<Emphasis Type="Italic">Oncorhynchus kawamurae</Emphasis> “Kunimasu,” a deepwater trout,discovered in Lake Saiko, 70 years after extinction in the original habitat,Lake Tazawa,Japan

Oncorhynchus kawamurae (Osteichthyes: Salmonidae) (common name “Kunimasu”), a species endemic to Lake Tazawa, Akita Prefecture, Japan, was believed to have been extinct since 1940. However, nine specimens were discovered in March and April 2010 in Lake Saiko, Yamanashi Prefecture, one of the lakes to which eyed eggs of the species were introduced in 1935. These were identified as O. kawamurae because of having 47–62 pyloric caeca, 37–43 gill-rakers, a black-colored body, and spawning at 30–40 m depth in early spring, which are unique characteristics within Oncorhynchus. Furthermore, the distinctiveness of Kunimasu from sympatric kokanee (O. nerka) was supported by microsatellite DNA data.     

Accelerated Recovery of Mitochondrial Membrane Potential by GSK-3β Inactivation Affords Cardiomyocytes Protection from Oxidant-Induced Necrosis

Loss of mitochondrial membrane potential (ΔΨ_m) is known to be closely linked to cell death by various insults. However, whether acceleration of the ΔΨ_m recovery process prevents cell necrosis remains unclear. Here we examined the hypothesis that facilitated recovery of ΔΨ_m contributes to cytoprotection afforded by activation of the mitochondrial ATP-sensitive K⁺ (mK_ATP) channel or inactivation of glycogen synthase kinase-3β (GSK-3β). ΔΨ_m of H9c2 cells was determined by tetramethylrhodamine ethyl ester (TMRE) before or after 1-h exposure to antimycin A (AA), an inducer of reactive oxygen species (ROS) production at complex III. Opening of the mitochondrial permeability transition pore (mPTP) was determined by mitochondrial loading of calcein. AA reduced ΔΨ_m to 15±1% of the baseline and induced calcein leak from mitochondria. ΔΨ_m was recovered to 51±3% of the baseline and calcein-loadable mitochondria was 6±1% of the control at 1 h after washout of AA. mK_ATP channel openers improved the ΔΨ_m recovery and mitochondrial calcein to 73±2% and 30±7%, respectively, without change in ΔΨ_m during AA treatment. Activation of the mK_ATP channel induced inhibitory phosphorylation of GSK-3β and suppressed ROS production, LDH release and apoptosis after AA washout. Knockdown of GSK-3β and pharmacological inhibition of GSK-3β mimicked the effects of mK_ATP channel activation. ROS scavengers administered at the time of AA removal also improved recovery of ΔΨ_m. These results indicate that inactivation of GSK-3β directly or indirectly by mK_ATP channel activation facilitates recovery of ΔΨ_m by suppressing ROS production and mPTP opening, leading to cytoprotection from oxidant stress-induced cell death.     

The Sphyraena obtusata group (Perciformes: Sphyraenidae) with a description of a new species from southern Japan

Sphyraena iburiensis sp. nov. is described, and taxonomic reviews are provided for S. obtusata and S. pinguis. These species, characterized by having 2 gill rakers, are defined as the S. obtusata group. Sphyraena iburiensis, known only from the Pacific coast of southern Japan, is characterized by 8.5–9.5 scales above the lateral line, a single row of scales in the groove along the lower margin of the suborbital region from the posterior tip of the maxilla to below the eye (=suborbital groove) not covered with skin, 2 distinct longitudinal stripes on the lateral surface of the body when fresh (upper stripe usually lost in preserved specimens), the lower stripe reaching the caudal-fin base just below the lateral line. Sphyraena obtusata, distributed in the Indo-West Pacific, is characterized by 5–7.5 scales above the lateral line, a single row of scales in the suborbital groove covered with skin, 2 somewhat indistinct longitudinal stripes on the lateral surface of the body when fresh (upper stripe usually lost in preserved specimens), the lower stripe joining the lateral line midway between the end of the second dorsal-fin base and caudal peduncle and extending to the middle of the caudal-fin base. Sphyraena pinguis, distributed in the Indo-West Pacific, is characterized by 7.5–9.5 scales above the lateral line, a single row of scales in the suborbital groove not covered with skin, and a single longitudinal stripe on the lateral surface of the body joining the lateral line slightly before or just below the end of the second dorsal-fin base and extending to the middle of the caudal-fin base. Seven (S. aureoflammea, S. brachygnathos, S. flavicauda, S. grandisquamis, S. langsar, S. lineata, and S. strenua) and 2 (S. chrysotaenia and S. schlegelii) nominal species are regarded as junior synonyms of S. obtusata and S. pinguis, respectively. In addition, lectotypes are designated for S. flavicauda, S. langsar, S. lineata, and S. obtusata. A key to the three species of the S. obtusata group is provided.     

Novel relationship between the antifungal activity and cytotoxicity of marine-derived metabolite xestoquinone and its family

Xestoquinone and related metabolites (the xestoquinone family) occur in marine sponges and are known to show a variety of biological activities. In this study, the first comprehensive evaluation of antifungal activity was performed for xestoquinone and nine natural and unnatural analogues in comparison with their cytotoxicity. The cytotoxicity against two human squamous cell carcinoma cell lines, A431 and Nakata, indicated that the terminal quinone structure of the polycyclic molecules was important (xestoquinone, etc.) and that the presence of a ketone group at C-3 of the opposite terminus dramatically diminished the activity (halenaquinone, etc.). In contrast, a ketone group at C-3 enhanced the antifungal activity against the plant pathogen, Phytophthora capsici, regardless of the presence of a quinone moiety. The cytotoxicity and antifungal activity of the xestoquinone family were negatively correlated with each other.     

The ensemble of hetero-proteins in inorganic nanochannels

The assembly and proper alignment of two heterofluorescent proteins (sGFP and DsRed) in the mesoporous channels of ethanol-treated FSM6.2 (a folded-sheet mesoporous material with a pore diameter of 6.2 nm) was confirmed using a fluorescence resonance energy transfer (FRET) technique. The sGFP-DsRed-FSM6.2 conjugate showed a large decrease in the emission of donor (sGFP) fluorescence, indicating that the conjugate functions as an energy transfer system through the combination of the two heteroproteins, due to the successful encapsulation of the sGFP-DsRed pairs in the mesopores. Fluorescence spectral analysis demonstrated that the proteins were highly dispersed and homogeneously encapsulated in the mesopores of FSM6.2, even at high concentration, although they spontaneously aggregated and showed a red shift in solution at the concentration corresponding to that in the conjugate. Furthermore, an increase in the amount of sGFP and DsRed adsorbed to the pores of FSM6.2 led to a decrease in the distance between these proteins, resulting in enhancement of FRET efficiency.     

Release of fibroblast growth factor-1 by human squamous cell carcinoma correlates with autocrine cell growth

Summary A squamous cell carcinoma cell line Nakata proliferated in serum-free culture and was not responsive to exogenous fibroblast growth factor-1 (FGF-1). Immunostaining revealed that Nakata cells expressed FGF-1 in their cytoplasms and nuclei. Two molecular mass species of FGF-1 (16 and 18 kDa) were identified in cell extracts by Western blot. These cells also expressed high-affinity FGF-1 binding sites (Kd=360 pM, 28 000 sites/cell). The results of cross-linking with [¹²⁵I]FGF-1 demonstrated the presence of two bands with molecular masses of 160 and 140 kDa. The addition of FGF-1 specific antisense oligonucleotides at 25 μM to Nakata cells resulted in an 82% inhibition in cell growth and suppressed FGF-1 expression. This effect was dose-dependent and specific, because sense oligonucleotides were ineffective in inhibiting cell growth. In addition, Nakata cell growth was suppressed by an anti-FGF-1 neutralizing antibody, which resulted in a 52% inhibition at 8 μg/ml. These results demonstrate that Nakata cells produce FGF-1, and indicate that this growth factor acts in an autocrine manner by interacting with FGF-1 binding sites on Nakata cells.     

Characterization of Japanese flounder karyotype by chromosome bandings and fluorescence in situ hybridization with DNA markers

The chromosomes of Japanese flounder, Paralichthys olivaceus, were examined by conventional differential staining methods including G-, Q-, C-, silver (Ag)-, fluorochrome, and replication R-bandings and by fluorescence in situ hybridization (FISH) with 5S and 18S rDNAs and telomeric DNA as probes. Replication R-banding substantially made it possible to identify 24 homologous pairs by their RBG-banding pattern and relative length. Both rDNA loci were mapped to chromosome 1, where 5S and 18S rDNA loci were located at the centromeric region and secondary constriction, respectively. C-banding revealed that both rDNA loci were heterochromatic, and 18S rDNA loci were positive for chromomycin A₃ but negative for 4′,6-diamidino-2-phenylindole (DAPI) staining. Telomeric FISH signals were observed at all chromosome ends and at the interstitial region of some chromosomes. The observed results were discussed in relation to the karyotype evolution in the order Pleuronectiformes.     

Developmental changes in crossover frequency in Arabidopsis

Parental genomes are generally rearranged by two processes during meiosis: one is the segregation of homologous chromosomes and the other is crossing over between such chromosomes. Although the mechanisms underlying chromosome segregation and crossing over are well understood because of numerous genetic and molecular investigations, their contributions to the rearrangement of genetic information have not yet been analysed at a genome-wide level in Arabidopsis thaliana. We established 343 CAPS or SSLP markers to identify polymorphisms between two different Arabidopsis ecotypes, Col and Ler, which are distributed at an average distance of approximately 400kb between pairs of markers throughout the entire genome. Using these markers, crossover frequencies and chromosome segregation were quantified with respect to sex and age. Our large-scale analysis demonstrated that: (i) crossover frequencies during pollen formation were 1.79 and 1.37 times higher than those during megaspore formation in early and late flowers, respectively (P<0.001); (ii) the crossover frequencies during pollen formation were not significantly different between early and late flowers of main shoots (P>0.05), whereas the frequencies increased 1.30 times with shoot age during megaspore formation (P<0.001); (iii) the effect of aging depended on the developmental age of the individual shoot rather than on the age of the whole plant; and (iv) five chromosomes were randomly selected and mixed during meiosis.