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Biomedical subjects

K Weber

Publications and source records attributed to K Weber.

At least 757 records · Page 42Linked to original sources
PubMed1975

[Sézary's syndrome. Case report].

A patient with Sézary syndrome is presented. The symptoms persisted for 5 years when a sudden involvement of internal organs led to the death of the patient. Much evidence indicates that the Sézary syndrome is a special form of mycosis fungoides with erythroderma and a constant release of atypical cells into the blood. The nature of the Sézary cell has not yet been clearly elucidated. Cytogenetic and immunological findings identified the Sézary cell as an abnormal T-lymphocyte whereas cytochemical data support the concept of the presence of different atypical cell populations with lymphocytic respectively monocytic character.

Blood Cells↗
PubMed1974

Antibody to myosin: the specific visualization of myosin-containing filaments in nonmuscle cells.

Myosin in human, rat, mouse, and chicken fibroblasts was localized by indirect immunofluorescence microscopy using antibodies prepared in rabbits against highly purified chicken gizzard myosin. Filaments containing myosin span the interior of the cells and are often parallel to each other. The majority of the fibers are concentrated toward the adhesive side of the cell. Most of the myosin-containing filaments show "interruptions" or "striations." From a comparison of these fibers in fluorescence and phase microscopy and from previous results on actin-containing fibers, we conclude that at least some of the cytoplasmic myosin can be found in the actin-containing fibers, which themselves have been shown to be very similar or identical to the microfilament bundles. The occurrence of both myosin and actin in the microfilament bundles provides a basis for the motility and contractility of the cell.

Animals↗
PubMed1974

Translational reinitiation: reinitiation of lac repressor fragments at three internal sites early in the lac i gene of Escherichia coli.

Three early amber mutations in the lac i gene have been shown to arise from the codons corresponding to residues 7, 12, and 17 of the lac repressor polypeptide chain. All three mutations allow translational reinitiation at the same two sites, resulting in the synthesis of two lac repressor fragments. The amino-terminal sequences of these fragments show that the first site is the triplet coding for valine residue 23, while the second is the first internal in-phase AUG codon corresponding to residue 42. Translational reinitiation appears to be a common event in E. coli, since there are at least three such sites in the first 70 in-phase codons of the i-gene messenger RNA, and all amber mutants found in this region show translational reinitiation. Only one of these sites involves an AUG codon; the other two involve an in vivo ambiguity of the genetic code, in that the same codon can be translated into two different amino acids depending on whether it is recognized during initiation or elongation of protein biosynthesis. The two non-AUG codons are the codons corresponding to leucine residue 62 and valine residue 23 of the lac repressor.

Amino Acid Sequence↗
PubMed1974

Actin antibody: the specific visualization of actin filaments in non-muscle cells.

Actin purified from mouse fibroblasts by sodium dodecyl sulfate gel electrophoresis was used as antigen to obtain an antibody in rabbits. The elicited antibody was shown to be specific for actin as judged by immunodiffusion and complement fixation against partially purified mouse fibroblast actin and highly purified chicken muscle actin. The antibody was used in indirect immunofluorescence to demonstrate by fluorescence light microscopy the distribution and pattern of actin-containing filaments in a variety of cell types. Actin filaments were shown to span the cell length or to concentrate in "focal points" in patterns characteristic for each individual cell.

Actins↗
PubMed1973

Reinitiation of a lac repressor fragment at a codon other than AUG.

52 Spontaneous nonsense mutants in the lac i gene of Escherichia coli were isolated and characterized. All mutants located early in the gene show negative complementation in vivo with a wild-type i gene in a recA diploid strain. In vitro studies show that those mutants that display negative complementing activity in vivo also make lac repressor fragments retaining inducer binding and immunological crossreactivity with wild-type repressor. Amino-acid sequence analysis of these fragments shows that they arise by reinitiation at internal sities of the i message after chain termination at a prior amber or ochre codon. There are at least two different internal reinitiation sites in the first 200 nucleotides of the translated part of the i message. The first site corresponds to the first internal in phase AUG codon, which specifies the methionine residue at position 42 of the repressor protein. This site can be activated by an amber codon, 45 nucleotides before the AUG codon. The second site is only 60 nucleotides past the first site and can be activated by an amber mutation derived from residue 60 of the protein. The second initiation codon specifies the amino-acid leucine in the wild-type repressor, but the reinitiated fragment shows an amino-terminal methionine residue at this position. Therefore, the second initiation site seems to involve an in vivo ambiguity of the genetic code in that the same codon can be translated into two different amino acids depending on the recognition of this codon during initiation (when methionine is inserted) or elongation of protein synthesis (when leucine is inserted). The possibility that a codon other than AUG can act as an initiation codon in vivo is discussed.

Adenine Nucleotides↗