bluuebunny/crossref_metadata_2025 huggingface dataset:
Luminescence and Binding Studies on tRNA
Phe
Authors: Eisinger J. , Feuer B. , Yamane T.
Published: May 2006

The phenylalanine transfer RNA of baker's yeast (tRNA
Phe
) contains a base Y of unknown molecular structure next to the anticodon triplet. Since the base Y fluoresces at room temperature (λ
max
= 431 nm), its emission properties offer a unique tool for studying conformational and binding properties of tRNA
Phe
. The results obtained by these experiments include the following: (
1
) The quantum yield of fluorescence of Y in tRNA
Phe
(φF) is 0.07 ± 0.01 at high Mg
2+
concentrations (>10
-2
M
) and about half that at 10
-3
M
or less, indicating a [Mg
2+
]-dependent conformational change of the anticodon loop. (
2
) The fluorescence of Y isolated from tRNA
Phe
(Y
+
) is red-shifted by 15 nm compared to Y in tRNA
Phe
which suggests a stacked (more hydrophobic) environment for Y in the intact anticodon loop. φF of Y
+
is 0.035. (
3
) The solvent isotope effect φF(D
2
O)/φF(H
2
O) is 1.5 for tRNA
Phe
and 1.9 for Y
+
i.e., Y in tRNA is still hydrated. (
4
) The temperature dependence of φF in a polar glass shows that quenching occurs only at temperatures at which the glass has sufficiently low viscosity to permit solvent shell relaxation in the excited state. The low-temperature (80°K) fluorescence is blue shifted (λ
max
= 409 nm) and the phosphorescence has a decay time of 1.5 seconds, a threshold at 392 nm and a spectral shape like that of guanine. (
5
) In the presence of 10
-2
M
Mg
2+
penta-uridylate, which contains the codon triplet, a small blue shift and a decrease in φF are observed. This shift can be used to establish the formation of a binary complex between the codon and the anticodon with an association constant of 4 × 10
2
M
-1
, approximately. A similar complex is formed with poly-uridylate but not with poly-cytidylate. In the absence of Mg
2+
the binary complex is not formed.
Comparison of the Peptide Composition of Two Histocompatibility-2 Alloantigens
Authors: Shimada Akira , Yamane Kunio , Nathenson Stanley G.
Published: May 2006

The peptide composition of purified Histocompatibility-2 (
H-2
) reactive glycoprotein fragments from two murine strains allelic at the
H-2
locus (

H-2
b

and

H-2
d

) were compared by a cellulose thin-layer peptide mapping micro technique. Approximately 70 per cent of the theoretical maximum number of peptides produced by cyanogen bromide cleavage and trypsin digestion were visualized by this technique. Most (38) of the peptides for the glycoproteins from these strains allelic for the
H-2
locus were identical; however, three peptides of the

H-2
b

and four peptides of the

H-2
d

alloantigen were unique. The results demonstrate the remarkable similarity in protein structure between these two allelic products, but also show a small but reproducible difference in their peptide composition. The findings are consistent with the hypothesis that protein primary structure may determine wholly or in part their alloantigenic activities.
ACTH Receptors in the Adrenal: Specific Binding of ACTH-
125
I and Its Relation to Adenyl Cyclase
Authors: Lefkowitz Robert J. , Roth Jesse , Pricer William , Pastan Ira
Published: May 2006

Pure monoiodo ACTH-
125
I was prepared that was biologically active and free of unlabeled ACTH. Extracts of adrenal cortex that contained ACTH-sensitive adenyl cyclase, bound ACTH-
125
I; extracts that lacked the ACTH-sensitive cyclase did not bind ACTH-
125
I. Unlabeled ACTH inhibited the binding of ACTH-
125
I. Five ACTH derivatives which varied widely in biological activity were tested. All inhibited the binding of ACTH-
125
I in direct proportion to their biological activity. Albumin, insulin, and four unrelated iodinated hormones were inert. The addition of excess hormone or acetic acid produced rapid dissociation of bound ACTH-
125
I. This study demonstrates directly the binding of ACTH to its biologically significant site.
Virus-Specific, Labile, Nonvirion Antigen in Herpesvirus-Infected Cells
Authors: Tarro Giulio , Sabin Albert B.
Published: May 2006

The search for a specific, serologically identifiable nonvirion antigen (i.e., not a structural component of the virus) in cells infected with herpes simplex virus (HSV) was undertaken as an approach to the problem of the possible role of this virus in certain types of human cancer.

Synthesis of structural components of HSV could not be prevented by a variety of inhibitors of DNA synthesis or by incubation at certain high or low temperatures, and it was, therefore, necessary to devise methods for the detection of nonvirion antigen in the presence of virion antigens. This was achieved by means of specially prepared and absorbed antisera only after the unusual lability and sedimentability of the nonvirion component became apparent. The special sera were derived from guinea pigs hyperimmunized with
uncentrifuged
extracts of guinea pig kidney culture cells
freshly
prepared three hours after infection with 20 to 30 plaque-forming units (PFU) of HSV per cell. It was possible to remove the neutralizing (N) antibodies for live virus and the complement-fixing (CF) antibodies for the sedimentable and soluble virion antigens, without loss of CF antibodies for nonvirion antigen, by absorption of these sera with
uncentrifuged
, HSV infected cell extracts that had been
stored
at +4° or -66°C, or both,
for a sufficiently long time
to permit the disappearance of the labile, nonvirion components. Human, rabbit, and guinea pig sera obtained after infection or after „ordinary” hyperimmunization had no CF antibodies for the labile, nonvirion antigen after comparable absorption.

The nonvirion antigen detected in this manner is specific not only for HSV but also for the type (or strain?) of HSV, since infection of guinea pig kidney culture cells with vaccinia virus or type 2 (genital) HSV yielded no antigen detectable with the absorbed serum prepared against the type 1 HSV strain; the type 2 HSV produced large amounts of type 1 HSV virion antigen under these conditions, and the vaccinia virus large amounts of antigen reactive with ordinary rabbit antivaccinial serum. The nonvirion antigen was formed at maximum concentration early (3 hr) after high multiplicity HSV infection in guinea pig cells but late in the infectious process (12-24 hr) in rabbit or HEp 2 cells. The supernatant fluid had only 50 per cent of the activity after centrifugation at 1500
g
for ten minutes and none after a further centrifugation at 33,360
g
for one hour. Storage at +4°C for eight to nine days led to complete loss of activity of the nonvirion antigen but no loss of activity of the various sedimentable and soluble virion antigens. At -66°C or lower temperatures 50 per cent of the activity was lost in seven days and further loss occurred at different rates in extracts of guinea pig, rabbit and HEp 2 cells.
Implications of TL Phenotype Changes in an H-2-Loss Variant of a Transplanted H-2
b
/H-2
a
Leukemia
Authors: Boyse Edward A. , Stockert Elisabeth , Iritani Chika A. , Old Lloyd J.
Published: May 2006

An H-2-loss variant line, lacking H-2
a
antigens, was obtained from an H-2
b
/H-2
a
(C57BL × A)F
1
transplanted leukemia by immunoselection. The TL phenotype of the unselected line was TL.1,2,3,4 and that of the variant TL.1,2,4, which is the phenotype of TL
+
leukemias of C57BL. This finding, and the observed quantitative alterations of antigens TL.1,2 and 4, indicate that the
Tla
(
Thymus leukemia antigen
) locus was functionally deleted together with the
H-2
locus in the process of variant formation, despite absence of selection against cells carrying TL antigens. Representation of H-2 antigens of the remaining haplotype, H-2
b
, was quantitatively unchanged.
Studies on Genetic Organization in Higher Organisms, II. Complementation and Fine Structure of the Maroon-like Locus of
Drosophila melanogaster
Authors: Finnerty Victoria G. , Duck Peter , Chovnick Arthur
Published: May 2006

Mutants of the maroon-like complex, representative of the five known complementation classes, were subjected to fine structure mapping experiments utilizing a nutritional selective procedure which permits the survival of rare
ma-l
+
progeny from large-scale crosses. The analysis provides an internally consistent, unique map, colinear with the complementation map. Noncomplementers exhibit a polarized mapping distribution. In addition to
ma-l
+
recombinants, the selective medium permitted the survival of
ma-l
+
exceptionals not associated with recombination for adjacent markers. Analysis of the exceptionals favors their origin as convertants.
Conditions Determining Initiation of DNA Synthesis in 3T3 Cells
Authors: Dulbecco R. , Stoker M. G. P.
Published: May 2006

Experiments were designed to discriminate between inhibition of growth due to contacts or exhaustion of serum factors. The cell layer was wounded and the migrating cells were followed by time-lapse cinematography; DNA synthesis in the same cells was recognized by means of
3
H-thymidine labeling and radioautography. In this way, the complete history of individual cells migrating to the wound could be described. The results show that topographical relationships between cells play an important role in controlling initiation of DNA synthesis. It is still unclear whether initiation is promoted by release from contacts or by the increased ability of the cells to utilize serum factors because of their changes in shapes and activities.
Interconvertible Forms of Glycogen Phosphorylase in
Neurospora crassa
Authors: Téllez-Iñón María T. , Torres Héctor N.
Published: May 2006

Glycogen phosphorylase in extracts of
N. crassa
mycelia has two interconvertible forms: one active (
a
form) and the other inactive (
b
form) in the absence of 5′-AMP. The conversion of the
b
to the
a
form requires ATP-Mg
2+
and proceeds at higher rate in the presence of 3′,5′-cyclic AMP.
Implications of Heavy Chain Disease Protein Sequences for Multiple Gene Theories of Immunoglobulin Synthesis
Authors: Terry William D. , Ohms Jack
Published: May 2006

The sequence of the amino-terminal 34 amino acids of γ-heavy chain disease (γ-HCD) protein Hi is homologous with the amino-terminal region of immunoglobulin heavy chains. γ-heavy chain disease is smaller than a normal γ-chain, but has the carboxy-terminal composition expected for γ-chains and must, therefore, contain an internal deletion. Comparison of the Hi sequence with that of γ-heavy chain disease Zu, which also has an internal deletion, indicates that the site of internal deletion is not a constant characteristic of γ-heavy chain disease proteins.

Heavy chains can be assigned to subgroups on the basis of variable region sequences. The variable regions of Hi and one other protein differ significantly from those determined for other heavy chains, and these two proteins are assigned to a new heavy chain variable region subgroup,
V

H
IV

.

It has been suggested that single immunoglobulin heavy chains are the products of two separate structural genes and that variable region genetic information is translocated and integrated into common region information. These multiple gene theories make no prediction as to whether DNA or RNA is translocated. γ-heavy chain disease proteins provide unique information that indicates that if translocation is required for the production of immunoglobulin heavy chains, it is DNA, not RNA, that is translocated.
Role of RNA Synthesis in the Estrogen Induction of a Specific Uterine Protein
Authors: DeAngelo Anthony B. , Gorski Jack
Published: May 2006

The rate of amino acid incorporation into a specific uterine protein (induced protein band) isolated by gel electrophoresis has been shown to be markedly stimulated within an hour after estrogen administration. Injection of actinomycin D (8 mg/kg) prior to estrogen blocks the synthesis of induced protein. The accumulation of the product of the actinomycin D-sensitive step (induced protein band RNA) is significant 15 minutes after estrogen, and its synthesis would appear to be initiated as soon as the estrogen-receptor complex reaches the nucleus. Blocking protein synthesis with puromycin or cycloheximide did not affect the accumulation of induced protein band RNA, indicating that this is one of the earliest macromolecular synthetic events to occur after estrogen administration.
Proteins Specified by Herpes Simplex Virus, IV. Site of Glycosylation and Accumulation of Viral Membrane Proteins
Authors: Spear Patricia G. , Roizman Bernard
Published: May 2006

The membrane glycoproteins specified by herpes simplex virus are synthesized concurrently with structural viral proteins and accumulate in the cytoplasm and in the membranes lining it. Analyses of free and membranebound polyribosomes, the cytoplasmic pool of soluble proteins, and purified smooth membranes showed that viral membrane proteins bind to membranes soon after synthesis and become glycosylated
in situ
.
Circadian Systems, VI. Photoperiodic Time Measurement in
Pectinophora gossypiella
Authors: Pittendrigh Colin S. , Eichhorn John H. , Minis Dorothea H. , Bruce Victor G.
Published: May 2006

Diapause (100% incidence) occurs in the moth
Pectinophora gossypiella
when it is exposed to 24-hour light/dark cycles involving 12 hours of red light (600 nm); only 2% occurs when the photoperiod is extended to 14 hours, again with 600-nm light. This wavelength fails to synchronize all the known circadian oscillations of the moth. These observations appear, therefore, to constitute positive evidence that the photoperiodic time measurement is not mediated by a circadian oscillation. However, it remains possible, even plausible, that the photoperiodic clock is a separate circadian oscillator coupled to light by a red-absorbing pigment. That possibility is testable. The nature of the clock—oscillator or not—remains open.
Temporal Resolution of Individual Steps in an Enzymic Reaction at Low Temperature
Authors: Douzou P. , Sireix R. , Travers F.
Published: May 2006

Media are described which make it possible to study mechanisms of enzyme action at low temperature. The applicability of techniques developed are illustrated by results obtained on formation kinetics of complexes produced by the interaction of horseradish peroxidase with hydrogen peroxide. It is shown that the various steps in the time course of the reaction can be readily resolved with isolation of each intermediate in concentrations sufficient to permit rate studies between consecutive steps. The potential of the method for elaboration of enzyme mechanisms is discussed.
Mitochondrial Longevity
In Vitro
: The Retention of Respiratory Control
Authors: Romani Roger , Monadjem Anna
Published: May 2006

Isolated mitochondria were maintained metabolically active and coupled, i.e., capable of respiratory control, for several hours at 25°C. An increase in respiratory control generally occurred during the first 4-8 hr of incubation followed thereafter by a decline. Longevity is a dynamic function as evidenced by its dependency on substrate and cofactors, thiamine pyrophosphate, in particular. Magnesium was also essential to longevity; coenzyme A, bovine serum albumin, and reducing agents were not. The findings are discussed in terms of cytoplasmic-mitochondrial interrelationships and mitochondrial autonomy.
Localization of Cytochromes in Intact and Fragmented Mitochondrial Membranes
Authors: Chance Britton , Erecinska M. , Lee C. P.
Published: May 2006

Differences in the reactivity of cytochrome
c
toward external oxidants ferricyanide and cytochrome
c
peroxidase enzyme-substrate complexes in the intact and fragmented membranes may be easily explained on the basis of different locations of cytochrome
c
. The oxidation of cytochrome
c
is nearly 100% in the intact mitochondria, suggesting its location to be on the outside of the membrane permeability barrier and freely accessible to the external oxidants. In the sonicated membrane fragments, only 40% of cytochrome
c
reacts with ferricyanide or ES complex. Cytochromes
c, c
1
,
a
, and
a
3
are oxidized roughly in the same proportion by the external oxidants. These data suggest the existence of complete cytochrome chains on both sides of the membrane permeability barrier in the submitochondrial particles, and serve to explain a number of hitherto unresolved complexities concerning their electron transfer and energy coupling reactions. Energy coupling and controlled electron flow occurs in sets of cytochromes
c
1
,
a, a
3
on the same side of the membrane permeability barrier.
SPIN-STATE CHANGES IN CYTOCHROME P-450
cam
ON BINDING OF SPECIFIC SUBSTRATES
Authors: Tsai R. , Yu C. A. , Gunsalus I. C. , Peisach J. , Blumberg W. , Orme-Johnson W. H. , Beinert H.
Published: May 2006

The electron paramagnetic resonance signals of the soluble P-450 cytochrome from
Pseudomonas putida
were observed at temperatures from 4.2 to 80°K. As isolated, P-450 has a signal typical of a low spin ferric-heme compound with sulfur as one of the axial ligands (
g
= 2.45, 2.26, 1.91
5
). We also detected a minor signal typical of high spin ferric heme (
g
= 8, 4, 1.8) equivalent to less than 7% of the heme at temperatures below 20°K. On titration with the substrate, (+)-camphor, the low spin signal decreased and the high spin signal increased, maximally representing about 60% of the heme. For reasons not thus far understood, 40% of the heme is not converted to high spin by either (+) or (-)-camphor. The high spin signal has a rhombic character which is stronger than any previously observed with a heme compound (
E
= 0.33 cm
-1
;
D
= 3.8 cm
-1
;
E
/
D
= 0.087).

We conclude that P-450
cam
as isolated is equal to or more than 95% in a low spin form probably having sulfur as one of the axial ligands. The binding of substrate displaces this ligand sufficiently to allow for conversion from a low to a high spin form.
IMMUNOGLOBULIN SYNTHESIS AND SECRETION, V. INCORPORATION OF LEUCINE AND GLUCOSAMINE INTO IMMUNOGLOBULIN ON FREE AND BOUND POLYRIBOSOMES
Authors: Sherr Charles J. , Uhr Jonathan W.
Published: May 2006

Mouse myeloma cells pulse-labeled
in vitro
with
3
H-leucine or
3
H-glucosamine were fractionated on sucrose gradients, and membrane-bound and free polyribosomes were separated. Nascent polypeptides released from polyribosomes were precipitated with antiserum specific for mouse immunoglobulin. The results indicate that immunoglobulin is synthesized preferentially by bound polyribosomes.
Correction of Cellular Metachromasia in Cultured Fibroblasts in Several Inherited Mucopolysaccharidoses
Authors: Danes B. Shannon , Bearn Alexander G.
Published: May 2006

Cultured fibroblasts from the genetic mucopolysaccharidoses store higher than normal amounts of the polyanionic glycosaminoglycans (mucopolysaccharides); histochemical staining with the cationic dyes toluidine blue O and Alcian blue detects such intracellular accumulation. With these stains as phenotypic markers, correction of the cellular abnormality by fibroblasts derived from different patients and their heterozygous parents has been observed among several genetic types of mucopolysaccharidoses. In this way, syndromes previously considered clinically homogeneous have been separated into distinct groups.
The „Transformation” from Marxian „Values” to Competitive „Prices”: A Process of Rejection and Replacement
Authors: Samuelson Paul A.
Published: May 2006

The well-known transformation procedure for transforming from Marxian values to competitive prices is shown to be logically of the form: „Anything” equals „anything else” multiplied by „anything/anything else.”
Crystal and Molecular Structure of
N,N
′-Diethyl-
N,N
′-Diphenylurea
Authors: Ganis P. , Avitabile G. , Benedetti E. , Pedone C. , Goodman M.
Published: May 2006

N,N
′-diphenyl-
N,N
′-diethylurea (C
17
H
20
N
2
O) crystallizes in the space group P2
1
/
c
. The unit cell constants are:
a
= 10.42 ± 0.01 Å,
b
= 16.86 ± 0.02 Å,
c
= 10.66 ± 0.001 Å, β = 125°16′ ± 5′;
Z
= 4,

D
x

= 1.16 g·cm
-3
, D
meas
= 1.16 ± 0.01 g·cm
-3
. Data for 1392 reflections were collected at room temperature on a Picker automated diffractometer. The crystal structure was solved by direct methods and refined by bloc-diagonalized matrix least-squares calculations. The molecule is characterized by a pseudo C
2
symmetry; both phenyl groups are
trans
with respect to the oxygen atom. The hybridization of the two nitrogen atoms is intermediate between trigonal and tetrahedral; the nonplanar distortion of the amide groups is about 30°. The amide C-N bond lengths are 1.37 Å.
Reciprocal Hunger-Regulating Circuits Involving Alpha-and Beta-Adrenergic Receptors Located, Respectively, in the Ventromedial and Lateral Hypothalamus
Authors: Leibowitz Sarah Fryer
Published: May 2006

The injection of adrenergic and adrenolytic drugs directly into the brain through permanently implanted cannulas has yielded results showing that food consumption in the rat is regulated by a hypothalamic alpha-adrenergic „hunger” system. and a hypothalamic beta-adrenergic „satiety” system. The rats' differential responses to alpha-adrenergic and beta-adrenergic drugs injected into different hypothalamic sites indicate the following: (1) the lateral hypothalamic „feeding” center contains beta receptors, the activation of which produces satiation, presumably by inhibition of the lateral „feeding” cells; (2) the ventromedial hypothalamic „satiety” center contains alpha receptors, the activation of which produces eating, presumably by inhibition of the ventromedial „satiety” cells; and (3) the medio-lateral perifornical area of the hypothalamus contains both alpha and beta receptors, which lead to inhibition of the ventromedial or lateral hypothalamic centers respectively. It is suggested that the ventromedial and lateral hypothalamus are connected by reciprocal circuits, so that activation of the ventromedial center results in stimulation of the lateral beta receptors which inhibit the lateral „feeding” cells, and activation of the lateral center results in stimulation of the ventromedial alpha receptors which inhibit the ventromedial „satiety” cells.
Role of Phosphorylation Coupling Factor in Light-Dependent Proton Translocation by
Rhodopseudomonas capsulata
Membrane Preparations
Authors: Melandri Bruno A. , Baccarini-Melandri Assunta , Pietro Anthony San , Gest Howard
Published: May 2006

The activity of the light-dependent proton pump (in the absence of phosphorylation substrates) of
Rhodopseudomonas capsulata
„membrane vesicles,” in contrast to that of chloroplasts, is not appreciably affected by detachment of phosphorylation coupling factor(s). Proton uptake by such „uncoupled” (low phosphorylation activity) preparations is also unaffected by the addition of phosphorylation substrates (ADP + arsenate + Mg
2+
). The H
+
pump of „coupled” preparations, however, is stimulated when all of the substrates are present simultaneously. Oligomycin appears to affect both photophosphorylation and the H
+
pump by interaction with a component of the energy transfer sequence that is distinct from coupling factor. The results obtained suggest that in photosynthetic bacteria light-dependent cyclic electron flow (the driving force for photophosphorylation) is accelerated by active phosphorylation which, in turn, is dependent on the presence of protein coupling factors in the energy-converting membrane.
Non-Chromosomal Antibiotic Resistance in Bacteria, III: Isolation of the Discrete Transfer Unit of the R-Factor R1
Authors: Cohen Stanley N. , Miller Christine A.
Published: May 2006

A covalently-closed circular DNA species, banding at a buoyant density of ρ = 1.709 g/cm
3
in CsCl, has been identified in
antibiotic-sensitive
colonies of
E. coli
strain AB2463 (rec A
-
) after mating with a
Proteus mirabilis
strain that carries the R-factor, R1. This plasmid, which represents a stable segregant of R1 that has lost all of the drug resistance determinants present on the parent R-factor but which has retained its ability to be transferred by conjugation, fulfills the functional definition of the R-factor transfer unit (RTF).
Immunogenicity of
Mycoplasma pneumoniae
Glycolipids: A Novel Approach to the Production of Antisera to Membrane Lipids
Authors: Razin Shmuel , Prescott Benjamin , Chanock Robert M.
Published: May 2006

The glycolipid haptens of
Mycoplasma pneumoniae
were bound to membrane proteins of
acholeplasma laidlawii
(formerly
Mycoplasma laidlawii
) by reaggregation. This process consisted of the solubilization of lipid-depleted
A. laidlawii
membranes and
M. pneumoniae
glycolipids in 20 mM sodium dodecyl sulfate, and dialysis of the mixed solutions against 20 mM Mg
2+
. The hybrid reaggregate, collected by centrifugation, was highly immunogenic in rabbits, eliciting the production of a high titer of antibodies that fixed complement with the purified glycolipids and inhibited the metabolism of
M. pneumoniae
cells. The free glycolipids, or their mixture with
A. laidlawii
proteins, were much less effective in stimulating these antibodies. The antibodies to the hybrid reaggregate agglutinated
M. pneumoniae
cells and inhibited their ability to absorb erythrocytes, which indicates that at least some of the serologically-active glycolipids are exposed at the outer membrane surface. The ability to bind selected membrane lipids to membrane proteins of a serologically unrelated species provides a new tool for producing antibodies to lipid haptens.
Isogeneic Lymphocyte Interaction: Recognition of Self Antigens by Cells of the Neonatal Thymus
Authors: Howe Michael L. , Goldstein Allan L. , Battisto Jack R.
Published: May 2006

Cells with the ability to recognize self antigens have been demonstrated in the thymus of the neonatal mouse. The detection of these cells is based upon a newly described
in vitro
phenomenon termed the isogeneic lymphocyte interaction. This interaction is demonstrable by [
14
C]thymidine uptake in cultures containing mixtures of neonatal thymus cells and adult spleen cells from the CBA strain of mice. The response observed in these mixtures has been shown to be almost entirely due to thymic cell proliferation. Other isogeneic lymphoid cells cannot replace adult spleen cells. Thymic isogeneic lymphocyte interaction activity increases sharply after birth, begins to decline within the first week of life and is lost by adulthood. It is suggested that the isogeneic lymphocyte interaction may represent an
in vitro
model for cognitory and discriminatory cellular events occurring routinely
in vivo
.
A DNA-Acrylamide Gel Column for Analyzing Proteins That Bind to DNA, I. DNA Polymerase
Authors: Cavalieri Liebe F. , Carroll Elizabeth
Published: May 2006

A new procedure is described for purifying proteins that specifically bind to DNA. DNA is entrapped in polyacrylamide gel particles which can then be used in standard column chromatographic procedures. The method was developed using
Escherichia coli
DNA polymerase as the test material. The crude enzyme was applied at low ionic strength and eluted at high ionic strength with a 200-fold increase in specific activity on a single passage through the column. The method is versatile and simple and is not restricted to DNA-protein systems. Any macromolecule can be entrapped in the gel particles; these can interact with other large or small molecules in the liquid phase. The gel is stable at elevated temperatures and can therefore be used in hybridization experiments.
Absence of a Cell Membrane Alteration Function in Non-transforming Mutants of Polyoma Virus
Authors: Benjamin Thomas L. , Burger Max M.
Published: May 2006

A surface receptor for an agglutinin, exposed in transformed but not in normal cells, arises in normal mouse cells during lytic infection by polyoma virus. The structural change in the surface membrane characteristic of transformed cells and of cells productively infected by wild type virus fails to occur in normal mouse cells infected by mutants of the virus that are unable to cause transformation. The exposure of the receptor site by wild type virus is reversibly blocked by inhibitors of DNA synthesis.
Sites of Synthesis and Processing of Ribosomal RNA Precursors within the Nucleolus of
Urechis caupo
Eggs
Authors: Das Nirmal K. , Micou-Eastwood Julie , Ramamurthy Gollu , Alfert Max
Published: May 2006

Nucleoli from unfertilized
Urechis
eggs, labeled with tritiated RNA precursors, have been isolated for simultaneous autoradiographic localization and biochemical analysis of labeled RNA. The production of the ribosomal RNA precursor (38S) and its first cleavage occur at the fibrillar core region of the nucleolus. The products, predominantly 30S RNA, are then rapidly transported and stored in the granular cortex of the nucleolus. The formation of the nucleolar cortex, therefore, seems to result from an accumulation of partially processed ribosomal RNA with its associated proteins.
Carbon-13 Fourier Transform Nuclear Magnetic Resonance, II. Ribonuclease
Authors: Allerhand Adam , Cochran David W. , Doddrell David
Published: May 2006

High-resolution Fourier transform nuclear magnetic resonance was used to observe the natural abundance
13
C spectrum of a 0.02 M solution of bovine pancreatic ribonuclease A. Peaks assignable to only three carbons were easily observed after 10 hr of signal averaging. A number of tentative assignments were made.

As expected, the
13
C spectrum was appreciably richer in detail than the corresponding proton spectrum. Natural abundance
13
C Fourier transform nmr appears to be a practical tool for the study of biopolymers in solution.
Location of the Coat Cistron on the RNA of Phage Qβ
Authors: Hindley J. , Staples D. H. , Billeter M. A. , Weissmann C.
Published: May 2006

A new approach for the localization of a cistron on a phage RNA has been developed. The coat protein cistron of phage Qβ was found to begin between the 1100th and 1400th nucleotide from the 5′ terminus of Qβ RNA and therefore lies in the middle of the genome.
The γ-Glutamyl Cycle: A Possible Transport System for Amino Acids
Authors: Orlowski Marian , Meister Alton
Published: May 2006

Evidence is presented that rat kidney contains enzymes that catalyze the synthesis and utilization of glutathione; these reactions, which involve the uptake and release of amino acids from γ-glutamyl linkage, constitute a cyclical process which is termed „the γ-glutamyl cycle.” The γ-glutamyl cycle has properties that fulfill the requirements of an amino acid transport system. Thus, γ-glutamyl transpeptidase may function in translocation and γ-glutamylcysteine synthetase and glutathione synthetase may catalyze energy-requiring „recovery” steps in transport. These and other considerations suggest that glutathione serves a carrier function in amino acid transport.
Evidence of Heterosis Associated with an Enzyme Locus in a Natural Population of
Drosophila
Authors: Richmond Rollin C. , Powell Jeffrey R.
Published: May 2006

A wild population of
Drosophila paulistorum
(Andean semispecies) was analyzed by starch gel electrophoresis for a sex-linked enzyme locus,
Tetrazolium oxidase
. The results of the analysis of F
1
progenies from 106 single female lines from São José do Rio Prêto, Brazil, has allowed us to determine the genotype of 106 wild-collected females and 104 wild-collected males. The population is polymorphic for two alleles with frequencies of 0.56 and 0.44. The observed frequencies among the females of the two homozygotes were 0.23 and 0.13 and of the heterozygote 0.64. The deviation from the frequencies expected according to the Hardy-Weinberg formula is statistically significant (
P
< 0.005). There is a substantial excess of heterozygotes over the expected number. This observation is interpreted to mean that this polymorphism is maintained by heterosis. This is probably the first reported case of heterosis associated with an enzyme locus in a natural population of
Drosophila
.
Relationship between the
Intra
and
Inter
molecular Cross-links of Collagen
Authors: Kang Andrew H. , Gross Jerome
Published: May 2006

Spontaneous cross-linking
in vitro
, during incubation of purified collagen in nonstriated and native type fibrils, was studied to elucidate the relationship between
intra
and
inter
molecular cross-links. In nonbanded fibrils, the aldol condensation products of two allysyl residues, previously shown to constitute the
intra
molecular cross-link, formed spontaneously and could be isolated as such, whereas in native type fibrils, these compounds were found to be incorporated into an
inter
molecular cross-link; after chemical reduction they could not be isolated. Similar results were obtained from studies on a native collagenous tissue, rat tail tendon. It is suggested that the
intra
molecular cross-link is not a separate entity but only an intermediate of an
inter
molecular cross-link and that its existence in solubilized collagen is a result of the extraction procedure. The quantitative formation of
intra
molecular cross-links
in vitro
and identification of the cross-link compound are also reported.
Amino Acid Sequence of the Basic Protein of the Myelin Membrane
Authors: Eylar E. H.
Published: May 2006

The amino acid sequences of the encephalitogenic basic protein, A1, from bovine and human myelin are similar, differing by only 11 residues. The sequence reveals that while basic residues are spread randomly over most of the polypeptide chain, several regions (8-10 residues) exist that are nonpolar in character. The bovine protein has 170 residues with molecular weight 18,400. The human protein, which has an additional His-Gly sequence, contains 172 residues. The major encephalitogenic determinant (tryptophan region) of the bovine protein differs from the human only by a lysine to arginine substitution. The structural features of the A1 protein are discussed, with special reference to its role in stabilization of the myelin membrane, and its relation to multiple sclerosis.
Unilaterally Patterned Neural Activity of Gynandromorphs, Mosaic for a Neurological Mutant of
Drosophila Melanogaster
Authors: Ikeda Kazuo , Kaplan William D.
Published: May 2006

A neurophysiological study of a behavioral phenotype caused by a sex-linked single gene mutation has been performed with gynandromorphs, mosaic for the mutant gene,
Hyperkinetic

1
P

(
Hk

1
P

), in
Drosophila melanogaster
. The male tissue of this gynandromorph is hemizygous for
Hk

1
P

, while the female tissue is heterozygous. The characteristic neural activity caused by the
Hk

1
P

gene can be recorded only in the presumptive male region of the thoracic ganglion. Motor regions of one side were found to function independently of their counterparts in the opposite side of the thoracic ganglion and were unaffected by the genotype of other parts of the body. Thus, expression of the
Hk

1
P

gene is autonomous in the genetic sense, and each side of the ganglion is independent of the other side. Also, there is a high correlation between the external genotype and the genotype of underlying neural tissue of the thorax.
Mutations Altering Chloroplast Ribosome Phenotype in
Chlamydomonas
, II. A New Mendelian Mutation
Authors: Boynton John E. , Gillham Nicholas W. , Burkholder Barbara
Published: May 2006

A new mutation of
Chlamydomonas reinhardi, cr-1
, is characterized. The mutation exhibits Mendelian inheritance and affects the sedimentation velocity and formation of intact chloroplast ribosomes. The mutant grows reasonably well when supplied with sodium acetate as a carbon source, but poorly when forced to grow photosynthetically using carbon dioxide. Since the mutant
cr-1
accumulates large subunits of the chloroplast ribosome, we postulate that it is blocked in the formation of the small subunit. A tentative model explaining the behavior of the several mutants in
Chlamydomonas
now known to have altered chloroplast ribosomal phenotypes is presented.
Conformations of the Single-Stranded DNA of Bacteriophage M13
Authors: Forsheit Arleen B. , Ray Dan S.
Published: May 2006

At least two conformations of M13 single-stranded DNA have been demonstrated by measuring differences in sedimentation coefficient and by direct visualization in the electron microscope. Which form is obtained from infected cells and/or intact phage depends on the pH, ionic strength, and temperature. The slower-sedimenting form can be converted to the faster-sedimenting, single-stranded form by low ionic strength, alkali treatment, formamide, or formaldehyde, but not by exposure to 100°C in 1.0 M NaCl. The ability to assume either conformation appears to be a function of the nucleic acid alone. Whether or not these different conformations are of biological significance is still unknown.
DNA-Induced Transformation in
Drosophila:
Locus-Specificity and the Establishment of Transformed Stocks
Authors: Fox Allen S. , Yoon Sei Byung
Published: May 2006

The genetic changes induced in
Drosophila melanogaster
by DNA obtained from flies differing at specified genetic loci exhibit the general features of transformation, namely locus specificity and heritability. These properties have provided the basis for the establishment of transformed stocks. The phenomenon also exhibits striking special features, prominent among which is the observation that transformed individuals are always mosaics and that whole-body transformants are absent even in established stocks. The exosome model (which proposes that DNA segments enter the cells of treated individuals and become firmly associated with their homologous chromosome segments, but are never integrated into the linear structure of the chromosome) is formulated to fit these observations.
Evidence for a Precursor to Circulating Parathyroid Hormone
Authors: Sherwood Louis M. , Rodman John S. , Lundberg Walter B.
Published: May 2006

Bovine parathyroid glands incubated in organ culture synthesize and secrete parathyroid hormone in response to physiologic alterations in cation concentration. Hormone synthesized in the glands is immunologically different and higher in molecular weight than that released into the culture medium or circulating in bovine blood, although it is identical to purified hormone extracted from the glands. On the basis of the physiologic responses of tissue and medium hormone to cation, the transfer of radioactive label from one moiety to another, and interconversion of the two forms by a gland homogenate, it is suggested that the parathyroid glands synthesize a precursor hormone (proparathormone) that is modified to the smaller molecule that circulates in blood.
Mechanism and Stereochemistry of 5-Dehydroquinate Synthetase
Authors: Rotenberg S. L. , Sprinson D. B.
Published: May 2006

3-Deoxy-D-
arabino
-heptulosonic acid 7-phosphate (DAHP) labeled at C-7 randomly or stereospecifically with tritium and at C-1 with
14
C was converted enzymically to 5-dehydroquinate. Tritium of all three substrates was completely retained in 5-dehydroquinate, in accord with formation of a non-ketonizing 6,7-enol intermediate. The 5-dehydroquinates were dehydrated to 5-dehydroshikimate by 5-dehydroquinate dehydratase, which is known to catalyze a
cis
-elimination. Only 5-dehydroquinate derived from [7-
3
H](7
R
)-DAHP lost its tritium in this dehydration, indicating that the configuration at C-7 was inverted in the conversion of DAHP to 5-dehydroquinate.
Ecological Consequences of Island Colonization by Southwest Pacific Birds, II. The Effect of Species Diversity on Total Population Density
Authors: Diamond Jared M.
Published: May 2006

Among southwest Pacific birds colonizing a species-poor island from a species-rich island, spatial expansion of the niche to include a wider range of altitudes, habitats, or vertical strata is often an immediate response, while changes in foraging techniques and diet usually occur more slowly and require genotypic change.
Despite
occupation of spatially broader niches by some colonizing species and increases in abundance by others, the total population density of the whole avifauna is up to nine times lower on a species-poor island than in a comparable habitat on a species-rich island. Total population density varies among islands approximately linearly with the number of species in the lowlands, supralinearly at higher elevations. Part of the explanation is that many birds on small islands expand into niche space which is suboptimal for them and from which they would be excluded by species utilizing this niche space optimally on a species-rich island. The other suggested explanation is an intrinsic inefficiency or loss of fitness among populations on small Pacific islands compared to large-island populations, due to impoverished gene pools, reduced selection pressure, and low degree of endemism.
Determination of Arterial Blood Flow by Percutaneously Introduced Flow Sensors in an External Magnetic Field, I. The Method
Authors: Kolin Alexander , Grollman Julius H. , Steckel Richard J. , Snow Harold D.
Published: May 2006

A method for determining the rate of blood flow in arteries without surgical intervention is described. It is shown that a probe capable of securing such information about flow in a blood vessel can be introduced into the vascular tree by means of a needle puncture in the skin made by a no. 18-guage hypodermic needle. A snugly-fitting guide wire is passed through the needle, which is then withdrawn. A Teflon catheter is then passed over the wire and pushed through the skin and subcutaneous tissues into the superficial branch artery from which the wire guides it deep into the aorta to a desired location. The guide wire is then withdrawn and a suitable sensing device of wire-like structure can be passed through the catheter into the major arterial trunk and, if desired, into some of its branches. Two types of sensors are used, loop-shaped ones which are used as volume-flow meters, and L-shaped probes used as volume-flow meters when they fir the artery precisely and as velometers when they do not. The sensors are used in conjunction with an apparatus consisting of a flat coil mounted over the animal and a standard electromagnetic sinusoidal flow meter channel.
Temperature-Dependent Properties of Cells Transformed by a Thermosensitive Mutant of Polyoma Virus
Authors: Dulbecco Renato , Eckhart Walter
Published: May 2006

In cells transformed by ts-3, a thermosensitive mutant of polyoma virus, the loss of inhibition of DNA synthesis by topographical factors (topo-inhibition), is rendered temperature-dependent, providing evidence that the viral genome controls this essential aspect of transformation. The expression of two other attributes of transformed cells, growth in agar and serum requirement for initiation of DNA synthesis in a wound in culture, is not made temperature-dependent. In productive infection of BALB-3T3 cells by ts-3, virus-induced stimulation of cellular DNA synthesis and movement is rendered temperature-dependent.
An
In Vitro
System That Simulates Plant Cell Extension Growth
Authors: Rayle David L. , Haughton Peter M. , Cleland Robert
Published: May 2006

A new technique is described for studying controlled
in vitro
extension of plant cell walls. This technique uses frozen-thawed
Avena
coleoptile segments in which turgor is replaced by a constant applied force. In this system rapid extension is induced by low pH (3.0-3.6) but not by auxins or CO
2
. Extensions of over 30% have been achieved. Our results indicate that cell wall synthesis is not required for rapid cell extension, and suggest that wall extension may be controlled by acid-labile, alkali-stable cell wall bonds.
T4 Endonuclease Involved in Repair of DNA
Authors: Yasuda Seiichi , Sekiguchi Mutsuo
Published: May 2006

An enzyme activity, named T4 endonuclease V, was purified from T4-infected
Escherichia coli
. The enzyme induces single-stranded breaks in ultraviolet-irradiated DNA but does not act on native or heat-denatured DNA. The enzyme activity is dependent on the dose of ultraviolet irradiation, and the number of the breaks formed is approximately equal to the number of pyrimidine dimers present in the DNA. Denatured DNA, which has been exposed to ultraviolet light, is also attacked by the enzyme although the extent of the reaction is greater with irradiated native DNA. The enzyme shows optimal activity at pH 7.5 and does not require added divalent ions. When the enzyme-treated, irradiated DNA is subjected to stepwise degradation by spleen phosphodiesterase, dimers are released more rapidly than thymine into the acid-soluble fraction, suggesting that the enzyme induces a break at the 5′-side of a pyrimidine dimer. The enzyme, whose formation is controlled by the
v
+
gene of T4, appears to be responsible for the first step of excision repair.
Regulation of Specific Functions of Glial Cells in Somatic Hybrids, II. Control of Inducibility of Glycerol-3-Phosphate Dehydrogenase
Authors: Davidson Richard L. , Benda Philippe
Published: May 2006

Glycerol-3-phosphate dehydrogenase (EC 1.1.1.8) is induced when glial cells are exposed to hydrocortisone
in vitro
. In contrast, the enzyme activity in fibroblasts is not affected by the steroid. In an attempt to elucidate the mechanisms controlling inducibility, hybrids between glial cells and fibroblasts were studied. It was found that the activity of the enzyme does not increase when the hybrids are exposed to hydrocortisone. It was also shown that inducibility and the noninduced activity of enzyme are controlled independently. Comparisons of S-100 and glycerol phosphate dehydrogenase activity in the hybrids suggest that all the specialized functions characteristics of glial cells are not coordinately controlled.
Production of 19S IgM Antibodies with Restricted Heterogeneity from Sharks
Authors: Clem L. William , Leslie Gerrie A.
Published: May 2006

Two of three nurse sharks,
Ginglymostoma cirratum
, immunized with streptococcal A-variant vaccine, produced over 7 mg/ml serum of 19S IgM antibody to the group-specific carbohydrate. The light chains of this specific antibody from one shark were separated into multiple bands by disc electrophoresis. The light chains from the other antibody-producing animal were much less heterogeneous and gave only one predominant band.
A Rapidly Acting Metabolite of Vitamin D
3
Authors: Haussler M. R. , Boyce D. W. , Littledike E. T. , Rasmussen H.
Published: May 2006

A vitamin D
3
metabolite in intestine more polar than 25-hydroxy-vitamin D
3
(25-OH D
3
) has been detected by countercurrent distribution. The intestinal metabolite is found also after administration of labeled hydroxy D
3
, indicating that it arises from vitamin D
3
via the intermediate 25-hydroxy derivative. The more polar metabolite is localized in the nuclear-chromatin fraction and appears in the gut before the physiological response to vitamin D
3
.

3.5 μg of the intestinal metabolite was isolated from 1250 chickens; the resulting purified material proved to be a potent mediator of calcium absorption. On a weight basis, it was at least 5 times as effective as vitamin D
3
, and acted 3 times faster than either hydroxy D
3
or D
3
in stimulating intestinal calcium transport in the rachitic chick. It is proposed that this as yet uncharacterized steroid represents the active form of vitamin D
3
in the intestine.
Strand-Specific Supercoiled DNA-Protein Relaxation Complexes: Comparison of the Complexes of Bacterial Plasmids
Col
E
1
and
Col
E
2
Authors: Blair D. G. , Clewell D. B. , Sheratt D. J. , Helinski D. R.
Published: May 2006

Certain bacterial plasmids can be isolated as unique complexes of supercoiled circular DNA and protein. These complexes are distinguished by the conversion of the supercoiled DNA to the relaxed or open-circular DNA form upon treatment with ionic detergents, proteases, or alkali. This report demonstrates that the open-circular DNA resulting from the pronase-induced relaxation of the complexes of colicinogenic factors E
1
(
Col
E
1
) and E
2
(
Col
E
2
) possesses a strand-specific break. In each case this break is found in the heavy strand of the DNA as defined by CsCl centrifugation in the presence of poly(U,G). In addition, the
Col
E
1
and
Col
E
2
complexes exhibit certain properties that are plasmid specific. Heat treatment, and to a lesser extent pronase treatment, inactivates the
Col
E
2
complex, making it insensitive to agents that formerly were capable of inducing relaxation (conversion of the DNA to the open-circular form). In contrast, the
Col
E
1
complex is not inactivated by these treatments. The potential role of these strand-specific relaxation complexes in DNA replication is discussed.