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981.
Complete accounts of the natural products chemistry of Bonnemaisonia nootkana, B. asparagoides, B. hamifera and Trailliella intricata are described. In contrast to the chemistry of the closely related alga Asparagopsis, Bonnemaisonia spp. do not produce halomethanes, but instead an array of C7-C9 halogen-containing ketones, alcohols and carboxylic acids. Biomimetic syntheses of these compounds suggest they are precursors and products of in vivo Favorsky rearrangements. 相似文献
982.
A variety of preparative methods for in situ X-ray energy dispersive analysis were tested to determine their effects on the elemental composition of polyphosphate bodies in P. boryanum. The bodies were found to contain large amounts of P and K and small amounts of Ca and Mg. Air drying, freeze-drying and freeze-drying from a liquid nitrogen slush all gave similar results. Fixation of the cells in glutaraldehyde and/or OsO4 resulted in loss of the K and enhancement of the Ca peak. Magnesium was lost during embedding in epoxy. 相似文献
983.
Garner William D. Farmer Jeffrey L. Prager Morton D. 《Cancer immunology, immunotherapy : CII》1980,10(1):7-16
Summary Extraction of Cohn IV-1, an -globulin enriched fraction of human plasma, with a high-salt, low-pH solution, followed by sequential ultrafiltration steps yielded an immunosuppressive preparation (UM05R) of mol.wt. 500–10,000. UM05R inhibited antibody formation in the mouse in vivo and transformation in vitro of lymphocytes treated with either T-or B-cell stimulants. Suppression of lymphocyte transformation, indicated by inhibition of 3H-thymidine incorporation into DNA, was confirmed by inhibition of blast cell formation. From dose-response curves the UM05R concentration to produce 50% suppression of lymphocyte blast transformation was 15–50 g protein/ml. Selectivity for lymphoid cells was suggested by growth inhibition in vitro of L1210 and P1798 leukemias but not murine neuroblastoma or human fetal fibroblasts. This observation also rules out the presence of an agent which is broadly cytotoxic. Fractionation of UM05R on Sephadex G-25 in 10% acetic acid yielded an early-emerging fraction, mol. wt. 5,000–10,000, containing B-cell inhibitor, and a late fraction, mol. wt. 1,400, inhibitory for both T- and B-cell transformation and growth of L1210. The inhibitory activity for B cells was removed from the other two activities by 5% trichloroacetic acid (TCA). The possibility is raised that the inhibitory activity for T cells and L1210 may reside in the same molecule. Sensitivity of the early-emerging B-cell inhibitor to carboxypeptidase B suggests that it is a polypeptide, but resistance of the T-cell inhibitor to various treatments leaves its nature uncertain. The properties of these factors suggest consideration of them as lymphocyte chalones occurring in plasma complexed to high-molecular-weight components. 相似文献
984.
Joseph S. Lam Dan M. Granoff Janet R. Gilsdorf J. William Costerton 《Current microbiology》1980,3(6):359-364
We prepared outer membrane derivatives ofHaemophilus influenzae type b to determine whether the residual capsular and noncapsular surface components are immunogenic and protective. These
fragments consist primarily of six major proteins and lipopolysaccharide. By transmission electron microscopy, they appeared
as small, membrane-like fragments or larger, cellshaped double-track ghosts. Rabbits immunized with ghosts responded with
increases in serum anticapsular antibody and bactericidal activity. Antisera absorbed with capsular antigen to remove anticapsular
antibody remained bactericidal and passively protected infant rats. These data suggest that antibodies to noncapsular surface
antigens are protective, and that outer membrane derivatives retain some of the constituents responsible for stimulating immunity. 相似文献
985.
Terrance O. Kurtz Drew J. Winston William J. Martin Lowell S. Young William L. Hewitt 《Current microbiology》1980,4(1):21-26
Moxalactam (LY127935), a novel beta-lactam antibiotic, was compared with semisynthetic penicillins, cephalosporins, and aminoglycosides
by the agar dilution method against 5,317 recent clinical isolates of facultative and anaerobic bactria. At 0.5 μg/ml, moxalactam
inhibited 90% of all Gram-negative bacilli tested except forPseudomonas aeruginosa (81% inhibited by 32 μg/ml) andAcinetobacter calcoaceticus (88% inhibited by 32 μg/ml). More than 90% ofBacteroides fragilis andStaphylococcus aureus were inhibited by 4 μg/ml and 8 μg/ml, respectively. Moxalactam was at least 16-fold more active by weight than cephalothin,
cefamandole, and cefoxitin forEscherichia coli, Klebsiella pneumoniae, andEnterobacter species, and 2- to 4-fold more active than cefoxitin forB. fragilis. Moxalactam was 4-fold less active than cefamandole and cephalothin forS. aureus and 2- to 4-fold less active than piperacillin forP. aeruginosa. Moxalactam was as active or more active than the aminoglycosides for all facultative Gram-negative bacilli except forP. aeruginosa. Moxalactam was inhibitory (minimal inhibitory concentration <16 μg/ml) for 20/27 gentamicin-resistant isolates and 8/13
amikacin-resistant organisms. Moxalactam’s in vitro activity against Gram-negative bacilli is markedly superior to presently
available cephalosporins and, except forP. aeruginosa, is comparable to the aminoglycosides. 相似文献
986.
Murine splenic B lymphocytes are induced to proliferate and undergo polyclonal activation in the presence of Fc fragments, AHGG, antigen-antibody complexes, and CH3 fragments derived from plasmin digestion of human Ig. The unifying feature of the polyclonal antibody response induced by these agents is that in all cases a portion of the constant region of the Ig molecule (ie, Fc region) is present. Fragments of Ig lacking the Fc piece, such as Fab and F(ab′)2 were found not to be stimulatory. In addition, a model is proposed to account for the regulatory effects of antigen-antibody complexes on an ongoing humoral immune response. 相似文献
987.
988.
Selective isolation and culture of a proliferating epithelial cell population from the hamster trachea 总被引:7,自引:0,他引:7
William E. Goldman Joel B. Baseman 《In vitro cellular & developmental biology. Plant》1980,16(4):313-319
Summary A reliable cell isolation technique was developed to allow the cultivation of cells from the hamster respiratory tract. Repeated
thermolysin treatments and gradient centrifugation yielded a cell culture completely free from contamination by fibroblasts.
Viable cells could be isolated from as little tissue as a single hamster trachea, but in vitro proliferation occurred only
if the hamster was less than 4 months of age. The cultured cells could be repeatedly passaged and subcultured for weeks by
employing normal tissue culture techniques. Morphologically, the monolayers appeared to be a homogeneous population of epithelial
cells, and successful cloning of freshly isolated single cells resulted in apparently identical cultures. The epithelial origin
of these cells was also suggested by continued growth in minimum essential medium withd-valine substituted forl-valine. The relative ease with which this cell type can be isolated, cultured, and manipulated in vitro should encourage
its application as a model of the respiratory epithelium.
This research was supported by Public Health Service Grant P50-HL 19171 and Research Career Development Award 1-K04-AI 00178
to J. B. B. 相似文献
989.
William H. J. Douglas James A. McAteer Robert T. Dell'orco David Phelps 《In vitro cellular & developmental biology. Plant》1980,16(4):306-312
Summary A one-step vital stain is described for the macroscopic visualization of histotypic cell aggregates in fetal rat lung organotypic
cultures. Organotypic cultures are incubated in 0.05-0.1% 2,3,5′-triphenyl tetrazolium chloride (TTC) in culture medium (37°C).
Living cells reduce the tetrazole to a water-insoluble red colored formazan. Cell aggregates appear as densely stained foci
against the lighter background of the Gelfoam substrate. Stained cultures may be scanned macroscopically to determine the
degree of reaggregation and assess cell viability. Identification of aggregates by TTC staining improves the efficiency of
tissue processing for electron microscopy and does not alter the ultrastructural appearance of the cultured cells.
This work was funded in part by the United Cerebral Palsy Research and Educational Foundation, Inc. and the National Heart,
Lung, and Blood Institute (Grants 1ROHL19513 and 1 R01HL21008). 相似文献
990.
William A. Horton Nena Dockery David Sillence David L. Rimoin 《Biotechnic & histochemistry》1980,55(1):19-29
We have used glycol methacrylate to study undecalcified skeletal growth plate and subchondral bone. Minor modifications of the original technique including dehydration in glycol methacrylate vacuum infiltration and polymerization in the cold make it quite suitable for embedding of such tissues. Moreover, specimens can be processed quickly and the morphologic and biochemical integrity of the tissue retained so that histochemical procedures can be readily applied. Collagen, glycosaminoglycan, glycogen, lipid, calcium and the activity of alkaline and acid phosphatase were localized. This technique appears to be very useful for studying skeletal tissues. 相似文献