bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimulation of RNA Synthesis by Two Protein Factors in Extracts of
Escherichia coli
Authors: Murooka Yoshikatsu , Lazzarini Robert A.
Published: May 2006

Two separate protein factors that markedly stimulate DNA-dependent RNA polymerase have been partially purified from ribosome-free extracts of
E. coli
Q13 cells. These proteins appear to differ from sigma, M, H, psi, and the factor described by Mahadik and Srinivasan. The stimulation by either factor requires the presence of the sigma protein. Using RNA-DNA hybridization competition analyses, we also demonstrate that neither of the new factors preferentially stimulates the synthesis of ribosomal RNA. The purification, properties, and mechanism of action of these new factors are examined.
A Unique Form of Terminal Redundancy in Adenovirus DNA Molecules
Authors: Garon Claude F. , Berry Karen W. , Rose James A.
Published: May 2006

A unique form of terminal redundancy has been observed in DNA molecules extracted from several human adenovirus serotypes. Electron microscopic studies reveal that single-stranded circular molecules are formed when native DNA is denatured and then annealed. Temperatures approaching the

T
m

of native DNA are required to convert circles to linear molecules, indicating a high degree of self-complementarity between terminal base sequences of DNA strands. Single-stranded circles are not generated if a limited number of nucleotides (2-4%) are removed from the 3′ ends of native DNA by digestion with
Escherichia coli
exonuclease III before denaturation and annealing. The lenght of the redundant segment appears to differ among major serotypic groups, and a possible association between increased length of the redundant segment and increased oncogenic capability of virus serotype is suggested. Evidence for the configuration of the duplex closure region of circular molecules is also presented.
Antibody Response
In Vitro
to an Animal Virus: Production of Rabies Virus Neutralizing Antibodies by Mouse Cells in Culture
Authors: Koprowski H. , Mocarelli P. , Wiktor T. J.
Published: May 2006

Rabies virus neutralizing antibodies were produced
in vitro
by the exposure of mouse spleen cells to live and inactivated rabies virus suspensions and to sheep erythrocytes coated with rabies virus. These antibodies did not neutralize two other rhabdoviruses: Kern Canyon and vesicular stomatitis viruses, and were precipitable by treatment with an antiserum to mouse IgG. Removal of “glass-adhering” cells from mouse spleen cell suspensions abolished the antibody response, which could be restored by the addition of mouse peritoneal exudate cells, rich in macrophages.
ω-Theorems for Quotients of Zeta-Functions at Combinations of Points
Authors: Levinson Norman
Published: May 2006

Theorem A. Let
q
≥
O
and
r
≥
O
be integers. Let
s
= σ +
it
, let ζ(
s
) be the Riemann zeta-function, let

G
o

(
s
) = 1, and [Formula: see text] and let
F
(
s
) =

G
q

(
s
)/

H
r

(
s
). Then as
t
→ ∞ lim sup [unk]
F
(1 +
it
)[unk]/(log log
t
)
q+r+1
≥ (6/π)
2
)
r+1
exp {(
q
+
r
+ 1)γ}, where γ is Euler's constant.

Stronger results such as proved in [1] are valid, and in particular
q
and
r
can be allowed to increase with
t
as in [1]. Results involving the real part of the sum of the factors of

G
q

and of the reciprocals of the factors of

H
r

can be proved much as in [3].
Parallel Subtraction of Matrices
Authors: Anderson W. N. , Duffin R. J. , Trapp G. E.
Published: May 2006

A new Hermitian semidefinite matrix operation is studied. This operation—called parallel subtraction—is developed from the theory of parallel addition. Since the theory of parallel addition is motivated by the analysis of interconnected electrical networks, parallel subraction may be interpreted in terms of the synthesis of electrical networks. The idea of subtraction is also extended to hybrid addition.
Z
-Average Sedimentation Coefficient in Reversibly Self-Aggregating Systems
Authors: Kegeles G.
Published: May 2006

A theoretical treatment of the determination of the
Z
-average sedimentation coefficient in reversibly self-aggregating systems is presented. These equations are useful for determination of formation constants of polymers.
Cohomology of Various Completions of Quasicoherent Sheaves on Affines
Authors: Laudal Olav Arnfinn
Published: May 2006

Let O be a complete discrete valuation ring and let A be a commutative O-algebra. Let
M
be any
A
-module. In this paper, a class of completions
M̃
on the affine
X
corresponding to
A
, which includes, e.g., the Washnitzer-Monsky completion [1], and the full completion is studied. We then prove that for all of these completions we have,

H
i

(
X
,
M̃
+
) =
O
for
i
≥ 1,
H°
(
X
,
M̃
+
) =
M
+
.
Extranuclear Temperature-Sensitive Lethality in
Nicotiana tabacum
L
Authors: Matzinger D. F. , Wernsman E. A.
Published: May 2006

Tobacco seedlings from progeny of a single aberrant plant, either self-fertilized or used as the female in crosses, failed to become autotrophic at 13° day and 8° night temperatures, but grew normally at 26° day and 20° night temperatures. After initial normal growth at 26° day and 20° night temperatures, autotrophic plants from the aberrant line also died after subsequent exposure to 13° day and 8° night temperatures. The temperature-sensitive lethality was transmitted only through the female parent. When seedlings were grown at normal 26° day and 20° night temperatures, mutant selfs, normal selfs, and reciprocal F
1
hybrids were indistinguishable.
In Situ
Hybridization of RD114-Virus RNA with Human Metaphase Chromosomes
Authors: Price Peter M. , Hirschhorn Kurt , Gabelman Norman , Waxman Samuel
Published: May 2006

In situ
hybridization was used to detect regions of human metaphase chromosomes exhibiting complementarity with radioactively-labeled RNA isolated from RD114-virus. The region of homology, as identified by autoradiography, was confined to one D-group chromosome.
Human Lymphotoxin: Purification and Some Properties
Authors: Granger G. A. , Laserna E. C. , Kolb W. P. , Chapman F.
Published: May 2006

Lymphotoxin is secreted by human lymphocytes stimulated with phytohemagglutinin
in vitro
. Combinations of DEAE-cellulose and Sephadex chromatography, acrylamide gel electrophoresis, and isoelectric focusing were used to purify lymphotoxin 2000- to 4000-fold; 15-25% of the activity has been recovered. Lymphotoxin appears to be a weakly charged molecule(s) of molecular weight about 90,000-100,000 that migrates in Pevikon block electrophoresis as a β- or α2 globulin. It is a discrete molecule(s), because it is completely separable from medium serum proteins and carrier and phytohemagglutinin proteins. Isoelectric-focusing studies indicate that there may be a limited heterogeneity among lymphotoxin molecules.
Release of Amplified Ribosomal DNA from the Chromomeres of
Acheta
Authors: Lima-De-Faria A. , Jaworska Halina , Gustafsson T.
Published: May 2006

The major chromomeres of pachytene chromosomes 6 and 11 in the oocytes of
Acheta
(Orthoptera) are regions of amplification for ribosomal RNA cistrons (28 S and 18 S). During late prophase the amplified DNA copies are released from the chromomeres, which decrease in size as the amount of DNA decreases. The number of nucleotide pairs released from the major chromomere of chromosome 11 is about 1.38 × 10
9
.
Induction of Immunological Tolerance in Bone Marrow-Derived Lymphocytes of the IgE Antibody Class
Authors: Katz David H. , Hamaoka Toshiyuki , Benacerraf Baruj
Published: May 2006

Administration of the 2,4-dinitrophenyl (Dnp) determinant conjugated to the “nonimmunogenic” copolymer of D-glutamic acid and D-lysine (D-GL) induces Dnp-specific immunological tolerance which is essentially restricted to bone marrow-derived (B) lymphocytes. Previous studies have demonstrated tolerance induction by Dnp-D-GL in predominantly B lymphocytes of the IgG class. The present studies establish and analyze conditions for tolerance induction in Dnp-specific B lymphocytes of the IgE antibody class by taking advantage of: (
i
) the relatively easy capacity to induce tolerance with Dnp-D-GL in an animal or cell population previously primed to the Dnp determinant; (
ii
) previously established parameters for the successful adoptive transfer of Dnp-specific IgE antibody responses; and (
iii
) the capacity to induce, and maintain a state of Dnp-specific tolerance with Dnp-D-GL in adoptive transfer responses. Using these approaches, we have successfully rendered Dnp-specific B cells of the IgE class profoundly and apparently irreversibly tolerant after exposure of such cells to Dnp-D-GL. These observations represent a starting point of wide potential for solving many therapeutic problems concerned with clinical allergies.
Isolation of Circular DNA Molecules from Whole Cellular DNA by Use of ATP-Dependent Deoxyribonuclease
Authors: Mukai Tsunehiro , Matsubara Kenichi , Takagi Yasuyuki
Published: May 2006

A technique is described for isolation of plasmid DNA in closed and open circular double-stranded forms from bacterial cells, by use of ATP-dependent deoxyribonuclease purified from
Micrococcus luteus
. This DNase, acting only upon linear DNA molecules, degrades all bacterial chromosomal DNA extracted in the linear form. Circular plasmid DNAs are left intact, and are then separated by sedimentation through a sucrose gradient. Unlike previous techniques for analysis of plasmid DNA, this technique can be used to isolate not only closed circular DNA but also open circular DNA. Several plasmids, such as those from phage (λdv1 and λdv21), a colicinogenic factor (Col E2), a sex factor (F
8
′ gal), and “minicircles” in
Escherichia coli
15, in both the open and closed circular forms, were well separated from chromosomal DNA by this technique.
In Vitro
Production of Mouse Mammary Tumor Virus in a Mouse Mammary Tumor Ascites Line
Authors: Keydar Jafa , Gilead Zvee , Hartman Jacob R. , Ben-Shaul Yehuda
Published: May 2006

An ascites line derived from a spontaneous mouse mammary carcinoma produces, on explantation and cultivation
in vitro
, large amounts of oncornavirus particles. The biochemical, biophysical, and electron microscopic characteristics of the virions are described. Molecular hybridization and immunological methods identify these virions as mouse mammary tumor virus.
Two Independently Inherited Electrophoretic Variants of the Lysine-Rich Histones of Maize (
Zea mays
)
Authors: Stout John T. , Phillips Ronald L.
Published: May 2006

We report here the first instance of inherited intraspecific histone variation in plants. Maize lysine-rich histone I is composed of four subfractions that are electrophoretically distinct in long polyacrylamide gels. Initial segregation studies indicate that at least one subfraction shows mobility differences inherited as if controlled by a single Mendelian locus. The locus is not on the short arms of chromosomes 2 or 4. The third subfraction also shows variants. Indirect evidence indicates that the genes controlling the variants of this subfraction segregate independently of those of the first. We suggest the symbols
alh-A188
and
alh-W23
to designate two of the alleles we have discovered of the first subfraction (a) of the lysine-rich histones and
clh-A188
and
clh-W23
the alleles of the third subfraction (c) of the lysine-rich histones. Other strains of maize show other differences in their histone I fractions, suggesting that there is inbredline-specific polymorphism with respect to histone I variants.

The meiotic chromosome mutants,
elongate
and
sticky
, do not appear to condition maize histone alterations that can be detected electrophoretically.
Preservation of Erythrocyte Ghost Ultrastructure Achieved by Various Fixatives
Authors: McMillan Paul N. , Luftig Ronald B.
Published: May 2006

We have evaluated the quality of ultrastructural preservation of erythrocyte ghosts achieved under various electron microscopic preparative conditions. Initially, negative staining was used to monitor gross morphology of the ghosts. Of several negative stains used (phosphotungstate, silicotungstate, ammonium molybdate, and uranyl acetate), all but uranyl acetate resulted in fragmentation of membranes and the appearance of small vesicular structures. Further, preservation of gross membrane ultrastructure was greatly enhanced when samples were fixed with either 4.0-5.0% glutaraldehyde or 1% osmium tetroxide (OsO
4
) before they were stained with uranyl acetate. We then examined the ability of these fixatives to preserve membrane fine structure, as monitored by thin-sectioning procedures. In these studies, fixation with 1% osmium tetroxide (alone or in conjunction with 5% glutaraldehyde) resulted in a trilamellar image about 95 Å in width. Fixation with 5% glutaraldehyde alone provided a markedly different result. The membrane now appeared as a single line about 160 Å wide with regions of varying electron density throughout. This result suggests that glutaraldehyde used alone may reveal the location of membrane proteins that are obscured or removed by OsO
4
fixation. This point would seem to be supported by the results obtained when erythrocyte membranes were extracted with 5 mM EDTA after fixation in either 5% glutaraldehyde or 1% OsO
4
. While only 10% of the detectable protein was solubilized from glutaraldehyde-treated erythrocyte membranes, 85% was solubilized from OsO
4
-treated ghosts. Among these latter proteins are three that migrated on Ouchterlony double-diffusion agar plates at the same position as three known proteins with molecular weights of about 200,000. Additional studies indicated that, even during a routine pre-embedding procedure, OsO
4
led to solubilization of as much as 8 times the amount of protein as glutaraldehyde
alone
. Although the erythrocyte membrane has a notoriously weak association with its proteins, we feel that our studies provide a cautionary note with regard to the use of OsO
4
as a fixative in other membrane systems.
Cs
2
SO
4
Gradients Containing Both Hg
2+
and Ag
+
Effect the Complete Separation of Satellite Deoxyribonucleic Acids Having Identical Densities in Neutral CsCl Gradients
Authors: Skinner Dorothy M. , Beattie Wanda G.
Published: May 2006

A combination of both Ag
+
and Hg
2+
in Cs
2
SO
4
effects the complete separation of two DNAs having identical densities in CsCl. Satellite DNAs of hermit crab,
Pagurus pollicaris
, and lobster,
Homarus americanus
, have been isolated by this means.
In Vitro
Translation of Oogenetic Messenger RNA of Sea Urchin Eggs and Picornavirus RNA with a Cell-Free System from Sarcoma 180
Authors: Jenkins Nancy , Taylor Milton W. , Raff Rudolf A.
Published: May 2006

A cell-free protein-synthesizing system prepared from mouse sarcoma 180 was characterized by use of RNA from mengo virus and sea urchin egg. In the presence of exogenous mammalian transfer RNA, total sea urchin egg RNA and mengo RNA direct incorporation of [
3
H]leucine into acid-insoluble material. The system is extremely efficient in that a stimulation of 100-times over background can be obtained. Studies with formylmethionyl-transfer RNA, as well as with inhibitors of initiation, indicate that multiple initiation occurs; further, 85-90% of all chains made
in vitro
are subsequently released from ribosomes. An average translation time of 3.5 min was determined with messenger RNA of sea urchin egg, and product analysis indicates that high-molecular-weight products (greater than 50,000 molecular weight) are being made
in vitro
. Sequences of sea urchin egg RNA containing poly(A) act as messenger RNA.
T7 Early RNAs and
Escherichia coli
Ribosomal RNAs are Cut from Large Precursor RNAs
In Vivo
by Ribonuclease III
Authors: Dunn John J. , Studier F. William
Published: May 2006

The early region of T7 DNA is transcribed as a single unit in a Ribonuclease III-deficient
E. coli
strain to produce large molecules essentially identical to those produced
in vitro
by
E. coli
RNA polymerase. As with the
in vitro
RNAs, these molecules are cut by purified RNase III
in vitro
to produce the messenger RNAs normally observed
in vivo
. Thus, the normal pathway for producing the T7 early messenger RNAs
in vivo
appears to involve endonucleolytic cleavage by RNase III. The uninfected RNase III-deficient strain contains several RNAs not observed in the parent strain. Patterns of labeling
in vivo
suggest that the largest of these RNAs, about 1.8 × 10
6
daltons, may be a precursor to the 16S and 23S ribosomal RNAs. When this large molecule is treated
in vitro
with purified RNase III, molecules the size of precursor 16S and 23S ribosomal RNAs are released; hybridization competition experiments also indicate that the 1.8 × 10
6
dalton RNA does indeed represent ribosomal RNA. Thus, RNase III cleavage seems to be part of the normal pathway for producing at least the 16S and 23S ribosomal RNAs
in vivo
. Several smaller molecules are also released from the 1.8 × 10
6
dalton RNA by RNase III, but it is not yet established whether any of these contain 5S RNA sequences.
Microsurgically Fused Human Somatic Cell Hybrids: Analysis and Cloning
Authors: Diacumakos Elaine G.
Published: May 2006

Cell fusion by microsurgery permits production of specified bicellular hybrid cells with very high efficiency. Systematic analysis of the fate of bicellular hybrids reveals fundamental properties of cells in accordance with cell type. Bicellular hybrids that do not proliferate survive 1-21 days; those that do proliferate form clones 8-9 days after fusion.
Inhibition of the Oxidation of Glutamate and Isocitrate in Liver Mitochondria at a Specific NADP+-Reducing Site
Authors: Lin Diane C. , Kun Ernest
Published: May 2006

The cation-complexing carboxylic-acid antibiotic X-537A, at concentrations far below that required for ionophorous activity, selectively inhibits the oxidation of glutamate and isocitrate by liver mitochondria in steady-state 3. The site of inhibition has been localized specifically at the reduction of NADP
+
. Glutamate and isocitrate dehydrogenases, the oxidation of NAD
+
-dependent substrates, pyridine nucleotide transhydrogenations, and the respiratory chain between NADH (or NADPH) and O
2
are unaffected by the antibiotic X-537A. Kinetic evidence, i.e., competition between chlorotetracycline (a fluorescence probe for membrane-bound bivalent cation) and X-537A, indicates that the NADP
+
-reducing, antibiotic-sensitive site is most probably associated with the inner mitochondrial membrane.
The Interaction of Elongation Factor G with
N
-Acetylphenylalanyl Transfer RNA·Ribosme Complexes
Authors: Modolell Juan , Cabrer Bartolomé , Vázquez David
Published: May 2006

N
-Acetyl-Phe-tRNA, nonenzymically bound to the acceptor site of
Escherichia coli
ribosomes, readily undergoes translocation in the presence of elongation factor (EF)-G and GTP. The translocated
N
-acetyl-Phe-tRNA, bound to the ribosomal donor site, prevents further interaction of EF-G with the ribosome, for it inhibits the GTP hydrolysis that takes place in the presence of EF-G and ribosomes and it decreases the formation of either the GDP·EF-G·fusidic acid·ribosome complex or the 5′-guanylylmethylenediphosphonate·EF-G·ribosome complex. Deacylation with puromycin of the donor site-bound
N
-acetyl-Phe-tRNA reverses these inhibitions, even though the tRNA
Phe
moiety remains bound to the ribosme. These results suggest that ribosomes complexed with messenger RNA and peptidyl-tRNA may be restricted in their ability to interact with EF-G to that part of the elongation cycle when peptidyl-tRNA is in the acceptor site, and deacylated tRNA in the donor site. Deacylation of the donor site-bound peptidyl-tRNA associated with peptide bond formation may control the interaction of EF-G with the ribosome.
Cell-Surface Immunoglobulin of Human Thymus Cells and Its Biosynthesis
In Vitro
Authors: Moroz Chaya , Hahn Yafa
Published: May 2006

Human thymus cells synthesize immunoglobulin in short-term culture, the nascent immunoglobulin appearing in both cytoplasmic and membrane fractions. Surface immunoglobulin was demonstrated by lactoperoxidase radioiodination of the cells. The demonstration of intracellular and surface immunoglobulin required procedures that minimize proteolytic degradation. Noncovalently linked, monomeric μ chains and light chains were found in the cytoplasm and on the surface of the cells by means of acrylamide gel electrophoresis and by specific immunoprecipitation of the isolated chains.
Oxaloacetate as the Hill Oxidant in Mesophyll Cells of Plants Possessing the C
4
-Dicarboxylic Acid Cycle of Leaf Photosynthesis
Authors: Salin Marvin L. , Campbell Wilbur H. , Black Clanton C.
Published: May 2006

Isolated mesophyll cells from leaves of plants that use the C
4
dicarboxylic acid pathway of CO
2
fixation have been used to demonstrate that oxaloacetic acid reduction to malic acid is coupled to the photochemical evolution of oxygen through the presumed production of NADPH. The major acid-stable product of light-dependent CO
2
fixation is shown to be malic acid. In the presence of phosphoenolpyruvate and bicarbonate the stoichiometry of CO
2
fixation into acid-stable products to O
2
evolution is shown to be near 1.0. Thus oxaloacetic acid acts directly as the Hill oxidant in mesophyll cell chloroplasts. The experiments are taken as a firm demonstration that the C
4
dicarboxylic acid cycle of photosynthesis is the major pathway for the fixation of CO
2
in mesophyll cells of plants having this pathway.
Effect of Interferon Treatment on Cellular Messenger RNA
Authors: Levy Hilton B. , Riley Freddie L.
Published: May 2006

Cell monolayers wre treated with interferon, and then were labeled with RNA precursors. Messenger ribonucleoprotein and transfer RNA were liberated from isolated polysomes, and analyzed by electrophoresis on polyacrylamide gels. The messenger ribonucleoproteins and transfer RNA from interferon-treated cells migrated slightly slower than did the corresponding components from control cells. It was shown that the differences in migration speeds was attributable to the fact that the messenger RNAs and transfer RNA that were polysomebound (i.e., being translated) were slightly larger than control-cell RNAs. This phenomenon was seen in mouse L cells, primary mouse-embryo cells, and rabbit-kidney cells. Ribosomal 28S and 18S RNA was not altered, nor was nuclear RNA. Several types of evidence indicate that the biochemical changes are attributable to the interferon in the preparations, and not to impurities. These data may bear on the mechanism by which interferon-treated cells recognize and translate viral RNA poorly. It is tentatively suggested that interferon treatment of cells leads to a change in cellular messenger RNA such that the cell can distinguish it from the subsequently infecting viral RNA.
Reduction of Acetylene and Hydrazine with a Molybdenum-Glutathione Complex
Authors: Werner Dietrich , Russell Sterling A. , Evans Harold J.
Published: May 2006

Crystalline preparations of a molybdenum-glutathione complex catalyze the reduction of acetylene to ethylene in the presence of borohydride. The reaction proceeds at rates up to 6 mol of C
2
H
2
produced per min per mol of bound Mo, which is 4% of the activity of a quantity of nitrogenase with an equivalent amount of Mo. The activity of the complex is enhanced 100-fold by ATP, but the addition of ADP has no effect. Stimulation in activity by GTP is about the same as that by ATP, and the effects of CTP or UTP are considerably less. Inhibition of acetylene-reduction activity by the addition of 32 mM orthophosphate was 14%, by 32 mM pyrophosphate 62%, by 0.2 atm of O
2
65%, and by 0.5 atm of CO 12%; 0.5 atm of H
2
had no effect. The molybdenum-glutathione complex also catalyzes the reduction of hydrazine to ammonia in a reaction that is dependent upon borohydride. The reaction is enhanced about 7-fold by ATP and proceeds at a rate of 2 mol of NH
3
produced per min per mol of bound Mo.
“Metodo Rapido” for Finding Real Quadratic Fields of Class-Number 1
Authors: Chowla S. , Chowla P.
Published: May 2006

The authors state and prove a rapid criterion to determine whether the class-number of certain real quadratic fields is 1.
The Energy of Substituted Ethanes. Asymmetry Orbitals
Authors: Salem Lionel , Hoffmann Roald , Otto Peter
Published: May 2006

The leading terms in the energy of a general substituted ethane are derived in explicit form as a function of the torsional angle
θ
, the substituent electronegativities, and their mutual overlaps. The energy is found to be the sum of all four overlaps between pairs of asymmetry orbitals, and satisfies the requisite symmetry properties.
p
-Algebras of Arbitrary Exponents
Authors: Yuan Shuen
Published: May 2006

To a purely inseparable Galois field extension
C
over
A
we associate a certain differential polynomial ring
D
. We show that all central simple
A
-algebras that contain
C
as a maximal commutative subalgebra can be obtained from
D
by factoring out certain ideals determined by Witt vectors.
Biosynthesis of Cytokinins in Cytokinin-Autotrophic Tobacco Callus
Authors: Einset John W. , Skoog Folke
Published: May 2006

A cytokinin-autotrophic strain of tobacco callus contained cytokinin-active compounds with chromatographic mobilities on Sephadex LH-20 corresponding to ribosylzeatin, zeatin, and 6-Δ
2
-isopentenylaminopurine. Zeatin, the apparent major cytokinin, was estimated to be present at a concentration of 10
-4
μmol/kg of tissue. Cytokinin-autotrophic callus supplied with [
14
C]adenine produced radioactive components with the same chromatographic properties as zeatin and 6-Δ
2
-isopentenylaminopurine. These components were not obtained from cytokinin-dependent tissue supplied with [
14
C]adenine in the same manner.
Generalized Isoperimetric Inequalities
Authors: Luttinger J. M.
Published: May 2006

A new class of isoperimetric inequalities is described and illustrated.
Interaction of Amines with Ketone Aldehydes and Unsaturated Aldehydes
Authors: Kon Hideo , Szent-Györgyi Albert
Published: May 2006

The optical changes occurring during the interaction of amines with ketone aldehydes or unsaturated aldehydes are accompanied by strong electron spin resonance signals, and can thus be explained as due to the transfer of one whole electron in the ground state.
5-Hydroxymethyluracil in the DNA of a Dinoflagellate
Authors: Rae Peter M. M.
Published: May 2006

During the characterization of DNA from the dinoflagellate
Gyrodinium cohnii
, a large discrepancy was detected between the estimation of guanine + cytosine content from the buoyant density of the DNA in CsCl (56.1% G+C) and from the midpoint (T
m
) of its hyperchromicity induced by a thermal gradient (35.6% G+C). Composition analyses of
32
P-labeled nucleotides revealed an actual G+C content of 41.3%, and the presence of an unusual nucleotide amounting to about 37% of the expected thymidylate in unfractionated DNA-a feature that can explain the aberrant behavior of the DNA. The chromatographic properties of the unusual base and UV spectral analyses of the base and its corresponding nucleotide are consistent with its identification as hydroxymethyluracil. This base is not uniformly interspersed with thymine in the DNA. About 10% of
Gyrodinium
DNA is contributed by a fraction with low hydroxymethyluracil content, which behaves anomalously in Ag
+
-Cs
2
SO
4
density gradients but not in CsCl.
Direct Measurement of the pK Values of an Alkaline Bohr Group in Human Hemoglobin
Authors: Kilmartin J. V. , Breen J. J. , Roberts G. C. K. , Ho C.
Published: May 2006

Proton nuclear magnetic resonance spectra of normal and des-(his 146β) human hemoglobin in the aromatic resonance region have been compared at different pH values. From these measurements, a pK value for histidine 146β of 7.1 in carbonmonoxyhemoglobin and 8.0 in deoxyhemoglobin has been found. These pK values confirm the proposed role of histidine 146β in the alkaline Bohr effect.
The Reaction of
N
-Iodosuccinimide with the Goitrogens: A Model for the Active Iodine of the Thyroid Gland
Authors: Jirousek Ludek , Soodak Morris
Published: May 2006

The reactivities of
N
-iodosuccinimide and iodine with various goitrogenic compounds were studied with dimethylsulfoxide through which nitrogen had been bubbled as a solvent. Although iodine does not react with all of the compounds,
N
-iodosuccinimide does react with all of them.
N
-Iodosuccinimide may, therefore, serve as an interesting model for the “active iodine” of the thyroid.
Organization of Memory
Authors: Ehrenfeucht Andrzej , Mycielski Jan
Published: May 2006

A new learning algorithm is presented that may have applications in the theory of natural and artificial intelligence.
Regulation of the β-Methylgalactoside Transport System and the Galactose-Binding Protein by the Cell Cycle of
Escherichia coli
Authors: Shen Bernard H. P. , Boos Winfried
Published: May 2006

The synthesis of the periplasmic galactose-binding protein of
E. coli
is regulated by events occurring during its cell cycle, and proceeds in synchronized cells for only a short period after cell division is completed. Transport activity mediated by the β-methylgalactoside transport system follows closely the synthesis pattern of the binding protein.

A mutant,
E. coli
BUG-6, exhibits temperature-sensitive cell division [Reeve
et al
. (1970)
J. Bacteriol
. 104, 1052-1064], synthesizing galactose-binding protein at the permissive but not at the nonpermissive temperature. Galactose-binding protein synthesized at the permissive temperature is not degraded after the culture is shifted to the nonpermissive temperature. Polyacrylamide gel electrophoresis of the periplasmic proteins of BUG-6 grown at the permissive and nonpermissive temperatures suggests that several, but not all, periplasmic proteins are subject to the same regulatory control by the cell cycle as the galactose-binding protein.
Differentiation of Lens Tissue from the Progeny of Chick Retinal Pigment Cells Cultured
In Vitro
: A Demonstration of a Switch of Cell Types in Clonal Cell Culture
Authors: Eguchi Goro , Okada T. S.
Published: May 2006

Clonal cell lines isolated from the pigmented retina of 8.5-day chick embryos initially retained the capacity to form pigment. After several passages, however, many cells lost pigment granules and differentiated into lens-like structures. The lens-specific nature of the structures formed in cultures originally derived from retinal pigment cells was established by both ultrastructural and immunological studies.
Minimax Principles for the Solution of Semilinear Gradient Operator Equations in Hilbert Space
Authors: Berger Melvyn S.
Published: May 2006

A new variational characterization of solutions for an important class of nonlinear operator equations is obtained. The result obtained is used to derive sharp necessary and sufficient conditions for the solvability of such operator equations. Examples of the applicability of the results obtained to nonlinear Dirichlet problems and global differential geometry are discussed.
Multiple Repressor Binding at the Operators in Bacteriophage λ
Authors: Maniatis Tom , Ptashne Mark
Published: May 2006

Short DNA duplexes are protected when λ DNA is digested with nuclease in the presence of λ repressor. As the ratio of repressor to operator is increased, six successively larger fragments are recovered, ranging in size from 35 to 100 base pairs, each of which binds repressor. Study of these fragments indicates that, at each of the two λ operators (
o
L
and
o
R
), repressor first binds to a unique site (not necessarily terminal), and that five additional sites are then filled in linear right-ward or left-ward order. The nucleotide sequences and affinities for repressor of
o
L
and
o
R
are not identical, although six fragments of similar size are protected at each operator. Evidence is presented arguing against the existence of hairpin-like structures in the operator fragments, and, moreover, it is shown that the operator duplex does not unwind when repressor binds to it.
Localization of Idiotypic Antigenic Determinants in the Fv Region of Murine Myeloma Protein MOPC-315
Authors: Wells J. Vivian , Fudenberg H. Hugh , Givol David
Published: May 2006

Rabbit antisera were prepared against the idiotypic determinants of the mouse IgA myeloma protein-315, its purified heavy and light chains, and the Fv fragment comprising the variable region of both heavy and light chains. Agar diffusion demonstrated a line of identity between protein-315 and its Fv fragment against either homologous antiserum. Protein-315 and Fv fragment were labeled with
125
I and reacted with their anti-idiotypic antisera. Inhibition studies confirmed that the Fv fragment contained all the idiotypic specificities present in the intact protein. Fv was as effective as protein-315 on a weight basis in inhibiting the reaction between anti-idiotypic antiserum and protein-315. Protein-315 has high affinity for the 2,4-dinitrophenyl group, and such ligands can inhibit the reaction between protein-315 and its anti-idiotypic antibodies. Hapten inhibition was also obtained with the Fv fragment and its anti-idiotypic antiserum, implying that Fv contains an intact combining site. In this system with protein-315 the antigenic determinants expressed as idiotypic specificities are entirely within the variable region and are not influenced in their expression by the constant region. We therefore suggest that, in general, idiotypic determinants are antigenic determinants of the Fv protions of immunoglobulins.
Difference Between Functional and Structural Integrity of Messenger RNA
Authors: Puga Alvaro , Borrás María-Teresa , Tessman Ethel S. , Tessman Irwin
Published: May 2006

Messenger RNA molecules that are structurally stable, as measured by their ability to hybridize to DNA, may nevertheless be considerably less stable in retaining their ability to function in protein synthesis. The structure of the majority of the mRNA of phage S13 decays with a half-life of 10.6 ± 0.5 min. In contrast, much of the function of the mRNA that is involved in synthesis of a capsid protein (product of the F gene) decays rapidly with a half-life of 1.4 ± 0.8 min; a residual amount of function decays with a half-life of 14.0 ± 4.0 min. The measurements were made in the presence of rifampicin, which was used to prevent the formation of new mRNA. A proposed model for the functional decay is based on the polycistronic nature of the mRNA. Degradation of the mRNA would proceed in two steps: the first step would be a fast attack at a region near the 5′-terminus of each molecule that would eliminate the function of the proximal message; the second step would be a slow attack on the remaining messenger molecule precipitating a subsequent rapid degradation of the physical structure.
Internal Swash and Surf
Authors: Emery K. O. , Gunnerson C. G.
Published: May 2006

114 temperature sections, each containing an average of 10 bathythermograms, show that internal waves commonly become altered on crossing the shoaling bottom of the continental shelf in Santa Monica Bay, Calif. The alteration takes the form of internal swash (in which the lower isotherms reach farther landward than would be expected from their depth above the outer shelf or above deeper bottom) and of internal surf (that is, denoted by temperature inversions, isolated boluses of colder water at the bottom, and complex short wave-length variations of isotherms).
Two Classes of Membrane Binding of Replicative RNA of Bacteriophage MS2
Authors: Haywood Anne Mowbray
Published: May 2006

Escherichia coli
membranes were isolated in the presence of 6 mM Mg
++
. They were washed with buffer containing no Mg
++
to yield a fraction containing material bound only in the presence of divalent cations, “membrane eluate,” and that bound in the absence of divalent cations, “membrane.” When
E. coli
infected with bacteriophage MS2 are labeled with [
14
C]uracil,
all
MS2 replicative RNA, i.e., the RNA species containing MS2 complementary RNA, is in the membrane eluate and membrane. The amount of [
14
C]uracil in replicative RNA found in the membrane eluate increases with time of labeling, whereas that in the replicative RNA in the membrane reaches a plateau in 1-2 min. This finding is consistent with a precursor-product relationship. Most of the label entering single-stranded viral RNA comes from the replicative RNA in the membrane eluate. This result suggests that polymerase components or factors required for complementary-strand synthesis are bound to membrane even in the absence of divalent cations and that the polymerase is no longer bound to these factors when it is making the bulk of the progeny single-stranded RNA.
The Synthesis
In Vitro
of RNA Polymerase Subunits of
Escherichia coli
Authors: Austin Stuart , McGeoch Duncan
Published: May 2006

DNA from transducing bacteriophage that carry the structural gene for the β subunit of RNA polymerase has been used to direct protein synthesis in a cell-free transcription-translation system. A polypeptide species has been detected which appears to be β-subunit material made
in vitro
.
Guanosine 5′-Diphosphate, 3′-Diphosphate: Assignment of Structure by
13
C Nuclear Magnetic Resonance Spectroscopy
Authors: Que Lawrence , Willie Glen R. , Cashel Michael , Bodley James W. , Gray Gary R.
Published: May 2006

Guanosine tetraphosphate, recently discovered to mediate the regulatory relationship between protein synthesis and RNA accumulation in various bacteria, has been synthesized
in vitro
in large quantities and analyzed by natural-abundance
13
C nuclear magnetic resonance spectroscopy in order to confirm its structure and establish the positions of phosphate attachment. These studies have established its structure as guanosine 5′-diphosphate, 3′-diphosphate.
Biosynthesis of Transfer RNA:
In Vitro
Conversion of Transfer RNA Precursors from
Bombyx mori
to 4S RNA by
Escherichia coli
Enzymes
Authors: Chen G. S. , Siddiqui M. A. Q.
Published: May 2006

Evidence for the presence of rapidly labeled short-lived RNA species, presumed to be precursors to transfer RNA (tRNA), in the silk glands of
Bombyx mori
is presented. These precursors, which migrate between 4S and 5S markers on acrylamide gels, can be converted
in vitro
into molecules indistinguishable in size from tRNA. The conversion is also catalyzed by a crude enzyme fraction isolated from ribosomes of
E. coli
. Since a similar enzyme preparation cleaves the suppressor tRNA
Tyr
sequence of
E. coli
from its precursor molecule, it would appear that the precursor to
E. coli
tRNA
Tyr
and the precursors to silk-gland tRNAs share common structural features.
Regulation of Subunit Synthesis of
Escherichia coli
RNA Polymerase
Authors: Kirschbaum Joel B.
Published: May 2006

λcI857s7d
rif
d
18 phage is a defective, specialized transducing phage carrying the RNA polymerase mutation
rif
d
, a dominant rifampicin-resistant allele. This phage DNA directs
in vitro
synthesis of the β subunit of RNA polymerase in a DNA-dependent protein-synthesizing system. Prophage induction in cells that are lysogenic for this phage increases the rate of β-subunit synthesis
in vivo
by at most 2-fold. No increase in subunit synthesis above the haploid level is observed in cells diploid for the β gene.
Effect of Chemical Substitution on Absorption Spectra and Magnetic Circular Dichroism of Molecules in Dense Media
Authors: Shieh D. J. , Fu Y. C. , Lin S. H. , Eyring H.
Published: May 2006

The purpose of this paper has been to study the effect of chemical substitution on the magnetic circular dichroism and absorption spectra for the parent molecule which has the
C

2
v

symmetry. Four electronic transitions,
A
1
→
A
1
,
A
1
→
B
1
,
A
1
→
B
2
, and
A
1
→
A
2
have been considered. In each case, the intensity changes in magnetic circular dichroism and absorption spectra due to substitution have been expressed in terms of number of substituents and positions of substitution.
Proteins at the tRNA Binding Sites of
Escherichia coli
Ribosomes
Authors: Czernilofsky Armin P. , Collatz Ekkehard E. , Stöffler Georg , Kuechler Ernst
Published: May 2006

p
- Nitrophenylcarbamyl - phenylalanyl-tRNA binds to ribosomes in response to poly(U) and reacts with ribosomal proteins via covalent bond formation. Ribosomal proteins of
Escherichia coli
were characterized by two-dimensional gel electrophoresis and by reaction with specific antibodies. The affinity label is shown to react with the 50S proteins L27, L15, L2, L16, and L14. We therefore conclude that these particular proteins are located at or near tRNA-binding sites within the 50S ribosomal subunit.
Reinvestigation of the Proton Resonance Spectrum of Vindolinine at 300 MHz
Authors: Durham Lois J. , Shoolery James N. , Djerassi Carl
Published: May 2006

A reinvestigation of the proton resonance spectrum of vindolinine based on new data at 300 MHz is now completely consistent with the recently modified structure. These data are presented as an example of possible pitfalls in the interpretation of complex spectral data for structural analysis. Spectra and assignments are included.
Kinetics of Methylation of DNA by a Restriction Endonuclease from
Escherichia coli
B
Authors: Vovis Gerald F. , Horiuchi Kensuke , Zinder Norton D.
Published: May 2006

The restriction endonuclease from
E. coli
B is both an endonuclease and a DNA methylase. Both activities either require or are stimulated by Mg
+2
, adenosine triphosphate, and
S
-adenosyl-L-methionine. The particular activity which the enzyme exhibits depends upon the nature of the SB sites, the genetic sites that identify substrate DNA. Enzymatic treatment of DNA that has an unmodified, wild-type SB site results in either rapid restriction of the DNA or very slow methylation of the SB site. On the other hand, a hybrid SB site (modified), which protects the DNA molecule from restriction, results in rapid methylation of that SB site.
The Physical State Dependence of Carboxypeptidase A
α
and A
γ
Kinetics
Authors: Spilburg Curtis A. , Bethune J. Lemuel , Vallee Bert L.
Published: May 2006

Spectrochemical probes have demonstrated that the conformations of carboxypeptidase A (EC 3.4.12.2) differ in solution and in the crystalline state. Detailed kinetic studies of carboxypeptidase A
α
and A
γ
crystals and solutions now show that the physical state of the enzyme is also a critical parameter that affects the function of the A
α
and A
γ
enzymes in the same manner. The kinetic profiles and the corresponding kinetic constants of substrate hydrolysis are, therefore, important functional indices of the known conformational differences of the enzyme in these two physical states. The complex kinetic behavior of this enzyme, however, precludes meaningful comparisons of activity measurements for crystals and solutions obtained at only one substrate concentration. Underlying differences in varying substrate-inhibiting or -activating binding modes can result in either high or low activity ratios, concealing the true, functional consequences of the change in physical state. Thus, for all substrates examined, crystallization of the enzyme markedly reduces catalytic efficiency,
k
cat
, from 20- to 1000-fold. Equally as important, the substrate inhibition, apparent in solution for some di- and depsipeptides, is abolished with crystals, while for longer substrates the normal solution kinetics may acquire activation with the crystals. Hypothetical modes of substrate-enzyme interaction, generated by superimposing substrate models on the crystal structure of carboxypeptidase to simulate kinetics in solution, have failed to detect both of these changes, which affect inhibitory or activating binding modes. The only structure of carboxypeptidase yet published and that of its functionally inert complex with the pseudosubstrate, glycyl-L-tyrosine, derive from a unique form of carboxypeptidase A
α
crystals. These crystals differ from all others with regard both to their spectral properties and activity toward carbobenzoxy-glycyl-L-phenylalanine, which is 30% of that in solution, though the significance of this value cannot be gauged without knowledge of the relevant kinetic constants. The rapidly accumulating evidence for functional and conformational differences between crystals and solutions and the recent stress on the nonproductive aspects of the carboxypeptidase A
α
-glycyl-L-tyrosine complex, based on 30% site occupancy, suggest that the functional implications of its structural features require reevaluation.
Generalization of Recent Method Giving Lower Bound for
N
o
(
T
) of Riemann's Zeta-Function
Authors: Levinson Norman
Published: May 2006

Let
h
(
s
) = π

-
s
/2

τ(
s
/2). Then,
h
(
s
)ζ(
s
) ∼
h
(
s
)
H
(
s
) +
h
(1 -
s
)
H
(1 -
s
) where
H
(
s
) = Σ(1 - (log
n
)/log
t
/2π)
n

-
s

,
n
≤
t
/2π, led to
N
o
(
T
) ≥
N
(
T
)/3. Here the extension to
H
(
s
) ∼ Σ P (1 - (log
n
)/log
t
/2π)
n

-
s

is made where P(
x
) is a polynomial such that P(0) = 0 and
P
(
x
) + P(1 -
x
) = 1. The earlier case is P(
x
) =
x
. The relevant formulas in the general case can be obtained explicitly by the earlier method used for P(
x
) =
x
, and, indeed, in some respects there is greater simplicity for the general case.
On Reconstitution of Bacterial Photophosphorylation
In Vitro
Authors: Garcia Augusto F. , Drews Gerhart , Kamen Martin D.
Published: May 2006

Membranes active in oxidative phosphorylation but inactive in photophosphorylation were isolated from a carotenoid-less and bacteriochlorophyll-less mutant strain of
Rhodopseudomonas capsulata
. These membranes were uncoupled and recombined with coupling factor from the same strain and with reaction centers from a photosynthetically active revertant strain. The reconstituted system was able to form ATP from ADP and inorganic phosphate under anaerobic conditions in the light. Rates of 2 nmoles of ATP formed per min per μg of bacteriochlorophyll were obtained. A high incorporation of
32
P from inorganic phosphate into ADP in the light as well as in the dark was observed, the activity of which was associated with coupling factor. This incorporation occurs both aerobically and anaerobically and appears to be independent of photophosphorylation.
Reciprocal Inhibition of Mouse Leukemia Virus Infection by
Fv-1
Allele Cell Extracts
Authors: Tennant Raymond W. , Schluter Bonnie , Yang Wen-Kuang , Brown Arthur
Published: May 2006

Soluble extracts of mouse cells with

Fv-1
n

or

Fv-1
b

gene alleles specifically and reciprocally inhibit infection of B- or N-tropic mouse leukemia viruses in permissive cell cultures. NB-tropic virus infection was not inhibited by either cell extract. Extracts from

Fv-1
-

cells did not inhibit infection by the three virus host-range types, but N- or B-tropic virus infection of

Fv-1
-

cells was inhibited by extracts of the nonpermissive cells, and

Fv-1
nb

cell extracts inhibited both viruses. The maximum degree of inhibition was 50-80% as determined by immunofluorescent or plaque assays, with extracts containing up to 500 μg/ml of nonpermissive cell protein. The inhibitor(s) is relatively unstable since activity is lost after 2 hr at 37° or 30 min at 56°. The inhibitor(s) was most effective if added 2 hr before or within 2 hr after infection, did not react with the virus directly, inhibit virus attachment, or inhibit the normal cell functions tested. These results indicate that nonpermissive mouse cells contain a product, possibly determined by the
Fv-1
gene, which inhibits some early postpenetration event(s) in leukemia virus infection.
Enhancement of Tumor Growth by Graft-versus-host Reaction
Authors: Okubo S. , Oettgen H. F. , Caiazza S. S. , Ovary Z.
Published: May 2006

A graft-versus-host reaction was induced in (BALB/c × C5 7BL/6)F
1
mice by intravenous injection of BALB/c spleen cells. Six days later, the mice received subcutaneous grafts of a chemically induced BALB/c sarcoma. The growth of the tumor grafts was accelerated.
A Pyruvate-Valine Enzyme Complex that is Dependent upon the Metabolic State of the Mitochondria
Authors: Bergquist A. , Eakin E. A. , Murali D. K. , Wagner R. P.
Published: May 2006

Data are presented suggesting that intact
Neurospora crassa
mitochondria contain an enzyme complex incorporating five enzymes necessary for the biosynthesis of isoleucine and valine. The functional integrity and stability of the complex has been shown to be dependent on the metabolic state of the mitochondria. The complex has been solubilized by digitonin and has an approximate molecular weight of 400,000.