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151.
Expression and Regulation of the Arsenic Resistance Operon of Acidiphilium multivorum AIU 301 Plasmid pKW301 in Escherichia coli 总被引:1,自引:0,他引:1
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Katsuhisa Suzuki Norio Wakao Tetsuya Kimura Kazuo Sakka Kunio Ohmiya 《Applied microbiology》1998,64(2):411-418
The arsenic resistance (ars) operon from plasmid pKW301 of Acidiphilium multivorum AIU 301 was cloned and sequenced. This DNA sequence contains five genes in the following order: arsR, arsD, arsA, arsB, arsC. The predicted amino acid sequences of all of the gene products are homologous to the amino acid sequences of the ars gene products of Escherichia coli plasmid R773 and IncN plasmid R46. The ars operon cloned from A. multivorum conferred resistance to arsenate and arsenite on E. coli. Expression of the ars genes with the bacteriophage T7 RNA polymerase-promoter system allowed E. coli to overexpress ArsD, ArsA, and ArsC but not ArsR or ArsB. The apparent molecular weights of ArsD, ArsA, and ArsC were 13,000, 64,000, and 16,000, respectively. A primer extension analysis showed that the ars mRNA started at a position 19 nucleotides upstream from the arsR ATG in E. coli. Although the arsR gene of A. multivorum AIU 301 encodes a polypeptide of 84 amino acids that is smaller and less homologous than any of the other ArsR proteins, inactivation of the arsR gene resulted in constitutive expression of the ars genes, suggesting that ArsR of pKW301 controls the expression of this operon. 相似文献
152.
153.
Stability of pre- and post-fire spatial structure of pine trees in Aleppo pine forest 总被引:2,自引:0,他引:2
The study reported here describes for the first time the similarity between pre- and post-fire spatial patterns of the trees in a Mediterranean pine forest demonstrating that the pre-fire ancestor microsite is occupied also by the next generation. Although Aleppo pine Pinus halepensis Mill, is an obligatory post-fire seeder, it is adapted to regenerate in its pre-fire growing microsite. thus keeping suitable growing sites from generation to generation. We studied the effect of the dead burned adult pines on the density and size of their recruited saplings 2, 5, 11 and 20 yr after fire. A comparison of pine sapling density and size was made between the "near" zone (under the former effect of the burned canopy) and the'far'zone (beyond the former effect of the burned canopy).
In the site 2 yr after fire, seedling density was 56% higher in the "far" zone than in the'near'zone, but seedling .size was similar. However in the site 20 yr after fire, densities were similar in both zones, but the size was bigger by 89% in the "near" zone. Thus, population recruitment after fire seems to peak near the burned pine trees rather than at u distance from them, in contrast to Janzen's original'distance hypothesis' model suggested for undisturbed rainforest. Mere we present a new hypothetical model for the spatial pattern of post-fire regeneration of obligate seeder tree species forming open forests. It is proposed that in such trees the microsites which were kept by the burned adult trees, which are killed by the fire, are also the favorable regeneration microsite for the post-fire generation. 相似文献
In the site 2 yr after fire, seedling density was 56% higher in the "far" zone than in the'near'zone, but seedling .size was similar. However in the site 20 yr after fire, densities were similar in both zones, but the size was bigger by 89% in the "near" zone. Thus, population recruitment after fire seems to peak near the burned pine trees rather than at u distance from them, in contrast to Janzen's original'distance hypothesis' model suggested for undisturbed rainforest. Mere we present a new hypothetical model for the spatial pattern of post-fire regeneration of obligate seeder tree species forming open forests. It is proposed that in such trees the microsites which were kept by the burned adult trees, which are killed by the fire, are also the favorable regeneration microsite for the post-fire generation. 相似文献
154.
The juvenile development of four Japanese flatheads (Platycephalidae),Onigocia macrolepis. O. spinosa, Inegocia japonica andRogadius asper, is described and illustrated from specimens trawled in Tosa Bay, southern Japan. Juveniles of twoOnigocia species are diagnosed by an ocular flap and absence (O. macrolepis) or presence (O. spinosa) of distinct dark bars on the body.Inegocia japonica juveniles are distinctive in having a heavily pigmented body and 12 dorsal and anal fin soft rays.Rogadius asper has a unique antrorse preopercular spine prior to 15 mm SL. During the early juvenile stage, strongly negative allometric
growth occurs in the interorbital region, accompanied by migration of the eyes from the lateral to dorsal surface of the head. 相似文献
155.
Yasuo Ido Albert Duranton Fan Lan Karen A. Weikel Lionel Breton Neil B. Ruderman 《PloS one》2015,10(2)
The aging process is perceived as resulting from a combination of intrinsic factors such as changes in intracellular signaling and extrinsic factors, most notably environmental stressors. In skin, the relationship between intrinsic changes and keratinocyte function is not clearly understood. Previously, we found that increasing the activity of AMP-activated protein kinase (AMPK) suppressed senescence in hydrogen peroxide (H2O2)-treated human primary keratinocytes, a model of oxidative stress-induced cellular aging. Using this model in the present study, we observed that resveratrol, an agent that increases the activities of both AMPK and sirtuins, ameliorated two age-associated phenotypes: cellular senescence and proliferative dysfunction. In addition, we found that treatment of keratinocytes with Ex527, a specific inhibitor of sirtuin 1 (SIRT1), attenuated the ability of resveratrol to suppress senescence. In keeping with the latter observation, we noted that compared to non-senescent keratinocytes, senescent cells lacked SIRT1. In addition to these effects on H2O2-induced senescence, resveratrol also prevented the H2O2-induced decrease in proliferation (as indicated by 3H-thymidine incorporation) in the presence of insulin. This effect was abrogated by inhibition of AMPK but not SIRT1. Compared to endothelium, we found that human keratinocytes expressed relatively high levels of Forkhead box O3 (FOXO3), a downstream target of both AMPK and SIRT1. Treatment of keratinocytes with resveratrol transactivated FOXO3 and increased the expression of its target genes including catalase. Resveratrol’s effects on both senescence and proliferation disappeared when FOXO3 was knocked down. Finally, we performed an exploratory study which showed that skin from humans over 50 years old had lower AMPK activity than skin from individuals under age 20. Collectively, these findings suggest that the effects of resveratrol on keratinocyte senescence and proliferation are regulated by the AMPK-FOXO3 pathway and in some situations, but not all, by SIRT1. 相似文献
156.
Akiko Takasuga Kunio Sato Ryouichi Nakamura Yosuke Saito Shinji Sasaki Takehito Tsuji Akio Suzuki Hiroshi Kobayashi Tamako Matsuhashi Koji Setoguchi Hiroshi Okabe Toshitake Ootsubo Ichiro Tabuchi Tatsuo Fujita Naoto Watanabe Takashi Hirano Shota Nishimura Toshio Watanabe Makio Hayakawa Yoshikazu Sugimoto Takatoshi Kojima 《PLoS genetics》2015,11(8)
Recessive skeletal dysplasia, characterized by joint- and/or hip bone-enlargement, was mapped within the critical region for a major quantitative trait locus (QTL) influencing carcass weight; previously named CW-3 in Japanese Black cattle. The risk allele was on the same chromosome as the Q allele that increases carcass weight. Phenotypic characterization revealed that the risk allele causes disproportional tall stature and bone size that increases carcass weight in heterozygous individuals but causes disproportionately narrow chest width in homozygotes. A non-synonymous variant of FGD3 was identified as a positional candidate quantitative trait nucleotide (QTN) and the corresponding mutant protein showed reduced activity as a guanine nucleotide exchange factor for Cdc42. FGD3 is expressed in the growth plate cartilage of femurs from bovine and mouse. Thus, loss of FDG3 activity may lead to subsequent loss of Cdc42 function. This would be consistent with the columnar disorganization of proliferating chondrocytes in chondrocyte-specific inactivated Cdc42 mutant mice. This is the first report showing association of FGD3 with skeletal dysplasia. 相似文献
157.
Virginia Bilanchone Kristina Clemens Robyn Kaake Anthony R. Dawson Dina Matheos Kunio Nagashima Parth Sitlani Kurt Patterson Ivan Chang Lan Huang Suzanne Sandmeyer 《PLoS genetics》2015,11(9)
Retrotransposition of the budding yeast long terminal repeat retrotransposon Ty3 is activated during mating. In this study, proteins that associate with Ty3 Gag3 capsid protein during virus-like particle (VLP) assembly were identified by mass spectrometry and screened for roles in mating-stimulated retrotransposition. Components of RNA processing bodies including DEAD box helicases Dhh1/DDX6 and Ded1/DDX3, Sm-like protein Lsm1, decapping protein Dcp2, and 5’ to 3’ exonuclease Xrn1 were among the proteins identified. These proteins associated with Ty3 proteins and RNA, and were required for formation of Ty3 VLP retrosome assembly factories and for retrotransposition. Specifically, Dhh1/DDX6 was required for normal levels of Ty3 genomic RNA, and Lsm1 and Xrn1 were required for association of Ty3 protein and RNA into retrosomes. This role for components of RNA processing bodies in promoting VLP assembly and retrotransposition during mating in a yeast that lacks RNA interference, contrasts with roles proposed for orthologous components in animal germ cell ribonucleoprotein granules in turnover and epigenetic suppression of retrotransposon RNAs. 相似文献
158.
Daniele Magistro Hikaru Takeuchi Keyvan Kashkouli Nejad Yasuyuki Taki Atsushi Sekiguchi Rui Nouchi Yuka Kotozaki Seishu Nakagawa Carlos Makoto Miyauchi Kunio Iizuka Ryoichi Yokoyama Takamitsu Shinada Yuki Yamamoto Sugiko Hanawa Tsuyoshi Araki Hiroshi Hashizume Yuko Sassa Ryuta Kawashima 《PloS one》2015,10(9)
Processing speed is considered a key cognitive resource and it has a crucial role in all types of cognitive performance. Some researchers have hypothesised the importance of white matter integrity in the brain for processing speed; however, the relationship at the whole-brain level between white matter volume (WMV) and processing speed relevant to the modality or problem used in the task has never been clearly evaluated in healthy people. In this study, we used various tests of processing speed and Voxel-Based Morphometry (VBM) analyses, it is involves a voxel-wise comparison of the local volume of gray and white, to assess the relationship between processing speed and regional WMV (rWMV). We examined the association between processing speed and WMV in 887 healthy young adults (504 men and 383 women; mean age, 20.7 years, SD, 1.85). We performed three different multiple regression analyses: we evaluated rWMV associated with individual differences in the simple processing speed task, word–colour and colour–word tasks (processing speed tasks with words) and the simple arithmetic task, after adjusting for age and sex. The results showed a positive relationship at the whole-brain level between rWMV and processing speed performance. In contrast, the processing speed performance did not correlate with rWMV in any of the regions examined. Our results support the idea that WMV is associated globally with processing speed performance regardless of the type of processing speed task. 相似文献
159.
Tetsu Yamane Masako Mitsumata Noriko Yamaguchi Tadao Nakazawa Kunio Mochizuki Tetsuo Kondo Tomonori Kawasaki Shin-ichi Murata Yoji Yoshida Ryohei Katoh 《Cell and tissue research》2010,340(3):471-479
Remodeling of endothelial basement membrane is important in atherogenesis. Since little is known about the actual relationship
between type IV collagen and matrix metalloprotease−2 (MMP-2) in endothelial cells (ECs) under shear stress by blood flow,
we performed quantitative analysis for type IV collagen and MMP-2 in ECs under high shear stress. The mRNA of type IV collagen
from ECs exposed to high shear stress (10 and 30 dyn/cm2) had a higher expression compared to ECs exposed to a static condition or low shear stress (3 dyn/cm2) (P < 0.01). 3H-proline uptake analysis and fluorography revealed a remarkable increase of type IV collagen under high shear stress (P < 0.01). In contrast, zymography revealed that exposing to high shear stress, however similar positivity was leveled in the
intracellular MMP-2 in the control and high shear stress-exposed ECs, reduced the secretion of MMP-2 in ECs. The results of
Northern blotting, gelatin zymography and monitoring the intracellular trafficking of GFP-labeled MMP-2 revealed that MMP-2
secretion by ECs was completely suppressed by high shear stress, but the intracellular mRNA expression, protein synthesis,
and transport of MMP-2 were not affected. In conclusion, we suggest that high shear stress up-regulates type IV collagen synthesis
and down-regulates MMP-2 secretion in ECs, which plays an important role in remodeling of the endothelial basement membrane
and may suppress atherogenesis. 相似文献
160.
Masakatsu Kamiya Keisuke Oyauchi Yoshinori Sato Takuya Yokoyama Mofei Wang Tomoyasu Aizawa Yasuhiro Kumaki Mineyuki Mizuguchi Kunio Imai Makoto Demura Koichi Suzuki Keiichi Kawano 《Journal of peptide science》2010,16(5):242-248
We previously reported that yamamarin, a pentapeptide with an amidated C‐terminus (DILRG‐NH2) isolated from larvae of the silkmoth, and its palmitoylated analog (C16‐DILRG‐NH2) suppressed proliferation of rat hepatoma (liver cancer) cells. In this study, we investigated the structure–activity relationship of yamamarin by in vitro assay and spectroscopic methods (CD and NMR) for various analogs. The in vitro assay results demonstrated that the chemical structure of the C‐terminal part (‐RG‐NH2) of yamamarin is essential for its activity. The CD and NMR results indicated that yamamarin and its analog adopt predominantly a random coil conformation. Moreover, a comparison of NMR spectra of DILRG‐NH2 and C16‐DILRG‐NH2 revealed that the N‐terminal palmitoyl group of C16‐DILRG‐NH2 did not affect the conformation of the C‐terminal part, which is essential for activity. Together, these results should assist in the design of more sophisticated anticancer drugs. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献