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11.
Epitopes recognized by the neutralizing antibodies of an HIV-1-infected individual. 总被引:35,自引:0,他引:35
A T Profy P A Salinas L I Eckler N M Dunlop P L Nara S D Putney 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(12):4641-4647
Sera from individuals infected by HIV-1 usually neutralize multiple viral isolates. To determine the extent to which these neutralizing antibodies recognize a principal neutralizing determinant in the V3 region of the envelope protein gp120 (amino acids 308-332), one broadly neutralizing serum was fractionated by affinity chromatography on immobilized peptide columns. Antibodies that neutralize one isolate (HTLV-IIIMN) were substantially but not completely absorbed by the peptide corresponding to a portion of its V3 determinant, whereas the antibodies that neutralize two other isolates (HTLV-IIIB and HTLV-IIIRF) were not absorbed by homologous peptides corresponding to their neutralizing determinants. Neutralizing antibodies also failed to be absorbed by full length envelope protein gp160 and by two other envelope peptides previously reported to be broadly neutralizing epitopes (amino acids 254-274 and 735-752). We conclude that the infected individual had raised a type-restricted neutralizing response targeted at a linear epitope in the V3 region, and that broad neutralization resulted from recognition of epitopes not yet identified. 相似文献
12.
The ratio of the extracellular to the intracellular activityof carbonic anhydrase (CA) in cells of Chlorella ellipsoideaC-27, adapted to low levels of CO2 for 24 h (low-CO2 cells),was about one to one. Treatment of intact cells with PronaseP inactivated about one-half of the extracellular CA activitywithout affecting photosynthetic activity. The CA activity incell homogenates and in cell-wall ghosts liberated during celldivision was completely inactivated by the same treatment. Pretreatmentwith Glycosidase mix, Chitosanase and Macerozyme enhanced theinactivation of the CA activity in intact cells. These resultssuggest that extracellular CA is evenly distributed throughoutthe whole cell-wall region. The apparent K1/2 for dissolved inorganic carbon (DIC) in low-CO2cells doubled when extracellular CA was inactivated by treatmentwith Pronase P, but the K1/2 obtained was still one-half ofthat in high-CO2 cells. Photosynthetic 14CO2-fixation in low-CO2cells was enhanced by acetazolamide, whereas H14CO3-fixationwas suppressed. The results suggest that CO2 is a dominant substrateutilized by cells and that HCO3 is utilized after conversionto CO2. The present results show that both intracellular andextracellular CA contribute to the increase in affinity forDIC during photosynthesis in low-CO2 cells of Chlorella ellipsoideaC-27. (Received May 7, 1990; Accepted July 18, 1990) 相似文献
13.
Kenji Takeuchi Sayumi Shibamoto Makio Hayakawa Takamitsu Hori Keiji Miyazawa Naomi Kitamura Fumiaki Ito 《Experimental cell research》1996,223(2):420
Hepatocyte growth factor (HGF) stimulated cell migration of human gastric carcinoma cell lines MKN1, MKN7, and MKN28. Epidermal growth factor (EGF) also stimulated the cell migration of these three cell lines. In MKN7 cells, HGF-stimulated cell migration was rather reduced in the presence of EGF, whereas such an observation was not made with MKN1 and MKN28 cells. Therefore, we compared the effect of EGF on HGF-stimulated HGF receptor phosphorylation in these cell lines. HGF induced a rapid tyrosine phosphorylation of the HGF receptor in all these cell lines. In MKN7 cells, the increased phosphorylation was further enhanced by EGF, although EGF alone did not affect tyrosine phosphorylation of the HGF receptor. In MKN1 and MKN28 cells, EGF did not influence tyrosine phosphorylation of the HGF receptor, whether HGF was present or not. The data presented here suggest that EGF negatively modulates the cellular response to HGF by increasing tyrosine phosphorylation of the HGF receptor in certain types of epithelial cells, e.g., MKN7 cells. 相似文献
14.
Prosaposin Facilitates Sciatic Nerve Regeneration In Vivo 总被引:3,自引:0,他引:3
Yasunori Kotani Seiji Matsuda Masahiro Sakanaka Keiji Kondoh Shu-ichi Ueno Akira Sano 《Journal of neurochemistry》1996,66(5):2019-2025
Abstract: Prosaposin, a multifunctional protein, is the precursor of saposins, which activate sphingolipid hydrolases. In addition to acting as a precursor for saposins, prosaposin has been shown to rescue hippocampal CA1 neurons from lethal ischemic damage in vivo and to promote neurite extension of neuroblastoma cells in vitro. Here we show that prosaposin, when added to a collagen-filled nerve guide after sciatic nerve transection in guinea pigs, increased dramatically the number of regenerating nerve fibers within the guide. To identify the target neurons of prosaposin during peripheral nerve regeneration, we determined the degree of atrophy and chromatolysis of neurons in the spinal anterior horn and dorsal root ganglia on the prosaposin-treated and untreated side. The effect of prosaposin on large spinal neurons and small neurons of the dorsal root ganglion was more conspicuous. Subsequent immunohistochemistry demonstrated that the atrophy of cholinergic large neurons in the anterior horn is prevented to significant extent by prosaposin treatment. These findings suggest that prosaposin promotes peripheral nerve regeneration by acting on α-motor neurons in the anterior horn and on small sensory neurons in the dorsal root ganglion. The present study raises the possibility of using prosaposin as a tool for the treatment of peripheral nerve injuries. 相似文献
15.
Yuriko Osakabe Kazuya Nanto Hiroko Kitamura Shinya Kawai Yuki Kondo Tomoyuki Fujii Keiji Takabe Yoshihiro Katayama Noriyuki Morohoshi 《Planta》1996,200(1):13-19
The polypeptide encoded by the partial fragment of cDNA of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), PALcDNAl (Osakabe et al., 1995, Plant Sci. 105: 217–226), isolated from Populus kitakamiensis (P. sieboldii x P. grandidentata), was expressed in Escherichia coli cells. The polypeptide was purified and an antiserum raised against it. The antiserum recognized a protein of 77 kDa on nitrocellulose blots after sodium dodecyl sulfate-poly-acrylamide gel electrophoresis of total protein and the partially purified PAL protein from P. kitakamiensis. Moreover,the antiserum recognized a protein on the blot after non-denaturing polyacrylamide gel electrophoresis of P. kitakamiensis proteins and this protein had PAL activity. Furthermore, the antibody inhibited PAL activity of extracts from stem tissues. These results showed that the antiserum against the partial PAL peptide recognized only the PAL subunits in extracts of P. kitakamiensis. Immunolocalization studies of P. kitakamiensis tissues revealed that the PAL protein was specifically localized in the xylem and the phloem fibers and no immunogold signal was found in the epidermis, the cortex, the pith, or the cambium of either stems or leaves.Abbreviations IgG
immunoglobulin G
- IPTG
isopropylthio--d-galactoside
- PAL
phenylalanine ammonia-lyase
The authors thank Dr. Kunio Hata of Nippon Paper Industries Co., Ltd. (Japan) for supplying P. kitakamiensis. This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (No. 07406008). 相似文献
16.
Food habits of sika deer on the Boso Peninsula,central japan 总被引:6,自引:0,他引:6
The rumen contents of sika deer (Cervus nippon Temminck) on the Boso Peninsula, central Japan, were analyzed to identify local, sexual and age-specific differences in food
habits. Graminoids and woody plants were the primary foods throughout the year. In winter, the use of evergreen broad leaves
increased. The food habits of sika deer on Boso Peninsula were intermediate between those of populations inhabiting northern
and southern Japan. Acorns, mainlyLithocarpus edulis Nakai, were consumed in fall and winter with a peak in October. Since the availability of acorns is not influenced by foraging
in previous years, it can be regarded as a stable food supply and hence may be important for deer on the Boso Peninsula. The
local difference between the Amatsukominato (AT) area, having a large plantation ofLithocarpus producing acrons, and the Kamogawa-Katsuura (KK) area, having a small plantation ofLithocarpus, was recognized; seeds and fruit were consumed more in AT than in KK in fall and winter. Males consumed more seeds and fruit
than females at both sites in fall. This can be attributed to sexual differences in nutritional requirement. 相似文献
17.
Hiraishi Katsuya; Suzuki Keiji; Hakomori Sen-itiroh; Adachi Masakazu 《Glycobiology》1993,3(4):381-390
Apoptosis (programmed cell death) is a basic physiological processwhich determines specific patterns of tissue size and shape,and balance of cell number, during morphogenesis, and seemsto play an integral role in oncogenic progression. Since dramaticchanges of cellular glycosylation pattern are well known tobe closely correlated with differentiation, development andoncogenesis, it is likely that similar specific changes areassociated with apoptosis. However, this possibility has notbeen systematically investigated. We therefore carried out histologicalstudies of many tumours and normal tissues for which a highincidence of apoptosis is believed to occur. Sections were stainedwith monoclonal antibodies (MoAbs) directed to carbohydrateantigens Ley and Lex, proliferating cellular nuclear antigen(PCNA) and Fas (previously claimed to be an apoptosis-inducingantigen). Antibody staining patterns were compared with morphologicalcell characteristics as revealed by haematoxylin/eosin staining,and DNA fragmentation patterns (a marker of apoptosis) as revealedby 3'-OH nick-end labelling technique. We found that expressionof Ley (defined by MoAb BM1) is closely correlated with theprocess of apoptosis, but not with cell proliferation or necrosis.Within Ley-positive areas of tissue sections, typical apoptoticmorphological changes and DNA fragmentation (as revealed bypositive nick-end labelling) were frequently observed in certainloci, although not all Ley-positive cells showed such signsof apoptosis. Ley-positive areas showed consistent negativestaining by MoAb directed to PCNA and negative or weak stainingby MoAb directed to Fas antigen, regardless of tissue source.No such trends were observed for Lex glycosylation. We concludethat Ley expression is a useful phenotypic marker predictiveof apoptosis, i.e. some (although not all) Ley-positive cellssubsequently become apoptotic. apoptosis expression glycosylation patterns Ley antigen 3'-OH nick-end labelling 相似文献
18.
The density of a Japanese serow (Capricornis crispus) population, which has been in stable habitat conditions and free from hunting and predation, was investigated by direct
observation of serows at Kusoudomari (336 ha), Wakinosawa village, Aomori Prefecture, Japan, during 1977–89. The vegetation,
composed of mature mixed forest ofThujopsis with deciduous trees (43.2%), secondary forest of deciduous trees (23.4%) and a plantation of coniferous trees (30.0%) showed
little change during the study period. The serows were counted 17 times each winter for 14 consecutive years. The serow population
maintained a stable density with a mean of 12.5 individuals km−2 (SD=1.4) ranging from 8.6 to 14.6 km−2. The ratio of the proportion of kids (<1 year old) to serows more than 1 year old decreased, but density did not decrease
during the study period. Though extremely severe winters with heavy snowfall in 1984–86 caused a decline in serow density,
the density recovered within a few years. It was considered that the stability of the serow density resulted mainly from the
stable food supply and the lack of human disturbance, such as forest cutting in the habitat. Stable population density for
a long period is probably related to the social organization of the serow. 相似文献
19.
Kanji Hori Yoshiharu Shimada Chihiro Oiwa Keisuke Miyazawa Keiji Ito 《Journal of applied phycology》1993,5(2):219-223
Nine species of marine algae have been assessed for the presence of novel hemagglutinins not extractable with buffer, unless
the algal tissue was pretreated with Pronase. All species examined contained hemagglutinins, indicating the existence of a
novel group of hemagglutinins which differed from those reported previously in marine algae. 相似文献
20.
Yoshihiro Takasugi Keiji Kawata Takahiko Okuda Yoshihisa Koga Nobuyuki Mizuguchi Shigeaki Yamanaka Shinsuke Watanabe 《Experimental Animals》2003,52(5):429-432
Age-related alterations and differences of weights and those of amino acid concentrations in the cerebrospinal fluid (CSF) were evaluated between Sprague Dawley (SD) rats and Wistar Kyoto (WKY) rats from eight to twenty weeks of age. The weights of SD rats were heavier than WKY rats at all ages. The age-related alterations of the CSF concentration of many amino acids within each strain were significant but showed no significant trend with age. Between the strains, the concentration differences of excitatory and inhibitory amino acids were not frequent although the concentrations of arginine, alanine and threonine were significantly higher in SD rats than in WKY rats. These results suggest that the different CSF concentrations of amino acids may relate to characteristics of rat strains. 相似文献