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81.
Summary Dysgenic hybrids of Drosophila melanogaster were screened for the induction of mutations in the Y chromosomal fertility genes. Out of 2,417 Y chromosomes analysed 13 male steriles (ms (Y)) were isolated. This high rate of mutation is most probably due to the unusually large physical size of the fertility genes. 相似文献
82.
Ulrich Lehmann 《Pal?ontologische Zeitschrift》1985,59(1-2):99-108
The ink sacs within the living chambers of ammonites as hitherto published seem to be remains of the stomach-crop-complex. Ammonites had no ink sacs. Fossilised remains of gills were found within the living chambers of three ammonoid specimens (generaOphiceras, Hildoceras, Eleganticeras). Their state of preservation is not good enough to identify their numbers. Their shape seems to be not quite dissimilar to that of recentNautilus. Reflections concerning the eyes of ammonites suggest that they were of the pinhole type like those of recentNautilus. 相似文献
83.
Summary The distribution and storage of major elements in acid soils from a spruce and a beech forest was investigated after fertilization of NH4NO3 and KCl followed by Ca and Mg fertilization by 2 liming applications. All fertilizers were applied on top of the soil without mixing. Most of the added Ca and Mg was detected in the humus layer, a significant part of it still in carbonatic form. The effect of liming on mineral soil pH is very low, and was only observed in the 0–10 cm layer. However, base saturation of the mineral soil increased. The storage of C and N of the humus layer was not affected. N fertilization increased the N storage of the soil only under beech, but was followed by heavy NO3-losses with seepage water under spruce. High leaching rates for K were also found in the spruce stand. The amount of K that was not leached increased the pool of exchangeable K in the deeper soil layer. 相似文献
84.
W. Stauber V. Fritz B. Dahlmann F. Gauthier H. Kirschke R. Ulrich 《The Histochemical journal》1985,17(7):787-796
Summary Proteinases and proteinase inhibitors have become suspect in a wide variety of muscle wasting conditions that might be treatable if knowledge of the cellular locale and function of these molecules were known. Fluorescent probes have been useful in the localization of proteinases in muscle samples from human and animal specimens. These include the histochemical localization of proteinases based on the specific fluorescence of hydrolysis product derivatives, but this approach has been limited to the lysosomal proteinases because of the acidic requirements of the trapping reaction of the primary reaction product. Immunohistochemical techniques do not have the same restrictions and a number of lysosomal and nonlysosomal proteinases have been identified in muscle by this means. Unfortunately, they do not yield any information as to the activity of the enzymes. This is an important consideration since the extracellular environment contains a number of proteinase inhibitors, some of which may be internalized by the cell. 相似文献
85.
Nucleotide sequence analysis of a variant human T-cell leukemia virus (HTLV-Ib) provirus with a deletion in pX-I. 总被引:11,自引:9,他引:2
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L Ratner S F Josephs B Starcich B Hahn G M Shaw R C Gallo F Wong-Staal 《Journal of virology》1985,54(3):781-790
A variant of human T-cell leukemia virus subgroup I (HTLV-I), designated HTLV-Ib, has been isolated from a transformed T-lymphocytic cell line established from a Zairian patient with adult T-cell lymphoma. A recombinant phage clone of the variant provirus, denoted lambda MC-1, hybridizes under high stringency to HTLV-I DNA probes, but 17 of 43 restriction enzyme sites differ from those of HTLV-I, 10 of them clustering within 1.5 kilobases in the env-pX region. Since this variant virus retains its capacity to transform T-cells in vitro, and since a pX product is suspected to be important in transformation, we have determined the nucleotide sequence of the entire pX region of this virus for comparison to the prototype HTLV-I. In addition, the region between the gag and pol genes, parts of the pol and env genes, and a portion of the U3 region of the long terminal repeat sequence were also analyzed. We noted 141 single-base-pair changes among 3,897 base pairs, which were relatively well distributed over those portions of the provirus that were examined. In addition, an 11-base-pair deletion was found which included the potential initiator ATG codon of the first open reading frame of pX (pX-I). The next potential initiator codon predicted by the sequence is followed by 10 codons and then a termination codon. An identical deletion was also demonstrated in the only provirus present in another cell line established from the same patient on a different occasion after transformation in vitro of normal human umbilical cord blood cells. These results indicate that pX-I is not required for transformation. 相似文献
86.
By use of the pressure-clamp technique, the hydraulic conductivity of the brackish-water alga Lamprothamnium was found to be 5·10-6 cm s-1 bar-1. The dimensions of the internodes are so small that it is possible, for the first time, to measure a complete volume relaxation upon clamping the turgor pressure to a preset value by a feedback control of the pressure probe. As theoretically predicted, the values of the hydraulic conductivity obtained from the initial slope of the volume relaxation induced by the pressure clamp are in agreement (within experimental error) with those obtained from the half-time of the relaxation process. The cell volume also obtained from the analysis of the volume relaxation is the osmotically effective cell volume and is therefore slightly smaller than the value obtained by taking the dimensions of the cell including the cell wall.Abbreviations and symbols Lp
hydraulic conductivity
- P
turgor pressure
- Sv
initial slope of volume relaxion
- T1/2
half-time of volume relaxation
Dedicated to Professor Dr. H. Ziegler on the occasion of his 60th birthday 相似文献
87.
K. D. Hahn F. Buck H. Rüterjans B. K. Chernov K. G. Skryabin M. P. Kirpichnikov 《European biophysics journal : EBJ》1985,12(2):87-95
The 17 base pair operator O
R
3 oligonucleotide, which is the preferential binding site for the Cro repressor of phage , was studied by two-dimensional NMR spectroscopy. A sequential assignment procedure based on two-dimensional Nuclear Overhauser Effect (NOESY) and scalar coupling correlated (COSY) NMR spectroscopy, together with the knowledge of the oligodesoxynucleotide sequence, made it possible to assign the non-exhangeable base protons and the H1 and the H2-H2 sugar protons of the O
R
3 operator DNA. The pattern of the observed NOE connectivities is consistent with a right-handed helical DNA structure. The base and sugar proton assignments provide the necessary information for further studies of the O
R
3 operator — Cro repressor interaction.Abbreviations COSY
correlated spectroscopy
- FID
free induction decay
- NOE
nuclear Overhauser effect
- NOESY
nuclear Overhauser effect spectroscopy
- RD
relaxation delay
- TSP
sodium 3-trimethylsilyl-(2,2,3,3-2H4)propionate
- EDTA
sodium ethylendiamine tetraacetate 相似文献
88.
The potential use of multiple-frequency-band radiometry as a means of noninvasive sensing of one-dimensional temperature profiles is presented in this communication. The radiative energy transfer equation is solved numerically. Ideal-condition thermal noise spectra and distributions of received energy, associated with specific temperature-depth profiles, are presented. Performance characteristics are discussed. 相似文献
89.
Methanobacterium thermoaggregans is a new thermophilic autotrophic rod-shaped methane producing bacterium. The organism likes to form aggregates during growth and utilizes only H2 and CO2 as substrates. Growth optimum is at 65°C with a doubling time of 3.5 h. Optimal growth occurs at pH-values between 7 and 7.5. The addition of yeast extract to the mineral salt medium stimulates growth. The DNA base composition is 42 mol% G+C. The organism was isolated from mud taken from a cattle pasture. Because of its optimal growth temperature and its tendency to form aggregates the nameMethanobacterium thermoaggregans is suggested.Abbreviations G+C
Guanine+cytosine 相似文献
90.