects of CO₂ alone, fishes were anesthetized with dissolved CO₂ in 20°C seawater. Within 30 minutes, all fishes, regardless of species, died suddenly due to CO₂-induced narcosis, even when the water was saturated with oxygen. Death was attributed to respiration failure caused by hypoxemia. When ultrafine oxygen-carrying bubbles were supplied along with dissolved CO₂, five chicken grunts were able to remain anesthetized for 22 hours and awoke normally within 2–3 hours after cessation of anesthesia. Conclusions: The high internal pressures and oxygen levels of the ultrafine bubbles enabled efficient oxygen diffusion across the branchia and permitted the organismal oxygen demands of individual anesthetized fish to be met. Thus, we demonstrated a method for safe, long-duration carbon dioxide anesthesia in living fish under normal water temperatures.     

Molecular phylogeny of monocotyledons inferred from combined analysis of plastid<Emphasis Type="Italic"> matK</Emphasis> and<Emphasis Type="Italic"> rbcL</Emphasis> gene sequences

Using matK and rbcL sequences (3,269 bp in total) from 113 genera of 45 families, we conducted a combined analysis to contribute to the understanding of major evolutionary relationships in the monocotyledons. Trees resulting from the parsimony analysis are similar to those generated by earlier single or multiple gene analyses, but their strict consensus tree provides much better resolution of relationships among major clades. We find that Acorus (Acorales) is a sister group to the rest of the monocots, which receives 100% bootstrap support. A clade comprising Alismatales is diverged as the next branch, followed successively by Petrosaviaceae, the Dioscoreales–Pandanales clade, Liliales, Asparagales and commelinoids. All of these clades are strongly supported (with more than 90% bootstrap support). The sister-group relationship is also strongly supported between Alismatales and the remaining monocots (except for Acorus) (100%), between Petrosaviaceae and the remaining monocots (except for Acorus and Alismatales) (100%), between the clade comprising Dioscoreales and Pandanales and the clade comprising Liliales, Asparagales and commelinoids (87%), and between Liliales and the Asparagales–commelinoids clade (89%). Only the sister-group relationship between Asparagales and commelinoids is weakly supported (68%). Results also support the inclusion of Petrosaviaceae in its own order Petrosaviales, Nartheciaceae in Dioscoreales and Hanguanaceae in Commelinales.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s10265-003-0133-3     

Antihypertensive effect of gamma-amino butyric acid enriched soy products in spontaneously hypertensive rats

The effect of gamma-amino butyric acid (GABA)-enriched soybean on blood pressure was investigated in male spontaneously hypertensive rats. Ten-week-old rats were given diets containing graded levels of GABA-enriched soybean powder for 8 weeks. The systolic blood pressure in rats fed 0.15% GABA diet was significantly lower at 1st week and maintained lower values for 4 weeks as compared with 0% GABA controls. No effect on blood pressure was found in those of 0.03 and 0.3% GABA. The results suggest that there exist appropriate dietary GABA level to get the blood pressure lowering effect.     

Structure-activity study of L-amino acid-based N-type calcium channel blockers

Synthesis and structure-activity relationship (SAR) study of L-amino acid-based N-type calcium channel blockers are described. The compounds synthesized were evaluated for inhibitory activity against both N-type and L-type calcium channels focusing on selectivity to reduce cardiovascular side effects due to blocking of L-type calcium channels. In the course of screening of our compound library, N-(t-butoxycarbonyl)-L-aspartic acid derivative 1a was identified as an initial lead compound for a new series of N-type calcium channel blockers, which inhibited calcium influx into IMR-32 human neuroblastoma cells with an IC(50) of 3.4 microM. Compound 1a also exhibited blockade of N-type calcium channel current in electrophysiological experiment using IMR-32 cells (34% inhibition at 10 microM, n=3). As a consequence of conversion of amino acid residue of 1a, compound 12a, that include N-(t-butoxycarbonyl)-L-cysteine, was found to be a potent N-type calcium channel blocker with an IC(50) of 0.61 microM. Thus, L-cysteine was selected as a potential structural motif for further modification. Optimization of C- and N-terminals of L-cysteine using S-cyclohexylmethyl-L-cysteine as a central scaffold led to potent and selective N-type calcium channel blocker 21f, which showed improved inhibitory potency (IC(50) 0.12 microM) and 12-fold selectivity for N-type calcium channels over L-type channels.