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41.
Rowena Brandt Elisabeth Günther Heidrun Herrmann 《Molecular & general genetics : MGG》1984,197(2):292-296
Summary Three loci coding for different steps in the pathway of cysteine biosynthesis have been mapped by R68.45-mediated coconjugation analysis. The cysteine auxotrophic mutants could be subdivided into sulfite and sulfide-requiring mutants. Sulfide-requiring mutants (cysIV group) were localized at a single position between pyrF and pur-67, while sulfite-requiring mutants (cysI and cysII) mapped at two different regions. The cysI group was also localized between pyrF and pur-67, although more distal to pyrF than the cysIV group. This group included the cys-54 marker, which has been mapped previously. The second group of sulfite-requiring mutants, designated as cysII, was cotransducible with hisI and localized at the end of the PAO chromosomal map. This location was also confirmed for the marker cys-59.The marker cys-59 (which was cotransducible with his1) was cotransferred by R68.45-mediated conjugations with both the late marker pur-67 and the early marker ilv-226. As the late marker hisI was positioned at about 60–65 min (Herrmann and Günther, in press) the length of the PAO chromosome was estimated to be about 70 min. 相似文献
42.
Use of monoclonal antibodies as a diagnostic tool in human leukemia. I. Acute myeloid leukemia and acute phase of chronic myeloid leukemia 总被引:1,自引:0,他引:1
Various monoclonal antibodies (mAbs) detecting certain different epitopes on myeloid cells (VIMD5, D5 D6, OKM1, Leu-M3, VIEG4, OKIa 1) have been used in combination with conventional markers (antihuman myeloid hetero-antiserum, FcIgG-receptors, C3d-receptors) to further define the phenotypic heterogeneity of myeloid leukemia. Subsequent leukemic samples from previously untreated patients with acute myeloid leukemia (AML) (51 adults, 24 children) and from nine adult patients in the acute phase of chronic myeloid leukemia (CML-BC) were studied. It was possible to demonstrate quantitative differences in the expression of antigens on the various leukemia subtypes which could be exploited for diagnosis. Furthermore our results revealed that there is a very close correlation between the different surface phenotypes and the types morphologically assessed according to FAB-criteria. 相似文献
43.
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45.
Determination of Melting Sequences in DNA and DNA-Protein Complexes by Difference Spectra 总被引:1,自引:0,他引:1
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A graphical formula is presented for determining the base ratio of melted DNA. By use of this formula, the composition of sequences which melt in different portions of the melting curves of Clostridium DNA, Escherichia coli DNA, and mouse DNA were determined. As the DNA melts, the per cent of adenine and thymine (AT) in the melted sequences decreases linearly with temperature. The average composition of sequences which melt in a given part of the melting curve is proportional to the base ratio of the DNA. The concentration and average composition of sequences were determined for three parts of the melting curves of the DNA samples, and a frequency distribution curve was constructed. The curve is symmetrical and has a maximum at about 56% AT. The distribution of GC-rich sequences on the E. coli chromosome was estimated by shearing, partially melting, and fractionating the DNA on hydroxylapatite. GC-rich sequences appear to occur every thousand base pairs, and have a maximum length of about 180 base pairs. The graphical formula was applied to the determination of the composition of sequences which melt in different parts of the melting curve of chromatin. Throughout the melting curve, the composition of the melting sequences is about 60% AT, which appears to suggest that relatively long sequences are melting simultaneously. Their melting temperature may be a function of the composition of the protein on different parts of the DNA. The problem of light scattering in DNA-protein and DNA was also investigated. A formula is presented which corrects for light scattering by relating the intensity of the scattered light to the rate of change of absorbance of DNA with wavelength. 相似文献
46.
A method previously reported for detecting virus in a model system composed of cottage cheese contaminated with coxsackievirus type A9 has been adapted to detecting selected strains of enteroviruses in a variety of foods. Bentonite is omitted and serum is added for extracting virus from low-protein foods. Samples of foods, usually 25 g, must contain at least 3 to 4 plaque-forming units for a 50% probability of detecting virus. Sensitivity in detecting echovirus type 6 was lower than that for the other viruses used. After extraction from potato salad, poliovirus type 2 was completely reactivated if it had been neutralized with coproantibody, but it was only partially reactivated if neutralized with hyperimmune rabbit serum. 相似文献
47.
Jürgen Herrmann 《Human genetics》1966,3(1):1-16
Assuming that in sibships with sporadic hemophilia the mothers of the patients are already carriers the relationship between the age of the mother's father at birth of the mother and frequency of hemophilia among his grandsons was examined.The ages of the mother's father at birth of the mother of 40 patients with sporadic hemophilia A was compared with that of a control-group as well as with the ages of the mother's fathers at birth of the mothers of patients from families where hemophilia A is inherited. The mean age of these grandfathers was found to be increased. Using the Mann-Whitney-U-test for comparing the ages of grandfathers of sporadic cases with the control-group there is to be found P=.0025, which is highly significant statistically. Comparing data from sibships with sporadic hemophilia with data from sibships where hemophilia is inherited there is no significant difference — perhaps according to the small number of inherited cases (19, P=0.065) —, but the deviation is in the same direction. Comparison of data both from the inherited cases and the control-group with data of sporadic cases gives P=.0087.There is perhaps a connection between parental age and number of children, but it is shown to have no important influence in our material. On the other hand fathers with a higher number of children are significant more frequent among the grandfathers than among the controls. This difference cannot be explained sufficiently. Between cases of sporadic and inherited hemophilia there is no clear cut difference.Certainly there exists a relationship between parental age and birth-rank. Therefore the mothers of sporadic cases — unlike to carriers of sibships with inherited hemophilia — take clearly higher ranks in birth-order than it is theoretically to be expected. Penrose published a method of separating the relative aetiological effects of birth-order and parental age. Using this method an influence of birth-order cannot be found after excluding the influence of parental age. Hence, paternal age seems to be the determining factor.It is discussed which model of mutation the hemophilia-mutation belongs to because of this relationship. We would count it to No. 2 of the classification given by Vogel where mutations are due to copy errors. So cases of sporadic hemophilia seem equal to those of sporadic achondroplasia.
Diese Arbeit wurde der Medizinischen Fakultät der Universität Hamburg als Inaugural-dissertation vorgelegt.
Herrn Prof. Dr. F. Vogel danke ich für wertvolle Hinweise, insbesondere zur statistischen Methodik. 相似文献
Diese Arbeit wurde der Medizinischen Fakultät der Universität Hamburg als Inaugural-dissertation vorgelegt.
Herrn Prof. Dr. F. Vogel danke ich für wertvolle Hinweise, insbesondere zur statistischen Methodik. 相似文献
48.
BIOSYNTHESIS OF COLLAGEN AND NON-COLLAGEN PROTEIN DURING DEVELOPMENT OF THE CHICK CORNEA 总被引:3,自引:2,他引:1
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The relationship between the rates of increase of corneal protein fractions and incorporation of labeled precursors has been examined during embryonic and early posthatching development of the chick corneal stroma. Non-collagen protein increased gradually from 9 through 20 days of incubation. Collagen accumulated approximately logarithmically through the 19th day, the most rapid rate occurring between 13 and 20 days of incubation. The rates at which labeled amino acids are incorporated into collagen in vivo and in vitro undergo marked changes during the last week of embryonic development, corresponding closely to the rate of collagen accumulation in vivo; whereas incorporation into non-collagen protein changes much less markedly. Changes in the rate of incorporation of precursors into collagen are not due to changes in the rate of conversion of collagen from the soluble to insoluble form, or to changes in the endogenous amino acid pool size. Chick embryo corneal stroma collagen turns over very slowly, if at all. Non-collagen protein turns over more rapidly. An increase in cell number, as indicated by DNA content, does not account for the increased rate of collagen synthesis between the 9th and 16th day of incubation. It is concluded that the observed changes in collagen synthesis reflect changing activities in the individual cornea fibroblasts. These activities are comparable in the intact tissue in vivo and in isolated corneas in vitro. 相似文献
49.
Zusammenfassung An männlichen weißen Ratten wurde das Verhalten des Enzymmusters der Leber 72 Std nach Verbrühung untersucht. Es fanden sich Veränderungen im Sinne einer Aktivitätsverminderung bei der NAD-Cytochrom-c-Reduktase, Isocitronensäuredehydrogenase, ATPase und den PJS-positiven Substanzen. Eine Zunahme der Aktivität wurde bei der alkalischen Phosphatase und einigen Esterasen beobachtet, ebenso traten auch die scharlachrotfärbbaren Substanzen auf. Uneinheitliche Reaktionen zeigten die Succinodehydrogenase sowie die Leucinaminopeptidase, unverändert blieben Glukose-6-phosphat-dehydrogenase, -Glucuronidase, saure Phosphatase, die o-Diacetylbenzol- und die DDD-Reaktion. 相似文献
50.
HIV-gp120 can block CD4-class II MHC-mediated adhesion 总被引:9,自引:0,他引:9
Y Rosenstein S J Burakoff S H Herrmann 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(2):526-531
A possible component of the immune dysfunction associated with infection by HIV is the inhibition of CD4 function resulting from the avid binding of soluble HIV envelope glycoprotein (gp120) to cell surface CD4. We assessed CD4 function by measuring the ability of CD4+ T cells to form conjugates with cell size lipid vesicles, artificial target cells (ATC), bearing the natural ligand for CD4, MHC class II proteins. Conjugate formation was a transient process with the greatest number of specific cell to ATC conjugates found after approximately 30 min of incubation at 37 degrees C. Addition of gp120 specifically blocked conjugates between CD4+ cells and class II ATC in a concentration-dependent manner. These data indicate that T lymphocyte adhesion mediated by CD4 is a dynamic event and that binding of gp120 to CD4 is able to disrupt the normal progression of the interaction between CD4+ T lymphocytes and class II+ APC. 相似文献