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81.
82.
Philip Skehan Susan J. Friedman 《In vitro cellular & developmental biology. Plant》1985,21(5):288-290
Summary A rapid method has been developed for measuring the cellular protein content of mono- and multilayered anchorage cultures.
Fixed or air dried cultures are stained for 30 min with 0.2% Naphthol Yellow S (NYS) dissolved in 1% acetic acid. Unbound
dye is removed by a series of four 2.5 min washes in 1% acetic acid, and protein-bound dye extracted with 10 mM unbuffered Tris base for spectrophotometric optical density determination at 433 nm. The NYS method exhibited a least-squares
correlation coefficient of 0.99997 with the Oyama-Eagle Lowry method. 相似文献
83.
A method is described which allows a large number of bacterial strains to be rapidly and easily screened for the presence of site-specific endonucleases. The method involves selective permeabilization of the bacterial cell and analysis of the exuded material. Type II restriction endonucleases from cyanobacteria and Gram-negative eubacteria have been detected and new enzymes have been found. The method should be widely applicable and easy to modify for use in genera other than those tested. Three-site-specific endonuclease activities, detected by this method in Aphanothece halophytica PCC 7412, were purified and their recognition and cleavage specificities were determined AhaI and AhaII recognise and cleave the same DNA sequences as CauII and AcyI respectively; the specificity of AhaIII (TTTAAA) has been reported previously (Whitehead and Brown, 1982, FEBS Letters 143:296–300).Abbreviations Brij-58
20 cetyl ether
- Pu
purine nucleoside
- Py
pyrimidine nucleoside 相似文献
84.
DNA probe localization at 18p113 band by in situ hybridization and identification of a small supernumerary chromosome 总被引:46,自引:9,他引:37
M. G. Mattei N. Philip E. Passage J. P. Moisan J. L. Mandel J. F. Mattei 《Human genetics》1985,69(3):268-271
Summary Recombinant plasmid clone B74 (also named D18S3) containing a human single-copy DNA segment of 6 kilobases (kb) was localized by in situ hybridization on band p113 of chromosome 18. This probe was then used in cytogenetic diagnosis to identify precisely a small supernumerary chromosome as an isochromosome i(18p). 相似文献
85.
Scott H. Ligman Philip H. Brownell 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,157(1):31-37
Summary The peptide-secreting bag cell neurons ofAplysia californica activate a long-lasting, complex behavior called egg laying. During egg laying some organ systems (reproductive) are more active than others (digestive) suggesting that blood flow to these tissues may change in accordance with their activities during egg laying. To examine this possibility we used a semi-intact preparation of the three major arteries innervated by the abdominal ganglion. We found that electrically stimulated bursts of bag cell activity triggered a long-lasting (>1 h) increase in contractile activity in two arteries, the anterior and gastroesophageal, but did not affect contractions of the third (abdominal) artery. The arterial responses were not affected either in form or duration by denervation of the arteries, suggesting that the increase in contractile activity was mediated by hormonal actions of bag cell transmitters on vasoconstrictor muscles. In intact animals this differential action on the arterial system may cause a long-term decrease in blood flow to relatively inactive tissues (digestive and locomotory organs) while increasing circulation to tissues involved in egg production (ovotestis and oviduct).Abbreviations
ASW
artificial sea water
-
BCA
bag cell activation
-
ELH
egg laying hormone 相似文献
86.
An Autosomal Gene That Affects X Chromosome Expression and Sex Determination in CAENORHABDITIS ELEGANS 总被引:4,自引:3,他引:1
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Recessive mutant alleles at the autosomal dpy-21 locus of C. elegans cause a dumpy phenotype in XX animals but not in XO animals. This dumpy phenotype is characteristic of X chromosome aneuploids with higher than normal X to autosome ratios and is proposed to result from overexpression of X-linked genes. We have isolated a new dpy-21 allele that also causes partial hermaphroditization of XO males, without causing the dumpy phenotype. All dpy-21 alleles show hermaphroditization effects in XO males that carry a duplication of part of the X chromosome and also partially suppress a transformer (tra-1) mutation that converts XX animals into males. Experiments with a set of X chromosome duplications show that the defects of dpy-21 mutants can result from interaction with several different regions of the X chromosome. We propose that dpy-21 regulates X chromosome expression and may be involved in interpreting X chromosome dose for the developmental decisions of both sex determination and dosage compensation. 相似文献
87.
Christopher E. Taylor Philip W. Stashak George Caldes Benjamin Prescott B.J. Fowlkes Phillip J. Baker 《Cellular immunology》1984,83(1):26-33
Several lectins were tested for their capacity to alter the antibody response to type III pneumococcal polysaccharide (SSS-III). The antibody response was enhanced by concanavalin A (Con A), phytohemagglutinin (PHA), as well as lectins from Phytolacca americana (Pa-2), Pisum sativum (PSA), and Lens culinaris (LCH), when these lectins were given 2 days after immunization with SSS-III; however, suppression was obtained when Con A and Pa-2 were given at the time of immunization. By contrast the lectins from Vicia villosa (VVL) and Bauhinia purpurea (BPA) did not alter the antibody response. Since the lectins PSA and LCH bind to the same monosaccharide as Con A, whereas the other lectins bind to different monosaccharides, these findings indicate that there is no relationship between nominal monosaccharide specificity and the capacity to modulate the antibody response. Substantial increases in the magnitude of the IgG1 antibody response was noted after the administration of Con A whereas profound enhancement of IgG2a antibody response was noted after PHA was given. 相似文献
88.
Extraction with dimethyl sulfoxide of wood-meal of the stem of bracatinga (Mimosa scabrella), a south Brazilian hardwood, that was defatted and delignified by treatment with aqueous chlorine at 0–5° followed by extraction with cold ethanol, gave a soluble O-acetylated 4-O-methyl-d-glucurono-d-xylan having (1→4)-linked β-d-xylopyranosyl residues that were unsubstituted (65%) and 2-O-(14%), 3-O- (16%), and 2,3-di-O-acetylated (5%), as determined by methylation analysis. Another preparation obtained by use of refluxing ethanol in the delignification process showed neither removal nor migration of acetyl groups. By comparison with synthetic, partly O-acetylated d-xylans of known composition, 13C-n.m.r. spectroscopy indicated that O-acetyl group migration does not occur during treatment with cold aqueous chlorine, refluxing ethanol, or water at 70°. Methyl 2-O-acetyl-4-O-methyl-β-d-xylopyranoside (6) was also unaffected by aqueous chlorine. O-Acetyl group migration took place more readily in aqueous and dimethyl sulfoxide solutions of 6 than of O-acetyl-d-xylans. The lowest temperatures at which migration was observed in monosaccharides was at 50 and 70° for solutions in D2O and (CD3)2SO, respectively. 相似文献
89.
Summary Studies of the diel feeding patterns of the planktivorous fish, Xenomelaniris venezuelae, in Lake Valencia, Venezuela, revealed that, although the fish is primarily a diurnal feeder, it consumes substantial numbers of Chaoborus larvae and pupae at night. A number of fish species are known which feed on plankton at night, but these fish are filter feeders and their diets largely consist of relatively small, nonevasive prey. Chaoborus, however, is large and agile. Predation by Xenomelaniris in the dark was also studied experimentally. Captured fish were placed in completely darkened aquaria with zooplankton from Lake Valencia. After several hours the plankton was removed and examined for evidence of feeding. The fish were found to consume Chaoborus pupae and fourth instar larvae but not other types of prey. The mode of feeding by Xenomelaniris in the dark is unknown. 相似文献
90.
Phospholipid-Sensitive Ca2+ -Dependent Protein Kinase Preferentially Phosphorylates Serine-115 of Bovine Myelin Basic Protein 总被引:1,自引:0,他引:1
R. Scott Turner C.-H. Jen Chou† Gonzalo J. Mazzei Philip Dembure ‡ J. F. Kuo 《Journal of neurochemistry》1984,43(5):1257-1264
Phospholipid-sensitive Ca2+ -dependent protein kinase (PL-Ca-PK) and cyclic AMP-dependent protein kinase (A-PK) both preferentially phosphorylated serine residues of bovine myelin basic protein (MBP). Tryptic peptide maps of MBP phosphorylated by PL-Ca-PK or A-PK, however, revealed different phosphopeptides, suggesting a difference in the intramolecular substrate specificity for the two enzymes. Serine-115 of MBP, in the sequence (-Arg-Phe-Ser(115)-Trp-), was found to be a preferred and probably major phosphorylation site for PL-Ca-PK. Because serine-115 of bovine MBP corresponds to serine-113 of rabbit MBP, an in vivo phosphorylation site reported by Martenson et al. (1983), and PL-Ca-PK is present at a very high level in brain and myelin, it is suggested that the enzyme may be responsible for the in vivo phosphorylation of this and other sites in MBP. 相似文献