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As previously shown, purified 14S RNA of mouse myeloma MOPC-41 forms a single peak on sucrose gradients and gel electrophoresis and codes for a single polypeptide chain, the immunoglobulin light chain produced by the same myeloma in vivo . This 14S mRNA was used for the enzymatic synthesis of DNA (cDNA) which is complementary to the RNA template. A DNA fraction was isolated which has an average size of 300 nucleotides. Kinetic studies of the hybridization of the 14S RNA with the cDNA indicate that about 40% of the RNA consists of a single RNA sequence. From the size of the cDNA fraction and from the direction of DNA synthesis, it can be concluded that the cDNA includes the sequence complementary to the constant region of light chain mRNA. This radioactive cDNA was used for DNA·DNA reannealing experiments with unlabeled DNA from mouse liver or myeloma tumor in 3 × 10 6 -fold excess. This allowed the determination of the number of copies in the mouse genome of those sequences represented in the cDNA. The data show no significant reiteration in either liver or myeloma DNA and suggest that the gene coding for the constant part of immunoglobins is present in the haploid genome in one to five copies. Furthermore, this gene is not “amplified” in nuclear DNA of myeloma plasmocytes.

Aus der Auswertung interdiurner Temperaturanderungen wurde in fruheren Untersuchungen auf einen zum hohen Druck gerichteten ageostrophischen Massenflus in der Nullschicht (Nullschichteffekt) geschlossen. Aus der Arbeitshypothese, das die Starke des Nullschichteffekts proportional zum horizontalen Druckgradienten sei, konnten in Ubereinstimmung mit der Erfahrung mehrere atmospharische Erscheinungen gefolgert werden.

Die in der Literatur beschriebene spektroskopische 15N-Bestimmung wird dahingehend variiert, das zur Messung der Intensitatsverhaltnisse der N2-Isotopenmolekel ein Stufenfilter verwendet wird. Die in ihrem Prinzip einfache und schnelle Methode erreicht eine Genauigkeit von ±2%. Arbeitsverfahren sowie Einflusse auf Reproduzierbarkeit und Genauigkeit werden beschrieben.

Iron binding imparts a conformational rigidity and compactness to the ovotransferrin molecule. This appears to cause the inaccessibility of certain antigenic sites to antibody in the formation of antigen-antibody complexes. Iron ovotranseferrin had a lower apparent antigenic valence and formed preferably smaller soluble antigen-antibody complexes that ovotransferrin, as measured by fluorescence polarization, saturated ammonium sulfate precipitation, and sedimentation velocity ultracentrifugation experiments. In primary Ab binding tests and in quantitative precipitin tests, however, both antigens gave similar reactivity. These results and the known identity of the primary chemical structure of ovotransferrin and iron ovotransferrin indicated that conformation differences are responsible for the observed immunochemical behavior. Molecular models, based on hydrodynamic measurements on ovotransferrin, iron ovotransferrin, and antibody molecules, also support this view. The antigenic differences between ovotransferrin and iron ovotransferrin were manifested only in the secondary phase of the antigen-antibody complex formation, emphasizing the need for appropriate secondary phase immunochemical techniques in such studies.

Aus 2-Chlorathyl-trimethylammoniumchlorid 1 wird eine Reihe von Salzen hergestellt, die das gleiche kation enthalten. Weiterhin werden einige nucleophile Substitutionsreaktionen am 2-Chlorathyl-trimethylammoniumkation untersucht. β-Eliminierungen sind sowohl zum Vinyl-trimethylammoniumkation als auch zum Vinylchlorid moglich. Bei der Oxydation von 2-Chlorathyltrimethylammoniumchlorid entsteht Glykokollbetain, bei der Pyrolyse Methylchlorid.

The 14S messenger RNA, which contains poly(adenylic acid), of MOPC 41 (mouse plasmocytoma) immunoglobulin light chain, purified to a single peak as shown by polyacrylamide gel electrophoresis, was used to synthesize complementary DNA with the RNA-dependent DNA polymerase of avian myeloblastosis virus. DNA synthesis is entirely dependent on added RNA template and oligo(dT) primer. Both the size and the concentration of the primer affect the reaction. The product behaves similarly to DNA during centrifugation in cesium sulfate density gradients. It is shown by hybridization that the DNA made is complementary to the purified template, light-chain mRNA. The high specific activity of the complementary DNA should make it suitable for gene-dosage experiments. According to alkaline sucrose gradient analyses, some complete complementary DNA transcripts of the 14S mRNA seem to be made. Oligo(dG) can also function as a primer for DNA synthesis, possibly by annealing to an internal cluster of cytidines in the mRNA, that correspond to the bases coding for amino-acids 119 and 120 of the MOPC 41 light chain.

In fruheren Arbeiten (1, 2) ist uber den Einflus einer variierten N-Dungung, insbesondere einer spaten zur Zeit der Blute verabreichten N-Gabe, auf die Eiweiszusammensetzung des Gerstenkorns berichtet worden. Es konnte festgestellt werden, das mit steigendem N-Gehalt des Kornes dessen verschiedene Eiweise in unterschiedlichem Ausmas vermehrt werden. Zur Ubersicht ist in Abb. 1 die Lokalisation der verschiedenen Eiweise des Gerstenkornes, wie sie durch Extraktion gewonnen werden konnen, schematisch dargestellt und ihr Anteil sowie ihr recht unterschiedlicher Gehalt an der fur die Tierernahrung besonders bedeutungsvollen Aminosaure Lysin in Durchschnittswerten angegeben worden. Der Eiweisgehalt steigt in der Regel von geringen Werten der ausersten Schichten bis auf 30% in der Aleuronschicht an und fallt dann wieder allmahlich uber die kleinzelligen auseren bis zu den groszelligen inneren Schichten des Mehlkorpers ab. Einen ahnlich hohen Eiweisgehalt wie die Aleuronschicht besitzt der Keimling. An spezifischen Eiweisen finden sich im Keimling als „Konstitutionseiweise” Albumine und Globuline und in der Aleuronschicht vorwiegend Globuline, wahrend der Mehlkorper in erster Linie Prolamin und Glutelin als „Speichereiweise” enthalt1 ), die im Weizen als Klebereiweise Trager von dessen guten Backeigenschaften sind, die aber durch ihren relativ geringen Lysingehalt den Futterwert im Futtergetreide etwas herabsetzen.

In einer Ubersicht werden diewichtigsten Verfahren zurprobenchemischen Aufbereitung 15N-markierter Verbindungen wiedergegeben. Im Anschlus daran wird eine bewahrte Mikormethode zur Probenchemie von Stickstoffverbindungen fur die optische Isotopenanalyse des Stickstoffs beschrieben, die auf der Oxydation von Ammoniumchlorid mittels Natriumhypobromit zu N2 beruht und Stickstoffmengen von etwa · 10−6 Mol fur eine Probe benotigt. Aufbau der Apparatur und Arbeitsweise werden eingehend erlautert.

which this study is based is conducted under circumstances approximating those of public and private schools throughout the country; it has traditionally offered a program for Grades IX through XII and has never offered work at the college level. These differences from the situation of the College of the University of Chicago (which accepts students who have completed two, three, or four years of high school and places them, by examination, in its four-year program) invited the statement of principles of general education in a new context. First, with regard to terms: three concepts of secondary education should be distinguished and defined, that is, vocational training, collegepreparatory work, and general education. The first is determined by the needs and demands of various re

THE immunochemical reactivity of a protein molecule may be affected by its conformation in two ways: (1) a particular conformation may expose or mask primary antigenic sites on the polypeptide chain; (2) the con-formational flexibility (allosteric properties) of a protein may determine the steric fit between antigen (Ag) and antibody (Ab) molecules1–5. The effect of conformation may be particularly significant in the soluble Ag–Ab lattice formation, for the availability of antigenic sites and the steric fit between Ag and Ab would determine the size and stoichiometric composition of the lattice. A conformationally flexible protein would be expected to form Ag–Ab lattices more readily than a rigid protein, and this would be expressed either by an increased rate in lattice formation, an increased size of the Ag–Ab lattice, an increased amount of Ab in the lattice or an increased stability of the formed lattice.