bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of Altered Cell Foci by 3-Methylcholanthrene in Mouse Cells Infected with AKR Leukemia Virus
Authors: Rhim Johng S. , Creasy Betty , Huebner Robert J.
Published: May 2006

This report describes altered cell foci observed 9-14 days after treatment with 3-methylcholanthrene of mouse-embryo tissue cultures that had previously been infected with wild-type AKR (RNA tumor) virus. The foci consisted of randomly oriented, piled-up, spindle-shaped cells. When heavily stained with Giemsa, the colonies of transformed cells were grossly visible and countable. Under the same experimental conditions, such changes of morphology were not detectable in the uninfected cells treated with 3-methylcholanthrene or in untreated cells infected with virus. The procedure may provide a rapid, quantitative test system for measurement of the oncogenic potential of certain carcinogens. As in similar previous studies in rat and hamster cells, the results suggest that the infectious, but nontransforming, RNA tumor viruses provided nascent oncogenic information, which when activated by 3-methylcholanthrene served as the specific genetic determinants of transformation.
Determination of Blastoderm Cells in
Drosophila melanogaster
Authors: Chan L.-N. , Gehring W.
Published: May 2006

A method for culturing blastoderm cells of
Drosophila in vivo
has been developed that allows these cells to differentiate into larval or adult structures. By intermixture of genetically marked cells from bisected and whole embryos, it was shown that blastoderm cells are restricted in their potential for forming adult epidermal structures. Cells isolated from anterior-half embryos are determined for forming head and thoracic structures, whereas cells from posterior-half embryos are determined for forming thoracic and abdominal structures. The specificity of determination and the localization of determinative factors is discussed.
Alteration of a 30S Ribosomal Protein Accompanying the
ram
Mutation in
Escherichia coli
Authors: Zimmermann Robert A. , Garvin Robert T. , Gorini Luigi
Published: May 2006

The functional peculiarities of
ram
mutants correlate with an observed alteration in chromatographic mobility of P4
a
, a specific protein of the 30S ribosomal subunit. This finding is supported by ribosomal reconstitution experiments. These facts, together with the known location of the
ram
mutational site in the vicinity of other 30S genetic determinants, suggest that
ram
is the structural gene for P4
a
.

The known contrasting roles of
ram
and
strA
in determining translational efficiency require that the function of P4
a
should be explained in relation to P10 (the 30S-subunit protein defined by
strA
). One consequence of altering P4
a
, a key protein in ribosome assembly, might be to change the interaction of P10 with the 30S subunit. The functional interrelationship of P4
a
and P10 is discussed in terms of the possible roles of these two proteins in regulating access of tRNA molecules to the decoding site.
Geometry of the First Step in the Action of Ribonuclease-A
Authors: Usher D. A. , Erenrich Evelyn S. , Eckstein F.
Published: May 2006

Advantage was taken of the reversibility of the first step of ribonuclease-A action to synthesize the dinucleoside phosphorothioate Up(S)C from the crystalline isomer of uridine 2′,3′-cyclic phosphorothioate [Up̂(S)] and cytidine. Cyclic phosphorothioate was then reformed from Up(S)C by a nonenzymic reaction known to proceed by an in-line mechanism. The geometry of the enzymic reaction was determined to be in-line by a comparison of the Up̂(S) product with the Up̂(S) originally used. By the principle of microscopic reversibility, the geometry of the first step in the action of ribonuclease-A is shown to be in-line.
Early Estrogen Action: Stimulation of the Metabolism of High Molecular Weight and Ribosomal RNAs
Authors: Luck Dennis N. , Hamilton Terrell H.
Published: May 2006

Samples of RNA, isolated from uteri of ovariectomized adult rats treated with estrogen, have been analyzed on sucrose gradients. Treatment with estrogen either for 20 min or 2 hr increased the specific activity of all classes of uterine RNA, but produced no significant alteration in the distribution of radioactivity in the gradients, when animals received [
3
H]uridine intraperitoneally 15 min before they were killed. After labeling periods of 30 min, 1 hr, or 2 hr, however, the RNAs isolated from animals treated with estrogen had a smaller percentage of rapidly sedimenting (faster than 28S) species of RNA than did RNA from animals not treated with the hormone. The decreased percentage of high molecular weight RNA correlated with increases in both the specific activity of 28S and 18S RNA and the concentration of RNA in the whole organ. The labeled RNA of high molecular weight was also demonstrated, by the use of actinomycin D
in vivo
, to have a more rapid turnover rate in the estrogen-stimulated uterus. Our results indicate that estrogen increases not only the rate of synthesis of ribosomal RNA in the uterus of the ovariectomized adult rat, but also the rate or efficiency of processing of precursor RNA species of high molecular weight.
Preparation of Amorphous Solid Water
Authors: Olander David S. , Rice Stuart A.
Published: May 2006

A method of preparation of solid amorphous water is reported, along with a demonstration of the absence of crystalline ice. The samples described are the first to be completely free of contamination with crystalline ice.
Studies of Mice with a Balanced Complement of 36 Chromosomes Derived from F
1
Hybrids of T1Wh and T1Ald Translocation Homozygotes
Authors: White Beverly J. , Tjio Joe-Hin , Water Lisa C. Van De , Crandall Clare
Published: May 2006

F
1
hybrids with 38 chromosomes, including single T1Wh and T1Ald translocations, resulted when mice homozygous for the Robertsonian translocations T1Wh and T1Ald were crossed. Meiotic studies of the hybrids showed two trivalents, indicating nonhomology of the T1Wh and T1Ald chromosomes. The hybrids had frequent (25%) unbalanced meiotic metaphase II complements; one trisomic mouse resulted from six F
1
crosses. The F
1
crosses also produced one mouse with 36 chromosomes homozygous for both T1Wh and T1Ald, as well as mice with balanced polymorphic complements of 37, 38, 39, and 40 chromosomes. By crossing the F
2
, a homogeneous line with 36 chromosomes was established. The line is phenotypically normal, fertile, and has balanced meiotic metaphase II complements. Analysis of the chromosomes of these mice with quinacrine mustard and the Giemsa-banding technique confirmed that T1Wh and T1Ald consisted of chromosomes 5;19 and 6;15, respectively.

Crosses between this line and other existing translocation stocks may produce new strains of mice with even further reduction in chromosome number. Accumulation of Robertsonian translocations, a possible evolutionary mechanism in the wild, can be studied in the laboratory. F
1
hybrids from certain crosses are also an important model for human translocation carriers; both have similar meiotic abnormalities and often have aneuploid offspring.
Induction of Avidin Synthesis by RNA Obtained from Chick Oviduct
Authors: Tuohimaa Pentii , Segal Sheldon J. , Koide S. S.
Published: May 2006

RNA was extracted from oviduct, shell gland, and liver of chicks treated with diethylstilbestrol and a combination of diethylstilbestrol and progesterone. Preparations containing 500 or 2500 μg of RNA were put in the oviductal lumen of diethylstilbestrol-treated chicks for 24 hr, and the avidin content of the oviduct was determined by measurement of [
14
C]biotin binding.

The results of the present study demonstrate that oviduct RNA from chicks treated with progesterone induces synthesis of avidin in chick oviduct. In contrast, liver or shell gland RNA from chicks treated with progesterone, and liver or oviduct RNA from chicks treated with diethylstilbestrol are incapable of inducing avidin synthesis. The inducing capacity of oviduct RNA is destroyed when it is treated with ribonuclease. It is hypothesized that progesterone induces the synthesis of new species of oviduct RNA, which serve as messenger(s) for avidin synthesis. This hypothesis is offered in consideration of the findings: (
i
) that the residual amount of progesterone present as a contaminant in oviduct RNA from chicks treated with progesterone is far too low to account for the induced avidin synthesis; (
ii
) that such oviduct RNA from chicks treated with progesterone induces a slight synthesis of avidin in chick shell gland, which ordinarily does not produce avidin in response to progesterone administration and; (
iii
) that such RNA added
in vitro
to minces of oviductal tissues incubated in biotin-free medium for 24 hr induces synthesis of avidin.
Reducing the Number of Inferior Treatments in Clinical Trials
Authors: Flehinger B. J. , Louis T. A. , Robbins Herbert , Singer B. H.
Published: May 2006

In clinical trials comparing two treatments, one would often like to control the probability of erroneous decision while minimizing not the
total sample size
but
the number of patients given the inferior treatment
. To do this obviously requires that one use a datadependent allocation rule for the two treatments rather than the conventional equal sample size scheme, whether fixed or sequential. We show here how this may be done in the case of deciding which of two normally distributed treatment effects has the greater mean, when the variances are assumed to be equal and known. Similar methods can be used under other hypotheses on the underlying probability distributions, and will provide a considerable increase in flexibility in the design of sequential clinical trials.
Nucleotide Sequence at the Binding Site for Coat Protein on RNA of Bacteriophage R17
Authors: Bernardi Alberto , Spahr Pierre-François
Published: May 2006

The binding of a few molecules [1-6] of RNA bacteriophage coat protein to 1 molecule of RNA represses
in vitro
translation of the RNA synthetase cistron. Digestion of the complex, R17 coat protein-R17 RNA, by T1 RNase yields an RNA fragment bound to the coat protein. The nucleotide sequence of this fragment (59 residues) reveals that it contains the punctuation signal between the coat protein and RNA synthetase cistrons, suggesting that this is the site on the RNA where the coat protein acts as a translational repressor.
Particles Containing RNA-Instructed DNA Polymerase and Virus-Related RNA in Human Breast Cancers
Authors: Axel R. , Gulati S. C. , Spiegelman S.
Published: May 2006

Human breast cancers contain an RNA related to that of mouse mammary tumor virus. In 79% of the breast malignancies examined, this type of RNA is a 70S-component encapsulated with RNA-instructed DNA polymerase in a particle possessing the density characteristics of RNA tumor viruses. Further, the DNA synthesized by the human RNA enzyme complex hybridizes specifically with the RNA of mouse mammary tumor virus. Thus, four features diagnostic of agents similar to mouse mammary tumor virus are also exhibited by a particle found with high frequency in human breast cancers. The accumulating evidence for the involvement of RNA tumor viruses in at least some human neoplasias is becoming increasingly compelling.
Electron Paramagnetic Resonance of Nitrogenase and Nitrogenase Components from
Clostridium pasteurianum W5
and
Azotobacter vinelandii OP
Authors: Orme-Johnson W. H. , Hamilton W. D. , Jones T. L. , Tso M.-Y. W. , Burris R. H. , Shah V. K. , Brill W. J.
Published: May 2006

The electron paramagnetic resonance of nitrogenase components, separately and together with the other reactants in the nitrogenase system (namely, reductant and Mg·ATP), have been examined at low temperatures (<20°K). The MoFe protein, component I or molybdoferredoxin, in the oxidized (but not oxygen-inactivated) state yields signals with g-values of 4.3, 3.7, and 2.01, and when reduced has no observable electron paramagnetic resonance. The Fe protein, component II, or azoferredoxin, yields a signal with g-values of 2.05, 1.94, and 1.89 in the reduced state that is converted by Mg·ATP into an axial signal with g-values near 2.05 and 1.94, and a second split signal near g = 4.3. The Fe protein has no definite electron paramagnetic resonance in the oxidized (not oxygen-denatured) state under these conditions. The Mg·ATP complex of reduced Fe protein reduces the MoFe protein, whereas dithionite alone does not reduce the MoFe protein. Reoxidation of the system by substrate leads to disappearance of the Fe protein signal and the reappearance of the MoFe protein signal. Thus Mg·ATP, which is hydrolyzed during substrate reduction, converts the Fe protein to a reductant capable of transferring electrons to MoFe protein, after which substrate reduction occurs.
Biogeographic Kinetics: Estimation of Relaxation Times for Avifaunas of Southwest Pacific Islands
Authors: Diamond Jared M.
Published: May 2006

When species diversity
S
on an island is displaced from the equilibrium value by injection or removal of species,
S
relaxes to equilibrium by an imbalance between immigration and extinction rates. Estimates of exponential relaxation times,

t
r

, for avifaunas of New Guinea satellite islands are calculated from analysis of four “experiments of nature”: recolonization of exploded volcanoes, contraction in island area due to rising sea level, severing of land bridges, and disappearance of landbridge relict species.

t
r

is in the range 3,000-18,000 years for avifaunas of islands of 50-3000 square miles (130-7800 km
2
), and increases with island area. Immigration coefficients decrease and extinction coefficients increase with increasing
S
. The results may be relevant to the design of rainforest preserves.
Inactivation of Bovine Trypsinogen and Chymotrypsinogen by Diisopropylphosphorofluoridate
Authors: Morgan Paul H. , Robinson Neal C. , Walsh Kenneth A. , Neurath Hans
Published: May 2006

Diisopropylphosphorofluoridate reacts with trypsinogen and chymotrypsinogen and inhibits the potential activity of both zymogens. The reactions follow pseudo first-order kinetics and proceed approximately four orders of magnitude slower than diisopropylphosphorylation of the corresponding enzymes. Correlation of initial rates of inactivation with incorporation of the reagent indicates that zymogen inactivation results from incorporation of 1 mol of organic phosphate per mol of protein. Peptides isolated from the active-site region of trypsinogen account for more than 60% of the label originally present in the [
14
C]diisopropylphosphoryl zymogen. It is concluded that loss of activation of trypsinogen is due to alkylphosphorylation of Ser
183
. It is proposed that reduced reactivity of the zymogen, as compared to the enzyme, primarily reflects inefficient binding of substrates and inhibitors, and that Ser
183
of the active site exists in trypsinogen in an activated state.
Kinetics of Integration of Transforming DNA in Pneumococcus
Authors: Shoemaker Nadja B. , Guild Walter R.
Published: May 2006

Integration of donor genes, as measured by recovery of their transforming activity from eclipse in lysates of newly transformed cells of pneumococcus, has been followed at temperatures from 0 to 40°. There is a lag in the recovery curve that is marker-dependent and increases as temperature falls. An Arrhenius plot of the rates shows a sharp break between 15 and 20°. Brief exposure of the system to 37° before incubation at 10 or 15° removes the lag and raises the subsequent rate of recovery. This activation is unstable, however, and disappears when the cells are held at 0° after the exposure at 37° and before incubation at 15°. The results are interpreted in terms of a reaction sequence A ⇌ B → C, with activation energies for the first forward rate-constant of the order of 50 Cal/mol, for the second, 20-21 Cal/mol, and for the reverse reaction, less than 20 Cal/mol. The properties of the first step, including its marker dependence, are the same as those observed earlier for stabilization of donor markers against intracellular inactivation, and it is suggested they may reflect an activation of the recipient chromosome prerequisite to synapsis.
On the Primary Nature of Fluorescence Yield Changes Associated with Photosynthesis
Authors: Butler Warren L.
Published: May 2006

Absorbance changes of C-550 and cytochrome
b
559
, and fluorescence-yield changes were measured during irradiation of chloroplasts at -196°. The photo-reduction of C-550 proceeded more rapidly than the photo-oxidation of cytochrome
b
559
, and the fluorescence-yield change had similar kinetics to the cytochrome
b
559
change. The fluorescence yield of chloroplasts exposed to a 16-μsec flash at -196° did not increase during the flash, but increased in the dark after the flash. Both of these experiments indicate that the fluorescence yield follows the dark reduction of the primary electron donor of Photosystem II, not the photoreduction of the acceptor. This explanation would also account for the recent results of Mauzerall [
Proc. Nat. Acad. Sci. USA
(1972)
69
, 1358-1362] showing that the fluorescence yield of chloroplasts at room temperature requires about 20 μsec to reach a maximum after a very brief flash.
Fine-Structure Deletion Map of the
Escherichia coli
L-Arabinose Operon
Authors: Schleif Robert
Published: May 2006

A fine-structure deletion map of the L-arabinose operon of
E. coli
was constructed by mapping deletion endpoints against point mutations. Of 350 independent deletions with average endpoint separation of ten nucleotides, 51 ended in the control region between the
C
and
B
genes, and the rest ended in the structural genes
A, B, C
, and
D
. If deletion endpoints are randomly distributed, the
C
and
B
genes are separated by about 510 nucleotides. Deletion endpoints and locations of point mutations in fact do appear randomly interspersed in the
C
and
B
genes, but no point mutations were found in the control region between them. Deletions were isolated with the aid of a heat-inducible λ phage inserted into leucine genes adjacent to the arabinose genes. A high-capacity mating technique was developed for rapidly generating fine structure maps from many deletions and point mutations.
Human Parathyroid Hormone: Amino-Acid Sequence of the Amino-Terminal Residues 1-34
Authors: Brewer H. B. , Fairwell T. , Ronan R. , Sizemore G. W. , Arnaud C. D.
Published: May 2006

Human parathyroid hormone has been isolated in highly purified form from human parathyroid adenomas. The primary sequence of the amino-terminal 34 residues of the human hormone was obtained by automated degradation with a Beckman Sequencer. The phenylthiohydantoin amino acids were identified by gas chromatography and mass spectrometry. The first 34 residues of human parathyroid hormone differ from the bovine hormone by six residues, and from the porcine hormone by five residues. The amino-terminal residue is serine, similar to the porcine parathyroid hormone; bovine parathyroid hormone contains an amino-terminal alanine. Human parathyroid hormone contains two methionine residues, similar to the bovine species, whereas porcine parathyroid hormone contains a single methionine residue. Amino-acid residues in the first 34 that are unique to the human sequence include an asparagine at position 16, glutamine at position 22, lysine at position 28, and a leucine at position 30.
Globin Messenger-RNA Induction During Erythroid Differentiation of Cultured Leukemia Cells
Authors: Ross Jeffrey , Ikawa Yoji , Leder Philip
Published: May 2006

A cloned line of murine proerythroblastoid cells (T-3-Cl-2), transformed by Friend leukemia virus, undergoes changes associated with erythroid differentiation when treated with dimethylsulfoxide in culture. This line, which does not undergo spontaneous differentiation, develops specific erythrocyte-membrane antigen and accumulates detectable amounts of heme within four days of dimethylsulfoxide treatment. In the present study, we have followed the phenotypic expression of the globin genes by measuring globin mRNA in differentiating cells. Our hybridization probe for this purpose is [
3
H]DNA, which is complementary to purified globin mRNA, synthesized by viral RNA-directed DNA polymerase. This probe is sufficiently sensitive to detect less than 1 ng of globin mRNA. Using it, we find little or no hybridizable globin mRNA in either uninduced cells or in treated control lymphoid cells. In contrast, globin mRNA can be detected in T-3-Cl-2 cell 2 days after induction by dimethylsulfoxide; it reaches a maximum concentration four days after induction. At this time, cells that stain positively for heme appear. The hybridizable cytoplasmic RNA induced in these cells has the sedimentation properties of 9S globin mRNA. Considering the stable character of globin mRNA, our results are most readily explained in terms of a transcriptional activation of the globin genes.
Intracellular Iron-Binding Macromolecules in HeLa Cells
Authors: Robbins Elliott , Fant Jane , Norton William
Published: May 2006

The concentration of the iron-chelating agent, desferrioxamine (Desferal), that just inhibits iron entry into HeLa cells is also the concentration that inhibits DNA synthesis. As a first step in clarification of the mechanism whereby iron may partake in DNA synthesis, we have partially characterized several of the intracellular iron-binding sites. Most cytoplasmic iron appears to be bound to a polysaccharide containing glucose that sediments at about 32 S. Nucleolar iron is bound to a single protein, the mobility of which is independent of the concentration of sodium dodecyl sulfate in an acrylamide gel. In contrast the pattern and mobility of nuclear iron, other than nucleolar, is heterogeneous and markedly affected by the concentration of sodium dodecyl sulfate. The evidence suggests that nuclear iron is bound to protein through one or more intermediate(s).
Assignment of Three Human Genes to Chrosomes (LDH-A to 11, TK to 17, and IDH to 20) and Evidence for Translocation between Human and Mouse Chrosomes in Somatic Cell Hybrids
Authors: Boone Charlotte , Chen Tchaw-Ren , Ruddle Frank H.
Published: May 2006

Independently derived man-mouse somatic cell hybrids and their derivative subclones show a positive correlation between the expression of human lactate dehydrogenase A subunits and the occurrence of the human C-11 chromosome. Data are also presented that confirm the previously reported linkage of the thymidine kinase locus to the E-17 chromosome. A translocation of the E-17 chromosome provides presumptive evidence for the assignment of the thymidine kinase locus to the long arm segment of the E-17 chromosome. This translocation also provides evidence for translocation between man and mouse chromosomes in somatic cell hybrids. A presumptive association between the human phenotype for isocitrate dehydrogenase and the human F group is also described. Identification of specific human chromosomes was achieved by the application of several new cytological techniques: measurement of chromosome arm length,
in situ
annealing with mouse satellite complementary RNA, constitutive heterochromatin staining with Giemsa, and quinacrine mustard fluorochromatic staining.
Identification of the Proteins Associated with Subparticles Produced by Mild Ribonuclease Digestion of 30S Ribosomal Particles from
Escherichia coli
Authors: Schendel Peter , Maeba Peter , Craven Gary R.
Published: May 2006

Digestion of 30S ribosomal subunits from
E. coli
by insoluble ribonuclease produces three subparticles. The ribosomal proteins associated with each of these particles were identified. Some of the proteins are associated with only one of the three subparticles. The protein compositions of the three particles can be arranged in an overlapping linear sequence of five groups. Furthermore, inspection of the previously determined assembly sequence of the 30S proteins indicates that proteins associated in the subparticles are interdependent in the assembly process.
Proparathyroid Hormone: Identification of a Biosynthetic Precursor to Parathyroid Hormone
Authors: Kemper Byron , Habener Joel F. , Potts John T. , Rich Alexander
Published: May 2006

Biosynthesis of a precursor to bovine parathyroid hormone has been demonstrated in slices of parathyroid tissue incubated
in vitro
. The proparathyroid hormone is 15-20 amino acids larger than the bovine hormone, and has a molecular weight of about 11,500 as determined by polyacrylamide gel electrophoresis. Upon incubation of parathyroid slices with [
14
C]aminoacids, radioactivity is detected initially in the precursor. If incorporation of [
14
C]aminoacids is inhibited after a short incubation either by replacement of radioactive amino acids with unlabeled amino acids or by addition of puromycin, the amount of radioactivity in the precursor decreases, while the radioactivity in the hormone continues to increase. The precursor is bound by an antibody that is specific for parathyroid hormone, and its binding can be inhibited by addition of the hormone. Analysis of tryptic digests indicates that the precursor and the hormone have common tryptic peptides, and that there are at least two additional peptides in the precursor.
A Mutant of
Escherichia coli
That Requires High Concentrations of Biotin
Authors: Campbell Allan , del Campillo-Campbell Alice , Chang Robin
Published: May 2006

A recessive mutation (
bir
) of
E. coli
, at 77 min on the standard map, destroys ability of the bacteria to take up biotin or to grow except at high concentrations of biotin. In a biotin prototroph, the
bir
mutation causes overproduction and excretion of biotin, and derepression of at least one biosynthetic gene (
bioD
). Growth of the
bir
mutant is inhibited by avidin or high concentrations of dethiobiotin. Both effects are reversed by biotin.
Development and Stability of Positional Information in
Xenopus
Retinal Ganglion Cells
Authors: Hunt R. K. , Jacobson Marcus
Published: May 2006

Neuronal specificity in retinal ganglion cells of
Xenopus
subserves the orderly connections of the optic nerve fibers in the tectum. This specificity derives from positional information acquired by the developing retina at embryonic stages 28-31. Here we report that ganglion cells of embryonic stage 28 eyes can acquire positional information with reference to the major axes of the body not only in the ocular orbit but also at other positions on the side of the body. When returned to the orbit this eye will form appropriate retinotectal connections. Conversely, retinal ganglion cells of stage 31 eyes, which have acquired positional information in the orbit, will retain their original neuronal positional specificities if the formation of retinotectal connections is delayed by grafting the eye to the flank for 30 days before returning it to the orbit. We conclude that neuronal specificity of retinal ganglion cells (
a
) does not derive from “inducers” unique to the periocular tissues; and (
b
) persists for some time independently of the establishment of retinotectal connections.
Carbon Monoxide Binding by Hemoglobin and Myoglobin under Photodissociating Conditions
Authors: Brunori Maurizio , Bonaventura Joseph , Bonaventura Celia , Antonini Eraldo , Wyman Jeffries
Published: May 2006

Carbon monoxide binding by myoglobin and hemoglobin has been studied under conditions of constant illumination. For hemoglobin, the homotropic heme-heme interaction (cooperativity) and the heterotropic Bohr effect are invariant with light intensity over a 1000-fold change of
c
½
. The dissociation constant, measured as
c
½
, increases linearly with light intensity, indicating that photodissociation is a one-quantum process. At sufficiently high illumination the apparent enthalpy of ligand binding becomes positive, although in the absence of light it is known to be negative. This finding indicates that light acts primarily by increasing the “off” constants by an additive factor. The invariance of both cooperativity and Bohr effect raises a perplexing issue. It would appear to demand either that the “off” constants for the various elementary steps are all alike (which is contrary to current ideas) or that the additive factor is in each case proportional to the particular “off” constant to which it is added (a seemingly improbable alternative).
Complete Amino-Acid Sequence of Calf-Thymus Histone III
Authors: Delange Robert J. , Hooper John A. , Smith Emil L.
Published: May 2006

Calf-thymus histone III is a single polypeptide chain of 135 residues (combined molecular weight of 15,324) with alanine at both the amino and carboxyl ends. The NH
2
-terminal region (Residues 1-53) of histone III is strongly basic (net charge of +18) and contains lysines-14 and -23, which are ε-
N
-acetylated in a fraction of the molecules, as well as lysines-9 and -27, which are partially ε-
N
-methylated. The COOH-terminal region (Residues 54-135) is only slightly basic (net charge of +4), contains most of the hydrophobic residues, and has a 29-residue sequence that lacks a basic residue. The two cysteines are in the nonbasic region at positions 96 and 110. A few sequence similarities of calf-thymus histone III with other histones have been noted.
On Zeta Functions Associated with Prehomogeneous Vector Spaces
Authors: Sato Mikio , Shintani Takuro
Published: May 2006

In this note, we construct certain families of Dirichlet series that satisfy functional equations. We shall also indicate an arithmetical application of our results. The work presented here depends upon the theory of prehomogeneous vector spaces.
Proximity Relationships in Rhodopsin
Authors: Wu Cheng-Wen , Stryer Lubert
Published: May 2006

Energy transfer was used as a spectroscopic ruler to deduce proximity relationships within bovine rhodopsin in digitonin solution. Rhodopsin was specifically labeled with fluorescent chromophores at three sites. Site A was alkylated by fluorescent derivatives of iodoacetamide. Site B was labeled by fluorescent disulfides, by a disulfide-sulfhydryl interchange reaction. Sites A and B are sulfhydryl residues. Acridine derivatives were tightly bound to site C by noncovalent interactions. The labeled rhodopsins retained their 500-nm absorption band and were regenerable after bleaching, suggesting that the fluorescent probes did not grossly perturb the conformation of the protein. A fluorescent chromophore at one of these sites served as the energy donor, while 11-
cis
retinal was the energy acceptor. The efficiency of singlet-singlet energy transfer was determined from the quantum yield and excited-state lifetime of the donor in the presence and absence of the acceptor. By Förster's theory, the apparent distances between 11-
cis
retinal and sites A, B, and C were calculated to be 75,55, and 48 Å, respectively. Energy transfer measurements on rhodopsin labeled at two of these sites gave these apparent distances: 35 Å for A to B, 32 Å for A to C, and 30 Å for B to C.

These energy transfer studies suggest that the rhodopsin molecule has a length of at least 75 Å. Thus, the rhodopsin molecule appears to be sufficiently long to traverse the disc membrane. Rhodopsin might act as a light-controlled gate.
Proof That Unsuccessful Speculators Confer Less Benefit to Society Than Their Losses
Authors: Samuelson Paul A.
Published: May 2006

It is well known that successful speculation can be a boon to society, whether or not the successful speculator is ruled to be the legitimate appropriator of his profits. It is also understood that unsuccessful speculation can naturally impose losses on the unsuccessful speculator himself. Little, however, is known about the effect of the unsuccessful speculator on the rest of society: one view is that the others gain what he loses, so that in a sense he is their benefactor and only his own enemy; a more plausible view is that his loss must in some sense exceed the gain splashed on others. Nothing seems to have been proved in a rigorous way in this matter.

Here, the problem is subjected to mathematical analysis. It is shown that others do definitely gain from an act of unsuccessful speculation, thus providing rigorous proof of what has long been surmised. But it is also shown that their gain is necessarily less, in an objective sense, than the loss to the speculator himself. Indeed, in the model of unnecessary positive carryover of grain into the future, the gain to the nonspeculators is proved to be actually of a second-order of smallness of infinitesimals compared to the speculator's loss.
Accumulation of Adenosine 3′:5′-Cyclic Monophosphate in Clonal Glial Cells: Labeling of Intracellular Adenine Nucleotides with Radioactive Adenine
Authors: Schultz Joachim , Hamprecht Bernd , Daly John W.
Published: May 2006

The accumulation of endogenous adenosine 3′:5′-cyclic phosphate (cAMP) and of [
14
C]cAMP, derived from nucleotides labeled by prior incubation of cells with [
14
C]adenine, has been investigated in four glial cell lines from rats. The following results are similar to data reported for brain slices: (
i
) rat glial cells contain a system that readily incorporates [
14
C]adenine into nucleotides that serve as precursors for cAMP. (
ii
) norepinephrine stimulates accumulation of
both
[
14
C]cAMP and endogenous cAMP, and (
iii
) the phosphodiesterase inhibitors, papaverine and isobutylmethylxanthine, are effective in enhancing the stimulatory effect of norepinephrine. In contrast to results reported for brain slices, histamine, veratridine, and adenosine, the purine either alone or with a biogenic amine,
do not
cause an enhanced accumulation of cAMP in rat glial cells, and
repetitive
accumulations of cAMP
can be
elicited during a series of restimulations of the cells with norepinephrine. The magnitude of the accumulation of cAMP elicited by the catecholamine decreases markedly by the fifth restimulation in the absence of, but only slightly in the presence of, papaverine. In glial cells, a large portion of the [
14
C]adenine is incorporated into intracellular compounds that do not serve as precursors of [
14
C]cAMP.
Conformationally Dependent Low-Frequency Motions of Proteins by Laser Raman Spectroscopy
Authors: Brown K. G. , Erfurth S. C. , Small E. W. , Peticolas W. L.
Published: May 2006

Low-frequency Raman bands (lower than 50 cm
-1
) exist in certain proteins. They are dependent upon the conformation of the protein molecule, but are relatively independent of the form of the sample, i.e., whether it is a film or a crystal.

Low-frequency Raman spectra were obtained from samples of α-chymotrypsin that had been prepared in several ways. A peak at about 29 cm
-1
was found for all samples except the one that had been denatured with sodium dodecyl sulfate. Such low frequency motions must arise from vibrations that involve all, or very large portions, of the protein molecule.
Myeloma Proteins as Tumor-Specific Transplantation Antigens
Authors: Lynch Richard G. , Graff Ralph J. , Sirisinha Stitaya , Simms Ernest S. , Eisen Herman N.
Published: May 2006

BALB/c mice immunized with myeloma proteins 315 or 460 made antibodies to the individually specific (“idiotypic”) determinants of these proteins and suppressed growth of the corresponding transplanted tumor cells (MOPC-315 or MOPC-460). Stable, variant MOPC-315 tumors that produce only the light chain of protein 315 grew in several of the mice immunized with this protein, probably because the anti-idiotypic immune response selects against those myeloma cells that form the intact myeloma protein.
Dissipative Properties of Quantum Systems
Authors: Grecos A. P. , Prigogine I.
Published: May 2006

We consider the dissipative properties of large quantum systems from the point of view of kinetic theory. The existence of a nontrivial collision operator imposes restrictions on the possible collisional invariants of the system. We consider a model in which a discrete level is coupled to a set of quantum states and which, in the limit of a large “volume,” becomes the Friedrichs model. Because of its simplicity this model allows a direct calculation of the collision operator as well as of related operators and the constants of the motion. For a degenerate spectrum the calculations become more involved but the conclusions remain simple. The special role played by the invariants that are functions of the Hamiltonion is shown to be a direct consequence of the existence of a nonvanishing collision operator. For a class of observables we obtain ergodic behavior, and this reformulation of the ergodic problem may be used in statistical mechanics to study the ergodicity of large quantum systems containing a small physical parameter such as the coupling constant or the concentration.
Magnetic Circular Dichroism of Molecules in Dense Media: Benzene
Authors: Shieh D. J. , Lin S. H. , Eyring H.
Published: May 2006

This paper presents some calculated results on the vibrational structuring of the magnetic circular dichroism of the benzene
1
A

1
g

“
1
B

2
u

transition. The good agreement between the experimental and calculated relative intensities of the B-bands (positive magnetic circular dichroism bands) indicates that these bands are mainly induced by the
e

2
g

1596 cm
-1
mode. The unfavorable results obtained by comparison of the theoretical results with experimental results for the A-bands (negative magnetic circular dichroism bands) is presumably due to neglect of the contribution from the
e

2
g

3056 cm
-1
mode, from hot bands, and from the transitions of normal modes other than the
A

1
g

992 cm
-1
mode. It should be noticed that while the
e

2
g

608 cm
-1
mode plays a dominating role in the ultraviolet spectrum of benzene, in the magnetic circular dichroism of benzene, the
e

2
g

1596 cm
-1
mode is, if not more important, at least as important as the
e

2
g

608 cm
-1
mode.
Control of the Rat Pineal Gland by Light Spectra
Authors: Cardinali Daniel P. , Larin Frances , Wurtman Richard J.
Published: May 2006

Control of pineal hydroxyindole-
O
-methyl transferase (
S
-adenosylmethionine:
N
-acetylserotonin-
O
-methyl transferase; EC 2.1.1.4) by light spectra was determined by placing groups of rats previously housed in continuous darkness under one of seven light sources for 96 hr; rats were exposed to the same intensity of irradiation. Activity of the enzyme was lowest in rats maintained under green light (λ peak = 530 nm); blue and yellow light were somewhat less effective; red and ultraviolet light did not significantly lower the enzyme activity. The suppression of pineal hydroxyindole-
O
-methyl transferase by full-spectrum light sources could be correlated with the proportions of their spectral outputs in the blue-green-yellow range. These observations suggest that the retinal photopigment that mediates pineal responses to light in rats is rhodopsin or another compound with similar absorption properties.
H
2
CO
3
as Substrate for Carbonic Anhydrase in the Dehydration of HCO
3
-
Authors: Koenig Seymour H. , Brown Rodney D.
Published: May 2006

Carbonic anhydrase, a metalloenzyme containing one zinc atom per protein molecule of molecular weight 30,000, catalyzes the interconversion of CO
2
and HCO
3
-
in solution. The rate of catalysis, among the fastest known, is pH-dependent, with a pK
Enz
near neutral. Arguments are presented to show that: (
i
) only the high-pH form of the enzyme is active both for the hydration and dehydration reactions (
ii
) at high pH there is an H
2
O ligand on the metal (not an OH
-
as is often argued), and (
iii
) the substrate for the dehydration reaction is the neutral H
2
CO
3
molecule. The arguments are based on data in the literature on the nuclear relaxation rates of Cl
-
ions and water protons in solutions of carbonic anhydrase, on strict application of the principle of microscopic reversibility, and on kinetic considerations. It has been argued that H
2
CO
3
cannot be the substrate for the dehydration reaction because the observed CO
2
production rate is somewhat faster than the maximum rate at which H
2
CO
3
molecules can diffuse to the active site of the enzyme. However, current models that consider HCO
3
-
as the substrate implicity require that protons diffuse to the enzyme at an even greater rate, well outside the limitations imposed by diffusion. We consider two mechanisms to obviate the diffusion limitation problem, and conjecture that at high substrate concentration, H
2
CO
3
reaches the active site by collision with the enzyme molecule, and subsequent surface diffusion to the active site. At lower substrate concentrations, corresponding to [HCO
3
-
] <1 mM, generation of H
2
CO
3
molecules near the enzyme by the recombination reaction H
+
+ HCO
3
-
→ H
2
CO
3
can supply an adequate flux of substrate to the active site.
The Gradient-Sensing Mechanism in Bacterial Chemotaxis
Authors: Macnab Robert M. , Koshland D. E.
Published: May 2006

A “temporal gradient apparatus” has been developed that allows the motility of bacteria to be studied after they have been subjected to a sudden change from one uniform concentration of attractant to another. A sudden decrease elicits the tumbling response observed with spatial gradients; it was found, however, that a sudden increase also elicits a response, namely supercoordinated swimming. This demonstrates that chemotaxis is achieved by modulation of the incidence of tumbling both above and below its steady-state value. The initial responses gradually revert to the steady-state motility pattern characteristic of a uniform distribution of attractant. The apparent detection of a spatial gradient by the bacteria therefore involves an actual detection of a temporal gradient experienced as a result of movement through space. Potential models for the chemotactic response based on some “memory” mechanism are discussed.
Double-Stranded Regions in Heterogeneous Nuclear RNA from Hela Cells
Authors: Jelinek Warren , Darnell James E.
Published: May 2006

Heterogeneous nuclear RNA from HeLa cells contains double-stranded regions that arise by base pairing of complementary sequences that exist as parts of the same molecule (intramolecular base pairing). When denatured, the RNA sequences that form the double-stranded regions hybridize rapidly to HeLa cell DNA, suggesting that they are transcribed from reiterated sites in the genome. The messenger RNA does not contain the same class or amount of double-stranded RNA regions found in heterogeneous nuclear RNA.
The Biosynthesis of Vitamin B
12
: A Study by
13
C Magnetic Resonance Spectroscopy
Authors: Brown Charles Eric , Katz Joseph J. , Shemin David
Published: May 2006

The origin of the methyl group on C-1 of Ring A of the corrin ring of vitamin B
12
was investigated by
13
C magnetic resonance spectroscopy. The proton-decoupled
13
C spectra of vitamin B
12
synthesized from [
5
-
13
C]δ-aminolevulinic acid by
Propionibacteria
were obtained by Fourier-transform nuclear magnetic resonance of high resolution, and spectra of high-resolution proton magnetic resonance of the
13
C-labeled B
12
were also taken. The δ-carbon atom of δ-aminolevulinic acid is the source of seven or eight known positions of vitamin B
12
, depending on whether the C-1 methyl group is also derived from the labeled substrate. We have found seven resonances whose chemical shifts enable us to identify the position of the
13
C atoms in the molecule from the assignment of Dodderell and Allerhand. We observed no
13
C resonance corresponding to the C-1 methyl group of Ring A. Furthermore, the proton magnetic resonance spectrum showed no spin-spin splitting of the proton peak at the τ values assigned for the H atoms in this methyl group. It would thus appear that the methyl group at C-1, which has been considered to have the same origin as the δ-methine bridge of porphyrins, does not originate from the δ-carbon atom of δ-aminolevulinic acid. This finding may aid in elucidation of the mechanism of synthesis of the functional isomer of vitamin B
12
and porphyrins. The
13
C-labeled vitamin B
12
enabled us to make further assignments to the
13
C magnetic resonance of the vitamin.
An Oligonucleotide Affinity Column for RNA-Dependent DNA Polymerase from RNA Tumor Viruses
Authors: Gerwin Brenda I. , Milstien Julie B.
Published: May 2006

Columns of (dT)
12-18
-cellulose provide a one-step enrichment procedure for RNA-dependent DNA polymerase. The enzyme of the virus from RD-114 cells, as well as that from Rauscher murine leukemia virus, have been purified in this way. The preference of viral as compared to cellular DNA polymerases for (dT)
12-18
as a primer is reflected in the fact that the DNA polymerases of uninfected cells do not bind to this column. Viral enzymes have been purified and identified from crude cellular extracts.
Emergence of Insulin Receptors on Human Lymphocytes During
In Vitro
Transformation
Authors: Krug Ulla , Krug Folker , Cuatrecasas Pedro
Published: May 2006

Essentially no specific binding sites for insulin are detected in small lymphocytes freshly isolated from human blood. Insulin-binding sites appear on the lymphocyte surface during transformation
in vitro
with concanavalin A, and the number of these receptors increases sharply to reach a maximum between 24 and 46 hr after exposure to the mitogen. The appearance of
de novo
binding sites for insulin coincides with the increase in [
3
H]thymidine uptake into nuclear DNA and clearly precedes the appearance of enlarged, morphologically transformed cells. No changes in insulin-binding are detected in unstimulated control cultures. A maximum of about 350 molecules of insulin can bind per transformed lymphocyte, while less than six insulin molecules bind to an untransformed cell. Circulating human leukemic lymphoblasts bind about as much insulin as the lymphocytes transformed
in vitro
. Giant, polynucleated, transformed lymphocytes cultured in the presence of cytochalasin B bind about 10 times more insulin than transformed lymphocytes, which is in harmony with a 10-fold increase in cell-surface area in these cells. Specific binding of insulin is a saturable process in transformed lymphocytes but not in the untransformed cells. In transformed cells, [
125
I]-insulin is displaced by as little as 2 ng/ml of native insulin, while in untransformed cells no significant displacement is observed with native insulin. Digestion of transformed cells with phospholipase C (EC 3.1.4.3.) enhances the specific binding of [
125
I]insulin 3-fold, but no effect occurs with untransformed cells. These observations indicate a possible functional role of insulin and of adenylate cyclase in cell growth and division.
Glucocorticoid Receptors and the Role of Glucocorticoids in Fetal Lung Development
Authors: Ballard Philip L. , Ballard Roberta A.
Published: May 2006

The cellular mechanism of glucocorticoid effects upon fetal lung was examined in studies of specific binding activity for corticosteroids. Cytoplasm of fetal rabbit lung contains receptor sites for [
3
H]dexamethasone at a concentration of 0.43 ± 0.04 pmol/mg of cytosol protein, and the apparent dissociation constant for the binding reaction is 2.7 ± 0.4 nM. The ability of various steroids to compete with labeled dexamethasone for binding to receptor correlates with their biologic potency. The hormone-receptor complex formed
in vitro
at 0° binds with high affinity at 20° to isolated lung nuclei. It is estimated that there are 9500 nuclear binding sites and 12,000 cytoplasmic receptor sites per fetal lung cell. During the last 12 days of gestation in a rabbit, the concentration of cytoplasmic receptor in lung is constant and is 2- to 5-times greater than receptor-site concentration in fetal skin, kidney, heart, muscle, gut, liver, brain, thymus, and placenta. These findings demonstrate that the early steps in the mechanism of glucocorticoid action in target tissues are present in lung cells, and suggest that these hormones accelerate fetal lung differentiation and surfactant production in animals by the induction of new protein synthesis mediated by receptor.