首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Summary The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F1; F2 and F3 progenies of the crosses of 21 resistant varieties with the susceptible variety TN 1 revealed that a single dominant gene governs resistance in Mushkan 41, Santhi, Siahnakidar 195, SM2-34, Tirisurkh 251, Zirijowaian 245, 18, 24A, 39, 76 S, 78, 180, 213 B, 267, 293, CI 6037-4, NP97, S39 JKW and Bansphul. In varieties 65 and 274 A, resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in N 22 revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties 65 and 274 A.  相似文献   

2.
Summary Human and rabbit masticatory muscles were analyzed immuno-and enzyme-histochemically using antibodies specific to cardiac , slow and fast myosin heavy chain isoforms. In human masseter, temporalis, and lateral pterygoid muscle cardiac myosin heavy chain is found in fibres that contain either fast, or fast and slow myosin heavy chain. In rabbit masseter, temporalis and digastric muscles, fibres are present that express cardiac myosin heavy chain either exclusively, or concomitantly with slow myosin heavy chain or fast myosin heavy chain. Our results demonstrate a much broader distribution of cardiac myosin heavy chain than hitherto recognized and these might explain in part the specific characteristics of masticatory muscles. The cardiac myosin heavy chain is only found in skeletal muscles originating from the cranial part of the embryo (including the heart muscle) suggesting that its expression might be determined by the developmental history of these muscles.  相似文献   

3.
On age morphological changes of males of Chydoridae (Cladocera)   总被引:2,自引:2,他引:0  
N. N. Smirnov 《Hydrobiologia》1967,30(3-4):555-571
Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.  相似文献   

4.
We have established a strain of transgenic mice in which the HLA-DRA gene was integrated into the X-chromosome and the xenogeneic mixed isotype molecule, DREb, was expressed in a cell type-specific manner, although the transgenic DRA gene contained only 268 base pairs of the 5-flanking region. The DREb molecules expressed in the transgenic mice functioned as major histocompatibility complex (MHC) class II to select T-cell repertoire, and to stimulate mixed lymphocyte reaction. In female transgenic mice homozygous for HLA-DRA (DR-B6-F-homo) and male transgenic mice (DR-B6-M), DREb molecules were expressed in almost all of the MHC class II Ab-positive cells. In contrast, the expression of DREb molecules in female transgenic mice hemizygous for HLA-DRA (DR-B6-F-hemi) was found only in part of the Ab positive cells, and the proportion of cells expressing the DREb molecules varied due to random inactivation of one of the X-chromosomes. Clonal deletions of the T cells and mature thymocytes bearing Tcrb-V5 and Tcrb-V11, which are eliminated from the peripheral repertoire in mice expressing self-superantigen and MHC class II E molecules, were incomplete in DR-B6-F-hemi as compared with those in DR-B6-F-homo, and were correlated with the proportion of DREb-positive spleen cells. These observations suggested that the number of bone marrow-derived cells expressing DREb molecules was critical for clonal deletions of Tcrb-V5+ and Tcrb-V11+ T cells in the thymus.  相似文献   

5.
A defined set of oligosaccharides and glycopeptides containing -linked fucose were used to examine the specificity of the immobilized fucose-binding lectin Lotus tetragonolobus agglutinin (LTA1), also known as lotus lectin. Glycans containing the Lewis x determinant (Lex) Gal1-4[Fuc1-3]GlcNAc1-3-R were significantly retarded in elution from high density LTA-Emphaze columns. The lectin also bound the fucosylated lacdiNAc trisaccharide GalNAc1-4[Fuc1-3]GlcNAc. The lectin did not bind glycans containing either sialylLex or VIM-2 determinants, nor did it bind the isomeric Lea, Gal1-3[Fuc1-4]GlcNAc-R. Although 2-fucosyllactose Fuc1-2Gal1-4Glc) was retarded in elution from the columns, larger glycans containing the H-antigen Fuc1-2Gal1-3(4)GlcNAc-R interacted poorly with immobilized LTA. Our results demonstrate that immobilized LTA is effective in isolating glycans containing the Lex antigen and is useful in analyzing specific fucosylation of glycoconjugates. Abbreviations: LTA, Lotus tetragonolobus agglutinin; UEA-1, Ulex europaeus agglutinin-I; LNT, AAL, Aleuria aurantia agglutinin; Gal1-3GlcNAc1-3Gal1-3Glc; LNnT, Gal1-4GlcNAc1-3Gal1-3Glc; Lex, Lewis x antigen; Lea, Lewis a antigen; GDPFuc, guanosine 5-diphosphate--L-fucose  相似文献   

6.
Summary Tobacco plants (Nicotiana tabacum L.) of four varieties (Badischer Burley, White Burley, Techne, Kupchunos) were raised at different temperatures and daylengths and the effect of genotype on embryogenic pollen grain formation in situ and on pollen plant formation in anther and pollen cultures from these plants was studied. Genotype controlled embryogenic pollen grain and pollen plant formation by defining productivity under standard growth conditions (long days at 24 °C). Kupchunos was the most productive variety, followed by White Burley, Techne, and Badischer Burley. Furthermore, genotype defined which environmental factor was able to affect embryogenic pollen grain and pollen plant formation and also to which degree. In anther cultures, in addition to these effects, genotype controlled the formation of (an) inhibitory substance(s) in the anther wall in interaction with the plant growth conditions. In Badischer Burley and Techne, inhibitor action could be prevented by isolation of the pollen after one week of anther culture. Finally, direct pollen cultures in Badischer Burley and Techne produced embryos were only when the pollen was isolated from nearly mature anthers, while in White Burley and Kupchunos, embryos also produced at earlier stages and at higher yields. This indicated that genotype controls the time when the embryogenic pollen grains become ready to divide. The results are discussed in relation to strategies to overcome recalcitrance of species and genotypes.  相似文献   

7.
Interferon- (IFN),4 a cytokine with modulatory activities on many cell types, is useful for treating many types of cancer and infectious diseases. This study investigates whether modification of a protein, using IFN as an example, with a lipophilic group can alter its distribution and kinetic properties in the body. Ser163 of IFN2a was mutated to Cys to generate a free sulfhydryl group for site-specific chemical modification. IFN2a(S163C) was conjugated by iodoacetamide derivatives of varying lengths, and the modified IFN2a was purified by gel filtration chromatography. The biological activities of IFN2a(S163C) and lipophilized IFN2a(S163C) were similar to that of IFN2a, as evidenced by their inhibitory effects on the growth of Daudi cells and on the replication of vesicular stomatitis virus in Madin-Darby bovine kidney cells. Lipophilized IFN2a(S163C) bound to human serum albumin and cell membranes more readily than did IFN2a. Future experiments will investigate whether lipophilized IFN2a(S163C) has improved pharmacokinetic properties.  相似文献   

8.
Myobacterium avium LM1 was exposed to concentrations of 5-fluorouracil (5FU) that ranged from 0 to 100 g/ml. Growth inhibition was inversely proportional to the concentration of the drug. DNA was extracted from cells grown in medium that contained [14C]5FU, but no carrier. The [14C]DNA was enzymatically hydrolyzed to deoxyribonucleotides, which were separated and fractionated by high-performance liquid chromatography (HPLC). The isotope was located in 2-deoxycytidine 5-monophosphate (dCMP) and 2-deoxythymidine 5-monophosphate (dTMP), with dCMP containing the majority. There was no radioactivity at the elution times for 5-fluoro-2-deoxyuridine 5-monophosphate or 2-deoxyuridine 5-monophosphate. These results suggested that 5FU was dehalogenated and the uracil moiety ultimately converted into cytosine and thymine deoxyribonucleotides. Cells were grown in [3H]uracil, and [3H]DNA was extracted and analyzed by HPLC. The isotope was found only in the pyrimidine deoxyribonucleotides, with dCMP containing 4.1 times that in dTMP. Thus, it was demonstrated that uracil and dehalogenated 5FU were not directly incorporated into DNA, but rather converted to cytosine and thymine and then incorporated into DNA by a salvage pathway.  相似文献   

9.
We have initiated embryogenic cell suspension cultures of barley (Hordeum vulgare L.) Igri from isolated microspore cultures. Data were obtained on the time required for establishment, frequency of establishment, i.e. number of calluses out of the total number of initiations giving rise to suspensions, and embryogenic capacity of the suspension cultures. For comparison, establishment of embryogenic cell suspensions from callus derived from immature zygotic embryos of Igri, Dissa and Golden Promise was also carried out. The results revealed that embryogenic suspension cultures were established in half the time and with a seven-fold higher frequency from microspore cultures than from zygotic embryo-derived calluses. The suspension cultures were still capable of embryo formation after two years. However, only albino plantlets were regenerated. For comparison, long term callus cultures derived from microspores, anthers and zygotic embryos were established. From the anther and zygotic embryo-derived callus cultures green plants were continuously regenerated, whereas the microspore-derived callus cultures lost this ability after the second subculture.  相似文献   

10.
Partitioning of water resources among plants of a lowland tropical forest   总被引:3,自引:0,他引:3  
Source water used by plants of several species in a semi-evergreen lowland tropical forest on Barro Colorado Island, Panama, was assessed by comparing the relative abundance of deuterium, D, versus hydrogen, H (stable hydrogen isotope composition, D) in xylem sap and in soil water at different depths, during the dry season of 1992. Ecological correlates of source water were examined by comparing xylem water D values with leaf phenology, leaf water status determined with a pressure chamber, and rates of water use determined as mass flow of sap using the stem heat balance method. Soil water D values decreased sharply to 30 cm, then remained relatively constant with increasing depth. Average D values were-13, for 0–30 cm depth and-36.7 for 30–100 cm depth. Soil water D values were negatively associated with soil water content and soil water potential. Concurrent analyses of xylem water revealed a high degree of partitioning of water resources among species of this tropical forest. Xylem water D of deciduous trees (average=-25.3±1.4) was higher than that of evergreen trees (average=-36.3±3.5), indicating that evergreen species had access to the more abundant soil water at greater depth than deciduous species. In evergreen shade-tolerant and high-light requiring shrubs and small trees, D of xylem water was negatively correlated with transpiration rate and leaf water potential indicating that species using deeper, more abundant water resources had both higher rates of water use and more favorable leaf water status.  相似文献   

11.
Summary The ratio of deuterium to hydrogen (expressed as D) in hydrogen released as water during the combustion of dried plant material was examined. The D value (metabolic hydrogen) determined on plant materials grown under controlled conditions is correlated with pathways of photosynthetic carbon metabolism. C3 plants show mean D values of-132 for shoots and -117 for roots; C4 plants show mean D values of -91 for shoots and-77 for roots and CAM plants a D value of-75 for roots and shoots. The difference between the D value of shoot material from C3 and C4 plants was confirmed in species growing under a range of glasshouse conditions. This difference in D value between C3 and C4 species does not appear to be due to differences in the D value (tissue water) in the plants as a result of physical fractionation of hydrogen isotopes during transpiration. In C3 and C4 plants the hydrogen isotope discrimination is in the same direction as the carbon isotope discrimination and factors contributing to the difference in D values are discussed. In CAM plants grown in the laboratory or collected from the field D values range from-75 to +50 and are correlated with 13C values. When deprived of water, the D value (metabolic hydrogen) in both soluble and insoluble material in leaves of Kalanchoe daigremontiana Hamet et Perr., becomes less negative. These changes may reflect the deuterium enrichment of tissue water during transpiration, or in field conditions, may reflect the different D value of available water in areas of increasing aridity. Whatever the origin of the variable D value in CAM plants, this parameter may be a useful index of the water relations of these plants under natural conditions.  相似文献   

12.
Summary The development of non-specific resistance to tumors following stimulation with poly(maleic-acid-styrene)-conjugated neocarzinostatin (SMANCS), a polymer-conjugated derivative of neocarzinostatin, was investigated in mice. The growth of syngeneic solid tumors (Meth-A fibrosarcoma and RL 1 leukemia) inoculated into BALB/c mice was suppressed after one treatment with SMANCS at doses ranging from 0.14 mg/kg to 3.4 mg/kg i.v. 24 h before tumor implantation. Since previously observations concerning SMANCS have shown that it disappeared within 1.5 h after i.v. administration in mice and that it was inactivated quickly in plasma, SMANCS evidently inhibited tumor growth by mediating non-specific resistance. In addition, the non-specific resistance to tumors stimulated by SMANCS could be passively transferred to untreated mice by serum which was shown to contain interferon (IFN) from 12 h to 20 h after SMANCS administration. However, the resistance was not produced by serum prepared from mice at 8 h or 32 h after administration presumably because of the observation that the interferon activity was only demonstrated from 12 h to 28 h after SMANCS stimulation. When the serum specimens were treated with anti-IFN- antiserum, the antitumor activity of the sera was abrogated. However, no significant change was detected in the antitumor activity of the specimens following treatment with anti-IFN-/ antiserum. Treatment of mice with SMANCS and anti-IFN- antiserum together resulted in the elimination of the non-specific resistance to tumors. The IFN induced in the sera of mice by SMANCS was shown to be 57% IFN- and 41% IFN-/. Half of the interferon produced in SMANCS-stimulated mice could be eliminated by treatment with anti-IFN-, and treatment of SMANCS-stimulated mice with both anti-IFN- and anti-IFN-/ antisera resulted in a total absence of detectable interferon. These findings suggest that while the administration of SMANCS induces both IFN- and IFN-/ production, in this case, it is only the former which mediates the non-specific resistance to tumors.  相似文献   

13.
Summary A mutant strain of Rhodococcus australis CSIR-236.457 which accumulates 3a-H-4-(3-propionic acid)-5-hydroxy-7a-methylhexahydro-indan-1-one--lactone from cholesterol, stigmasterol and -sitosterol was studied. The product is produced in a 60% molar yield in a dilute black strap molasses medium containing 6–12g/l cholesterol after a 72 hour fermentation period.  相似文献   

14.
The content of abscisic acid (ABA) in bulbs of two Allium wakegi Araki cultivars, Kiharabansei No. 1 (dormant type) and Ginoza (nondormant type), was similar and changed similarly during the development and storage of the bulbs. It increased during bulb development, reached a maximum shortly after bulb harvesting, and gradually decreased during bulb storage. The bulbs of Kiharabansei No. 1 showed dormancy correlated with the change in ABA content, but those of Ginoza did not show significant dormancy throughout the experimental period. The ABA content in the buds of dormant bulbs of Kiharabansei No. 1 did not change after planting of bulbs, but that of nondormant bulbs of Ginoza planted on the same day rapidly decreased after planting. Application of ABA to bulbs delayed sprouting of both cultivars, but dormant bulbs of Kiharabansei No. 1 had higher sensitivity to ABA than the bulbs of Ginoza or the bulbs of Kiharabansei No. 1 partly released from dormancy. These results suggest that the decrease in the ABA content after planting (watering) and low sensitivity to ABA are correlated with the nondormancy of Ginoza.  相似文献   

15.
EF-1a binds aminoacyl-tRNA to the ribosome with the hydrolysis of GTP; the complex facilitates the exchange of GDP for GTP to initiate another round of elongation. To examine the subunit structure of EF-1 and phosphorylation by protein kinase CKII, recombinant , , and subunits from rabbit were expressed in E. coli and the subunits were reconstituted into partial and complete complexes and analyzed by gel filtration. To determine the availability of the and subunits for phosphorylation by CKII, the subunits and the reconstituted complexes were examined as substrates for CKII. Formation of the nucleotide exchange complex increased the rate of phosphorylation of the subunit and reduced the Km, while addition of to or the complex inhibited phosphorylation by CKII. However, a had little effect on phosphorylation of . Thus, the and subunits in EF-1 were differentially phosphorylated by CKII, in that phosphorylation of was altered by association with other subunits, while the site on was always available for phosphorylation by CKII. From the availability of the subunits for phosphorylation by CKII and the composition of the reconstituted partial and complete complexes, a model for the subunit structure of EF-1 consisting of (22)2 is proposed and discussed.  相似文献   

16.
The study addressed to understand the regulation of Receptor-Ck gene atthe translational level revealed that exogenous cholesterol has the inherentcapacity to regulate the endogenous synthesis of Receptor-Ck by initiatingintracellular targeting of the Receptor-Ck to the mRNP pool within humanplatelets and this effect could be reversed when the platelets wereincubated with cholesterol coupled with either dB cAMP or dB cGMP. Basedupon these observations, we propose that Receptor-Ck initiated signalling,which involves second messengers like PA, cAMP and cGMP, may be responsiblefor the autoregulation of Receptor-Ck gene expression at the translationallevel.  相似文献   

17.
Summary The efficacy of tumor necrosis factor (TNF) as an anticancer agent is limited. This limitation might be related to the expression of a protein-synthesis-dependent resistance mechanism that prevents the lysis of tumor cells by TNF. To test this possibility eight randomly selected human cell lines, three derived from ovarian carcinomas and five derived from cervical carcinomas, were tested for their in vitro sensitivity to TNF-mediated lysis. The results of this analysis showed that all eight cell lines are normally resistant to lysis by TNF. However, in the presence of inhibitors of protein synthesis, seven of them showed a significant increase in TNF-mediated lysis. Measurement of protein synthesis showed that there is a linear correlation between the level of inhibition of protein synthesis and the level of TNF-mediated lysis. The fact that seven of eight randomly selected cell lines are resistant to TNF because they express a protein-synthesis-dependent resistance mechanism suggests that this mechanism of resistance may be common among gynecological cancers. The results also suggest that a therapy involving TNF and inhibitors of protein synthesis might be useful for the treatment of gynecological malignancies.  相似文献   

18.
Summary A mentally retarded boy with trisomy 9p is described. This trisomy arose through aberrant segregation of translocation chromosome during meiosis in his mother, who has a complex translocation involving chromosomes 9, 13, and 14. Based on both G-, Q-banding, and DNA replication patterns, the patient's karyotype was identified as 47,XY,-13, +(9;13) (9pter9q12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter). We suppose his mother's karyotype to be 46,XX,-9,-13,-14,+t(9;13) (9pterq12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter), +t(9;14) (9qter9q12::14pl?14qter). His phenotypically normal brother and sister are also carriers, having the same translocation chromosome as their mother. Clinical findings of the patient included peculiar face with hypertelorism, prominent nasal bridge and deformed helix, marked delay of osseous development, hypoplastic phalangia in fingers and toes, dysplastic nails and absence of digital triradii.  相似文献   

19.
ATP synthase (F0F1) is driven by an electrochemical potential of H+ (H+). F0F1 is composed of an ion-conducting portion (F0) and a catalytic portion (F1). The subunit composition of F1 is 33. The active 33 oligomer, characterized by X-ray crystallography, has been obtained only from thermnophilic F1 (TF1). We proposed in 1984 that ATP is released from the catalytic site (C site) by a conformational change induced by the DELSEED sequence via -F0. In fact, cross-linking of DELSEED to stopped the ATP-driven rotation of in the center of 33. The torque of the rotation is estimated to be 420 pN·å from the H+ and H+-current through F0F1. The angular velocity () of is the rate-limiting step, because H+ increased theV max of H+ current through F0, but not theK m (ATP). The rotational unit of F0 (=ab2c10) is /5, while that in 33 is 2/3. This difference is overcome by an analog-digital conversion via elasticity around DELSEED with a threshold to release ATP. The distance at the C site is about 9.6 å (2,8-diN3-ATP), and tight Mg-ATP binding in 33 was shown by ESR. The rotational relaxation of TF1 is too rapid (=100 nsec), but the rate of AT(D)P-induced conformational change of 33 measured with a synchrotron is close to . The ATP bound between the P-loop and E188 is released by the shift of DELSEED from RGL. Considering the viscosity resistance and inertia of the free rotor (-c), there may be a stator containing OSCP (= of TF1) and F0-d to hold free rotation of 33.  相似文献   

20.
The effect of cycloheximide and puromycin on 20-hydroxyecdysone-induced protein synthesis in wing discs of Drosophila melanogaster has been studied by one-dimensional and two-dimensional SDS polyacrylamide electrophoresis. It is found that puromycin, but not cycloheximide, when applied simultaneously with the hormone enhanced the hormone-induced synthesis of the early and late proteins. However, when puromycin was applied after hormone treatment, only the late proteins were induced. The possible implication of these observations is discussed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号