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31.
32.
Data are presented on the cytokinin status of seeds and seed components, at different stages of development in Phaseolus coccineus L., as determined with the soybean callus growth bioassay: A change in cytokinin types according to developmental stage occurred: from biologically very active less polar types (zeatin=Z) at early stages to more polar types (zeatin glucoside=Z9G and zeatin riboside=Zr), with relatively low biological activity, at intermediate and late stages of seed development: When cytokinins were analyzed separately in embryos (embryo proper) and suspensors at two embryonic stages: heart-shaped (A) and middle cotyledonary embryos (stage B) respectively, it was found that: i) at stage A, the suspensor showed cytokinin activity at the level of Z, 2iPA (2-isopentenyladenosine) and Zr, whereas more polar cytokinins (Z9G, Zr) were present in the embryo; ii) at stage B, when the embryo seems to become autonomous for cytokinin supply, there was a relative abundance of active cytokinins (Z, 2iPA) in the embryo to which Z9G activity in the suspensor corresponded. It is concluded that the suspensor plays an essential role in embryogenesis by acting as a hormone source to the early embryo.Abbreviations GA
gibberellic acid
- 2iPA
2-isopentenyladenosine
- Stage A
heart-shaped embryo
- siage B
middle cotyledonary embryo
- Z
zeatin
- Z9G
zeatin glucoside
- Zr
Zeatin riboside 相似文献
33.
Larval competition between contest and scramble strategists was investigated using the two bruchid species, C. analis (contest species) and C. phaseoli (scramble species) with two different sized mung beans (large and small beans). In both sized beans, the adult emergences of each species dependen on total density of the initial larval densities of the two species and the ratio of the two densities. The emergence of one species was suppressed by the existence of the other species when the initial larval density per bean of the former species was less than that of the latter one. There were many cases in which both C. analis and C. phaseoli emerged from one bean in large beans, but such cases were quite rare in small beans. C. analis performed interference behavior only at late larval stages, whereas C. phaseoli was superior in exploitative competition all through their larval stages. These, combined with the niche segregation inside a bean, are throught to be the major factors of observed density- and frequency-dependent competition results. Based on the above experimental results, long-term competition results between the contest and scramble species were predicted. 相似文献
34.
Kenzo Yokozeki Shigeru Yamanaka Koichi Takinami Yoshio Hirose Atsuo Tanaka Kenji Sonomoto Saburo Fukui 《Applied microbiology and biotechnology》1982,14(1):1-5
Summary Lipase from Rhizopus delemar was immobilized by entrapment with photo-crosslinkable resin prepolymers or urethane prepolymers or by binding to various types of porous silica beads. The immobilized lipase preparations thus obtained were examined for their activity in converting olive oil to an interesterified fat (cacao butter-like fat), whose oleic acid moieties at 1- and 3-positions were replaced with stearic acid moieties, in the reaction solvent n-hexane. Although all of the immobilized preparations exhibited some activity, lipase adsorbed on Celite and then entrapped with a hydrophobic photo-crosslinkable resin prepolymer showed the highest activity, about 75% of that of lipase simply adsorbed onto Celite. Entrapment markedly enhanced the operational stability of lipase.Dedicated to Professor H. Holzer, Freiburg University, on his 60th birthday (June 13, 1981) 相似文献
35.
Koichi Hirata Tadashi Oku Aaron E. Freeman 《In vitro cellular & developmental biology. Plant》1982,18(9):789-799
Summary Twenty to twenty-two days postcoitum mouse fetal pancreas organ bits were cultured on the dermal surface of irradiated pigskin
as a substrate. The medium used for long term culture consisted of Eagle’s Minimum Essential Medium with the addition of 10%
bovine serum, 0.02 U/ml insulin, 0.025 μg/ml glucagon, 3.63 μg/ml hydrocortisone, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine. When the medium lacked trypsin inhibitor or atropine but contained the three hormones, the pigskin support began
to be destroyed after 2 to 4 wk in culture. Thereafter, the cultured cells could not grow and survive on the digested pigskin.
When 10−6
M atropine was added to the medium, amylase secretion from cultured cells and destruction of pigskin were inhibited completely
but pancreas cells could not grow or survive. In contrast, 100 μg/ml soybean trypsin inhibitor or 10−8
M atropine permitted cell growth, permitted amylase secretion from the cultured acinar cells, and prevented the destruction
of pigskin. Under these conditions pancreas cells migrated or grew or both from the organ bits onto the surface of the pigskin
dermis and organoid aggregations formed. Hydrocortisone was needed to permit growth for more than 2 wk. Glucagon and insulin
had additive effects. Light and electron microscopic observations indicated the culture of at least five kinds of cells, i.e.,
duct, acinar, centroacinar, endocrine, and mesenchymal. The majority of cultured cells were duct cells and acinar cells. There
were few mesenchymal cells. Mouse pancreas cells were cultured for at least 12 wk by this method.
This investigation was supported by PHS Grant CA 30220 awarded by the National Cancer Institute, DHHS, Grant 1203M awarded
by the Council for Tobacco Research, Inc., and Grant RD-65 (for equipment) awarded by the American Cancer Society. Nude mice
were provided by Dr. Wendall M. Farrow of Life Sciences, Inc., Resource Laboratory N01, CP6-1005 of the National Cancer Institute. 相似文献
36.
Summary When horseshoe crab embryos were treated with NaHCO3 at the developmental stage when the germ disc appears, multiple embryos were formed. NaHCO3 may effect the formation of multiple embryos by binding Ca2+ ions of the embryo since multiple embryos were also formed by treatment with Ca2+ free sea water.The treatment caused the blastoderm layer to tear. When the embryos were returned to normal sea water after the treatment, the blastoderm recovered. Some cell masses, probably derived from the germ disc or its prospective cells, formed during the process of the recovery. Each cell mass developed into an embryo.Contributions from the Shimoda Marine Research Center, Nor. 348 相似文献
37.
Summary Detailed histochemical studies have been conducted on the distribution of various enzymes such as thiamine pyrophosphatase,
α-glucan phosphorylase, hexokinase, glucose-6-phosphate dehydrogenase, aldolase, lactate dehydrogenase and succinate dehydrogenase
in various components of the nucleusEdinger-Westphali, nucleus n. oculomotorii, nucleus ruber and nucleus niger of healthy adult male Wistar strain rats.
The thiamine pyrophosphatase reaction showed the morphological patterns of the Golgi apparatus characteristic for each nucleus.
The Golgi apparatus was well developed in the nucleusEdinger-Westphali, composing a network of highly fenestrated plates in the nucleus n. oculomotorii and nucleus ruber, and a simple network
in the nucleus niger. These results indicate that the former three nuclei need a rich energy supply and argue against the
possibility that the four nuclei have a secretory role.
The neurons of the nucleusEdinger-Westphali may derive their energy mainly from glucose of the circulating blood, but glial cells may serve as energy donators to the
neurons in the pars compacta of the nucleus niger, and the neurons of the other nuclei may derive energy from both sources.
These conclusions are consistent with the morphological patterns of the Golgi apparatus.
It is suggested that the neurons of the nucleusEdinger-Westphali, nucleus n. oculomotorii, nucleus ruber and of the pars lateralis of the nucleus niger may be equipped almost equally with
the Embden-Meyerhof pathway and with the hexose monophosphate shunt. But, the hexose monophosphate shunt is dominant in the
pars compacta of the nucleus niger. It is also suggested that the pattern of distribution of succinate dehydrogenase may parallel
that of lactate dehydrogenase. The nucleus n. oculomotorii, and nucleus ruber have a higher level of oxidative metabolism
than the nucleusEdinger-Westphali and the nucleus niger. The nucleusEdinger-Westphali may be representative of autonomic nuclei with low oxidative metabolism whereas the nucleus n. oculomotorii may represent
motor nuclei with high oxidative metabolism. Predominance of hexose monophosphate shunt, intense hexokinase reaction around
the neurons, and weak activity of succinate dehydrogenase indicate that the pars compacta of the nucleus niger belongs to
the category of “exceptional nuclei”. 相似文献
38.
39.
Wakana Saso Masako Yamasaki Shin-ichi Nakakita Shuetsu Fukushi Kana Tsuchimoto Noriyuki Watanabe Nongluk Sriwilaijaroen Osamu Kanie Masamichi Muramatsu Yoshimasa Takahashi Tetsuro Matano Makoto Takeda Yasuo Suzuki Koichi Watashi 《PLoS pathogens》2022,18(6)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been transmitted across all over the world, in contrast to the limited epidemic of genetically- and virologically-related SARS-CoV. However, the molecular basis explaining the difference in the virological characteristics among SARS-CoV-2 and SARS-CoV has been poorly defined. Here we identified that host sialoglycans play a significant role in the efficient spread of SARS-CoV-2 infection, while this was not the case with SARS-CoV. SARS-CoV-2 infection was significantly inhibited by α2-6-linked sialic acid-containing compounds, but not by α2–3 analog, in VeroE6/TMPRSS2 cells. The α2-6-linked compound bound to SARS-CoV-2 spike S1 subunit to competitively inhibit SARS-CoV-2 attachment to cells. Enzymatic removal of cell surface sialic acids impaired the interaction between SARS-CoV-2 spike and angiotensin-converting enzyme 2 (ACE2), and suppressed the efficient spread of SARS-CoV-2 infection over time, in contrast to its least effect on SARS-CoV spread. Our study provides a novel molecular basis of SARS-CoV-2 infection which illustrates the distinctive characteristics from SARS-CoV. 相似文献
40.
A novel gene family defined by human dihydropyrimidinase and three related proteins with differential tissue distribution 总被引:6,自引:0,他引:6
Naoki Hamajima Koichi Matsuda Shigeko Sakata Nanaya Tamaki Makoto Sasaki Masaru Nonaka 《Gene》1996,180(1-2):157-163
We have isolated cDNA clones encoding dihydropyrimidinase (DHPase) from human liver and its three homologues from human fetal brain. The deduced amino acid (aa) sequence of human DHPase showed 90% identity with that of rat DHPase, and the three homologues showed 57–59% aa identity with human DHPase, and 74–77% aa identity with each other. We tentatively termed these homologues human DHPase related protein (DRP)-1, DRP-2 and DRP-3. Human DRP-2 showed 98% aa identity with chicken CRMP-62 (collapsin response mediator protein of relative molecular mass of 62 kDa) which is involved in neuronal growth cone collapse. Human DRP-3 showed 94–100% aa identity with two partial peptide sequences of rat TOAD-64 (turned on after division, 64 kDa) which is specifically expressed in postmitotic neurons. Human DHPase and DRPs showed a lower degree of aa sequence identity with Bacillus stearothermophilus hydantoinase (39–42%) and Caenorhabditis elegans unc-33 (32–34%). Thus we describe a novel gene family which displays differential tissue distribution: i.e., human DHPase, in liver and kidney; human DRP-1, in brain; human DRP-2, ubiquitously expressed except for liver; human DRP-3, mainly in heart and skeletal muscle. 相似文献