bluuebunny/crossref_metadata_2025 huggingface dataset:
Rodent Carcinogens: Setting Priorities
Authors: Gold Lois Swirsky , Slone Thomas H. , Stern Bonnie R. , Manley Neela B. , Ames Bruce N.
Published: October 2006

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticide residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals.
Diverse Migratory Pathways tn the Developing Cerebral Cortex
Authors: O'Rourke Nancy A. , Dailey Michael E. , Smith Stephen J. , McConnell Susan K.
Published: October 2006

During early development of the mammalian cerebral cortex, young neurons migrate outward from the site of their final mitosis in the ventricular zone into the cortical plate, where they form the adult cortex. Time-lapse confocal microscopy was used to observe directly the dynamic behaviors of migrating cells in living slices of developing cortex. The majority of cells migrated along a radial pathway, consistent with the view that cortical neurons migrate along radial glial fibers. A fraction of cells, however, turned within the intermediate zone and migrated orthogonal to the radial fibers. This orthogonal migration may contribute to the tangential dispersion of clonally related cortical neurons.
Intracellular Signaling by Hydrolysis of Phospholipids and Activation of Protein Kinase C
Authors: Nishizuka Yasutomi
Published: October 2006

Hydrolysis of inositol phospholipids by phospholipase C is initiated by either receptor stimulation or opening of Ca
2+
channels. This was once thought to be the sole mechanism to produce the diacylglycerol that links extracellular signals to intracellular events through activation of protein kinase C. It is becoming clear that agonist-induced hydrolysis of other membrane phospholipids, particularly choline phospholipids, by phospholipase D and phospholipase A
2
may also take part in cell signaling. The products of hydrolysis of these phospholipids may enhance and prolong the activation of protein kinase C. Such prolonged activation of protein kinase C is essential for long-term cellular responses such as cell proliferation and differentiation.
Chemically Induced Epileptiform Seizures in the Cat
Authors: Grossman Sebastian P.
Published: October 2006

Long-term epileptiform seizures were induced in the cat by a single stimulation of the basolateral components of the amygdala with cholinergic agents. These electro-physiological changes were accompanied by persisting alterations of the animal's "emotional responsiveness." It is evident that electroencephalographic seizure activity and overt behavior can be dissociated in this species.
Cortico-Subcortical Homeostasis in the Cat's Brain
Authors: Koella Werner P. , Ferry Alan
Published: October 2006

Transcortical polarization of one cerebral hemisphere, while producing the well-known changes in the amplitude of the evoked potentials in the ipsilateral cortex, induced opposite behavior of these indicators in the contralateral cortex. With the corpus callosum sectioned, the reciprocal relationship was enhanced. Anesthetic doses of barbiturates not only eliminated reciprocity but made the potentials on both sides react in unison to unilateral polarization. These findings suggest the existence of a negative feedback system between the cerebral cortex and the subcortex and the existence of a "left-right equalizing" mechanism carried by pathways in the corpus callosum.
Cosmic-Ray Exposure Age of the Farmington Meteorite from Radioactive Isotopes
Authors: DeFelice J. , Fazio G. G. , Fireman E. L.
Published: October 2006

The cosmic-ray exposure age of the Farmington meteorite was found to be greater than 7000 years from the ratio of the carbon-14 and argon-39 present and less than 25,000 years from the ratio of the aluminum-26 and argon-39 present. This exposure age is about an order of magnitude smaller than was estimated previously.
Double-Stranded Ribonucleic Acid Formation in vitro by MS 2 Phage-Induced RNA Synthetase
Authors: Weissmann Charles , Borst Piet
Published: October 2006

Part of the RNA synthesized from nucleoside triphosphate precursors by partially purified RNA synthetase, an enzyme induced in
Escherichia coli
by the RNA-containing phage MS 2, is resistant to hydrolysis by ribonuclease. Upon heating in 0.15
M
sodium chloride, 0.015
M
sodium citrate followed by fast cooling the material becomes ribonuclease-sensitive with a sharp transition at 102° to 104°C. The suggestion that the ribonuclease-resistant product is double-stranded RNA is reinforced by restoration of the ribonuclease resistance of the heat-denatured material by reannealing at temperatures just below the transition point and by its buoyant density in cesium sulfate. It is suggested that double-stranded RNA is the replicative form of MS 2 phage RNA.
Nasal Salt Excretion and the Possible Function of the Cloaca in Water Conservation
Authors: Schmidt-Nielson Knut , Borut Arieh , Lee Ping , Crawford Eugene
Published: October 2006

Secretion of concentrated salt solutions from the nasal region was observed in several terrestrial birds and reptiles. In the secreted fluid potassium usually exceeded sodium concentrations, with chloride and bicarbonate as the major anions. It is suggested that the extrarenal excretion of salts is related to the reabsorption of water in the cloaca, that it is necessary for the production of urine with a particularly low water content, and perhaps was prerequisite for the evolution of efficient cloacal water conservation.
Calcium: Unusual Sources in the Highland Peruvian Diet
Authors: Baker Paul T. , Mazess Richard B.
Published: October 2006

A dietary survey conducted in the southern highlands of Peru revealed two important sources of dietary calcium not previously reported. Mineral and ash calcium ingested as a food spice, and along with coca, raises the calcium intake from the low figures recorded by standard nutritional surveys to a more substantial level.
Culture of Small Barley Embryos on Defined Media
Authors: Norstog Knut , Smith Joyce E.
Published: October 2006

Barley embryos, measuring 90 μ in length, grew and became differentiated on a phosphate-enriched White's medium which was fortified with glutamine and alanine as major sources of organic nitrogen, and lesser amounts of five other amino acids. The
p
H of the medium was a critical factor in differentiation. On this medium, excised barley embryos developed more rapidly than embryos remaining in vivo, or embryos grown on media containing coconut milk.
Dolomitization: Observations on the Island of Bonaire, Netherlands Antilles
Authors: Deffeyes K. S. , Lucia F. J. , Weylt P. K.
Published: October 2006

Evaporation of sea water and gypsum precipitation on south Bonaire produce dense brines having a high ratio of magnesium to calcium. Recent dolomite is a common replacement product in the associated carbonate sediments. A mass balance indicates that brine is being refluxed downward today, and the Pleistocene dolomite on north Bonaire could have been produced by similar reflux of brine.
Actinomycin: Correlation of Structure and Function of Its Complexes with Purines and DNA
Authors: Reich E.
Published: October 2006

Actinomycin inhibits strand separation of helical DNA at concentrations corresponding to those which inhibit DNA polymerase activity in vitro. This report proposes first that actinomycin affects DNA polymerase indirectly by way of the changed physical properties of the template and that it functions in the major groove of helical DNA; second, that RNA polymerase functioning in the minor groove is subject to direct steric inhibition by bound actinomycin; and third, that the reaction of actinomycin with free purines is unrelated to its reaction with DNA.
Hemoglobin G
coushatta
: A New Variant in an American Indian Family
Authors: Schneider R. G. , Haggard M. E. , Mcnutt C. W. , Johnson J. E. , Bowman B. H. , Barnett D. R.
Published: October 2006

A new hemoglobin variant, G
Coushatta
(α2
A
β2
IIIglu→ala
), has been found in three generations of a family from the Alabama Coushatta Indian tribe in east Texas. The propositus suffers from an apparently unrelated, possibly genetic, agranulocytosis. According to the history and the blood-grouping data there is considerable inbreeding in the tribe and remarkably little admixture with other ethnic groups.
Virus-Specific Double-Stranded RNA in Poliovirus-Infected Cells
Authors: Baltimore D. , Becker Y. , Darnell J. E.
Published: October 2006

Poliovirus-infected HeLa cells contain a small amount of an RNA that sediments slightly faster than 16
S
. This RNA is less dense than viral RNA and resists digestion by ribonuclease. It is therefore, considered to be a double-stranded form of poliovirus RNA. A significant amount of this material is found in association with a membranous virus-specific particulate.
Dissociation of Olfactory Neural Response and Mucosal Potential
Authors: Shibuya Tatsuaki
Published: October 2006

The olfactory mucosal slow potential decreased remarkably or disappeared when part of the mucus on the olfactory epithelium was removed with absorbent paper. In contrast, the neural response was not changed much, while unitary spikes in response to odor also appeared in the epithelium. The paper reduced the thickness of the mucus by about half, but olfactory cilia were still present. This evidence suggests that the slow potential is not the generator potential.
Respiratory Distress: Relation to Prematurity and Other Factors in Newborn Monkeys
Authors: Windle William F.
Published: October 2006

A respiratory distress syndrome resembling that seen in human infants was encountered in 4 out of 90 rhesus monkey infants after uncomplicated births. These were nonviable immature infants weighing less than 350 grams. A much higher incidence of respiratory distress was observed in those whose births were complicated by experimental procedures, mainly asphyxiation. Thirty-four out of 68 infants developed the syndrome, the incidence being greatest among the least mature.
Erythromycin: Mode of Action
Authors: Wolfe Alan David , Hahn Fred E.
Published: October 2006

Erythromycin, a specific inhibitor of protein biosynthesis, inhibited the incorporation of phenylalanine by a cell-free ribosomal system prepared from
Escherichia coli
.
Unusual Aggregation of a Nonfunctional Tobacco Mosaic Virus Protein
Authors: Zaitlin Milton , Ferris Wayne R.
Published: October 2006

The nonfunctional virus protein isolated from plants infected with the PM2 strain of tobacco mosaic virus aggregates to form elongated, two-stranded, open helical structures, in marked contrast with functional tobacco mosaic virus protein which aggregates into rods. This unique type of aggregation may explain why the PM2 protein is unable to combine with viral nucleic acid to form stable infectious virus particles.
Immuno-PCR: Very Sensitive Antigen Detection by Means of Specific Antibody-DNA Conjugates
Authors: Sano Takeshi , Smith Cassandra L. , Cantor Charles R.
Published: October 2006

An antigen detection system, termed immuno-polymerase chain reaction (immuno-PCR), was developed in which a specific DNA molecule is used as the marker. A streptavidin-protein A chimera that possesses tight and specific binding affinity both for biotin and immunoglobulin G was used to attach a biotinylated DNA specifically to antigen-monoclonal antibody complexes that had been immobilized on microtiter plate wells. Then, a segment of the attached DNA was amplified by PCR. Analysis of the PCR products by agarose gel electrophoresis after staining with ethidium bromide allowed as few as 580 antigen molecules (9.6 × 10
-22
moles) to be readily and reproducibly detected. Direct comparison with enzyme-linked immunosorbent assay with the use of a chimera-alkaline phosphatase conjugate demonstrates that enhancement (approximately × 10
5
) in detection sensitivity was obtained with the use of immuno-PCR. Given the enormous amplification capability and specificity of PCR, this immuno-PCR technology has a sensitivity greater than any existing antigen detection system and, in principle, could be applied to the detection of single antigen molecules.
The B Cell Antigen Receptor Complex: Association of Ig-α and Ig-β with Distinct Cytoplasmic Effectors
Authors: Clark Marcus R. , Campbell Kerry S. , Kazlauskas Andrius , Johnson Sara A. , Hertz Marc , Potter Terry A. , Pleiman Chris , Cambier John C.
Published: October 2006

The B cell antigen receptor complex is a hetero-oligomeric structure composed of antigen binding, membrane immunoglobulin, and transducer-transporter substructures. The transducer-transporter substructure is composed of disulfide-linked dimers of immunoglobulin (Ig)-α and Ig-β/γ subunits that are products of the mb-1(α) and B29 (β/γ) genes. Although the receptor complex associates with Src family kinases that are activated after receptor ligation, the site of interaction of these and other cytoplasmic effector molecules with receptor subunits is unknown. The cytoplasmic tails of Ig-α and Ig-β chains were found to associate with distinct sets of effector molecules. The Ig-α chain cytoplasmic domain bound to the Src family kinases Lyn and Fyn, phosphatidylinositol-3 kinase (PI-3 kinase), and an unidentified 38-kilodalton phosphoprotein; the cytoplasmic tail of Ig-β bound PI-3 kinase and unidentified 40- and 42-kilodalton phosphoproteins. Binding activity was found to occur within a 26-amino acid sequence of Ig-α and Ig-β that contains a motif [(Asp or Glu)-(any amino acid)
7
-(Asp or Glu)-Tyr-(any amino acid)
3
-Leu-(any amino acid)
7
-Tyr-(any amino acid)
2
-(Leu or Ile)] previously implicated in signal transduction via other receptors including the Fc
ε
receptor I and the T cell antigen receptor. These findings indicate that the subunits act independently to activate distinct second messenger pathways.
Production of the Alzheimer Amyloid β Protein by Normal Proteolytic Processing
Authors: Shoji Mikio , Golde Todd E. , Ghiso Jorge , Cheung Tobun T. , Estus Steven , Shaffer Lillian M. , Cai Xiao-Dan , McKay Deborah M. , Tintner Ron , Frangione Bias , Younkin Steven G.
Published: October 2006

The 4-kilodalton (39 to 43 amino acids) amyloid β protein (βAP), which is deposited as amyloid in the brains of patients with Alzheimer's disease, is derived from a large protein, the amyloid β protein precursor (βAPP). Human mononuclear leukemic (K562) cells expressing a βAP-bearing, carboxyl-terminal βAPP derivative released significant amounts of a soluble 4-kilodalton βAPP derivative essentially identical to the βAP deposited in Alzheimer's disease. Human neuroblastoma (M17) cells transfected with constructs expressing full-length βAPP and M17 cells expressing only endogenous βAPP also released soluble 4-kilodalton βAP, and a similar, if not identical, fragment was readily detected in cerebrospinal fluid from individuals with Alzheimer's disease and normal individuals. Thus cells normally produce and release soluble 4-kilodalton βAP that is essentially identical to the 4-kilodalton βAP deposited as insoluble amyloid fibrils in Alzheimer's disease.
A GDP Dissociation Inhibitor That Serves as a GTPase Inhibitor for the Ras-Like Protein CDC42Hs
Authors: Hart Matthew J. , Maru Yoshiro , Leonard David , Witte Owen N. , Evans Tony , Cerione Richard A.
Published: October 2006

Members of the family of Ras-related guanosine triphosphate (GTP) binding proteins appear to take part in the regulation of a number of biological processes, including cell growth and differentiation. Three different classes of proteins that regulate the GTP binding and GTP hydrolytic activities of the Ras family members have been identified. These different regulatory proteins inhibit guanosine diphosphate (GDP) dissociation (designated as GDIs), stimulate GDP dissociation and GDP-GTP exchange (designated as GDSs), or stimulate GTP hydrolysis (designated as GAPs). In the case of the Ras-like protein CDC42Hs, which is the human homolog of a
Saccharomyces cerevisiae
cell division cycle protein, the GDI protein also inhibited both the intrinsic and GAP-stimulated hydrolysis of GTP. These findings establish an additional role for the GDI protein—namely, as a guanosine triphosphatase (GTPase) inhibitory protein for a Ras-like GTP binding protein.
The Evolutionary Convergence of Hearing in a Parasitoid Fly and Its Cricket Host
Authors: Robert Daniel , Amoroso John , Hoy Ronald R.
Published: October 2006

Parasitism is a widespread and diverse life strategy that connects species throughout the animal kingdom. Female parasitoid flies of the genus
Ormia
must find a specific cricket host on which to deposit their parasitic maggots. To reproduce, female flies must perform the same task as female crickets: find a singing male cricket. These flies have evolved a unique hearing organ that allows them to detect and locate singing male crickets. Through evolutionary convergence, these flies possess a hearing organ that much more resembles a cricket's ear than a typical fly's ear, allowing these parasitoids to take advantage of the sensory ecological niche of their host.
Ferrosilite (FeSiO
3
): Synthesis at High Pressures and Temperatures
Authors: Lindsley D. H. , Davis B. T.C. , Macgregor I. D.
Published: October 2006

The FeSiO
3
(ferrosilite) end member of the pyroxene series is not known as a pure mineral in nature and cannot be synthesized at atmospheric pressure. It is readily synthesized, however, at pressures from 18 to 45 kb and temperatures from 1150° to 1400°C. Its refractive indices approach those predicted for ferrosilite and it melts incongruently to an Fe
2
SiO
4
-rich liquid plus quartz.
Fission Damage in Calcite and the Dating of Carbonates
Authors: Sippel Robert F. , Glover Everett D.
Published: October 2006

Fission damage induced in calcite is shown by etch pits developed with weak acid at the damage sites. The damage can be differentiated from dislocations by annealing. By this method we have observed fossil fission damage in natural samples. Thus, some etch pits previously attributed to dislocations actually result from such damage. Annealing studies indicate that the damage should persist for about 4 × 10
7
years at 50°C, and direct evidence suggests that the fission damage has persisted for at least 10
6
years in one specimen.
Antiviral Activity of 1-Adamantanamine (Amantadine)
Authors: Davies W. L. , Grunert R. R. , Haff R. F. , McGahen J. W. , Neumayer E. M. , Paulshock M. , Watts J. C. , Wood T. R. , Hermann E. C. , Hoffmann C. E.
Published: October 2006

1-Adamantanamine (amantadine) causes a selective, reproducible, dose-related inhibition of influenza infections in tissue culture, chick embryos, and mice. The compound is not virucidal and appears to act by interfering with the penetration of the host cell by the virus. In influenza infections of mice, greatest efficacy occurs with treatment at the time of infection; however, there is significant antiviral activity with treatment delayed up to 72 hours after infection. Virus inhibition is not complete and survivors are immune to a challenge infection with the original infecting virus.
Site of Preference Energy and Selective Uptake of Transition-Metal Ions from a Magma
Authors: Burns Roger G. , Fyfe William S.
Published: October 2006

Results of absorption spectra measurements on silicate glasses of various compositions indicate that ions of the first transition-metal series are present in tetrahedral and octahedral sites in silicate melts (glasses). The fractionation patterns observed for transition-metal ions between magmas and silicate minerals can be interpreted according to crystal field theory in terms of octahedral "site preference energies" of transition ions in crystal lattices.
Antibody Production by Nonimmune Spleen Cells Incubated with RNA from Immunized Mice
Authors: Cohen Edward P. , Parks James J.
Published: October 2006

RNA isolated from the spleens of B
6
AF
1
mice immunized to sheep red blood cells was incubated with the spleen cells of nonimmunized mice. The number of antibody-forming cells detected by the Jerne plaque technique was significantly higher among the cells incubated with the RNA from immune animals than among cells incubated without RNA, or with RNA from nonimmune animals.
Iron Absorption: The Effect of an Iron-Deficient Diet
Authors: Pollack Simeon , Kaufman Richard M. , Crosby William H.
Published: October 2006

A diet deficient in iron causes a rapid, marked increase in iron absorption in rats. The increased absorption occurs in the absence of a significant change in iron stores as judged by the effect of an equivalent change in stores produced by phlebotomy, and in the absence of increased erythropoietic activity as judged by the rate of removal of iron-59 from the plasma.
Distribution of Narrow-Width Magnetic Anomalies in Antarctica
Authors: Behrendt John C.
Published: October 2006

Data for aeromagnetic profiles obtained in Antarctica during the 1963-64 austral summer were used together with earlier results to construct a map showing the areal distribution of narrow-width magnetic anomalies. Numerous anomalies are associated with known volcanic mountains in western Antarctica. A large area of few anomalies is probably a result of an extension of the thick metasedimentary section observed in the Ellsworth Mountains. Portions of the Trans-Antarctic Mountains have associated anomalies which are probably caused by late Cenozoic volcanic rocks.
Photoperiodic Reversibility of Diapause Induction in an Insect
Authors: Bell R. A. , Adkisson Perry L.
Published: October 2006

The diapause of the pink bollworm is under photoperiodic control. Diapause is prevented when the dark phases of the daily photoperiod are 8 to 10 hours in duration. If the dark period is extended to 12 hours, diapause is induced. Intercalation of 8- or 10-hour nights may reverse the diapause induction caused by exposure to photocycles having 12-hour dark phases. The 10-hour night was much more effective in reversing induction than the 8-hour night. The intensity of diapause, in part, appeared to be dependent on the previous photoperiodic experiences of the test animals.
Monoamine Oxidase Inhibitors: Augmentation of Pressor Effects of Peroral Tyramine
Authors: Tedeschi David H. , Fellows Edwin J.
Published: October 2006

Monoamine oxidase inhibitors markedly enhance the oral pressor potency of tyramine by preventing it from being destroyed by the monoamine oxidase normally present in liver and intestine. Since certain types of cheese contain high concentrations of tyramine, they should not be eaten by patients during treatment with a monoamine oxidase inhibitor.
Intercellular Channels in the Salt Secreting Glands of Marine Turtles
Authors: Ellis Richard A. , Abel John H.
Published: October 2006

Long, pleomorphic microvilli project from the walls of adjacent secretory cells in the lacrymal glands of sea turtles, and a substance identified histochemically as a mucopolysaccharide fills the intercellular channels. These features are not characteristic of the principal secretory cells in the salt glands of marine birds.
Adhesion and Emigration of Leukocytes Produced by Cationic Proteins of Lysosomes
Authors: Janoff Aaron , Zweifach Benjamin W.
Published: October 2006

A cationic protein fraction isolated from rabbit polymorphonuclear leukocyte lysosomes causes adhesion and emigration of leukocytes and petechial hemorrhage in the microcirculation of the rat and rabbit mesentery.
Chromic Oxide Indicator Method for Measuring Food Utilization in a Plant-Feeding Insect
Authors: McGinnis A. J. , Kasting R.
Published: October 2006

The chromic oxide indicator method was used to determine percentage utilization of three diets prepared from lyophilized plant tissues for fifth-instar larvae of the pale western cutworm. Because of the simplicity of the method and uniformity of results within each of the diets, the procedure can be used routinely in feeding trials with this insect, and perhaps others with biting and chewing mouth parts.
Flowage Differentiation
Authors: Bhattacharji Somdev , Smith Charles H.
Published: October 2006

Flowage differentiation is an experimentally demonstrable process capable of causing crystal and chemical fractionation in nature. It is a mechanism for forming olivine-rich rocks in a vertical or steeply dipping position without prior concentration on a flat floor. It explains the field observation that the chilled margin of a mafic intrusion may not be a representative sample of the average composition of the parent magma. In contrast to previous hypotheses of origin for composite dikes, it causes fractionation during and as a result of a single movement of magma rather than by multiple injections.
Biological Remnants in a Precambrian Sediment
Authors: Meinschein W. G. , Barghoorn E. S. , Schopf J. W.
Published: October 2006

A billion-year-old shale from the Nonesuch formation at White Pine Mine, Michigan, contains microfossils, porphyrins, and optically active alkanes. Pristane and phytane, which are isoprenoid hydrocarbons found in living plants and animals, are constituents of the ancient alkanes in the Nonesuch shale; the presence of porphyrins in this Precambrian sediment suggests that photosynthetic organisms have existed for more than a billion years.
Radio Map of the Andromeda Galaxy
Authors: MacLeod John M.
Published: October 2006

The University of Illinois radio telescope has resolved the 610.5 Mcy/sec disk component of radio emission from the large galaxy M 31 into several discrete concentrations. In two cases, these correspond to the crossing of the optical major axis by spiral arms. A spur of emission extends southeast from the galaxy near the minor axis.
Independent Action of Allele-Specific Suppressor Mutations
Authors: Brody Stuart , Yanofsky Charles
Published: October 2006

Two different allele-specific suppressor genes had an independent and nonadditive effect in restoring indoleglycerol phosphate → L-tryptophan activity in a double mutant strain lacking this activity.
Hybridization of Rapidly Labeled Nuclear Ribonucleic Acids
Authors: Perry R. P. , Srinivasan P. R. , Kelley D. E.
Published: October 2006

RNA, prepared from strain L fibroblasts which were incubated for 30 minutes in radioactive cytidine, was examined by quantitative DNA-RNA hybridization tests, autoradiography, and sedimentation analysis. About 60 percent of the radioactive RNA consists of 38 to 45
S
molecules located in the nucleoli and capable, under certain circumstances, of forming hybrids with DNA. Unlabeled 28
S
and 18
S
ribosomal RNA can compete with these components for DNA sites, indicating that the conversion of nucleolar RNA to ribosomal RNA occurs in such a way that base sequences are preserved. The polydisperse components associated with the chromatin region contain base sequences different from ribosomal and 4
S
RNA, and consequently have a uniquely high specific activity. These components are the only detectable hybridizing species in unfractionated preparations of RNA.
Quasi-Stellar Diameters and Intensity Fluctuations
Authors: Terrell James
Published: October 2006

It is shown that there are relativistic limits on the fluctuations in brightness which may be observed for a large spherical source, and also for more general sources, so that quasi-stellar objects are probably no more than light-days in size. There is thus a possibility that they may be close to our galaxy.
Fluoride: Its Effects on Two Parameters of Bone Growth in Organ Culture
Authors: Proffit William R. , Ackerman James L.
Published: October 2006

Bones of the forepaws of young rats were subjected to varying concentrations of fluoride ions in organ culture. The formation of DNA and protein synthesis were evaluated by measurements of the uptake of tritiated thymidine and C
14
-labeled proline. Fluoride concentrations as high as 10 to 20 parts per million had no demonstrable effect in vitro on these basic parameters of skeletal growth.
Self-Sterile Auxotrophs and Their Relation to Heterothallism in
Sordaria fimicola
Authors: El-Ani Arif S.
Published: October 2006

Eighty morphological mutants in the homothallic fungus
Sordaria fimicola
were tested on liquid minimal medium for nutritional requirements. Five had nutritional requirements, one for adenine, three for arginine, and one for lysine. All five were from among the eighty single gene mutants that were also partially or completely self-sterile. Nutritional requirements and centromere-locus intervals provide better criteria than morphological characters for selecting self-sterile mutants at complex loci governing heterothallism.
Perceptual Preferences and Imprinting in Chicks
Authors: Klopfer Peter H. , Hailman Jack P.
Published: October 2006

Whether initially exposed to a strikingly patterned model or to a plain white one, Vantress-cross chicks subsequently preferred to follow the striking model. Controls given the choice at the initial training age, and other (untrained) controls given the choice at the subsequent testing age, did not show a preference.
Intranuclear Site of Histone Synthesis
Authors: Birnstiel M. L. , Flamm W. G.
Published: October 2006

The nucleolus is implicated as a site of synthesis of nuclear basic proteins. Some of these newly synthesized proteins derived from the nucleolus have been characterized chemically as histones.
Blood Groups of Chimpanzees: Demonstrated with Isoimmune Serums
Authors: Moor-Jankowski J. , Wiener Alexander S. , Rogers C. M.
Published: October 2006

Of five chimpanzees injected with blood of other chimpanzees in Freund's adjuvant, three produced antiserums for simian blood factors designated A
c
, B
c
, and C
c
, respectively. Factors A
c
and B
c
determine four blood groups which were distributed among 60 chimpanzees in conformity with the triple-allele hypothesis. Factor C
c
appears to belong to an independent blood group system. All three simian blood factors are distributed independently of sex. An antithetical relation exists between the simian blood factor A
c
and blood factor N
v
, the latter being a blood factor shared by all human N cells. Since the simian blood factors A
c
and B
c
are also related, the three blood factors A
c
, B
c
, and N
v
must belong to one and the same blood group system, which is named the V-A-B blood group system of chimpanzees. The V-A-B blood group system of chimpanzees appears to be the counterpart of the M-N-S blood group system of man.
Meteorological Evaluation of the Sources of Iodine-131 in Pasteurized Milk
Authors: List R. J. , Telegadas K. , Ferber G. J.
Published: October 2006

An examination of possible sources of radioiodine found in samples of milk in the midwestern states during May and early June 1962 shows that atmospheric testing at Christmas Island was the principal contributor to incidents of significant concentrations of iodine-131 in milk (exceeding 300 picocuries per liter). Underground testing at Nevada played at most only a minor role during this period. There is a cause-and-effect relationship between the penetration of thunderstorms into high concentrations of nuclear debris in the lower stratosphere and the subsequent amount of iodine-131 in milk. Analyses of samples of rainwater confirm the importance of this "scavenging" mechanism. The relative contributions of atmospheric and underground testing to the iodine-131 found in milk samples from September 1961 to December 1963 has been reviewed and only one incident in which the amount of iodine-131 exceeded 300 picocuries per liter could be attributed to an underground test.
Auditory Nuclei: Distinctive Response Patterns to White Noise and Tones in Unanesthetized Cats
Authors: Galin David
Published: October 2006

Electrical responses to "white" noise and tonal stimuli were recorded from unanesthetized cats with permanently implanted bipolar electrodes. The cochlear nucleus, inferior colliculus, and medial geniculate each showed distinctive patterns of evoked activity. White noise and tones produced qualitatively different types of response. A decrease in activity characterized the response of the inferior colliculus to tonal stimuli.
Prehistoric Archeological Surveys and Excavations in Afghanistan: 1959-1960 and 1961-1963
Authors: Dupree Louis
Published: October 2006

Afghanistan has long been considered an important transmitter of culture in the historic periods. Buddhism, for example, reached the Far East from Gandhara (the classical name for southern Afghanistan and parts of northwestern West Pakistan). Recent research indicates that the foothills of northern Afghanistan may have been one of the early centers of incipient agriculture, transitional between the food gathering of the Paleolithic and the food production of the Neolithic. In addition, Upper and possibly Middle ("Mousterian") Paleolithic industries have been identified.
Meteoritic Zircon
Authors: Marvin Ursula B. , Klein Cornelis
Published: October 2006

Zircon (ZrSiO
5
) has been identified as an accessory mineral in the Vaca Muerta mesosiderite and in the troilite nodules of the Toluca iron meteorite. The occurrence in Vaca Muerta is a new discovery confirmed by electron-probe microanalysis of a grain in a polished section of the meteorite. Our identification of zircon in Toluca substantiates an occurrence in this meteorite reported in 1895 by Laspeyres and Kaiser.
Ionizing Radiation: Effect on Genetic Transcription
Authors: Pollard Ernest C.
Published: October 2006

Cells of
Escherichia coli
grown on maltose can be induced by the addition of thiomethyl galactoside to produce β-galactosidase. If cells are irradiated shortly after induction, the transcription of the DNA ceases, and the enzyme produced by the messenger RNA is observed to reach a maximum. From these data the calculated half-life of unstable messenger RNA is given over a temperature range from 8.1 minutes at 10°C to 0.7 minute at 45°C. The kinetics of cessation of transcription give information on both messenger RNA decay and rate of transcription. Arrhenius graphs for both these rates are given, and the activation energies measured are 11,000 calories per mole for decay and 22,000 calories per mole for transcription. This relation to temperature is characteristic of enzymatic behavior.
Collagenolytic Activity of Intact and Necrotic Connective Tissue
Authors: Goldstein E. R. , Patel Y. M. , Houck J. C.
Published: October 2006

Isotonic saline extracts of both intact and necrotic skin of the rat were capable of releasing over 50 percent of the hydroxyproline content of soluble collagen as dialyzable, peptide-bound amino acid only after prior, limited proteolytic activation of trypsin. These "activated" extracts could also solubilize insoluble collagen to release dialyzable hydroxyproline containing peptides. This collagenolytic activity was maximal at
p
H 5.5 and was not inhibited by soybean trypsin inhibitor, ethylenediaminetetraacetic acid, or heavy metal salt. The "activated" extracts showed no general proteolytic activity toward denatured hemoglobin. The collagenolytic activity was destroyed both by heat and by extensive tryptic proteolysis.
Association of Rapidly Metabolized DNA and RNA
Authors: Cherry Joe H.
Published: October 2006

An association of rapidly metabolized DNA and RNA labeled with P
32
has been found in peanut cotyledons by incorporation of either uridine-C
14
or thymidine-C
14
by peanut cotyledon slices. Chromatography of the extracted nucleic acids on methylated-albumin columns shows that the rapidly metabolized DNA and RNA are contained only in the first half of the DNA peak where RNA and DNA occur in equal amount. One-fourth of the radioactivity is recovered in ribonucleotides. Density-gradient centrifugation in cesium chloride indicates that the material containing the P
32
has a higher density than most of the DNA.
Hydroxyurea: Inhibitory Effect on DNA Metabolism
Authors: Young Charles W. , Hodas Sadie
Published: October 2006

Hydroxyurea, hydroxyurethane, and dihydroxyurea inhibit incorporation of thymidine into the DNA of monolayers of HeLa cells. They do not affect incorporation of uridine into RNA or of leucine into protein. In contrast, hydroxylamine inhibits cellular incorporation of all three precursors: thymidine, uridine, and leucine. Hydroxyurea does not affect thymidine kinase, thymidylate kinase, or DNA polymerase reactions, but it does inhibit incorporation of cytidylic and guanylic acids into DNA in cell-free supernatants.
Fatty Acid Synthesis by Subcellular Fractions of Lung Tissue
Authors: Tombropoulos Elias G.
Published: October 2006

The mitochondria-rich fraction of the lung tissue is the most active subcellular fraction for the synthesis of long-chain fatty acids. This observation is contrary to what has been reported for the subcellular fractions of the liver. The high rate of fatty acid synthesis observed with the mitochondria-rich fraction of the lung may be related to the morphological transformation of mitochondria.
Evolution of a Catabolic Pathway in Bacteria
Authors: Lerner S. A. , Wu T. T. , Lin E. C. C.
Published: October 2006

Genetic derepression of ribitol dehydrogenase in a mutant of
Aerobacter aerogenes
, strain 1033, enabled it to grow on xylitol, a substrate of the enzyme, but not its inducer. A derivative strain with an improved rate of growth on xylitol was obtained from the first mutant. The faster growth rate was made possible by the production of an altered ribitol dehydrogenase, as demonstrated by an increase in its activity on xylitol relative to ribitol and by its decreased heat stability.
Alterations in Signal Transduction Molecules in T Lymphocytes from Tumor-Bearing Mice
Authors: Mizoguchi Hiromoto , O'Shea John J. , Longo Dan L. , Loeffler Cynthia M. , McVicar Daniel W. , Ochoa Augusto C.
Published: October 2006

Impaired immune responses occur frequently in cancer patients or in tumor-bearing mice, but the mechanisms of the tumor-induced immune defects remain poorly understood. In an in vivo murine colon carcinoma model (MCA-38), animals bearing a tumor longer than 26 days develop CD8
+
T cells with impaired cytotoxic function, decreased expression of the tumor necrosis factor-α and granzyme B genes, and decreased ability to mediate an antitumor response in vivo. T lymphocytes from tumor-bearing mice expressed T cell antigen receptors that contained low amounts of CD3γ and completely lacked CD3ζ, which was replaced by the Fc
ε
γ-chain. Expression of the tyrosine kinases p56

lck

and p59

fyn

was also reduced. These changes could be the basis of immune defects in tumor-bearing hosts.
Imprinting: A Reassessment
Authors: Klopfer Peter H.
Published: October 2006

Chicks exposed to a moving model during their critical period for imprinting will subsequently demonstrate a preference for that model if it is stationary. In preference tests with moving models, other preferences appear to over-ride the effects of the imprinting experience.
Single-Unit Activity in the Cat's Visual Cortex: Modification After an Intense Light Flash
Authors: Robertson A. D. J. , Evans C. R.
Published: October 2006

In response to a brief, intense light flash at the retina, the cells of the visual cortex in the
cerveau isolé
preparation of the cat show prolonged excitation of a type not normally produced by physiological stimulation.
Cosmic X-ray Sources
Authors: Bowyer S. , Byram E. T. , Chubb T. A. , Friedman H.
Published: October 2006

Eight new sources of cosmic x-rays were detected by two Aerobee surveys in 1964. One source, from Sagittarius, is close to the galactic center, and the other, from Ophiuchus, may coincide with Kepler's 1604 supernova. All the x-ray sources are fairly close to the galactic plane.
Messenger RNA Utilization during Development of Chick Embryo Lens
Authors: Scott Robert B. , Bell Eugene
Published: October 2006

A marked increase in synthesis or availability of messenger RNA which can accommodate eight to ten ribosomes was observed in the chick embryo lens between 11 and 12 days of development. The increase is seen in a shift from polyribosomes consisting of predominantly two to five single ribosomes to polyribosomes of predominantly eight to ten ribosomes in lens cells. Short-lived (half-life, 3 hours) and long-lived (half-life, > 30 hours) messenger RNA's coexist in whole lenses on the 14th day of development.
Lead Isotopes in Gasoline and Aerosols of Los Angeles Basin, California
Authors: Chow Tsaihwa J. , Johnstone M. S.
Published: October 2006

The isotopic composition of lead isolated from antiknock gasolines and the aerosols of the Los Angeles basin was determined. The lead isotopic composition of the aerosols was similar to that of rural snow. The high concentration of lead in water of precipitation and that of the surface of the sea can be attributed to automobile exhausts.
Radiocarbon Dates from a Tomb in Mexico
Authors: Furst P. T.
Published: October 2006

The first series of radiocarbon dates to be obtained from a deep shaft-and-chamber tomb of the type restricted in Mesoamerica to parts of Nayarit, Jalisco, and Colima in western Mexico ranges from 2230 ± 100 years to 1710 ± 80 years. Examination of the evidence indicates that for the present a date equivalent to A.D. 250 should be accepted for at least one phase, possibly a late phase, of the shaft tomb culture and for the hollow, polychrome figurines associated with the tombs.
Fluorescence Polarization: Measurement with Ultraviolet-Polarizing Filters in a Spectrophotofluorometer
Authors: Chen Raymond F. , Bowman Robert L.
Published: October 2006

Ultraviolet-polarizing filters with large apertures facilitate the use of spectrophotofluorometers for measuring fluorescence polarization. Such filters (i) allow the use of polarized exciting light even in the ultraviolet region, (ii) make it possible to correct for grating anomalies which influence the observed polarization, and (iii) because of good transmission properties allow the entrance of sufficient light so that small slits and dilute solutions can be used. Under optimum conditions, polarization can be measured with a precision of ±0.002. Results obtained are in excellent agreement with values cited elsewhere and indicate that standard spectrophotofluorometers can easily be adapted for accurate measurement of polarization.
Interspecific Transfer of the "Sex-Ratio" Agent of
Drosophila willistoni
in
Drosophila bifasciata
and
Drosophila melanogaster
Authors: Ikeda Hiroshi
Published: October 2006

The maternally transmitted "sex-ratio" condition in several species of
Drosophila
appears to be due to infection by a microorganism of the genus
Treponema
.
Drosophila bifasciata
is an exception, since no microorganism has been found in the "sex-ratio" strains of this species. Normal
D. bifasciata
can be infected by injection of the hemolymph of a "sex-ratio" strain of
D. willistoni
containing treponemas. The progenies of the infected
D. bifasciata
, up to and including the F
4
and F
5
generations, have numerous treponemas in their hemolymph. Their progenies are, however, not unisexual, although both females and males are infected. The hemolymph of these
D. bifasciata
injected in
D. melanogaster
females causes typical "sex-ratio" symptoms in the progenies of the latter.
Indium Telluride (II′): Transitory Intermediate Phase in the Transformation InTe(II) to InTe(I)
Authors: Sclar C. B. , Carrison L. C. , Schwartz C. M.
Published: October 2006

The high-pressure cubic metallic form of indium telluride, InTe(II), transforms at 1 atmosphere to a new transitory polymorph, designated InTe(II′), which, in turn, transforms to the stable tetragonal polymorph InTe(I). The new polymorph is apparently tetragonal with unit-cell dimensions
a
0
= 6.06 Å,
c
0
= 6.55 Å. The transformation rates of InTe(II) to InTe(II′) and of InTe(II′) to InTe(I) are dependent on both time and temperature; the former is very rapid above 60° C and the latter is very rapid above 125° C.
Inheritance of Linoleic and Oleic Acids in Maize
Authors: Poneleit C. G. , Alexander D. E.
Published: October 2006

Gas-liquid chromatographic analysis of methyl esters of fatty acids of individual maize seeds of parental and segregating populations suggests that desaturation at the Δ
12-13
position in oleic acid is under simple Mendelian control. High linoleic acid content is recessive to low.
Cellular Proteins Bound to Immunodeficiency Viruses: Implications for Pathogenesis and Vaccines
Authors: Arthur Larry O. , Bess Julian W. , Sowder Raymond C. , Benveniste Raoul E. , Mann Dean L. , Chermann Jean-Claude , Henderson Louis E.
Published: October 2006

Cellular proteins associated with immunodeficiency viruses were identified by determination of the amino acid sequence of the proteins and peptides present in sucrose density gradient-purified human immunodeficiency virus (HIV)-1, HIV-2, and simian immunodeficiency virus (SIV). β2 microglobulin (β
2
m) and the α and β chains of human lymphocyte antigen (HLA) DR were present in virus preparations at one-fifth the concentration of Gag on a molar basis. Antisera to HLA DR, β
2
m, as well as HLA class I precipitated intact viral particles, suggesting that these cellular proteins were physically associated with the surface of the virus. Antisera to class I, β
2
m, and HLA DR also inhibited infection of cultured cells by both HIV-1 and SIV. The specific, selective association of these cellular proteins in a physiologically relevant manner has major implications for our understanding of the infection process and the pathogenesis of immunodeficiency viruses and should be considered in the design of vaccines.
Indole Compounds: Isolation from Pineal Tissue
Authors: McIsaac William M. , Farrell Gordon , Taborsky Robert G. , Taylor Anna N.
Published: October 2006

Five indole compounds have been isolated from bovine pineal tissue and characterized as 5-methoxytryptophol,
N
-acetyl-5-methoxytryptamine (melatonin), 5-hydroxytryptophol, 5-methoxyindole-3-acetic acid, and 5-hydroxyindole-3-acetic acid. Pineal hydroxyindole-
O
-methyltransferase, with
S
-adenosylmethionine, converts 5-hydroxytryptophol to 5-methoxytryptophol.
Silica: Role in the Buffering of Natural Waters
Authors: Garrels Robert M.
Published: October 2006

In the oceans, dissolved silica and degraded silicates appear to participate in a reaction which fixes silica and alkali metal cations and releases hydrogen ions, resulting in maintenance of the
p
H.
Fission-Track Dating of Bed I, Olduvai Gorge
Authors: Fleischer R. L. , Price P. B. , Walker R. M. , Leakey L. S. B.
Published: October 2006

The discoveries of a series of hominid remains in the Olduvai Gorge, Tanganyika, has focused attention upon the age of the deposits of Bed 1, in which both
Zinjanthropus
and
Homo habilis
were found. Because the age of 1.75 million years, as determined by the radioactive decay of potassium and argon, has been questioned several times, a fission-track age was measured for the pumice from Bed 1. The result is 2.03 ± 0.28 million years, in good agreement with the result obtained by the potassium-argon decay method.
Retinoyl Beta-Glucuronic Acid: A Major Metabolite of Vitamin A in Rat Bile
Authors: Dunagin Percy E. , Meadows E. Harris , Olson James Allen
Published: October 2006

The major metabolite in rat bile of injected C
14
-retinoic acid was purified by ion-exchange and silicic acid chromatography; it has the spectrum of methyl retinoate, releases retinoic acid upon basic hydrolysis or by treatment with β-glucuronidase, and contains glucuronic acid. The metabolite was characterized by treatment with diazomethane followed by hexamethyl-disilazane, or with periodate followed by semicarbazide, and the products were chromatographed. The metabolite has been tentatively identified as retinoyl β-glucuronide.