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101.
Yukie Takahashi Masako Sohnaka Minoru Nakao Kenji Miyamoto Masahito Fukunaga 《Microbiology and immunology》1993,37(9):721-727
Thirty-two Borrelia isolates were obtained from the adult stage of ixodid ticks, Ixodes ovatus, collected in various localities in Japan. Borrelial isolates were cultivated and analyzed by polyacrylamide gel electrophoresis, with monoclonal antibodies, by pulsed field gel electrophoresis, and by genomic Southern hybridization. All borrelial isolates showed similar protein profiles and monoclonal antibody reactivities, while plasmid profiles were rather diverse. Genomic hybridization using rRNA gene probes demonstrated the genetic similarities of those isolates. We found no significant differences among the borrelial isolates tested, and the restriction fragment length polymorphism patterns of I. ovatus isolates were quite distinct from those of borrelial strains associated with Lyme disease. Therefore, the isolates of Borrelia obtained from I. ovatus were thought to fall into different genospecies. 相似文献
102.
Hyung Suk Kim Karen M. Lyons Eiichi Saitoh Edwin A. Azen Oliver Smithies Nobuyo Maeda 《Mammalian genome》1993,4(1):3-14
We present the nucleotide sequences of four members of the six-member human salivary prolinerich protein (PRP) gene family. The four genes are PRB1 and PRB2, which encode basic PRPs, and PRB3 and PRB4, which encode glycosylated PRPs. Each PRB gene is approximately 4.0 kb in length and contains four exons, the third of which is entirely composed of 63-bp tandem repeats and encodes the proline-rich portion of the protein products. Exon 3 contains different numbers of tandem repeats in the different PRB genes. Variation in the numbers of these repeats is also responsible for length variations in different alleles of the PRB genes. We have determined a probable evolutionary history of the human PRP gene family by comparing the nucleotide sequences of the six PRP genes. The present-day six PRP loci probably evolved from a single ancestral gene by four sequential gene duplications, leading to six genes that fall into three subsets, each consisting of two genes. During this evolutionary process, multiple rearrangements and gene conversion occurred mainly in the region from the 3 end of IVS2 and the 3 end of exon 3. 相似文献
103.
Susumu Ikegami Yasunori Ooe Takahiko Shimizu Toshihiko Kasahara Tatsuhiko Tsuruta Masako Kijima Minoru Yoshida Teruhiko Beppu 《Development genes and evolution》1993,202(3):144-151
Summary External application of 10 rig/ml (R)-trichostatin A (TSA), a potent and specific inhibitor of mammalian histone deacetylase, to the embryo of the starfish Asterina pectinifera inhibited development during the early gastrula stage before formation of mesenchyme cells. The TSA-sensitive period was limited to the mid-blastula stage before hatching. The pulse-chase experiment clearly demonstrated that TSA induced an accumulation of acetylated histone species in blastulae through inhibition of historic deacetylation. Similar blockage of development at the early gastrula stage was observed with n-butyrate, which has been known as a weak inhibitor of historic deacetylase. These results suggest an intimate role for historic acetylation-deacetylation equilibria in starfish development.
Correspondence to: S. Ikegami 相似文献
104.
Using a physicochemical method, the distribution of endogenous indole-3-acetic acid (IAA) was measured in the peripheral and central cell layers, as well as in the illuminated and shaded sides of phototropically stimulated radish hypocotyls (Raphanus sativus var. hortensis f. gigantissimus Makino). The IAA was evenly distributed over the illuminated and shaded sides in the first and second positive phototropic curvatures induced by a pulse or a continuous unilateral illumination with blue light. Also, no net exchange of the IAA between the peripheral and central cell layers was observed during these curvatures. These results suggest that phototropism of radish hypocotyls cannot be described by the Cholodny-Went theory. 相似文献
105.
Yoshihiro Kuroda Yoshitaka Maeda Shinichi Sawa Kiyohiro Shibata Kazuhide Miyamoto Terumichi Nakagawa 《Journal of peptide science》2003,9(4):212-220
Pathogenic prion proteins (PrP(Sc)) are thought to be produced by alpha-helical to beta-sheet conformational changes in the normal cellular prion proteins (PrP(C)) located solely in the caveolar compartments. In order to inquire into the possible conformational changes due to the influences of hydrophobic environments within caveolae, the secondary structures of prion protein peptides were studied in various kinds of detergents by CD spectra. The peptides studied were PrP(129-154) and PrP(192-213); the former is supposed to assume beta-sheets and the latter alpha-helices, in PrP(Sc). The secondary structure analyses for the CD spectra revealed that in buffer solutions, both PrP(129-154) and PrP(192-213) mainly adopted random-coils (approximately 60%), followed by beta-sheets (30%-40%). PrP(129-154) showed no changes in the secondary structures even in various kinds of detergents such as octyl-beta-D-glucopyranoside (OG), octy-beta-D-maltopyranoside (OM). sodium dodecyl sulfate (SDS), Zwittergent 3-14 (ZW) and dodecylphosphocholine (DPC). In contrast, PrP(192-213) changed its secondary structure depending on the concentration of the detergents. SDS, ZW, OG and OM increased the alpha-helical content, and decreased the beta-sheet and random-coil contents. DPC also increased the alpha-helical content, but to a lesser extent than did SDS, ZW, OG or OM. These results indicate that PrP(129-154) has a propensity to adopt predominantly beta-sheets. On the other hand, PrP(192-213) has a rather fickle propensity and varies its secondary structure depending on the environmental conditions. It is considered that the hydrophobic environments provided by these detergents may mimic those provided by gangliosides in caveolae, the head groups of which consist of oligosaccharide chains containing sialic acids. It is concluded that PrP(C) could be converted into a nascent PrP(Sc) having a transient PrP(Sc) like structureunder the hydrophobic environments produced by gangliosides. 相似文献
106.
107.
Development of galactomannan-hydrolyzing activity in the micropylar endosperm tip of tomato seed prior to germination 总被引:6,自引:0,他引:6
Development of galactomannan-hydrolyzing activity, that is involved in the weakening of the mechanical restraint of the endosperm, was followed at pre-germinative stages in tomato ( Lycopersicon esculentum ) seed. Prior to germination the activity developed exclusively in the endosperm portion just adjacent to the radicle tip. In other parts of the endosperm, the activity developed only after germination occurred. Under the conditions where germination was suppressed (far-red light- or ABA-treatment). no activity was detected in the endosperm at the pre-germinative stages. Under the conditions where the inhibition of germination was alleviated (far-red + red or ABA + GA3 ), the activity developed prior to germination in the endosperm part in front of the radicle tip. Thus, a clear parallel relationship was observed between germinability of the seed and the pre-germinative development of activity in the part of the endosperm portion adjacent to the radicle tip. 相似文献
108.
Nanosecond time-resolved infrared spectroscopy distinguishes two K species in the bacteriorhodopsin photocycle. 总被引:1,自引:1,他引:0
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The photochemical reaction process of bacteriorhodopsin in the nanosecond time range (-120-860 ns) was measured in the 1400-900 cm-1 region with an improved time resolved dispersive-type infrared spectrometer. The system is equipped with a newly developed detection unit whose instrumental response to a 5-ns laser pulse has a full width of the half-maximum of 60 ns. It provides highly accurate data that enabled us to extract a kinetic process one order of magnitude faster than the instrumental response. The spectral changes in the 1400-900 cm-1 region were analyzed by singular value decomposition and resolved into three components. These components were separated by fitting with 10- and 1000-ns exponential functions and a step function, which were convoluted with the instrumental response function. The components with decay time constants of 10 and 1000 ns are named K and KL, respectively, on the basis of previous visible spectroscopy. The spectral shapes of K and KL are distinguishable by their hydrogen-out-of-plane (HOOP) modes, at 958 and 984 cm-1, respectively. The former corresponds to the K intermediate recorded at 77 K and the latter to a K-like photoproduct at 135 K. On the basis of published data, these bands are assigned to the 15-HOOP mode, indicating that the K and KL differ in a twist around the C14-C15 bond. 相似文献
109.
Takashi Hirayarna Tatsuya Maeda Haruo Saito Kazuo Shinozaki 《Molecular & general genetics : MGG》1995,249(2):127-138
Yeast cells can respond and adapt to osmotic stress. In our attempt to clarify the molecular mechanisms of cellular responses to osmotic stress, we cloned seven cDNAs for hyperosmolarity-responsive (HOR) genes from Saccharomyces cerevisiae by a differential screening method. Structural analysis of the clones revealed that those designated HOR1, HORS, HOR4, HOR5 and HOR6 encoded glycerol-3-phosphate dehydrogenase (Gpd1p), glucokinase (Glklp), hexose transporter (Hxtlp), heat-shock protein 12 (Hsp12p) and Na+, K+, Li+-ATPase (Enalp), respectively. HOR2 and HOR7 corresponded to novel genes. Gpdlp is a key enzyme in the synthesis of glycerol, which is a major osmoprotectant in S. cerevisiae. Cloning of HOR1/GPD1 as a HOR gene indicates that the accumulation of glycerol in yeast cells under hyperosmotic stress is, at least in part, caused by an increase in the level of GPDH protein. We performed a series of Northern blot analyses using HOR cDNAs as probes and RNAs prepared from cells grown under various conditions and from various mutant cells. The results suggested that all the HOR genes are regulated by common signal transduction pathways. However, the fact that they exhibited certain distinct responses indicated that they might also be regulated by specific pathways in addition to the common pathways. Ca2+ seemed to be involved in the signaling systems. In addition, Hog1p, one of the MAP kinases in yeast, appeared to be involved in the regulation of expression of HOR genes, although its function seemed to be insufficient for the overall regulation of expression of these genes. 相似文献
110.
An algal suspension containing protoplasmic detritus [termed, single cell detritus (SCD)] was prepared from freeze-dried fronds
of Ulva and its dietary value to Artemia nauplii was tested after size fractionation. The dissolved fraction (<0.22 μm) ofthe
Ulva suspension contained ca. 48% of theoriginal protein in the Ulva, but had no dietaryvalue to Artemia, which is a suspension
feeder. In contrast, the fraction passing through a 100-μm meshand containing SCD of 2–14 μm in diameter, contributedto the
survival of Artemia. The fraction remaining on the 100 μm mesh was further incubated with and without the bacterium Pseudoalteromonas
espejiana strain AR06 FERM BP-5024. The bacterium degraded
Ulva forming new SCD over 106 mL -1 level as rapidly as by 16 h of incubation. The dietary
value of Ulva for Artemia growth was elevated over four times by the incubation. The protein content of the SCD
was approximately doubled by the attaching of bacteria, suggesting the enhanced Artemia growth is attributable to
the combined effect of the SCD and the bacteria. Development of a hatchery diet from Ulva , a resource with a low
commercial value, is suggested utilizing the degrading and attaching ability of P. espejiana.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献