bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Conjugated Plasma Proteins of the American Cockroach
Authors: Siakotos A. N. 
Published: May 2004

Evidence has been presented for the possible transport function of conjugated roach plasma proteins during molting. Extensive changes in these proteins are evident during the premolt stage. The remainder of the instar appears to be devoted to a gradual return to the intermolt stage. This recovery process is characterized principally by a transformation of less mobile lipoproteins to lipoproteins of higher electrophoretic mobilities and may be indicative of a lipoprotein-lipase reaction in insects. This transformation also appears to give rise to a second sex-specific lipoprotein. Significant changes in the glycoproteins at the premolt and ecdysial stages may indicate transport of carbohydrate for storage or utilization. A total of six fractions has been shown to occur in roach plasma in the period from one molt to the next.
The process of clotting appeared to be concerned primarily with the blood lipoproteins. These protein fractions reacted to form two new lipoproteins, one of which was the relatively insoluble coagulum network. The second major protein fraction appearing as a result of the coagulation process also was a lipoprotein which contained a lower concentration of carbohydrate than the clot. A possible method of assaying or screening new anticoagulants for insect blood is proposed.
The Effect of Polarized Light on the Growth of a Transparent Cell
Authors: Jaffe L. F. 
Published: May 2004

It is shown that light lost by reflection before entering a clear and homogeneous sphere or infinite cylinder is precisely compensated by light retained within these bodies by internal reflection; compensation means that the total rate of light absorption by infinitely dilute photoreceptors as integrated through the whole of these bodies or even through any concentric or coaxial shell making them up is independent of surface reflection. In the Phycomyces sporangiophore this theorem precludes a reflection explanation of R, the polarization dependence of the light growth response.
An alternative explanation based upon anisotropic absorption by the receptors is explored and found tenable. Formulae are derived for R in any transparent cylindrical cell as a function of the constants of anisotropic absorption by the photoreceptors taken as a group (CH' and CL'), of the radial position of the receptors, and of the refractive indices of the cell (n) and of the medium (N). It is inferred that the photoreceptors in the Phycomyces sporangiophore are most absorbent for light vibrating in the direction of a hoop around a barrel. Orientation of the receptors by linkage to the cell wall is then shown to be a plausible explanation of the inferred anisotropy. On the basis of anisotropic reception, it is predicted that R should be constant for any N &gt; n, and it is shown how CH', C,L' and the radial position of the receptors may all be obtained from a careful determination of R as a function of N.
Effects of Polarization of the Receptor Membrane and of the First Ranvier Node in a Sense Organ
Authors: Loewenstein W. R. , Ishiko N. 
Published: May 2004

It has previously been shown that the site of production of the generator potential in Pacinian corpuscles is the receptor membrane of the non-myelinated ending, and the site of initiation of the nerve impulse, the adjacent (first) Ranvier node. Effects of membrane polarization of these sites were studied in the present work. Nerve ending and first Ranvier node were isolated by dissection, electric activity was recorded from, and polarizing currents were passed through them. All observations were done at steady levels of polarization, seconds after onset of current flow. The following results were obtained:
The amount of charge transferred through the excited receptor membrane is a function of the electrical gradients across the membrane. The generator potential in response to equal mechanical stimuli increases with resting potential of the receptor membrane. The refractory state of the generator potential is not affected by polarization.
The electrical threshold for impulse firing at the first Ranvier node (measured by the minimal amplitude of generator potential which elicits a nodal impulse) is nearly minimal at normal resting potential of the node. Both, hyperpolarization and depolarization lead to a rise in nodal threshold.
For any level of polarization of nodal and receptor membrane, the threshold for production of impulses by adequate (mechanical) stimulation appears determined by the generator potential-stimulus strength relation and by the electrical threshold of the node.
The Efflux of Potassium from Electroplaques of Electric Eels
Authors: Whittam R. , Guinnebault M. 
Published: May 2004

1. The movement of labeled potassium ions has been measured across the innervated membranes of single isolated electroplaques, obtained from the organ of Sachs of Electrophorus electricus, mounted in an apparatus which allowed a separate washing of the two membranes.
2. Equations have been derived for a 3 compartment system in series in which tracer from a large pool in one outer compartment is collected in the other outer compartment. The amount of unlabeled ion in the middle compartment may be calculated and also the fluxes across the two membranes.
3. The flux of potassium across the innervated membranes of resting cells in a steady state was between 700 to 1000 µµmoles/cm.2/sec. and was unaffected by d-tubocurarine.
4. Direct stimulation of electroplaques with external electrodes caused an increase in the efflux of potassium from the innervated membrane of 5 to 8 µµmoles/cm.2/impulse, which was unaffected by d-tubocurarine; no change occurred in the efflux across the non-innervated membrane.
5. It is concluded that the discharge of electroplaques is accompanied by a small outward movement of potassium ions across the innervated membrane of the same order of magnitude as that found on excitation of squid giant axons. The data show a basic similarity of potassium movements across these two entirely different types of conducting membranes and suggest that this phenomenon may be a general feature of bioelectric currents propagating an action potential.
The Surface of the Washed Human Erythrocyte as a Polyanion
Authors: Seaman G. V. F. , Heard D. H. 
Published: May 2004

The electrokinetic behaviour of normal erythrocytes is compared with that of trypsin-, N-bromosuccinimide-, and tosyl-treated erythrocytes. Reduction in the net negative charge with reduction in ionic strength of the suspending medium and also on treatment with N-bromosuccinimide and trypsin is discussed using a porous non-rigid polyanion as a model for the periphery of the cell membrane.
It is deduced from the equivalent binding of chloride and thiocyanate ions and the absence of any effect on treatment of red cells with tosyl chloride, that normal, N-bromosuccinimide- and trypsin-treated cells are polyanionic in character.
Reduction in erythrocyte charge on treatment with N-bromosuccinimide or trypsin is probably not due to the removal of phosphate groups from the interface, nor to physical adsorption of N-bromosuccinimide or trypsin. The charge reduction is probably produced by bond fission with possibly a net disappearance of carboxyl groups from the electrophoretic plane of shear either by loss from, or reorientation of, the membrane. The loss or reorientation of material associated with these carboxyl groups does not lead to any basic change in the character of the surface of the cell, nor to any obvious structural instability. The biconcave discoid form is maintained and there is no significant hemolysis of the erythrocytes even after contact with a solution of trypsin for 24 hours.
The Biological Mechanisms of Air Ion Action
Authors: Krueger Albert P. , Smith Richard F. ,   with the technical assistance of Eddie Reed
Published: May 2004

Negative air ions are shown to decrease 5-hydroxytryptamine concentrations in extirpated strips of rabbit trachea and in the respiratory tracts of living mice. An initial exposure of guinea pigs to (-) air ions causes a transient rise in urinary 5-hydroxyindoleacetic acid excretion which is not observed upon subsequent exposures.
These findings are compatible with the hypothesis advanced earlier that (-) air ion effects depend on the ability of (-) ions to accelerate enzymatic oxidation of 5-hydroxytryptamine.
The Partition of Calcium and Protein in the Blood of Oviparous Vertebrates during Estrus
Authors: Urist Marshall R. , Schjeide Arne O. 
Published: May 2004

Six classes of vertebrate animals were injected with massive doses of estrogen for various periods of time necessary to produce a grossly recognizable response. Swelling of the liver, associated with hypercalcemia, hyperproteinemia, and lipemia, occurred in Teleostei, Amphibia, Reptilia, and Aves, but not in Elasmobranchii or Mammalia. Calcium that was added to the serum was bound as a calcium proteinate complex, synthesized in the liver, and liberated into the plasma. The concentration of calcium per gram was considerably higher than in other oviparous animals.
Teleostei, Amphibia, and Reptilia, produced one new component, protein-X1, having a sedimentation constant of approximately 17S, and many properties of a protein previously described in birds as X2. Calcium-binding capacity of teleostean and amphibian serum proteins was estimated at 25 to 35 mg. per gm. of the mixed proteins of the serum; reptilian serum proteins bound 55 mg. per gm.
Estrogen-treated birds clearly produced two, rather than one, new proteins, a phosphoprotein, X1, having a rate of 8.5S, and X2, a phospholipid-lipoglycoprotein, 17S. The calcium-binding capacity was approximately 50 mg. per gm. of the mixed proteins of the serums. Circumstantial evidence suggests that the plasma proteins of oviparity appeared simultaneously with the evolution of bone as a tissue and an ultimobranchial gland having parathyroid function.
Studies on Sulfhydryl Groups during Cell Division of Sea Urchin Egg
Authors: Sakai Hikoichi 
Published: May 2004

The contractility of the thread model prepared from the KCl-soluble proteins of the egg and in vivo factors for the contraction are investigated in Hemicentrotus, Anthocidaris, and Pseudocentrotus eggs.
The contractility of the thread model induced by metal ions or cystine changes during development in the characteristic pattern of high at the metaphase and low at the monaster and the interkinetic stages. The change in contractility is paralleled by the change in the —SH content of the protein.
The water-soluble fraction of the eggs has activity in causing contraction of the thread model. This activity changes during development in the same way as the contractility itself. The contraction of the thread induced by the water-soluble fractions is accompanied by a decrease in the —SH content of the thread. The activity of the water-soluble fraction in inducing the contraction is proportional to its ability to decrease the number of —SH groups. On boiling, the activity is largely destroyed. The activity is due to two components, one being non-dialyzable and the other dialyzable. Separately each component has little effect, but when mixed, the activity of the original sample is completely restored.
The Metabolism of Serum Proteins in the Hen and Chick and Secretion of Serum Proteins by the Ovary of the Hen
Authors: Patterson R. , Youngner J. S. , Weigle W. O. , Dixon F. J. 
Published: May 2004

In the chicken, serum gamma globulin (CGG) is preferentially transferred by the follicular epithelium of the ovary to the developing ova. The concentration of gamma globulin in the yolk of the unfertilized egg is many times the concentration of chicken serum albumin (CSA). This transfer occurs largely during the 4 to 5 days preceding ovulation when the growth of the ovum is most rapid. Thus, in the chicken, the follicular epithelium of the ovary serves the same purpose in the passive immunization of offspring as does the acinar epithelium of the udder in ungulates and the extraembryonic membranes in rabbits and man.
The amount of gamma globulin synthesis by the chick is low during the first 2 weeks of life and is associated with low levels of serum gamma globulin. By the end of the 1st month of life, the level of serum gamma globulin increases, presumably reflecting an increased rate of synthesis.
In the adult hens the half-life of I131-labeled CSA is 66 hours and that of I131-labeled CGG, 35 hours, while in the newly hatched chick for I131-labeled CSA it is 42 hours and for I131-labeled CGG, 72 hours. Thus, this species shows a gamma globulin sparing in the first days of life, as do most mammalian species.
Theoretical Series Elastic Element Length in Rana pipiens Sartorius Muscles
Authors: Matsumoto Yorimi 
Published: May 2004

Assuming a two component system for the muscle, a series elastic element and a contractile component, the analyses of the isotonic and isometric data points were related to obtain the series elastic stiffness, dP/dls, from the relation,
See PDF for Equation
From the isometric data, dP/dt was obtained and shortening velocity, v, was a result of the isotonic experiments. Substituting (P0 - P)/T for dP/dt and (P0 - P)/(P + a) times b for v, dP/dls = (P + a) /bT, where P &lt; P0, and a, b are constants for any lengths l ≤ l0 (Matsumoto, 1965). If the isometric tension and the shortening velocity are recorded for a given muscle length, l0, although the series elastic, ls, and the contractile component, lc, are changing, the total muscle length, l0 remains fixed and therefore the time constant, T. Integrating,
See PDF for Equation
the stress-strain relation for the series elastic element,
See PDF for Equation
is obtained; lsc0 - ls + lc0where lco equals the contractile component length for a muscle exerting a tension of P0. For a given P/P0, ls is uniquely determined and must be the same whether on the isotonic or isometric length-tension-time curve. In fact, a locus on one surface curve can be associated with the corresponding locus on the other.
Sodium and Potassium Fluxes in Isolated Barnacle Muscle Fibers
Authors: Brinley F. J. 
Published: May 2004

Sodium and potassium influxes and outfluxes have been studied in single isolated muscle fibers from the giant barnacle both by microinjection and by external loading. The sodium influxes and outfluxes were 49 and 39 pmoles /cm2-sec (temperature = 15–16°C) respectively. The potassium influxes and outfluxes were 28 and 60 pmoles/cm2-sec (temperature = 13–16°C) respectively. Replacement of external sodium by lithium reduced sodium outflux by 67% but had no effect on potassium outflux. Removal of external potassum reduced the sodium outflux by 51% but had no effect on potassium outflux. External strophanthidin (10–30 µM) reduced sodium outflux by 80–90% and increased potassium outflux by 40% in normal fibers. The time constant for sodium exchange increased linearly with internal sodium concentration, as did the fraction of sodium outflux insensitive to a maximally inhibitory concentration of external strophanthidin in the range of 10 tO 80 mM internal sodium. The strophanthidin-sensitive component of sodium outflux could be related to the internal sodium concentration by the following empirical formula:
See PDF for Equation
An Analysis of Hamster Afferent Taste Nerve Response Functions
Authors: Frank Marion 
Published: May 2004

Sensitivities to moderately intense stimuli representing four taste qualities to man were determined for 79 hamster chorda tympani fibers. Some fibers were very sensitive to sucrose, sodium chloride, or hydrochloric acid, but none were very sensitive to quinine. These sensitivities were not randomly distributed among fibers: the sucrose sensitivity was separated from and negatively correlated with the other sensitivities which were associated and positively correlated with each other. Moreover, there were a limited number of sensitivity patterns: (a) fibers responding best to sucrose responded second-best to salt, less to acid, not to quinine; (b) fibers responding best to salt either responded second-best to sucrose and not to acid or quinine; or second-best to acid, less to quinine, and not to sucrose; and (c) fibers responding best to acid responded second-best to salt, more to quinine, and less to sucrose than other fibers. Therefore, if four stimuli of different taste qualities are ordered from acceptable to unacceptable, neural response functions of most hamster chorda tympani taste fibers peak at one point.
Sensitivities to nine other moderately intense stimuli which vary in quality to man were also determined for 46–49 of the fibers. Sensitivities to sweet stimuli were always associated with each other and separated from sensitivities to nonsweet stimuli. Sensitivities to nonsweet stimuli were all associated with each other; however, the strongest correlations were between sensitivities to stimuli of like quality, e.g., the three acids or the two sodium salts.
Energetics of Shortening Muscles in Twitches and Tetanic Contractions
Authors: Homsher E. , Mommaerts W. F. H. M. , Ricchiuti N. V. 
Published: May 2004

The extra heat liberation accompanying muscular shortening, the force-determined shortening heat, is defined as the difference between the heat produced when shortening occurs and that produced in an isometric contraction developing the same amount of force and performing the same amount of internal work. Based on this definition, the initial energy production in twitches and tetanic contractions (E) is given by
E = A + f (P, t) + αFx + W,
where A is the activation heat, f(P, t), the tension-related heat (a heat production associated with the development and maintenance of tension), αFx, the force-determined shortening heat, and W, the external work. It is demonstrated that this equation accurately accounts for the time-course of heat evolution and the total initial energy production in both twitches and tetani at 0°C. The force-determined shortening heat is liberated, during shortening, in direct proportion to (a) the distance shortened, and (b) the force against which shortening occurs. The normalized value of the force-determined shortening heat coefficient, αF/Po, is the same in both the twitch and the tetanus. Finally, this formulation of the muscle's energy production also accounts for the total energy production in afterload isotonic twitches at 20°C, where a Fenn effect is not demonstrable.
The Search for Genetic Risk Factors Associated With Suicidal Behavior
Authors: Hesselbrock Victor , Dick Danielle , Hesselbrock Michie , Foroud Tatiana , Schuckit Marc , Edenberg Howard , Bucholz Kathy , Kramer John , Reich Theodore , Goate Alison , Bierut Laura , Rice John P. , Nurnberger John I. 
Published: May 2004

Abstract:Background:Suicide and suicidal behavior are prevalent among individuals with psychiatric disorders, including alcohol dependence. A genome screen was performed in multiplex alcohol dependent families ascertained as part of the Collaborative Study on the Genetics of Alcoholism to identify chromosomal regions of interest related to two types of suicidal behavior: suicide attempts and suicidality.Methods:Sibling pair analyses were used to conduct linkage analyses using both qualitative and quantitative suicide‐related phenotypes. The qualitative trait of “suicide attempts” was examined using 59 affected sibling pairs. The quantitative trait of “suicidality” was examined using all possible 1366 sibling pairs and 705 independent sibling pairs.Results:For the qualitative phenotype suicide attempts, chromosome 2 yielded a maximum lod score of 4.2. For the quantitative suicidality index, a maximum lod score of 1.8 was observed on chromosome 3, and a lod score of 1.5 was found on chromosome 1.Conclusions:This study represents the first genome‐wide scan of suicidal behavior. Significant evidence of linkage was found on chromosome 2 for the phenotype suicide attempts, the same chromosomal region previously reported to be linked to alcohol dependence in this sample. This finding does not seem to be due solely to an association between suicide and alcohol dependence. There was more modest evidence of linkage to chromosomes 1 and 3 for suicidality; however, these findings did not reach statistical significance. There was no overlap in findings for these two phenotypes of suicidal behavior.
Viral Virulence Protein Suppresses RNA Silencing–Mediated Defense but Upregulates the Role of MicroRNA in Host Gene Expression[W]
Authors: Chen Jun , Li Wan Xiang , Xie Daoxin , Peng Jin Rong , Ding Shou Wei 
Published: May 2004

AbstractSmall interfering RNAs (siRNAs) and microRNAs (miRNAs) are processed by the ribonuclease Dicer from distinct precursors, double-stranded RNA (dsRNA) and hairpin RNAs, respectively, although either may guide RNA silencing via a similar complex. The siRNA pathway is antiviral, whereas an emerging role for miRNAs is in the control of development. Here, we describe a virulence factor encoded by turnip yellow mosaic virus, p69, which suppresses the siRNA pathway but promotes the miRNA pathway in Arabidopsis thaliana. p69 suppression of the siRNA pathway is upstream of dsRNA and is as effective as genetic mutations in A. thaliana genes involved in dsRNA production. Possibly as a consequence of p69 suppression, p69-expressing plants contained elevated levels of a Dicer mRNA and of miRNAs as well as a correspondingly enhanced miRNA-guided cleavage of two host mRNAs. Because p69-expressing plants exhibited disease-like symptoms in the absence of viral infection, our findings suggest a novel mechanism for viral virulence by promoting the miRNA-guided inhibition of host gene expression.
maternally expressed gene1Is a Novel Maize Endosperm Transfer Cell–Specific Gene with a Maternal Parent-of-Origin Pattern of Expression[W]
Authors: Gutieérrez-Marcos Jose F. , Costa Liliana M. , Biderre-Petit Corinne , Khbaya Bouchaib , O'Sullivan Donal M. , Wormald Mark , Perez Pascual , Dickinson Hugh G. 
Published: May 2004

AbstractGrowth of the maize (Zea mays) endosperm is tightly regulated by maternal zygotic and sporophytic genes, some of which are subject to a parent-of-origin effect. We report here a novel gene, maternally expressed gene1 (meg1), which shows a maternal parent-of-origin expression pattern during early stages of endosperm development but biallelic expression at later stages. Interestingly, a stable reporter fusion containing the meg1 promoter exhibits a similar pattern of expression. meg1 is exclusively expressed in the basal transfer region of the endosperm. Further, we show that the putatively processed MEG1 protein is glycosylated and subsequently localized to the labyrinthine ingrowths of the transfer cell walls. Hence, the discovery of a parent-of-origin gene expressed solely in the basal transfer region opens the door to epigenetic mechanisms operating in the endosperm to regulate certain aspects of nutrient trafficking from the maternal tissue into the developing seed.