Kochi Institute for Core Sample Research

The Antarctic sea ice diatom Navicular glaciei produced ice-binding protein (NagIBP) that is similar to the antifreeze protein (TisAFP) from snow mold Typhula ishikariensis. In the thermal hysteresis range of NagIBP, ice growth was completely inhibited. At the freezing point, the ice grew in a burst to 6 direction perdicular to the c-axis of ice crystal. This burst pattern is similar to TisAFP and other hyperactive AFPs. The thermal hysteresis of NagIBP and TisAFP could be increased by decreasing a cooling rate to allow more time for the proteins to bind ice. This suggests the possible second binding of proteins occurs on the ice surface, which might increase the hysteresises to a sufficient level to prevent freezing of the brine pockets which habitat of N. glaciei. The secondary ice binding was described as that after AFP molecules bind onto the flat ice plane irreversibly, which was based on adsorption-inhibition mechanism model at the ice-water interface, convex ice front was formed and overgrew during normal TH measurement (no annealing) until uncontrolled growth at the nonequilibrium freezing point. The results suggested that NagIBP is a hyperactive AFP that is expressed for freezing avoidance.

A total of 71 isolates were collected from lake sediment and soil surrounding lakes in the Skarvsnes area, Antarctica. Based on ITS region sequence similarity, these isolates were classified to 10 genera. Twenty-three isolates were categorized as ascomycetous fungi from five genera (Embellisia, Phoma, Geomyces, Tetracladium or Thelebolus) and 48 isolates were categorized as basidiomycetous fungi in five genera (Mrakia, Cryptococcus, Dioszegia, Rhodotorula or Leucosporidium). Thirty-five percent of culturable fungi were of the genus Mrakia. Eighteen isolates from eight genera were selected and tested for both antifreeze activity and capacity for growth under temperatures ranging from À1 to 25°C. Rhodotorula sp. NHT-2 possessed a high degree of sequence homology with R. gracialis, while Leucosporidium sp. BSS-1 possessed a high degree of sequence homology with Leu. antarcticum (Glaciozyma antarctica), and these two isolates demonstrated antifreeze activity. All isolates examined were capable of growth at À1°C. Mrakia spp., while capable of growth at À1°C, did not demonstrate any antifreeze activity and exhibited only limited secretion of extracellular polysaccharides. Species of the genus Mrakia possessed high amounts of unsaturated fatty acids, suggesting that members of this genus have adapted to cold environments by increasing their membrane fluidity.

Manganese superoxide dismutase (MnSOD) is considered a critical component of the antioxidant systems that protect against oxidative damage. We are interested in the role of oxidative stress in bladder detrusor smooth muscle (SM) in different disease states. In this study, we generated an inducible, SM-specific Sod2−/− mouse model to investigate the effects of MnSOD depletion on the function of the bladder. We crossbred floxed Sod2 ( Sod2lox/lox) mice with mice containing heterozygous knock-in of a gene encoding a tamoxifen-activated Cre recombinase in the SM22α promoter locus [SM-CreERT2(ki)Cre/+]. We obtained Sod2lox/lox,SM-CreERT2(ki)Cre/+ mice and injected 8-wk-old males with 4-hydroxytamoxifen to induce Cre-mediated excision of the floxed Sod2 allele. Twelve weeks later, SM-specific deletion of Sod2 and depletion of MnSOD were confirmed by polymerase chain reaction, immunoblotting, and immunohistochemistry. SM-specific Sod2−/− mice exhibited normal growth with no gross abnormali...

The Antarctic sea ice diatom Navicular glaciei produced ice-binding protein (NagIBP) that is similar to the 27 antifreeze protein (TisAFP) from snow mold Typhula ishikariensis. In the thermal hysteresis range of 28 NagIBP, ice growth was completely inhibited. At the freezing point, the ice grew in a burst to 6 direction 29 perdicular to the c-axis of ice crystal. This burst pattern is similar to TisAFP and other hyperactive AFPs. 30 The thermal hysteresis of NagIBP and TisAFP could be increased by decreasing a cooling rate to allow 31 more time for the proteins to bind ice. This suggests the possible second binding of proteins occurs on 32 the ice surface, which might increase the hysteresises to a sufficient level to prevent freezing of the brine 33 pockets which habitat of N. glaciei. The secondary ice binding was described as that after AFP molecules 34 bind onto the flat ice plane irreversibly, which was based on adsorption-inhibition mechanism model at 35 the ice-water interface, convex ice front was formed and overgrew during normal TH measurement (no 36 annealing) until uncontrolled growth at the nonequilibrium freezing point. The results suggested that 37 NagIBP is a hyperactive AFP that is expressed for freezing avoidance.

The study of environmental samples requires a preservation system that stabilizes the sample structure, including cells and biomolecules. To address this fundamental issue, we tested the cell alive system (CAS)-freezing technique for subseafloor sediment core samples. In the CAS-freezing technique, an alternating magnetic field is applied during the freezing process to produce vibration of water molecules and achieve a stable, super-cooled liquid phase. Upon further cooling, the temperature decreases further, achieving a uniform freezing of sample with minimal ice crystal formation. In this study, samples were preserved using the CAS and conventional freezing techniques at 4, -20, -80 and -196 (liquid nitrogen) °C. After 6 months of storage, microbial cell counts by conventional freezing significantly decreased (down to 10.7% of initial), whereas that by CAS-freezing resulted in minimal. When Escherichia coli cells were tested under the same freezing conditions and storage for 2.5 m...

Deep biosphere research has become one of the major scientific focuses in ocean drilling science. Increased scientific attention to microbiological research of the subseafloor environment raises the complications and concerns related to adherence to the Nagoya Protocol of the Convention on Biological Diversity (CBD). The Nagoya Protocol's implementation has prompted new legislation that could change international collaborative research on the geomicrobiology of the subseafloor. In this paper, we summarize the central points of the Nagoya Protocol on access and benefit-sharing (ABS) and discuss their relationship to ocean drilling research. In addition, we addressed the challenges faced by ocean drilling in complying with this international convention.

The study of environmental samples requires a preservation system that stabilizes the sample structure, including cells and biomolecules. To address this fundamental issue, we tested the cell alive system (CAS)-freezing technique for subseafloor sediment core samples. In the CAS-freezing technique, an alternating magnetic field is applied during the freezing process to produce vibration of water molecules and achieve a stable, super-cooled liquid phase. Upon further cooling, the temperature decreases further, achieving a uniform freezing of sample with minimal ice crystal formation. In this study, samples were preserved using the CAS and conventional freezing techniques at 4, -20, -80 and -196 (liquid nitrogen) °C. After 6 months of storage, microbial cell counts by conventional freezing significantly decreased (down to 10.7% of initial), whereas that by CAS-freezing resulted in minimal. When Escherichia coli cells were tested under the same freezing conditions and storage for 2.5 m...