ウニの性決定に関するRNaseの役割

一般にウニは成熟期に入る前，つまり未成熟期ではオスとメスの区別ができない。その時期の精巣のRNase活性を測っても常に一定の活性値を示している。そこで，バフンウニおよびムラサキウニの一年間においてオスとメスおよび未成熟の精巣のRNase活性をpH 5.0で比較したところ，バフンウニでは未成熟期の平均比活性が7.35 units/mgであったものがメスでは62.79 units/mg と急激に上昇し，オスでは1.90 units/mg と減少した。この現象はムラサキウニにおいても観察された。そしてこの変化は成熟期に入る１ヵ月前ぐらいから起こり，また未成熟期へと変化していく。この変化するRNaseは至適pHや基質特異性や温度安定性などから RNase T2タイプの酵素であることがわかった。そして，この酵素がウニの性の決定に何らかの影響を及ぼすものと考えられる。It is generally impossible to sort male and female sea urchins before they reach maturity, i.e., while they are still in the immature stage. The ribonuclease (RNase) activity of the gonads of immature stage sea urchins consistently shows a constant activity level. Comparison of the RNase activity of the gonads of mature male and female Hemicentrotus pulcherrimus and Anthocidaris crassispina species at pH 5.0 showed that while its mean specific activity in the immature stage of female H. pulcherrimus increased rapidly from 7.35 units/mg to 62.79 units/mg, its activity in male H. pulcherrimus decreased from 7.35 units/mg to 1.90 units/mg. The same phenomenon was observed in A. crassispina. Base on its optimal pH, substrate specificity, and heat stability the RNase that exhibited these changes was determined to be an enzyme of the RNase T2 type. This enzyme is also thought to exert an influence on sex determination in sea urchins

ウレアーゼ陽性高温性カンピロバクター（UPTC）のウレアーゼ遺伝子オペロンの分子解析

When cloning, sequencing and characterization of the genetic organization of urease genes within urease-positive thermophilic Campylobacter (UPTC) were carried out, an approximate 5.1 kilo base pair region encoding a urease gene operon was identified with recombinant plasmid DNAs from a genomic DNA library of a Japanese isolate (CF89-12). Six closely spaced and putative open reading frames (ORFs) for ureA, ureB, ureE, ureF, ureG and ureH were detected. ATG codons initiated each ORF of the UPTC urease operon except for ureB and ureH, which commenced with the most probable TTG codon. Overlaps were detected between ureA and ureB and also between ureB and ureE. Probable ribosome-binding sites and a putative p independent transcriptional termination region were identified. Two putative promoter structures, consisting of consensus sequences at the -35 and -10 like regions were also identified. Construction of a neighbor-joining tree based on the nucleotide sequence data of urease genes indicated that UPTC formed a cluster with some Helicobacter organisms separate from the other urease-producing bacteria, suggesting a commonly shared ancestry between UPTC and Helicobacter urease genes

Effects of Autoclave Sterilization and Multiple Use on Implant Scanbody Deformation In Vitro

In the intraoral scanner (IOS) impression technique for dental implants, a scanbody (SB) is connected to the implant and scanned. Poly(ether-ether-ketone) (PEEK) is a widely used material for SBs and it is recommended for single use. However, from the perspective of the Sustainable Development Goals, it is desirable to use these products multiple times. As SBs are used in patients’ mouths, proper sterilization is necessary for multiple uses. In the present study, the effect of autoclave treatment and connection/disconnection on SB deformation was investigated. The SB was connected to the implant and stereolithography (STL) data were obtained. Then, the SB was disconnected and underwent autoclave treatment, or was connected and disconnected multiple times, or underwent a combination of both processes. The results showed that there were significant differences in the distance and angle when comparing SBs before and after the autoclave treatment, but repeated connections with or without autoclave treatment had no significant impact on the measured values. The surface texture, observed with scanning electron microscopy, showed that a groove was observed on the surface of the SB, but the groove did not show major changes after 10 connection/autoclave processes. These results indicate that autoclave sterilization has some impact on SB deformation but connection/disconnection itself may not have a huge impact on SB deformation

Therapeutic Effect of Benidipine on Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) is an intractable disease that is typically observed in patients with osteoporosis or tumors that have been treated with either bisphosphonate (BP) or antiangiogenic medicine. The mechanism of MRONJ pathogenesis remains unclear, and no effective definitive treatment modalities have been reported to date. Previous reports have indicated that a single injection of benidipine, an antihypertensive calcium channel blocker, in the vicinity of a tooth extraction socket promotes wound healing in healthy rats. The present study was conducted to elucidate the possibility of using benidipine to promote the healing of MRONJ-like lesions. In this study, benidipine was administered near the site of MRONJ symptom onset in a model rat, which was then sacrificed two weeks after benidipine injection, and analyzed using histological sections and CT images. The analysis showed that in the benidipine groups, necrotic bone was reduced, and soft tissue continuity was recovered. Furthermore, the distance between epithelial edges, length of necrotic bone exposed in the oral cavity, necrotic bone area, and necrotic bone ratio were significantly smaller in the benidipine group. These results suggest that a single injection of benidipine in the vicinity of MRONJ-like lesions can promote osteonecrotic extraction socket healing

高温性カンピロバクターラリーのゲノム解析と多遺伝子配列情報に基づく分子識別 : ウレアーゼ陽性高温性カンピロバクターのウレアーゼ遺伝子の分離株間における遺伝的な不均一性に関する研究

Degenerate PCR primers were designed in silico based on two urease structural genes, namely ureA and ureB, for urease-positive thermophilic Campylobacter (UPTC) organisms. Resultant PCR amplification employing these primers generated an amplicon of approximately 2kb, which was cloned and sequenced, in UPTC organisms (n=12), isolated from various parts of Europe and Japan. Overall, sequence similarities were shown to be 96.7 to 99.9% and following sequence alignment analysis, the approximate 1.96kb regions from the 12 isolates were deduced to consist of parts of ureA (about 570 bps) and ureB (about 1390 bps) which contain an overlapping region between the ureA and ureB gene loci. Although a total of 144 heterogeneous sites of all substitutions were located throughout this region, the substitution ratio was higher in the ureA region (1/〓 10 bases) than in the ureB region (1/〓 15 bases). A resulting dendrogram was constructed, which was based on the nucleotide sequence data of 12 UPTC isolates examined and demonstrated that the UPTC organisms were genetically variable. UPTC organisms formed a major cluster with Helicobacter organisms, separate from the other urease-producing bacteria examined, suggesting a shared ancestry between UPTC organisms and Helicobacter