In Vitro Reconstitution of the Clostridium botulinum Type D Progenitor Toxin

Clostiridium botulinum D型4947株は蛋白分解作用を受けない完全型として、異なったサイズの2種類のプロジェニター毒素（MとL）を産生する。M毒素は神経毒素（NT）と非毒素系ー非血球凝集素（NTNHA）で構成されているのに対し、L毒素はM毒素と血球凝集素（HA-70、HA-17、HA-33）によって構成されている。HA-70サブコンポーネントとHA-33/17混合体は変成剤の存在下でクロマトグラフィーによりL毒素からほぼ単一の形で得られた。著者らは、純化したM毒素、HA-70とHA-33/17を混合してL毒素を再構成することに初めて成功した。再構成したL毒素とネイティブのL毒素はゲル濾過、PAGEプロファイル、血球凝集活性、赤血球への吸着活性、マウスへの経口毒力などの諸症状が全く同じであった。トリプシン処理によりニックを持つNTNHAで構成されたM毒素はHAサブコンポーネントと一緒にしてもL毒素を再構成することが出来なかったのに対し、プロテアーゼ処理したL毒素はM毒素とHAサブコンポーネントに隔離することが出来なかった。これらの結果から、著者らはM毒素が最初にNTとNTNHAの会合により形成され、その後HA-70とHA-33/17の会合によってL毒素へ変換されると結論ずけた

Spontaneous Nicking in the Nontoxic-Nonhemagglutinin Component of the costridium botulinum Toxin Conplex

Clostiridium botulinum D型4947株によって産生された毒素複合体から非毒素ー非血球凝集素（NTNHA）標品を蛋白分解酵素フリーの条件下で、単独の形と神経毒(NT)/NTNHA複合体の形で調製できた。両調製物質のNTNHAはスポンテニアスにニックの入ったNTNHAとなり、15-と115-kDaフラグメント及び特異的部分でいくつかのアミノ酸の削除を生じることが長時間培養のSDS-PAGEで認められた。しかし、NT/NTNHA/血球凝集素(HA)複合体は同じ条件下でニックの入らない一本鎖のペプチドのままであった。NTNHA調製物に少量のニック型の物が含まれていることから、NTNHAのニック型は精製の残物と/あるいはNTNHAがインタクトNTNHAをそれ自身との切断酵素活性によってニックを入れたことが考えられる

Role of C-Terminal Region of HA-33 Component of Botulinum Toxin in Hemagglutination

Clostridium botulinum D型1873株とC型Yoichi株の産生するプロジェニター毒素から得られた1種類のサブコンポーネントである血球凝集素（HA-33）は、C及びD型参照株のそれより少し小さい分子サイズであるが、他のコンポーネントのの大きさに違いがないことが、SDS-PAGEを用いて見いだされた。すなわち、HA-33のN-及びC-末端シーケンス分析に基つき、両株のHA-33淡白において特異的なサイトでC-末端から33アミノ酸残基の欠落があることが見いだされた。両株のプロジェニター毒素は、参照株毒素の血球凝集力価2かそれ以下の弱い血球凝集活性を示すが、赤血球に吸着することはできない。これらの結果はHA-33の短いC-末端部分が、ボツリヌスプロジェンター毒素の血球凝集活性において重要な役割を果たしていることを示す。さらに、シーケンスモチーフの探索により、HA-33のC-末端部分は炭化水素認識サブドメインを持っていることが推測された

A newly developed snack effective for enhancing bone volume

<p>Abstract</p> <p>Background</p> <p>The incidence of primary osteoporosis is higher in Japan than in USA and European countries. Recently, the importance of preventive medicine has been gradually recognized in the field of orthopaedic surgery with a concept that peak bone mass should be increased in childhood as much as possible for the prevention of osteoporosis. Under such background, we have developed a new bean snack with an aim to improve bone volume loss. In this study, we examined the effects of a newly developed snack on bone volume and density in osteoporosis model mice.</p> <p>Methods</p> <p>Orchiectomy (ORX) and ovariectomy (OVX) were performed for C57BL/6J mice of twelve-week-old (Jackson Laboratory, Bar Harbar, ME, USA) were used in this experiment. We prepared and given three types of powder diet <it>e.g.</it>: normal calcium diet (NCD, Ca: 0.9%, Clea Japan Co., Tokyo, Japan), low calcium diet (LCD, Ca: 0.63%, Clea Japan Co.,) and special diet (SCD, Ca: 0.9%). Eighteen weeks after surgery, all the animals were sacrified and prepared for histomorphometric analysis to quantify bone density and bone mineral content.</p> <p>Results</p> <p>As a result of histomorphometric examination, SCD was revealed to enhance bone volume irrespective of age and sex. The bone density was increased significantly in osteoporosis model mice fed the newly developmental snack as compared with the control mice. The bone mineral content was also enhanced significantly. These phenomena were revealed in both sexes.</p> <p>Conclusion</p> <p>It is shown that the newly developed bean snack is highly effective for the improvement of bone volume loss irrespective of sex. We demonstrated that newly developmental snack supplements may be a useful preventive measure for Japanese whose bone mineral density values are less than the ideal condition.</p

Biogeography of marine giant viruses reveals their interplay with eukaryotes and ecological functions

海洋巨大ウイルスの地理的分布を全球規模で解明 --海域による特異性が明らかに--. 京都大学プレスリリース. 2020-09-08.Nucleocytoplasmic large DNA viruses (NCLDVs) are ubiquitous in marine environments and infect diverse eukaryotes. However, little is known about their biogeography and ecology in the ocean. By leveraging the Tara Oceans pole-to-pole metagenomic data set, we investigated the distribution of NCLDVs across size fractions, depths and biomes, as well as their associations with eukaryotic communities. Our analyses reveal a heterogeneous distribution of NCLDVs across oceans, and a higher proportion of unique NCLDVs in the polar biomes. The community structures of NCLDV families correlate with specific eukaryotic lineages, including many photosynthetic groups. NCLDV communities are generally distinct between surface and mesopelagic zones, but at some locations they exhibit a high similarity between the two depths. This vertical similarity correlates to surface phytoplankton biomass but not to physical mixing processes, which suggests a potential role of vertical transport in structuring mesopelagic NCLDV communities. These results underscore the importance of the interactions between NCLDVs and eukaryotes in biogeochemical processes in the ocean

The Synthetic Curcumin Analogue GO-Y030 Effectively Suppresses the Development of Pressure Overload-induced Heart Failure in Mice

Curcumin is a naturally occurring p300-histone acetyltransferase (p300-HAT) inhibitor that suppresses cardiomyocyte hypertrophy and the development of heart failure in experimental animal models. To enhance the therapeutic potential of curcumin against heart failure, we produced a series of synthetic curcumin analogues and investigated their inhibitory activity against p300-HAT. The compound with the strongest activity was further evaluated to determine its effects on cardiomyocyte hypertrophy and pressure overload-induced heart failure in mice. We synthesised five synthetic curcumin analogues and found that a compound we have named GO-Y030 most strongly inhibited p300-HAT activity. Furthermore, 1 μM GO-Y030, in a manner equivalent to 10 µM curcumin, suppressed phenylephrine-induced hypertrophic responses in cultured cardiomyocytes. In mice undergoing transverse aortic constriction surgery, administration of GO-Y030 at a mere 1% of an equivalently-effective dose of curcumin significantly attenuated cardiac hypertrophy and systolic dysfunction. In addition, this low dose of GO-Y030 almost completely blocked histone H3K9 acetylation and eliminated left ventricular fibrosis. A low dose of the synthetic curcumin analogue GO-Y030 effectively inhibits p300-HAT activity and markedly suppresses the development of heart failure in mice