bluuebunny/crossref_metadata_2025 huggingface dataset:
Lysis of Pleuropneumonia-like Organisms by Staphylococcal and Streptococcal Toxins
Authors: Bernheimer Alan W. , Davidson Morton
Published: October 2006

Six strains representing three species of
Mycoplasma
were examined for susceptibility to lysis by staphylococcal and streptococcal toxins. All were sensitive to staphylococcal α-toxin, two to streptolysin S, and three to streptolysin O. The results support the concept that the limiting membrane of pleuropneumonia-like organisms is basically similar to those of many other cell types and provide additional evidence for the participation of cholesterol in cytolysis induced by streptolysin O.
Immunologic Tolerance in Thymectomized, Irradiated Rats Grafted with Thymus from Tolerant Donors
Authors: Isaković Katarina , Smith Stanley B. , Waksman Byron H.
Published: October 2006

Lewis rats, thymectomized at 5 weeks of age and irradiated at 8 weeks, received grafts of adult thymus and marrow, one or both grafts being derived from donors tolerant to bovine γ-globulin. Challenge 3 or 6 weeks after grafting showed that delayed sensitization could not be induced in animals which received a tolerant thymus or tolerant thymus and marrow, though sensitization to a heterologous antigen (chicken ovalbumin) occurred normally. Arthus reactivity was regained slowly in animals receiving normal thymus and marrow and, to an equal extent, in those receiving grafts from tolerant donors.
Skin Grafts: Delayed Rejection between Pairs of Cattle Twins Showing Erythrocyte Chimerism
Authors: Stone W. H. , Cragle R. G. , Swanson E. W. , Brown D. G.
Published: October 2006

Although dizygotic cattle twins with erythrocyte chimerism exhibit complete tolerance to each other's hematopoietic tissues exchanged
in utero
by way of chorionic anastomoses, they may not be completely tolerant to each other's histocompatibility antigens. Skin grafts exchanged between partners of 21 pairs of chimeric twins were rejected by more than half of the twins in an average of 250 days.
Phenotypic Alterations in Adrenal Tumor Cultures
Authors: Sato Gordon H. , Rossman Toby , Edelstein Leon , Holmes Stuart , Buonassisi Vincenzo
Published: October 2006

Adrenal tumor cells in culture gradually develop a requirement for glutamine and serum albumin in order to produce steroids in response to adrenocorticotropic hormone. Glutamine acts simply as a precursor for a protein or proteins whose synthesis is required for the response to the hormone. Albumin apparently binds steroid hormone products that otherwise would inhibit further biosynthesis of steroids.
Configuration of Inactive and Active Polysomes of the Developing Down Feather
Authors: Bell E. , Humphreys Tom , Slayter H. S. , Hall C. E.
Published: October 2006

Inactive four-ribosome polyribosomes, insensitive to ribonuclease, have the form of tight symmetrical squares and appear in feather cells during the early and intermediate periods of development. When, on the 13th day of incubation, the inactive polyribosomes become sensitive to ribonuclease and can then synthesize protein, the squares open up so that the four-ribosome polysomes are strung out in the configuration characteristic of functioning polysomes.
Pupillary Response of the Screech Owl,
Otus asio
Authors: Bishop Lewis G. , Stark Lawrence
Published: October 2006

The latent period of constriction in the owl is only half that in the human, and the latent period of dilatation is about equal to that in the human. Similarly, the rise time of constriction in the owl is much faster than that in the human. The owl system has the characteristics of a low-band-pass filter. The owl's frequency response is over an octave lower than that of the human, but its phase lags are shorter.
Active Uptake of Sodium by Softshell Turtles (
Trionyx spinifer
)
Authors: Dunson William A. , Weymouth Robert D.
Published: October 2006

Aquatic softshell turtles (
Trionyx spinifer spinifer
) show a net active uptake of sodium from solutions of this cation as dilute as 5 micromoles per liter. This probably occurs in the pharynx, a site of aquatic respiration. Inhibition of active sodium transport by low temperatures causes an extreme lowering of the sodium concentration in the plasma. Other fresh-water turtles may utilize this mechanism of ionic regulation. The ultrastructure of the pharyngeal villi is similar to that of frog skin and toad bladder.
Respiratory Water Exchange in Two Species of Porpoise
Authors: Coulombe Harry N. , Ridgway Sam H. , Evans William E.
Published: October 2006

Measurements of the respiratory water exchanges of
Tursiops truncatus
and
Lagenorhynchus obliquidens
indicate that these species lose, respectively, only 30 and 77 percent as much water through evaporation as would terrestrial mammals of the same body weight. Control of temperature and pressure within the respiratory system and a lower ventilation rate account for this relatively small loss of water.
Bacteria as an Indicator of Formation of Antibodies by Single Spleen Cells in Agar
Authors: Schwartz Stanley A. , Braun Werner
Published: October 2006

Bacteria can be used to measure the formation of specific antibody by suspensions of single spleen cells. The technique, based on localized immune lysis (plaque formation) in agar, permits assays on the kinetics of increase in the number of cells forming bactericidal antibody in the spleen of immunized mice. The procedure also is useful for testing nonspecific stimulation of antibody synthesis and for analyzing spleen cell populations from donors that have been immunized simultaneously with bacterial and red blood cell antigens.
Pleistocene Glaciation: A Criterion for Recognition of Its Onset
Authors: Krinsley David H. , Newman Walter S.
Published: October 2006

The various biostratigraphic boundaries proposed for the base of the Pleistocene are not necessarily synchronous with the onset of continental glaciation. Electron-microscopic examination of surface textures of sand grains suggests a widely applicable rock-stratigraphic and geologic-climate boundary that may mark the point at which glaciers of continental proportions began to launch debris-carrying icebergs into the world's oceans.
Cytopathic Effect of Rubella Virus in a Rabbit-Cornea Cell Line
Authors: Leerhøy J.
Published: October 2006

A rabbit-cornea cell line has been found susceptible to three strains of RK-13-adapted rubella virus. The lesions are very pronounced and appear within a week.
Reduction-like Effect of Carbohydrates on Cytochrome
c
Authors: Mora Peter T. , Creskoff Ellen , Person Philip
Published: October 2006

Certain carbohydrates cause changes in the absorption spectrum of cytochrome
c
; these changes are the same as those accompanying conversion from the oxidized to the reduced form. Various carbohydrates are compared by measuring changes in absorbance at a characteristic wavelength.
Polyribosomes from
Escherichia coli
: Enzymatic Method for Isolation
Authors: Dresden Marc , Hoagland Mahlon B.
Published: October 2006

Polyribosomes can be rapidly extracted from
Escherichia coli
by sequential passage of the cells through solutions of a chelating agent and lysozyme in a centrifugal field. Biosynthesis of protein in whole cells and in a cell-free system occurs almost exclusively in the polyribosomes.
Agouti Locus: Homology of Its Method of Operation in Rats and Mice
Authors: Silvers Willys K.
Published: October 2006

The action of genes at the agouti locus in rats is similar to that of genes at the same locus in mice—the color phenotype of hairs is determined by the operation of agouti-locus alleles in the follicle, rather than in the melanocytes. Hairs produced by mouse skin growing on partially tolerant infant rat hosts show that rat melanocytes also respond to the agouti-locus genotype of mouse follicles. This constitutes the first example in vivo of the behavior of a cell of one species being completely determined by the genotype of an alien host species.
Biosynthesis of Vitamin A with Rat Intestinal Enzymes
Authors: Goodman DeWitt S. , Huang Helen S.
Published: October 2006

Vitamin A is synthesized from β-carotene in cell-free homogenates of rat intestinal mucosa, the biosynthetic enzymatic activity being present in the soluble protein fraction of the homogenate. Also required are a heat-stable factor in the particulate fraction, molecular oxygen, and bile salts. The reaction is stimulated by glutathione. The product, obtained in yields of up to 50 percent, has been identified as vitamin A aldehyde (retinal) by way of its semicarbazone derivative. The reaction mechanism involves the central cleavage of β-carotene into two molecules of retinal.
Double Mating: Its Use To Study Heritable Factors in Dental Caries
Authors: Larson Rachel H. , Simms Mildred E.
Published: October 2006

When Osborne-Mendel female rats (white) were mated with both an Osborne-Mendel and an NIH Black rat male during the same breeding period, litters were born which contained both Osborne-Mendel (white) and crossbred (grey to black) offspring. The Osborne-Mendel and crossbred animals developed widely different levels of caries activity even though they were exposed to identical environmental conditions during the intrauterine, preweaning, and experimental periods. These findings are indicative of a strong heritable influence on the development of dental caries.
Hemadsorption-Negative Plaque Test: New Assay for Rubella Virus Revealing a Unique Interference
Authors: Marcus Philip I. , Carver David H.
Published: October 2006

A simple and rapid plaque procedure has been developed for detecting and accurately assaying rubella virus in a noncytopathic virus-cell relationship. Plaque-formation is based on the development, in individual cells infected with rubella virus, of a unique type of intrinsic interference to infection with Newcastle disease virus. Rubella virus—infected cells challenged with Newcastle disease virus and tested for hemadsorption 15 hours later stand out as hemadsorption-negative areas. Individual living cells infected with rubella virus can be resolved under conditions allowing standard cloning procedures. In principle, the hemadsorption-negative plaque test can be used to search for a new class of noncytopathic, nonhemadsorbing viruses—those that induce an intrinsic interference to infection by any hemadsorbing virus.
Cystathioninuria: Nature of the Defect
Authors: Frimpter George W.
Published: October 2006

A homogenate of liver obtained by biopsy from two patients with cystathioninuria, an inborn error of metabolism, cleaved radioactive cystathionine only slightly until an excess of pyridoxal phosphate was added. The apoenzyme failed to bind the coenzyme normally. Pyridoxine therapy of familial cystathioninuria thus has a sound basis.
Anesthesia of Artemia Larvae: Method for Quantitative Study
Authors: Robinson Arthur B. , Manly Kenneth F. , Anthony Michael P. , Catchpool John F. , Pauling Linus
Published: October 2006

Potency of anesthetics is quantitatively measured with laboratory-hatched larvae of the brine shrimp
Artemia salina
. Statistical fluctuations are minimized in that 100,000 animals are used to determine a single median anesthetic dose value. The technique was developed to study molecular mechanisms of general anesthesia.
Lymphocytes of Small Mammals: Spontaneous Transformation in Culture to Blastoids
Authors: Sabesin Seymour M.
Published: October 2006

Small lymphocytes from rabbit and guinea pig, grown in tissue culture in the absence of phytohemagglutinin, can transform spontaneously into cytologically immature cells that are indistinguishable morphologically from blast cells. The transformation occurs in 38 to 75 percent of peripheral lymphocytes and 55 to 75 percent of splenic lymphocytes on the 5th day of culture. The altered cells can synthesize RNA and DNA and show mitotic division; synthesis of DNA occurs after the 5th day of culture, whereas RNA is synthesized throughout the duration of culture.
Uncrossed Visual Pathways of Hooded and Albino Rats
Authors: Lund R. D.
Published: October 2006

The uncrossed visual pathways to the principal primary optic centers of hooded rats are substantially larger than those of albino rats. This provides an anatomical basis for the results of a recent study on behavior which showed differences in interocular transfer in the two varieties.
Bone Density Measurements in vivo: Improvement of X-ray Densitometry
Authors: Mason Rossie L. , Ruthven Courtney
Published: October 2006

An X-ray bone densitometer has been developed which makes direct tracings of absorption curves on a nearly linear scale. Speed and precision are increased by elimination of x-ray film. Results are reproducible to within 3 percent with a phantom finger, and within 6 percent with human subjects.
Hydrogen Emission Line n
110
→ n
109
: Detection at 5009 Megahertz in Galactic H II Regions
Authors: Höglund B. , Mezger P. G.
Published: October 2006

The hydrogen emission line n
110
→ n
109
at the frequency 5009 megahertz which was predicted by Kardashev has been detected in M 17, Orion, and nine other galactic H II regions with the 42.7-m (140-foot) telescope and a 20-channel receiver at the National Radio Astronomy Observatory. The measured product of the half-power width of the line times the ratio of line-to-continuum brightness temperature is larger than that predicted by Kardashev's theory. The radial velocity obtained for M 17 and Orion agrees well with optical measurements. The search for a similar line of excited helium was without success.
Synaptic Connections of the Centrifugal Fibers in the Pigeon Retina
Authors: Maturana H. R. , Frenk S.
Published: October 2006

The centrifugal fibers in the pigeon retina end in the inner nuclear layer and form two kinds of terminals, convergent and divergent. In the inner nuclear layer the fibers synapse with amacrine and displaced ganglion cells. Because of their great number and their even distribution these fibers appear to constitute a system for the localized centrifugal control of the retinal functions.
Paleotemperatures and Chronology at Archeological Cave Site Revealed by Thermoluminescence
Authors: Dort Wakefield , Zeller E. J. , Turner M. D. , Vaz J. E.
Published: October 2006

Contrasting values of remnant thermoluminescence of limestone samples from Jaguar Cave, eastcentral Idaho, reveal temperature differences attributable to position within the cave microenvironment. Absence of recorded temperature change during cave-filling by rock and human debris indicates brevity of human occupation, which was near the end of Wisconsin (Pinedale) time.
Gibberellic Acid: Action in Barley Endosperm Does Not Require Endogenous Auxin
Authors: Cleland Robert , McCombs Nancy
Published: October 2006

Endogenous auxin is not required for the increase in amylolytic activity induced by gibberellic acid in barley endosperm, as shown by the response of the system to anti-auxin. The action of gibberellic acid in this system is independent of the presence or absence of auxin.
Mazama and Glacier Peak Pumice Glass: Uniformity of Refractive Index after Weathering
Authors: Steen Virginia C. , Fryxell Roald
Published: October 2006

Weathering has had little differential effect on modal values of the index of refraction of pumice glasses from the eruptions of Mount Mazama and Glacier Peak thousands of years ago. Confidence is thus increased that the ranges of values for the index of refraction are reliable characteristics by which the two glasses may be distinguished from one another.
Hydroxyurea: Differential Lethal Effects on Cultured Mammalian Cells during the Cell Cycle
Authors: Sinclair Warren K.
Published: October 2006

Hydroxyurea has a differential lethal effect on cultured Chinese-hamster cells that are at different stages in their cell cycle. Cells synthesizing DNA at the time of exposure to the drug are lethally damaged. Cells in the phase of growth preceding DNA synthesis (G
1
) survive but are prevented from beginning DNA synthesis. Cells in the phase after DNA synthesis (G
2
) survive and appear to progress until just before the beginning of the next period of DNA synthesis. This differential lethal and inhibitory effect of hydroxyurea may be useful for synchronizing asynchronous cell populations and explaining effects of the drug in human therapy.
Medium for Selective Isolation of
Cryptococcus neoformans
Authors: Shields Alston B. , Ajello Libero
Published: October 2006

A medium has been developed that permits the selective recovery of
Cryptococcus neoformans
from heavily contaminated materials. It employs creatinine as a nitrogen source, diphenyl (C
6
H
5
C
6
H
5
) and chloramphenicol as mold and bacterial inhibitors, and
Guizotia abyssinica
seed extract as a specific color marker. The medium has proved to be effective in the direct isolation of
Cryptococcus neoformans
from pigeon nests and from the air.
Pheromone: Evidence in a Decapod Crustacean
Authors: Ryan Edward Parsons
Published: October 2006

Males of the speciesPortunus sanguinolentusdisplay a behavioral response to the presence of premolt females which is the same as their behavior when they are exposed to water in which premolt females have been kept. Release of a sex-attractant pheromone is indicated. When females are prevented from releasing urine, there is no evidence of the attractant.
Sex-Linked Anemia: A Hypochromic Anemia of Mice
Authors: Bannerman R. M. , Cooper R. G.
Published: October 2006

This hereditary anemia is most severe in young mice and tends to diminish with increasing age. Erythrocytes show great variation in size and form, with hypochromia and formation of target cells. Though the anemia occurs on a normal diet, it responds rapidly to iron-dextran injection. It may represent an unusual primary disturbance of iron metabolism.
Swimming Speed of a Pacific Bottlenose Porpoise
Authors: Lang Thomas G. , Norris Kenneth S.
Published: October 2006

Four kinds of speed runs showed a Pacific bottlenose porpoise (
Tursiops gilli
) to have a top speed of 29.9 kilometers per hour (16.1 knots) for 7.5 seconds and a top speed of 21.9 kilometers per hour (11.8 knots) for 50 seconds. These results compare closely with highest predictions based upon rigid body drag calculations, the same power output per unit body weight as for athletes, and a propulsive efficiency of 85 percent.
Tetraethylammonium and Tetrodotoxin: Effects on Cochlear Potentials
Authors: Katsuki Y. , Yanagisawa K. , Kanzaki J.
Published: October 2006

Tetraethylammonium chloride, which is believed to decrease potassium conductance, and tetrodotoxin, which apparently decreases sodium conductance in nerve fibers, were introduced iontophoretically into the organ of Corti or the scala media of guinea pig cochlea. The former depressed the direct-current endocochlear potential and also the alternating-current cochlear microphonics (the receptor potential of the ear), but tetrodotoxin was ineffective except on the nerve impulses.
Pentylenetetrazol Enhances Memory Function
Authors: Irwin Samuel , Benuazizi Ali
Published: October 2006

Pentylenetetrazol, in oral doses of 1 to 30 milligrams per kilogram of body weight, significantly facilitated one-trial learning and memory retention in CF1 mice, whether administered before or immediately after the initial trial. The effects appeared significantly greater than those observed in earlier studies with oral administration of strychnine or picrotoxin at 0.2 to 0.8 and 2.4 milligrams per kilogram, respectively.
Liver Carcinogenesis by Diethylnitrosamine in the Rat
Authors: Rajewsky M. F. , Dauber W. , Frankenberg H.
Published: October 2006

Diethylnitrosamine was continuously administered to rats at a dose rate of low toxicity. Ninety-two percent of the animals died with multicentrical hepatocellular carcinomata within a narrow and highly reproducible time interval. Discontinuing the carcinogen during the experiment resulted in a prolonged median time until death, a reduced tumor yield, and a lessened slope of the dose-response curve. Partial hepatectomy after discontinuation of the drug did not change either tumor yield or time of death. The obtained dose-response relationships support the concept that carcinogenic effects of single doses are irreversible and cumulative. Daily, low-dose, total-body x-irradiation had no significant effect on the response of rat liver to the carcinogen.
Arterial Constrictor Response in a Diving Mammal
Authors: Bron Klaus M. , Murdaugh H. V. , Millen J. Eugene , Lenthall Ronald , Raskin Philip , Robin Eugene D.
Published: October 2006

Angiograms were obtained in the harbor seal,
Phoca vitulina
, in air and during diving. During diving there is arterial constriction of the vascular beds of muscle, skin, kidney, liver, spleen, and presumably of all vascular beds except those perfusing the brain and heart. There is sudden constriction and narrowing of muscular arteries close to their origin from the aorta. Constriction of small arterial branches is so intense that blood flow is essentially lost in all involved organs.
Systemic Fungicidal Activity of 1,4-Oxathiin Derivatives
Authors: von Schmeling B. , Kulka Marshall
Published: October 2006

Treatment of pinto bean and barley seed with 1,4-oxathiin derivatives gave disease control by systemic fungicidal action of such pathogenic fungi as
Uromyces phaseoli
and
Ustilago nuda
. The two chemicals, D735 and F461, were highly specific and selective against the pathogens without injury of the hosts.
Ciliastatic Components in the Gas Phase of Cigarette Smoke
Authors: Walker Ted R. , Kiefer John E.
Published: October 2006

The gas phase of cigarette smoke, separated into its components by gas chromatography, was passed across a ciliated specimen. The acetaldehyde, acrolein, and hydrogen cyanide produced strong inhibition of the ciliary beat. A filter which removed most of the acetaldehyde and acrolein from smoke did not reduce the inhibitory effect of the gas phase of that smoke, whereas a filter that removed most of the hydrogen cyanide did reduce inhibition.
Polymorphism of Shock Loaded Fe-Mn and Fe-Ni Alloys
Authors: Loree T. R. , Warnes R. H. , Zukas E. G. , Fowler C. M.
Published: October 2006

Addition of nickel or manganese to iron lowers the pressure of the "130-kb" dynamic polymorphic transition to about 55 kilobars at the limits of the body-centered cubic alloy phase.
Accumulation of a Tetrahydroisoquinoline in Phenylketonuria
Authors: Lasala John M. , Coscia Carmine J.
Published: October 2006

3′,4′-Deoxynorlaudanosolinecarboxylic acid (DNLCA), a tetrahydroisoquinoline derived from dopamine and phenylpyruvic acid, has been detected by computerized mass fragmentography in urine of phenylketonuric children and in urine and brain of rats with experimentally induced hyperphenylalaninemia. Levels of DNLCA in brain of treated animals were more than tenfold higher than controls, and the excess tetrahydroisoquinoline appeared to accumulate in the cerebellum and cortex. DNLCA is a noncompetitive inhibitor of dopamine β-hydroxylase (inhibition constant,
K
i
, = 0.42 m
M
) and is taken up by the brain.
Long-Range Attraction and Molecular Rearrangements in Receptor-Ligand Interactions
Authors: Leckband D. E. , Israelachvili J. N. , Schmitt F. J. , Knoll W.
Published: October 2006

A surface force apparatus was used to measure a long-range attractive protein-ligand force at separations
D
< 85 angstroms. This force may effectively "steer" ligand trajectories, resulting in a greater than 27-fold enhancement of the association rate. A much stronger specific attraction is measured at contact (
D
< 4 angstroms). A sevenfold increase in intermembrane adhesion resulted from increased lateral mobility of the receptors and molecular rearrangements in membranes above the solid-fluid transition temperature.
Leukocyte Mitosis: Suppression in vitro Associated with Acute Infectious Hepatitis
Authors: Mella Barbara , Lang David J.
Published: October 2006

Inhibition of mitosis in vitro was observed in leukocytes from patients with acute infectious hepatitis. Similarly, in cultures of normal leukocytes, after the addition of small amounts of serum from patients with hepatitis, mitosis was suppressed. Although the incidence of mitosis became normal in leukocytes from convalescent patients, there were chromosomal abnormalities.
Diagnosis of Gaucher's Disease and Niemann-Pick Disease with Small Samples of Venous Blood
Authors: Kampine John P. , Bardy Roscoe O. , Kanfer Julian N. , Feld Minna , Shapiro David
Published: October 2006

Enzymes which catalyze the hydrolysis of glucocerebroside and sphingomyelin have been demonstrated in preparations of washed human white blood cells. The level of activity of these respective enzymes is markedly decreased in leukocyte preparations obtained from patients with Gaucher's and Niemann-Pick diseases. Assay of these enzymes may be useful in the differential diagnosis of the sphingolipidoses.
Fission-Fragment Synthesis of a New Nitrogen-Fluorine Compound
Authors: Miller Alan R. , Tsukimura Ray R. , Velten Robert
Published: October 2006

Fission-fragment radiolysis of a mixture of NF
3
and F
2
at room temperature has resulted in the formation of a new, unidentified nitrogen-fluorine compound that is stable at room temperature.
Synaptic Vesicles of Inhibitory and Excitatory Terminals in the Cerebellum
Authors: Larramendi L. M. H. , Fickenscher L. , Lemkey-Johnston N.
Published: October 2006

Populations of synaptic vesicles within cerebellar terminals considered excitatory or inhibitory on the basis of physiological evidence differ with respect to size and shape. Size rather than shape appears to be the main morphological difference between these populations. Elongation of vesicles is dependent on fixation with aldehyde fixatives, and both size and elongation change with age mainly during maturation.
Long Base Line Interferometry: A New Technique
Authors: Broten N. W. , Legg T. H. , Locke J. L. , McLeish C. W. , Richards R. S. , Chisholm R. M. , Gush H. P. , Yen J. L. , Galt J. A.
Published: October 2006

The technique of using magnetic-tape recorders and atomic frequency standards to operate two widely separated radio telescopes as a phase-coherent interferometer when the stations have no radio-frequency connecting link has been successfully tested at the National Research Council of Canada's Algonquin Radio Observatory.
Lupinus arcticus
Wats. Grown from Seeds of Pleistocene Age
Authors: Porsild A. E. , Harington C. R. , Mulligan G. A.
Published: October 2006

Seeds of the arctic tundra lupine (
Lupinus arcticus
) at least 10,000 years old were found in lemming burrows deeply buried in permanently frozen silt of Pleistocene age in unglaciated central Yukon. They readily germinated in the laboratory and have since grown into normal, healthy plants.
Electron Microprobe and Optical Absorption Study of Colored Kyanites
Authors: White Eugene W. , White William B.
Published: October 2006

The characteristic blue color of the mineral kyanite is shown to be caused by traces of Ti
+++
in the range of a few parts per million. Evidence from the intensity and position of optical absorption bands indicates that the unusually intense color probably arises from electron delocalization into narrow d-bands.
Immunological Time Scale for Hominid Evolution
Authors: Sarich Vincent M. , Wilson Allan C.
Published: October 2006

Several workers have observed that there is an extremely close immunological resemblance between the serum albumins of apes and man. Our studies with the quantitative micro-complement fixation method confirm this observation. To explain the closeness of the resemblance, previous workers suggested that there has been a slowing down of albumin evolution since the time of divergence of apes and man. Recent evidence, however, indicates that the albumin molecule has evolved at a steady rate. Hence, we suggest that apes and man have a more recent common ancestry than is usually supposed. Our calculations lead to the suggestion that, if man and Old World monkeys last shared a common ancestor 30 million years ago, then man and African apes shared a common ancestor 5 million years ago, that is, in the Pliocene era.
Histone Acetylation in Insect Chromosomes
Authors: Allfrey V. G. , Pogo B. G. T. , Littau V. C. , Gershey E. L. , Mirsky A. E.
Published: October 2006

Acetylation of histones takes place along the salivary gland chromosomes of
Chironomus thummi
when RNA synthesis is active. It can be observed but not measured quantitatively by autoradiography of chromosome squashes. The "fixatives" commonly used in preparing squashes of insect chromosomes preferentially extract the highly acetylated "arginine-rich" histone fractions; the use of such fixatives may explain the reported absence of histone acetylation in
Drosophila melanogaster
.
Reinforcement Reduction: A Method for Training Ratio Behavior
Authors: Huston Joseph P.
Published: October 2006

By use of intracranial stimulation as reinforcement, fixed-ratio performance could be established directly from continuous reinforcement by gradual reduction of the train duration of the stimuli contingent on all but the terminal response in the desired ratio. Furthermore, stimuli of subreinforcement strength enhanced ratio performance when introduced after training by the conventional method.
Tetanus Toxin: Fine Structure Localization of Binding Sites in Striated Muscle
Authors: Zacks S. I. , Sheff M. F.
Published: October 2006

When striated muscle from mice poisoned with purified tetanus neurotoxin was incubated with tetanus antitoxin labeled with horseradish peroxidase and stained for peroxidase activity, an electron-opaque reaction product was found in the transverse and terminal sacs of the longitudinal elements of the sarcotubular system. Demonstration of toxin in this location suggests that it acts by interfering with contraction coupling or mechanisms of contraction-relaxation.
Microstructure of Sediments: Investigation with Ultrathin Sections
Authors: Bowles Frederick A.
Published: October 2006

Examination of ultrathin sections of "undisturbed" marine sediments from the Gulf of Mexico indicates that they are characterized by a loose, open, random arrangement of particles. The microstructures do not appear to conform entirely to either cardhouse or honeycomb structures.
Immunity and Intracellular Infection: Resistance to Bacteria in Mice Infected with a Protozoan
Authors: Ruskin Joel , Remington Jack S.
Published: October 2006

Mice infected with the intracellular parasite
Toxoplasma
gondii for periods of as long as 7 months were resistant to challenge with numbers of
Listeria monocytogenes
and
Salmonella typhimurium
that were uniformly lethal to normal mice. This resistance did not appear to depend on the strain of toxoplasma employed or the route of inoculation of either toxoplasma or bacteria. Onset of immunity to listeria was demonstrable as early as 1 to 2 days after infection with toxoplasma. Resistance to toxoplasma was not demonstrable in mice immune to listeria. Interferon did not appear to be a mediator of the immunity observed in toxoplasma-infected mice.
Dating Works of Art through Their Natural Radioactivity: Improvements and Applications
Authors: Keisch Bernard
Published: October 2006

The method for approximately dating white lead, which is based upon the decay of lead-210 present in recently refined lead, has been modified to circumvent potential interferences. The modified method has been applied to additional samples of known age and finds increased utility through special treatment of the obtained data. The method was also successfully applied to a number of interesting problems of authentication.
Acetylation of Human Serum Albumin by Acetylsalicylic Acid
Authors: Hawkins David , Pinckard R. Neal , Farr Richard S.
Published: October 2006

Human serum albumin is acetylated when exposed to acetylsalicylic acid (aspirin) under physiologic conditions in vitro. Indications are that a similar phenomenon occurs in vivo after ingestion of aspirin.
Flocculation Mechanism: Charge Neutralization and Bridging
Authors: Ries Herman E. , Meyers Bernard L.
Published: October 2006

Electrophoresis measurements and electron-microscope observations with two model colloids and a polymeric flocculant show zeta-potential changes and details of floc structure. Fibers of the flocculant extend radially from the particle surface and vary in thickness from 20 to 300 angstroms. Both charge neutralization and bridging may function simultaneously.
Alga-Like Forms in Onverwacht Series, South Africa: Oldest Recognized Lifelike Forms on Earth
Authors: Engel Albert E. J. , Nagy Bartholomew , Nagy Lois Anne , Engel Celeste G. , Kremp Gerhard O. W. , Drew Charles M.
Published: October 2006

Spheroidal and cupshaped, carbonaceous alga-like bodies, as well as filamentous structures and amorphous carbonaceous matter occur in sedimentary rocks of the Onverwacht Series (Swaziland System) in South Africa. The Onverwacht sediments are older than 3.2 eons, and they are probably the oldest, little-altered sedimentary rocks on Earth. The basal Onverwacht sediments lie approximately 10,000 meters stratigraphically below the Fig Tree sedimentary rocks, from which similar organic microstructures have been interpreted as alga-like microfossils. The Onverwacht spheroids and filaments are best preserved in black, carbon-rich cherts and siliceous argillites interlayered with thick sequences of lavas. These lifelike forms and the associated carbonaceous substances are probably biological in origin. If so, the origins of unicellular life on Earth are buried in older rocks now obliterated by igneous and metamorphic events.
Red and Far-Red Light Effects on a Short-Term Behavioral Response of a Dinoflagellate
Authors: Forward Richard , Davenport Demorest
Published: October 2006

Cessation of movement (stop response) is used as a criterion for light reception by the dinoflagellate
Gyrodinium dorsum
Kofoid. Brief irradiation (2 seconds at 470 nanometers) elicits a stop response in cells any time during the 6-minute interval after removal from growth lights. This stop response is inactivated by exposure for 4 minutes to 470-nanometer light prior to stimulation. Red light (620 nanometers) reactivates this stop response, and far-red light (700 nanometers) reverses this reactivation. This red-far-red photo reversibility is taken as evidence for phytochrome involvement.
Echinoderms: An Autoradiographic Study of Assimilation of Dissolved Organic Molecules
Authors: Fontaine A. R. , Chia Fu-Shiang
Published: October 2006

In a holothurian and an ophiuroid, tritiated glucose and glycine in great dilution are removed from seawater by uptake through the skin. Cells differ in their competence to metabolize specific nutrients, an indication that there are specialized cellular responses to exogenous organic molecules. Embryonic ophiuroid tissues have an exceptional capacity for assimilation.
DNA Biosynthesis by Isolated Mitochondria: A Replicative Rather Than a Repair Process
Authors: Karol Meryl H. , Simpson Melvin V.
Published: October 2006

The previously observed incorporation of deoxynucleoside triphosphate precursors into DNA by isolated rat liver mitochondria could reflect either replication of DNA or a repair process. Density labeling experiments in cesium chloride demonstrate that DNA synthesized in the presence of 5-bromodeoxyuridine triphosphate instead of thymidine triphosphate shows an appreciable increase in density. In some of the molecules undergoing synthesis, the amount of the density increase indicated a replacement of thymine by bromouracil to the extent of 33 percent. This extensive replacement, which would compute to twice this amount if only a single strand of the duplex is labeled, provides evidence for the synthesis of fairly long pieces of DNA. Such synthesis is characteristic of replication rather than repair, and the results thus suggest that mitochondria are able to replicate their own DNA.
Plant-Herbivore Coevolution: Lupines and Lycaenids
Authors: Breedlove Dennis E. , Ehrlich Paul R.
Published: October 2006

Predation on lupine flowers by larvae of a lycaenid butterfly was studied by comparison of inflorescences exposed to and protected from infestation, and by comparison of lupine populations exposed to different degrees of attack. The lycaenids caused striking reduction in seed set, indicating that this small herbivore could act as a potent selective agent in lupine populations.
Infection of
Macaca nemestrina
by Human Immunodeficiency Virus Type-1
Authors: Agy Michael B. , Frumkin Lyn R. , Corey Lawrence , Coombs Robert W. , Wolinsky Steven M. , Koehler James , Morton William R. , Katze Michael G.
Published: October 2006

After observations that
Macaca nemestrina
were exceptionally susceptible to simian immunodeficiency virus and human immunodeficiency virus type-2 (HIV-2), studies of HIV-1 replication were initiated. Several strains of HIV-1, including a recent patient isolate, replicated in vitro in peripheral blood mononuclear cells (PBMCs) and in CD4-positive
M. nemestrina
lymphocytes in a CD4-dependent fashion. Eight animals were subsequently inoculated with either cell-associated or cell-free suspensions of HIV-1. All animals had HIV-1 isolated by cocultivation, had HIV-1 DNA in their PBMCs as shown by polymerase chain reaction, and experienced sustained seroconversion to a broad spectrum of HIV-1 proteins.
Macaca nemestrina
is an animal model of HIV-1 infections that provides opportunities for evaluating the pathogenesis of acute HIV-1 replication and candidate vaccines and therapies.
An Unlikely Sugar Substrate Site in the 1.65 Å Structure of the Human Aldose Reductase Holoenzyme Implicated in Diabetic Complications
Authors: Wilson David K. , Bohren Kurt M. , Gabbay Kenneth H. , Quiocho Florante A.
Published: October 2006

Aldose reductase, which catalyzes the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of a wide variety of aromatic and aliphatic carbonyl compounds, is implicated in the development of diabetic and galactosemic complications involving the lens, retina, nerves, and kidney. A 1.65 angstrom refined structure of a recombinant human placenta aldose reductase reveals that the enzyme contains a parallel β8/α8-barrel motif and establishes a new motif for NADP-binding oxidoreductases. The substrate-binding site is located in a large, deep elliptical pocket at the COOH-terminal end of the β barrel with a bound NADPH in an extended conformation. The highly hydrophobic nature of the active site pocket greatly favors aromatic and apolar substrates over highly polar monosaccharides. The structure should allow for the rational design of specific inhibitors that might provide molecular understanding of the catalytic mechanism, as well as possible therapeutic agents.
Giant Hepatic Mitochondria: Production in Mice Fed with Cuprizone
Authors: Suzuki Kinuko
Published: October 2006

Giant mitochondria in hepatocytes that have the average size of nuclei can be consistently produced in the liver of weanling mice by feeding them cuprizone (bis-cyclohexanone oxaldihydrazone). The simplicity of the procedure and the consistency of the results make the feeding of cuprizone a new and useful experimental tool for the study of mitochondrial metabolism.
Mosquitoes Feeding on Insect Larvae
Authors: Harris P. , Riordan D. F. , Cooke D.
Published: October 2006

Caged
Aedes aegypti
and
Culex tarsalis
are attracted to insect larvae, engorge on their body fluids, and produce viable eggs. Attractiveness of the larvae is related to their size, shape, and color but not to their movement. The possibility that wild mosquitoes substitute insect hemolymph for vertebrate blood is discussed.
Testicular Lactate Dehydrogenase Isozyme: Cyclic Appearance in Bats
Authors: Blanco Antonio , Gutierrez Mercedes , de Henquin Celia G. , de Burgos Nelia M. G.
Published: October 2006

In male bats
Tadarida brasiliensis
spermatogenesis occurs only during winter and spring. Two additional lactate dehydrogenase isozymes appear in testes containing mature spermatozoa. This type of isozymic change implies cyclic activation of genes and affords valuable markers for study of the factors involved.
Learning Sets in an Invertebrate
Authors: Morrow Joseph E. , Smithson Billy L.
Published: October 2006

Eight isopods,
Porcellio scaber
, were trained with water reinforcement to turn in a T-maze to criterion of correct responses. They were then tested through nine reversals of the turning response. An analysis of variance indicated that mean errors to criterion declined significantly over reversals (
F
= 4.78,
d.f.
= 9/63,
P
< .001).
Enzyme from Calf Thymus Degrading the RNA Moiety of DNA-RNA Hybrids: Effect on DNA-Dependent RNA Polymerase
Authors: Stein Hans , Hausen Peter
Published: October 2006

An enzyme present in extracts from calf thymus degrades specifically the RNA moiety of DNA-RNA hybrids. Other nucleic acids, such as single- or double-stranded DNA and single- or double-stranded RNA, are not affected to a comparable degree. If prepared free of the hybrid-degrading enzyme, RNA polymerase from calf thymus shows a fivefold increase in activity on denatured DNA as compared to native DNA.
Pulsar Test of a Variation of the Speed of Light with Frequency
Authors: Feinberg G.
Published: October 2006

The sharply defined optical and radio pulses from pulsars make possible a test of the variation of the speed of light with frequency, and of the possible existence of a photon mass. The data indicate that the mass of a real photon is less than 10
-44
gram. Detection of extragalactic pulsars could allow a substantial improvement of this limit.
Rhesus Monkeys: Mating Season Mobility of Adult Males
Authors: Lindburg D. G.
Published: October 2006

Groups of rhesus monkeys, heretofore described as closed social units, experience a seasonal exchange of a portion of the adult males. Male shifting corresponds with the season of mating, and results in copulation with females of newly joined groups. This pattern is socially disruptive, but provides opportunity for exchange of genetic material between groups of a region.
Localization of Antigenic Determinants in the Polypeptide Chains of Collagen
Authors: Michaeli D. , Martin George R. , Kettman J. , Benjamini E. , Leung D. Y. K. , Blatt B. A.
Published: October 2006

After being injected with collagen from rat or guinea pig skin, rabbits form high titer, species-specific antibodies to collagen. Antibody is directed primarily against the α2 chain of collagen with little reaction with the α1 chain. The amino terminal peptide of cyanogen bromide cleavage of the α2 chain of guinea pig skin collagen, α2-CBl, effectively inhibited the antigen-antibody reaction, an indication that a major antigenic determinant of collagen is located at the amino terminal of the α2 chain.
Intrasubunit Signal Transduction by the Aspartate Chemoreceptor
Authors: Milligan Daniel L. , Koshland D. E.
Published: October 2006

Receptors that transmit signals across cell membranes are typically composed of multiple subunits. To test whether subunit interactions are required for transmembrane signaling by the bacterial aspartate receptor, dimers were constructed with (i) two full-length subunits, (ii) one full-length subunit and one subunit lacking the cytoplasmic domain, or (iii) one full-length subunit and one subunit lacking both the cytoplasmic and the transmembrane domains. Methylation of the cytoplasmic domain of all three receptor constructs was stimulated by the binding of aspartate. These findings demonstrate that transmembrane signaling does not require interactions between cytoplasmic or transmembrane domains of adjacent subunits and suggest that signaling occurs via conformational changes transduced through a single subunit.
Inert Gases in Lunar Samples
Authors: Heymann D. , Yaniv A. , Adams J. A. S. , Fryer G. E.
Published: October 2006

Sample 10084,40 (fines, less than 1 millimeter) contains substantial amounts of the inert gases. Their concentrations are inversely proportional to particle size; hence the gases appear to be surface-correlated in the soil fragments. The most likely origin of the gas is solar wind or solar cosmic rays. Glass and feldspar are generally poorer in gas than lithic fragments. Ratios of elements in the sample differ significantly from solar values. Ratios of isotopes in the sample are similar to those in meteorites. Argon-40 appears to consist of a radiogenic and a surface-correlated component. An apparent potassium-argon age of 4.42
+0.24
-0.28
billion years is calculated.
Mineralogy and Petrography of Lunar Samples
Authors: Mason B. , Fredriksson K. , Henderson E. P. , Jarosewich E. , Melson W. G. , Towe K. M. , White J. S.
Published: October 2006

The lunar samples consist largely of augite, calcic plagioclase, and ilmenite. Olivine is a minor constituent of some rocks, as is cristobalite. Other minerals present in small amounts include tridymite, chromite, kamacite, taenite, and troilite. The principal rock types can be broadly grouped into ilmenite basalts and breccias. Except for their high ilmenite content, the lunar rocks resemble the calcium-rich achondritic meteorites (eucrites and howardites) in composition and structure. Evidence of a meteoritic increment in the lunar soil is provided by the presence of nickel-iron particles in glass and breccia, and the occurrence of metal-troilite spheroids; the breccias contain occasional silicate aggregates that resemble meteoritic chondrules. The lunar fines contain 325 parts of water-soluble calcium per million.
Mössbauer Spectroscopy of Moon Samples
Authors: Muir A. H. , Housley R. M. , Grant R. W. , Abdel-Gawad M. , Blander M.
Published: October 2006

Lunar bulk sample 10084,85 (< 1 mm size dust), and samples from rocks 10017,17 (fine grained, vesicular), 10046,17 (breccia), 10057,59 (fine grained, vesicular, top surface), 10057,60 (fine grained, vesicular, interior), and 10058,24 (medium grained, not vesicular) have been investigated by
57
Fe Mössbauer spectroscopy. Iron metal and the Fe
2+
minerals ilmenite, pyroxene, troilite, and iron containing glass have been identified. An iron line of sample 10084,85 (originally sealed in nitrogen) showed no significant intensity change when the sample was exposed to air. The antiferromagnetic transition in several lunar ilmenites at 57° ± 2°K corresponds to stoichiometric FeTiO
3
. Magneticallv separated 10057 showed troilite and some metallic iron.
Spectral Reflectivity of Lunar Samples
Authors: Adams John B. , Jones Robert L.
Published: October 2006

Twelve rock chips and two samples of fines all have electronic absorption bands in diffuse reflected light between 0.32 and 2.5 micrometers. Major bands occur between 0.94 and 1.00 micrometer and at 2.0 micrometers, and arise from Fe
2+
in clinopyroxene and to a lesser extent in olivine. A band at 0.95 micrometer and other details of curve slope and shape for the lunar surface fines match McCord's telescopic curve for an 18-kilometer area that includes the Apollo-11 site. Results confirm mineralogical predictions based on telescopic data and support the feasibility of obtaining mineralogical information by remote reflectivity measurements.
Asexual Reproduction in a Sipunculan Worm
Authors: Rice Mary E.
Published: October 2006

The sipunculan worm
Aspidosiphon brocki
reproduces asexually by transverse fission into two unequal parts, the smaller part comprising the posterior fifth of the animal. Prior to fission each part regenerates the structures essential to the formation of a new individual. The smaller posterior part (daughter) regenerates an anterior body, including introvert, anterior gut, retractor muscles, and nephridia, whereas the larger anterior part (parent) regenerates only the posterior body wall.
Starch Accumulation Associated with Growth Reduction at Low Temperatures in a Tropical Plant
Authors: Hilliard Joe H. , West S. H.
Published: October 2006

Growth of
Digitaria decumbens
is severely reduced by night temperatures of 10°C or below. Ultrastructure of leaves and chemical analyses show a high starch content in chloroplasts of plants illuminated and kept at a temperature of 30°C. This starch disappears after a period in the dark at 30°C, but it remains if the temperature during the dark period is 10°C. The inhibition or slowing of starch translocation out of chloroplasts appears to account for reduced photosynthesis and growth at low night temperatures.