Amyloid A (AA) amyloidosis is a protein misfolding disease characterized by extracellular deposition of AA fibrils. AA fibrils are found in several tissues from food animals with AA amyloidosis. For ...hygienic purposes, heating is widely used to inactivate microbes in food, but it is uncertain whether heating is sufficient to inactivate AA fibrils and prevent intra- or cross-species transmission. We examined the effect of heating (at 60 °C or 100 °C) and autoclaving (at 121 °C or 135 °C) on murine and bovine AA fibrils using Western blot analysis, transmission electron microscopy (TEM), and mouse model transmission experiments. TEM revealed that a mixture of AA fibrils and amorphous aggregates appeared after heating at 100 °C, whereas autoclaving at 135 °C produced large amorphous aggregates. AA fibrils retained antigen specificity in Western blot analysis when heated at 100 °C or autoclaved at 121 °C, but not when autoclaved at 135 °C. Transmissible pathogenicity of murine and bovine AA fibrils subjected to heating (at 60 °C or 100 °C) was significantly stimulated and resulted in amyloid deposition in mice. Autoclaving of murine AA fibrils at 121 °C or 135 °C significantly decreased amyloid deposition. Moreover, amyloid deposition in mice injected with murine AA fibrils was more severe than that in mice injected with bovine AA fibrils. Bovine AA fibrils autoclaved at 121 °C or 135 °C did not induce amyloid deposition in mice. These results suggest that AA fibrils are relatively heat stable and that similar to prions, autoclaving at 135 °C is required to destroy the pathogenicity of AA fibrils. These findings may contribute to the prevention of AA fibril transmission through food materials to different animals and especially to humans.
Replicative DNA polymerases are frequently stalled at damaged template strands. Stalled replication forks are restored by the DNA damage tolerance (DDT) pathways, error-prone translesion DNA ...synthesis (TLS) to cope with excessive DNA damage, and error-free template switching (TS) by homologous DNA recombination. PDIP38 (Pol-delta interacting protein of 38 kDa), also called Pol δ-interacting protein 2 (PolDIP2), physically associates with TLS DNA polymerases, polymerase η (Polη), Polλ, and PrimPol, and activates them in vitro. It remains unclear whether PDIP38 promotes TLS in vivo, since no method allows for measuring individual TLS events in mammalian cells. We disrupted the PDIP38 gene, generating PDIP38-/- cells from the chicken DT40 and human TK6 B cell lines. These PDIP38-/- cells did not show a significant sensitivity to either UV or H2O2, a phenotype not seen in any TLS-polymerase-deficient DT40 or TK6 mutants. DT40 provides a unique opportunity of examining individual TLS and TS events by the nucleotide sequence analysis of the immunoglobulin variable (Ig V) gene as the cells continuously diversify Ig V by TLS (non-templated Ig V hypermutation) and TS (Ig gene conversion) during in vitro culture. PDIP38-/- cells showed a shift in Ig V diversification from TLS to TS. We measured the relative usage of TLS and TS in TK6 cells at a chemically synthesized UV damage (CPD) integrated into genomic DNA. The loss of PDIP38 also caused an increase in the relative usage of TS. The number of UV-induced sister chromatid exchanges, TS events associated with crossover, was increased a few times in PDIP38-/- human and chicken cells. Collectively, the loss of PDIP38 consistently causes a shift in DDT from TLS to TS without enhancing cellular sensitivity to DNA damage. We propose that PDIP38 controls the relative usage of TLS and TS increasing usage of TLS without changing the overall capability of DDT.
•HERC2 and RNF8 are required for maintaining replication fork progression at UV lesions.•HERC2 and RNF8 are not required for PCNA mono-ubiquitination.•HERC2 and RNF8 promote translesion DNA synthesis ...past abasic sites.
The replicative DNA polymerases are generally blocked by template DNA damage. The resulting replication arrest can be released by one of two post-replication repair (PRR) pathways, translesion DNA synthesis (TLS) and template switching by homologous recombination (HR). The HERC2 ubiquitin ligase plays a role in homologous recombination by facilitating the assembly of the Ubc13 ubiquitin-conjugating enzyme with the RNF8 ubiquitin ligase. To explore the role of HERC2 and RNF8 in PRR, we examined immunoglobulin diversification in chicken DT40 cells deficient in HERC2 and RNF8. Unexpectedly, the HERC2−/− and RNF8−/− cells and HERC2−/−/RNF8−/− double mutant cells exhibit a significant reduction in the rate of immunoglobulin (Ig) hypermutation, compared to wild-type cells. Further, the HERC2−/− and RNF8−/− mutants exhibit defective maintenance of replication fork progression immediately after exposure to UV while retaining proficient post-replicative gap filling. These mutants are both proficient in mono-ubiquitination of PCNA. Taken together, these results suggest that HERC2 and RNF8 promote TLS past abasic sites and UV-lesions at or very close to stalled replication forks.
In the present study, we investigated the dose-dependent effect of δ-tocotrienol long term (48, 72 h) on the melanin content of cells treated with δ-tocotrienol, and whether cells treated with ...δ-tocotrienol for long a time show cytotoxicity. We also examined whether other enzymes responsible for melanin biosynthesis, tyrosinase-related protein-1 (TRP-1) and -2 (TRP-2), are involved in the decrease in melanin levels. Protein levels in cells treated with 25 or 50 μM δ-tocotrienol for 48 h or 72 h were similar to those in control cells. Melanin content decreased by 44 (25 μM δ-tocotrienol) to 50% (50 μM) at 48 h, and by 14 to 21% at 72 h, compared to control levels. Tyrosinase activity, amounts of tyrosinase and TRP-1 decreased dependent on dose : by 50 (25 μM δ-tocotrienol) to 75% (50 μM), 20 to 45% and 42 to 82% at 48 h, and by 25 to 50%, 75 to 80% and 78 to 77% at 72 h, respectively. Although the amount of TRP-2 increased by 20% on treatment with 25 μM δ-tocotrienol for 48 h, it decreased by 52% on treatment with 50 μM δ-tocotrienol for 48 h. The amount of TRP-2 dose-dependently decreased by 55% and 75% on 72 h by treatment with 25 and 50 μM δ-tocotrienol, respectively. From these findings, δ-tocotrienol at up to 50 μM dose-dependently caused a reduction in melanin content by the decrease of TRP-1 and TRP-2 as well as tyrosinase, and no cytotoxicity.
Measurements of DC magnetization for single crystal specimens of LiFeAs have been performed under pressure using liquid argon and NaCl as pressure transmitting media (PTM) to generate hydrostatic and ...nearly uniaxial pressure along c-axis, respectively. It has been found that Tc linearly decreases under pressure with pressure coefficient dTc/dP∼−1.6−1.7K/GPa, and then shows a pressure independent behavior with Tc∼8K above 5GPa. These behaviors are observed independently of whether we select liquid argon or NaCl as PTM. This suggests that c-axis lattice constant is not an important factor to determine Tc in LiFeAs, in contrast to KxFe2−ySe2 and (NH3)yAxFe2Se2 (A=alkali metal).
This paper proposes a color combination support system using image words clustering. In order to design color combination effectively, analyses of the relationship between various colors and the ...image humans have is important. We have collected such data produced by many color designers and analyzed them to find the relationships between hue, tone and the combinations. At the same time, several color combination techniques are also utilized to develop a software algorithm to implement a color combination support system. The proposed system has been examined in respect of user-friendliness, ease of use, and degree of coincidence between the output of the proposed system and human's image. According to the evaluation experiments, the proposed system obtained fairly good results.
Phys. Rev. B 87, 235111 (2013) Superconducting transition under pressure ($P$) has been investigated for
optimum-doped $R$FeAsO$_{\rm 1-x}$F$_{\rm x}$ ($R$=La, Ce$-$Sm) by dc
magnetization ...measurements. For $R$=La, $T_{\rm c}$ is found to be pressure
independent up to $P$$\sim$3.0 GPa and then shows a monotonic decrease with
increasing pressure. The plateau width decreases for the system with smaller
lattice constants, and shrinks to almost zero for $R$=Sm. From the $T_{\rm
c}$($P$) data, we construct the $T_{\rm c}$ evolution map on the height of the
As atom from the Fe-plane $h_{\rm As}$ versus lattice constant $a$ or $c$
plane. It is shown that the characteristic $T_{\rm c}$ variations under
pressure for all compounds and the rapid decrease in $T_{\rm c}$ induced by
changing $R$-element from Sm to La can be described by a common $T_{\rm
c}$($h_{\rm As}$, $a$ or $c$) surface, suggesting that $T_{\rm c}$ is
determined by $h_{\rm As}$ and lattice constant. It is also suggested that
there exists an upper limit of the lattice constant $a_{\rm ulm}$ (or $c_{\rm
ulm}$), above which $dT_{\rm c}$$da$ (or $dT_{\rm c}$$dc$) changes the sign
from positive to negative.
Superconducting transition under pressure (\(P\)) has been investigated for optimum-doped \(R\)FeAsO\(_{\rm 1-x}\)F\(_{\rm x}\) (\(R\)=La, Ce\(-\)Sm) by dc magnetization measurements. For \(R\)=La, ...\(T_{\rm c}\) is found to be pressure independent up to $P$$\sim\(3.0 GPa and then shows a monotonic decrease with increasing pressure. The plateau width decreases for the system with smaller lattice constants, and shrinks to almost zero for \)R\(=Sm. From the \)T_{\rm c}\((\)P\() data, we construct the \)T_{\rm c}\( evolution map on the height of the As atom from the Fe-plane \)h_{\rm As}\( versus lattice constant \)a\( or \)c\( plane. It is shown that the characteristic \)T_{\rm c}\( variations under pressure for all compounds and the rapid decrease in \)T_{\rm c}\( induced by changing \)R\(-element from Sm to La can be described by a common \)T_{\rm c}\((\)h_{\rm As}\(, \)a\( or \)c\() surface, suggesting that \)T_{\rm c}\( is determined by \)h_{\rm As}\( and lattice constant. It is also suggested that there exists an upper limit of the lattice constant \)a_{\rm ulm}\( (or \)c_{\rm ulm}\(), above which \)dT_{\rm c}$$da\( (or \)dT_{\rm c}$$dc$) changes the sign from positive to negative.
There are various diagnostic and therapeutic agents for prostate cancer using bombesin (BBN) derivatives, but astatine-211 (211At)-labeled BBN derivatives have yet to be studied. This study presented ...a preliminary evaluation of 211At-labeled BBN derivative. Several nonradioactive iodine-introduced BBN derivatives (IB-BBNs) with different linkers were synthesized and their binding affinities measured. Because IB-3 exhibited a comparable affinity to native BBN, 211AtAB-3 was synthesized and the radiochemical yields of 211AtAB-3 was 28.2 ± 2.4%, with a radiochemical purity of >90%. The stability studies and cell internalization/externalization experiments were performed. 211AtAB-3 was taken up by cells and internalized; however, radioactivity effluxed from cells over time. In addition, the biodistribution of 211AtAB-3, with and without excess amounts of BBN, were evaluated in PC-3 tumor-bearing mice. Despite poor stability in murine plasma, 211AtAB-3 accumulated in tumor tissue (4.05 ± 0.73%ID/g) in PC-3 tumor-bearing mice, which was inhibited by excess native BBN (2.56 ± 0.24%ID/g). Accumulated radioactivity in various organs is probably due to free 211At. Peptide degradation in murine plasma and radioactivity efflux from cells are areas of improvement. The development of 211At-labeled BBN derivatives requires modifying the BBN sequence and preventing deastatination.
Ferroptosis has recently attracted much interest because of its relevance to human diseases such as cancer and ischemia‐reperfusion injury. We have reported that prolonged severe cold stress induces ...lipid peroxidation‐dependent ferroptosis, but the upstream mechanism remains unknown. Here, using genome‐wide CRISPR screening, we found that a mitochondrial Ca2+ uptake regulator, mitochondrial calcium uptake 1 (MICU1), is required for generating lipid peroxide and subsequent ferroptosis under cold stress. Furthermore, the gatekeeping activity of MICU1 through mitochondrial calcium uniporter (MCU) is suggested to be indispensable for cold stress‐induced ferroptosis. MICU1 is required for mitochondrial Ca2+ increase, hyperpolarization of the mitochondrial membrane potential (MMP), and subsequent lipid peroxidation under cold stress. Collectively, these findings suggest that the MICU1‐dependent mitochondrial Ca2+ homeostasis‐MMP hyperpolarization axis is involved in cold stress‐induced lipid peroxidation and ferroptosis.
SYNOPSIS
This study identifies MICU1 as a key regulator for lipid peroxidation and subsequent ferroptosis under cold stress, suggesting that MICU1 can be a potential target for preventing cell death in organ preservation.
Genome‐wide CRISPR screening reveals that MICU1 is required for cold stress‐induced ferroptosis.
MICU1 deficiency attenuates lipid peroxidation via suppressing hyperpolarization of the mitochondrial membrane potential and mitochondrial Ca2 + uptake induced by cold stress.
Intracellular Ca2 + increase, partly through TRPM8, plays important roles in cold stress‐induced ferroptosis.
This study identifies MICU1 as a key regulator for lipid peroxidation and subsequent ferroptosis under cold stress, suggesting that MICU1 can be a potential target for preventing cell death in organ preservation.
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