bluuebunny/crossref_metadata_2025 huggingface dataset:
TGF-beta 1 is an autocrine-negative growth regulator of human colon carcinoma FET cells in vivo as revealed by transfection of an antisense expression vector.
Authors: Wu S P , Theodorescu D , Kerbel R S , Willson J K , Mulder K M , Humphrey L E , Brattain M G
Published: May 2004

Transforming growth factor-beta 1 (TGF-beta 1) has previously been implicated as a potential negative autocrine or paracrine growth regulator of certain cell types (Arteaga, C. L., R. J. Coffey, Jr., T. C. Dugger, C. M. McCutchen, H. L. Moses, and R. M. Lyons. 1990. Cell Growth & Differ. 1:367-374; Hafez, M. M., D. Infante, S. Winawer, and E. Friedman. 1990. Cell Growth & Differ. 1:617-626; Glick, A. B., K. C. Flanders, D. Danielpour, S. H. Yuspa, and M. B. Sporn. 1989. Cell Regulation. 1:87-97). This is based mainly on experiments assessing the effects of exogenous TGF-beta 1 or neutralizing antibodies to TGF-beta 1 on normal or tumor cell proliferation in vitro. However, direct evidence demonstrating such a negative regulation of tumor cell growth in vivo is still lacking. To overcome this problem we have constructed and used an antisense expression vector for TGF-beta 1 as a means of regulating endogenous TGF-beta 1 expression in tumor cells. Antisense-transfected FET human colon carcinoma cells showed a fivefold reduction in TGF-beta 1 mRNA and 15-fold reduction in TGF-beta 1 secretion. Antisense mRNA was detected in transfected cells by an RNase protection assay. Compared to control cells, cultured antisense-transfected cells showed a reduction in lag phase time rather than a change in doubling time. Cloning efficiencies of transfected cells were four times greater than control cells in anchorage-independent assays. Control cells did not form tumors at 5 x 10(5) in athymic nude mice. Antisense-transfected cells formed tumors in 40% of animals injected. At higher inocula (1 x 10(6) cells) antisense-transfected cells formed tumors in 100% of animals injected, but control cells still failed to form tumors. These results show that TGF-beta 1 acts as a negative growth regulator of human colon carcinoma cells in vivo as well as in vitro. Acquisition of partial or full resistance to such inhibitory effects may therefore contribute to tumor development and progression.
The invasin protein of Yersinia enterocolitica: internalization of invasin-bearing bacteria by eukaryotic cells is associated with reorganization of the cytoskeleton.
Authors: Young V B , Falkow S , Schoolnik G K
Published: May 2004

Yersinia enterocolitica, a facultative intracellular pathogen of mammals, readily enters (i.e., invades) cultured eukaryotic cells, a process that can be conferred by the cloned inv locus of the species. We have studied the mechanism by which the product of inv, a microbial outer membrane protein termed "invasin," mediates the internalization of bacteria by HEp-2 cells and chicken embryo fibroblasts. Invasin-bearing bacteria initially bound the filopodia and the leading edges of cultured cells. Multiple points of contact between the bacterial surface and the surface of the cell ensued and led to the internalization of the bacterium within an endocytic vacuole; the same multi-step process could be induced by an inert particle coated with invasin-containing membranes. Both adherence and internalization were blocked by an antisera directed against the beta 1 integrin cell-adherence molecule. Ultrastructural studies of detergent-insoluble cytoskeletons from infected cells and immunofluorescence microscopy of phalloidin-labeled cells showed alterations in the structure of the cytoskeleton during the internalization process including the accumulation of polymerized actin around entering bacteria. Bacterial entry was prevented by cytochalasin D indicating that the internalization process requires actin microfilament function. Possible linkages between beta 1 containing integrins and the cytoskeleton were examined during the internalization process through the use of protein-specific antibodies and immunofluorescence microscopy. Like actin, the actin-associated proteins filamin, talin and the beta 1 integrin subunit were also found to accumulate around entering bacteria. These findings suggest that the invasin-mediated internalization process is associated with cytoskeletal reorganization.
Divalent cation regulation of the function of the leukocyte integrin LFA-1.
Authors: Dransfield I , Cabañas C , Craig A , Hogg N
Published: May 2004

The integrin lymphocyte function-associated antigen-1 (LFA-1) expressed on T cells serves as a useful model for analysis of leukocyte integrin functional activity. We have assessed the role of divalent cations Mg2+, Ca2+, and Mn2+ in LFA-1 binding to ligand intercellular adhesion molecule-1 (ICAM-1) and induction of the divalent cation-dependent epitope recognized by mAb 24. Manganese strongly promoted both expression of the 24 epitope and T cell binding to ICAM-1 via LFA-1, suggesting that Mn2+ is able to directly alter the conformation of LFA-1 in a manner that favors ligand binding. Since Mn2+ also promotes functional activity of other integrins, parallels in mechanism of ligand binding may span the integrin family. In contrast, induction of 24 epitope expression by Mg2+ required removal of Ca2+ from T cell LFA-1 with EGTA. Furthermore, binding of mAb 24 to T cell LFA-1 in the presence of either Mn2+ or Mg2+ was found to be specifically inhibited by Ca2+, suggestive of a negative regulatory role for Ca2+ in the control of leukocyte integrin function. Analysis of T cell binding to ICAM-1 via LFA-1 in the presence of Mg2+ or Mn2+, confirmed that Ca2+ exerted inhibitory effects upon LFA-1 function. The implication of our findings is that Ca2+ bound with relatively high affinity to LFA-1 may serve to maintain an inactive state. Thus induction of function and 24 epitope expression may occur as a result of displacement of Ca2+ from leukocyte integrins or alternatively, such activators may be able to impose the required conformational change in the presence of bound Ca2+.
Differential utilization of regulatory domains within the alpha 1(I) collagen promoter in osseous and fibroblastic cells.
Authors: Pavlin D , Lichtler A C , Bedalov A , Kream B E , Harrison J R , Thomas H F , Gronowicz G A , Clark S H , Woody C O , Rowe D W
Published: May 2004

Type I collagen is expressed in a variety of connective tissue cells and its transcriptional regulation is highly complex because of the influence of numerous developmental, environmental, and hormonal factors. To investigate the molecular basis for one aspect of this complex regulation, the expression of alpha 1(I) collagen (COL1A1) gene in osseous tissues, we fused a 3.6-kb DNA fragment between bases -3,521 and +115 of the rat COL1A1 promoter, and three deletion mutants, to the chloramphenicol acetyltransferase (CAT) marker gene. The expression of these ColCAT transgenes was measured in stably transfected osteoblastic cell lines ROS 17/2.8, Py-la, and MC3T3-E1 and three fibroblastic lines NIH-3T3, Rat-1, and EL2. Deletion of the distal 1.2-kb fragment of the full-length ColCAT 3.6 construct reduced the promoter activity 7- to 30-fold in the osteoblastic cell lines, twofold in EL2 and had no effect in NIH-3T3 and Rat-1 cells. To begin to assess the function of COL1A1 upstream regulatory elements in intact animals, we established transgenic mouse lines and examined the activity of the ColCAT3.6 construct in various tissues of newborn animals. The expression of this construct followed the expected distribution between the high and low collagen-producing tissues: high levels of CAT activity in calvarial bone, tooth, and tendon, a low level in skin, and no detectable activity in liver and brain. Furthermore, CAT activity in calvarial bone was three- to fourfold higher than that in the adjacent periosteal layer. Immunostaining for CAT protein in calvaria and developing tooth germ of ColCAT3.6 mice also confirmed the preferred expression of the transgene in differentiated osteoblasts and odontoblasts compared to fibroblast-like cells of periosteum and dental papilla. This study suggests that the 3.6-kb DNA fragment confers the strong expression of COL1A1 gene in high collagen producing tissues of intact animals and that the 5' flanking promoter sequence between -3,521 and -2,295 bp contains one or more stimulatory elements which are preferentially active in osteoblastic cells.
Trans-repressor activity of nuclear glycosaminoglycans on Fos and Jun/AP-1 oncoprotein-mediated transcription.
Authors: Busch S J , Martin G A , Barnhart R L , Mano M , Cardin A D , Jackson R L
Published: May 2004

Heparin blocks the phorbol ester-induced progression of nontransformed cells through the G0/G1 phase (Wright, T.C., L.A. Pukac, J.J. Castellot, M.J. Karnovsky, R.A. Levine, H.-Y. Kim-Park, and J. Campisi. 1989. Proc. Natl. Acad. Sci. USA. 86: 3199-3203) or G1 to S phase (Reilly, C. F., M. S. Kindy, K. E. Brown, R. D. Rosenberg, and G. E Sonenshein. 1989. J. Biol. Chem. 264:6990-6995) of the cell cycle. Cell cycle arrest was associated with decreased levels of stage-specific mRNAs suggesting transcriptional regulation of cell growth. In the present report, we show that heparin selectively repressed TPA-inducible AP-1-mediated gene expression. Heparin-induced trans-repression was observed in primary vascular smooth muscle cells, as well as in the transformed HeLa cell line and in nondifferentiated F9 teratocarcinoma cells. Inhibition of AP-1-mediated trans-activation occurred with heparin and pentosan polysulfate but not with chondroitin sulfate A or C. Heparin-binding peptides or heparitinase I addition to nuclear lysates of heparin-treated cells allowed enhanced recovery of endogenous AP-1-specific DNA binding activity. We propose a model in which nuclear glycosaminoglycans play a trans-regulatory role in altering the patterns of inducible gene expression.
Casein kinase II is a predominantly nuclear enzyme.
Authors: Krek W , Maridor G , Nigg E A
Published: May 2004

Casein kinase II (CK II) has been implicated in regulating multiple processes related to cell growth, proliferation, and differentiation. To better understand the function(s) and regulation of this ubiquitous kinase, it is important to know its subcellular distribution. However, this issue has been the subject of contradictory reports. In this study, we have used indirect immunofluorescence microscopy and cell fractionation to study the subcellular distribution of all three subunits of chicken CK II, alpha, alpha', and beta. We examined primary chick embryo fibroblasts, virally transformed chicken hepatoma cells, as well as HeLa cells transiently transfected with cDNAs encoding chicken CK II subunits. We found that each of the three CK II subunits was located predominantly in the cell nucleus, irrespective of the cell type analyzed or the procedure used for cell fixation. No major differences were detected in the subcellular distributions of individual CK II subunits, and no evidence was obtained for subunit redistributions during interphase of the cell cycle. During mitosis, the bulk of the enzyme was dispersed throughout the cell, though a fraction of all three subunits was associated with the mitotic spindle. Biochemical studies based on mechanical enucleation of chicken cells confirmed the predominantly nuclear location of all three CK II subunits. Finally, immunoblotting experiments were carried out to study the expression of CK II subunits. A survey of different adult chicken tissues revealed substantial tissue-specific differences in the levels of CK II protein, but no evidence was obtained for pronounced tissue specificity in the expression of individual CK II subunits. These results strongly suggest that CK II functions primarily in regulating nuclear activities, and that the two catalytic subunits, alpha and alpha', may carry out overlapping functions.
Assembly and disassembly of the Golgi complex: two processes arranged in a cis-trans direction.
Authors: Alcalde J , Bonay P , Roa A , Vilaro S , Sandoval I V
Published: May 2004

We have studied the disassembly and assembly of two morphologically and functionally distinct parts of the Golgi complex, the cis/middle and trans cisterna/trans network compartments. For this purpose we have followed the redistribution of three cis/middle- (GMPc-1, GMPc-2, MG 160) and two trans- (GMPt-1 and GMPt-2) Golgi membrane proteins during and after treatment of normal rat kidney (NRK) cells with brefeldin A (BFA). BFA induced complete disassembly of the cis/middle- and trans-Golgi complex and translocation of GMPc and GMPt to the ER. Cells treated for short times (3 min) with BFA showed extensive disorganization of both cis/middle- and trans-Golgi complexes. However, complete disorganization of the trans part required much longer incubations with the drug. Upon removal of BFA the Golgi complex was reassembled by a process consisting of three steps: (a) exist of cis/middle proteins from the ER and their accumulation into vesicular structures scattered throughout the cytoplasm; (b) gradual relocation and accumulation of the trans proteins in the vesicles containing the cis/middle proteins; and (c) assembly of the cisternae, and reconstruction of the Golgi complex within an area located in the vicinity of the centrosome from which the ER was excluded. Reconstruction of the cis/middle-Golgi complex occurred under temperature conditions inhibitory of the reorganization of the trans-Golgi complex, and was dependent on microtubules. Reconstruction of the trans-Golgi complex, disrupted with nocodazole after selective fusion of the cis/middle-Golgi complex with the ER, occurred after the release of cis/middle-Golgi proteins from the ER and the assembly of the cis/middle cisternae.
Perturbation of the morphology of the trans-Golgi network following Brefeldin A treatment: redistribution of a TGN-specific integral membrane protein, TGN38.
Authors: Reaves B , Banting G
Published: May 2004

Brefeldin A (BFA) has a dramatic effect on the morphology of the Golgi apparatus and induces a rapid redistribution of Golgi proteins into the ER (Lippincott-Schwartz, J., L. C. Yuan, J. S. Bonifacino, and R. D. Klausner. 1989. Cell. 56:801-813). To date, no evidence that BFA affects the morphology of the trans-Golgi network (TGN) has been presented. We describe the results of experiments, using a polyclonal antiserum to a TGN specific integral membrane protein (TGN38) (Luzio, J.P., B. Brake, G. Banting, K. E. Howell, P. Braghetta, and K. K. Stanley. 1990. Biochem. J. 270:97-102), which demonstrate that incubation of cells with BFA does induce morphological changes to the TGN. However, rather than redistributing to the ER, the majority of the TGN collapses around the microtubule organizing center (MTOC). The effect of BFA upon the TGN is (a) independent of protein synthesis, (b) fully reversible (c) microtubule dependent (as shown in nocodazole-treated cells), and (d) relies upon the hydrolysis of GTP (as shown by performing experiments in the presence of GTP gamma S). ATP depletion reduces the ability of BFA to induce a redistribution of Golgi proteins into the ER; however, it has no effect upon the BFA-induced relocalizations of the TGN. These data confirm that the TGN is an organelle which is independent of the Golgi, and suggest a dynamic interaction between the TGN and microtubules which is centered around the MTOC.
Immunocytochemical characterization of the endocytic and phagolysosomal compartments in peritoneal macrophages.
Authors: Rabinowitz S , Horstmann H , Gordon S , Griffiths G
Published: May 2004

We have used endocytic and phagocytic tracers in an EM immunocytochemical study to define the compartments of the phagocytic and endocytic pathways in mouse peritoneal macrophages. Endocytosed BSA-gold appeared successively in early endosomes, spherical endosomal vesicles, a late endosomal tubuloreticular compartment (TC), and terminal lysosomes. The TC appeared as an elaborate structure enriched for the lysosomal membrane glycoproteins Lamp 1 and Lamp 2, and expressing significant levels of rab7, a late endosome-specific GTP-binding protein. The cation-independent mannose-6-phosphate receptor was restricted to specialized regions of the TC that were predominantly adjacent to the Golgi complex. Both the early endosome and the TC had coated bud structures whose composition and function are presently unknown. Phagolysosomes containing latex beads expressed the same membrane antigens and received endocytic tracers simultaneously with the TC. Since the membrane surrounding both organelles was also in direct continuity, we assume that both structures form one functional compartment. Macrosialin, an antigen confined to macrophages and dendritic cells, was heavily expressed in TC and phagolysosomal membranes with low levels being detected in other endosomal compartments and on the cell surface. Treatment of cells with wheat germ agglutinin drastically altered the morphology of the TC, giving rise to sheets of tightly adherent membrane and greatly expanded vesicles, in which cell-associated wheat germ agglutinin was concentrated. The spherical endosomal carrier vesicles loaded with internalized gold tracers clustered nearby, often making contact without fusing. Since the delivery of endocytic tracer to the TC was significantly delayed these experiments suggest that the lectin is somehow preventing the endosome vesicles from fusing with the TC. Collectively, our data argue first that the PLC is equivalent to the "tubular lysosomes" commonly described in macrophages, and second that the meeting of the phagocytic and endocytic pathway occurs in this compartment.
LIGHT AND THE MUSCLE TONUS OF INSECTS THE HELIOTROPIC MECHANISM
Authors: Garrey Walter E.
Published: May 2004

The tonus of the muscles of heliotropic insects is due chiefly to the action of light; it is markedly decreased in the dark. Each eye controls the tonus of a different group of muscles on both sides of the body. Different areas of each eye likewise are related to the tonus of different muscle groups, and the relationship is entirely analogous to that of the otic labyrinth of vertebrates. Asymmetrical conditions of muscle tension are produced by any procedure which establishes an unequal photochemical reaction in the two eyes, by difference in illumination, by partial or complete blackening of one eye, or establishing unequal sensitiveness in the two eyes. The unbalanced condition of muscle tonus expresses itself in unusual postures of the resting insects, and in movements in forced paths—circus motions when one eye has been blackened. These reactions vary directly with the intensity of the illumination, as shown not only by the variation in diameters of the circles, but also by the reactions of the insects on vertical surfaces and on the turntable.

The relation of the results of these experiments to the problem of heliotropic orientation is too obvious to require detailed discussion, which could only lead to a repetition of the description of the mechanism f heliotropism which Loeb has so clearly expounded. The experiments are so completely in accordance with Loeb's muscle tension theory of heliotropism, that they are tantamount to a complete proof of it.
A METHOD OF STUDYING RESPIRATION
Authors: Osterhout W. J. V.
Published: May 2004

An apparatus is described which makes it possible to measure rapidly and accurately small amounts of CO2 given off by organisms of all kinds. The apparatus can also be used to measure photosynthesis.
A THEORY OF THE MECHANISM OF DISINFECTION, HEMOLYSIS, AND SIMILAR PROCESSES
Authors: Brooks S. C.
Published: May 2004

1. The course of such processes as hemolysis is very largely dependent upon variations in resistance among the different individuals, and secondarily upon the course of the fundamental reaction.

2. The fundamental reaction may be either a simple process, or the expression of a complex series of changes whose rate is at all times governed by that of the slowest of the series. This might perhaps be regarded as another expression of the so called "Law of the minimum."

3. Unnatural assumptions would be requisite for the explanation of a resemblance between the course of such processes in general and that of a monomolecular reaction.

4. The supposition that such a general resemblance exists is not supported by the available evidence.

5. The independent determination of either the nature of the fundamental reaction, or the type of the variation curve for the particular case under observation, will further our knowledge of the nature of such processes and lead to a far deeper insight into the nature and reactions of living matter.
AN INDICATOR METHOD OF MEASURING THE CONSUMPTION OF OXYGEN
Authors: Osterhout W. J. V.
Published: May 2004

The blood of the horseshoe crab (Limulus) absorbs oxygen and turns blue when shaken in air. In the presence of certain organisms which consume oxygen it is quickly decolorized. By measuring the time required for the change of color the rate of consumption of oxygen may be determined.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Osterhout W. J. V.
Published: May 2004

A series of investigations on respiration with improved quantitative methods has been commenced. The first of these are here described. They show that when anesthetics are employed in sufficient concentration to produce any result, plants show a rise in the rate of respiration which is followed by a fall. In the animals studied, the rise (found in higher concentrations only) was preceded by a temporary fall which is not entirely due to lowering of muscular activity or tonus. In lower concentrations the effect on animals was merely a decrease of respiration.

The results of all the investigations are opposed to the theory of Verworn.
THE RATE OF TRANSMISSION IN THE NERVE NET OF THE CŒLENTERATES
Authors: Parker G. H.
Published: May 2004

Nerve net transmission in Metridium at 21°C. varies from 121 to 146 mm. per second.
AMPHOTERIC COLLOIDS
Authors: Loeb Jacques
Published: May 2004

1. It is shown by volumetric analysis that on the alkaline side from its isoelectric point gelatin combines with cations only, but not with anions; that on the more acid side from its isoelectric point it combines only with anions but not with cations; and that at the isoelectric point, pH = 4.7, it combines with neither anion nor cation. This confirms our statement made in a previous paper that gelatin can exist only as an anion on the alkaline side from its isoelectric point and only as a cation on the more acid side of its isoelectric point, and practically as neither anion nor cation at the isoelectric point.

2. Since at the isoelectric point gelatin (and probably amphoteric colloids generally) must give off any ion with which it was combined, the simplest method of obtaining amphoteric colloids approximately free from ionogenic impurities would seem to consist in bringing them to the hydrogen ion concentration characteristic of their isoelectric point (i.e., at which they migrate neither to the cathode nor anode of an electric field).

3. It is shown by volumetric analysis that when gelatin is in combination with a monovalent ion (Ag, Br, CNS), the curve representing the amount of ion-gelatin formed is approximately parallel to the curve for swelling, osmotic pressure, and viscosity. This fact proves that the influence of ions upon these properties is determined by the chemical or stoichiometrical and not by the "colloidal" condition of gelatin.

4. The sharp drop of these curves at the isoelectric point finds its explanation in an equal drop of the water solubility of pure gelatin, which is proved by the formation of a precipitate. It is not yet possible to state whether this drop of the solubility is merely due to lack of ionization of the gelatin or also to the formation of an insoluble tautomeric or polymeric compound of gelatin at the isoelectric point.

5. On account of this sudden drop slight changes in the hydrogen ion concentration have a considerably greater chemical and physical effect in the region of the isoelectric point than at some distance from this point. This fact may be of biological significance since a number of amphoteric colloids in the body seem to have their isoelectric point inside the range of the normal variation of the hydrogen ion concentration of blood, lymph, or cell sap.

6. Our experiments show that while a slight change in the hydrogen ion concentration increases the water solubility of gelatin near the isoelectric point, no increase in the solubility can be produced by treating gelatin at the isoelectric point with any other kind of monovalent or polyvalent ion; a fact apparently not in harmony with the adsorption theory of colloids, but in harmony with a chemical conception of proteins.
TEMPERATURE COEFFICIENT OF THE ACTION OF ß-RAYS UPON THE EGG OF NEREIS
Authors: Redfield Alfred C. , Bright Elizabeth M.
Published: May 2004

The temperature coefficient of the action of ß-rays from radium upon the egg of Nereis lies between 1.1 and 1.2. This is of a magnitude characteristic of photochemical reactions.
A COMPARATIVE STUDY OF PERMEABILITY IN PLANTS
Authors: Osterhout W. J. V.
Published: May 2004

Quantitative studies on Laminaria (a brown alga), Ulva (a green alga), Rhodymenia (a red alga), and Zostera (a flowering plant) show that the behavior of these plants, in respect to changes in permeability, is essentially alike in all cases.
NATURE OF THE RETARDING INFLUENCE OF THE THYMUS UPON AMPHIBIAN METAMORPHOSIS
Authors: Uhlenhuth Eduard
Published: May 2004

1. Though thymus-fed salamander larvæ often metamorphose normally, thymus feeding sometimes retards and in rare cases inhibits metamorphosis completely.

2. The addition of normal food to a thymus diet abolishes the inhibitory effect of the thymus.

3. Addition of a small quantity of iodothyrin leads rapidly to precocious metamorphosis of thymus-fed larvæ.

4. The inhibitory effect of the thymus is not due to a specific inhibiting substance in the thymus, but to the absence from the thymus of a substance required to develop the thyroid to the secretory state.
AMPHOTERIC COLLOIDS
Authors: Loeb Jacques
Published: May 2004

1. The method of removing the excess of hydrobromic acid after it has had a chance to react chemically with gelatin has permitted us to measure the amount of Br in combination with the gelatin. It is shown that the curves representing the amount of bromine bound by the gelatin are approximately parallel with the curves for the osmotic pressure, the viscosity, and swelling of the gelatin solution. This proves that the curves for osmotic pressure are an unequivocal function of the number of gelatin bromide molecules formed under the influence of the acid. The cc. of 0.01 N Br in combination with 0.25 gm, of gelatin we call the bromine number.

2. The explanation of this influence of the acid on the physical properties of gelatin is based on the fact that gelatin is an amphoteric electrolyte, which at its isoelectric point is but sparingly soluble in water, while its transformation into a salt with a univalent anion like gelatin Br makes it soluble. The curve for the bromine number thus becomes at the same time the numerical expression for the number of gelatin molecules rendered soluble, and hence the curve for osmotic pressure must of necessity be parallel to the curve for the bromine number.

3. Volumetric analysis shows that gelatin treated previously with HBr is free from Br at the isoelectric point as well as on the more alkaline side from the isoelectric point (pH ≧ 4.7) of gelatin. This is in harmony with the fact that gelatin (like any other amphoteric electrolyte) can dissociate on the alkaline side of its isoelectric point only as an anion. On the more acid side from the isoelectric point gelatin is found to be in combination with Br and the Br number rises with the pH.

4. When we titrate gelatin, treated previously with HBr but possessing a pH = 4,7, with NaOH we find that 25 cc. of a 1 per cent solution of isoelectric gelatin require about 5.25 to 5.5 cc. of 0.01 N NaOH for neutralization (with phenolphthalein as an indicator). This value which was found invariably is therefore a constant which we designate as "NaOH (isoelectric)." When we titrate 0.25 gm. of gelatin previously treated with HBr but possessing a pH < 4.7 more than 5.5 cc. of 0.01 N NaOH are required for neutralization. We will designate this value of NaOH as "(NaOH)n," where n represents the value of pH. If we designate the bromine number for the same pH as "Brn" then we can show that the following equation is generally true: (NaOH)n = NaOH (isoelectric) + Brn. In other words, titration with NaOH of gelatin (previously treated with HBr) and being on the acid side of its isoelectric point results in the neutralization of the pure gelatin (NaOH isoelectric) with NaOH and besides in the neutralization of the HBr in combination with the gelatin. This HBr is set free as soon as through the addition of the NaOH the pH of the gelatin solution becomes equal to 4.7.

5. A comparison between the pH values and the bromine numbers found shows that over 90 per cent of the bromine or HBr found was in our experiments in combination with the gelatin.
A COMPARISON OF PERMEABILITY IN PLANT AND ANIMAL CELLS
Authors: Osterhout W. J. V.
Published: May 2004

Quantitative studies show a striking agreement between frog skin and plant tissues in respect to certain important aspects of permeability, antagonism, injury, recovery, and death.
THE RELATION BETWEEN THE OXYGEN CONCENTRATION AND RATE OF REDUCTION OF METHYLENE BLUE BY MILK
Authors: Harvey E. Newton
Published: May 2004

The rate of reduction of methylene blue by milk and acetaldehyde is proportional to the concentration of oxygen in the milk. This fact may be made the basis of a method of determining oxygen in gaseous mixtures.
INFLUENCE OF TEMPERATURE AND HYDROGEN ION CONCENTRATION UPON THE SPORE CYCLE OF BACILLUS SUBTILIS
Authors: Itano Arao , Neill James
Published: May 2004

1. At 5°C. no germination took place.

2. At 25°C. and at 37°C. germination occurs if the hydrogen ion concentration of the broth is kept between pH 5 and pH 10, but not at higher or lower pH values.

3. The completion of the spore cycle likewise requires a hydrogen ion concentration between pH 5 and pH 10.

4. The spores can germinate when the pH value is 10, although after germination the vegetative cells multiply only to a very slight extent and soon pass into spores.

5. The slight growth and multiplication of vegetative cells in broth of pH 10 suggest that the formation of endospores in this medium must be caused largely by the unfavorable reaction of the medium rather than by the accumulation of metabolic products.

6. Automatic adjustment of the medium seems to play a rôle in the completion of the spore cycle.

7. The results are not only of theoretical importance but they have a practical application to the preservation of food by canning and by other methods.
PHOTOREACTIONS OF PARTIALLY BLINDED WHIP-TAIL SCORPIONS
Authors: Patten Bradley M.
Published: May 2004

The experiments dealt with in this paper were devised to ascertain (1) the relative effectiveness as photoreceptors of the whip-tail scorpion's median eyes, lateral eye groups, and cutaneous sensitive areas, and (2) the effect on orientation produced by symmetrical and by asymmetrical interference with the photoreceptive mechanism.

Each of the receptors was eliminated unilaterally and bilaterally, singly and in combinations with other receptors. In all, sixteen different abnormal conditions of the photoreceptive apparatus were produced.

The reactions of animals thus partially blinded were measured in terms of angular deflection from an initial path of locomotion. Measurements obtained under anterior, lateral, and bilaterally balanced illumination were compared with measurements made on normal animals under the same conditions of illumination. The change from the normal reaction induced by covering a photoreceptor was taken as an index of the effectiveness of the receptor prevented from functioning.

By comparing the values of the changes from normal reactions produced by the elimination of the several receptors, their relative effectiveness is approximated as median eyes : lateral eyes : cutaneous sensitive areas :: 1:1.6:2.2.

All animals in which the receptive mechanism was rendered functionally asymmetrical exhibited, when subJected to bilaterally balanced illumination, deflections toward the side which had been made less sensitive. In a series of measurements made on animals in ten different conditions of asymmetry the amplitudes of the deflections were proportional to the degree of unbalance which had been produced in the photosensitive mechanism.

Animals in which the receptive mechanism was reduced but left in a symmetrical condition maintained an undisturbed balance of reaction when subjected to equal, opposed lights. Under lateral or anterior illumination the rate of attaining a new direction of orientation was reduced in proportion to the extent of the interference with the receptive mechanism.

The reactions of symmetrically and asymmetrically blinded scorpions indicate that orientation is attained and maintained by a transmission of impulses to the muscles of locomotion which is proportional bilaterally to the excitation of the symmetrically located photoreceptors.

In their effect on orientation the three pairs of receptors are completely coordinated. Orientation depends upon bringing the excitation of the receptive mechanism as a whole into bilateral equilibrium.
A STUDY OF THE ACTION OF ACID AND ALKALI ON GLUTEN
Authors: Henderson L. J. , Cohn Edwin J. , Cathcart P. H. , Wachman J. D. , Fenn W. O.
Published: May 2004

In this paper there are reported studies of the acid-base equilibrium in systems containing gluten suspended in solution of hydrochloric acid and sodium hydroxide. The studies have involved measurements of the hydrogen ion concentration, of the electrical conductivity, and of the solution of the proteins. Further, measurements have been made of the swelling and of the viscosity of the gluten component of such systems.

The results seem to show that simple chemical phenomena are most important in such systems, and that the modifications of these, resulting from colloidal and heterogeneous characteristics, are of secondary importance in determining the condition of equilibrium, though somewhat more significant in the progress of the system toward the condition of equilibrium.
RELATION BETWEEN METAMORPHOSIS AND OTHER DEVELOPMENTAL PHENOMENA IN AMPHIBIANS
Authors: Uhlenhuth Eduard
Published: May 2004

1. The difference in time existing between the first shedding of the skin and the reduction of the gills to mere stubs without fringes is constant and unchangeable, which indicates that the fundamental cause for both is a common one.

2. This common cause is the action of iodine, and consequently both phenomena constitute, or at least are part of, the metamorphosis of the salamanders.

3. The development of the adult skin coloration and of the legs may take place either before or after metamorphosis. Iodine cannot enforce either of these phenomena.

4. The same is true of the development of the sex organs.

5. Development of the tongue and palatal teeth can be checked even in animals in which metamorphosis takes place.

6. Consequently development of the skin coloration, as well as development of the legs, sex organs, tongue, and palatal teeth are all caused by substances not identical with the substances causing metamorphosis and, since they are also all independent of each other in their development, it is probable that special chemical mechanisms exist for the development of each one of these six groups of organs.

7. This assumption is also supported by the fact that the order of development in several of these organ pairs can be changed by a difference in temperature, which would indicate that the development of each of these groups of organs is caused by chemical reactions with different temperature coefficients.

8. That the germ cells can develop in amphibians either before or after metamorphosis does not mean that the germ plasma is opposed as a unit to the somatic plasma, since other organs which are believed to be part of the somatic plasma behave in this respect like the germ cells.

9. The noteworthy feature of the amphibian metamorphosis is that instead of being controlled and kept in harmony by the organic individual the development of at least six groups of organs is controlled separately by the action of probably six different chemical mechanisms, each of which can be stopped or enforced independently either by directly supplying the substances required or by causing an increased formation within the body by suitable temperatures.
SENSORY EQUILIBRIUM AND DARK ADAPTATION IN MYA ARENARIA
Authors: Hecht Selig
Published: May 2004

1. The reaction time of Mya to light is composed of two parts. The first, a sensitization period, is an exceedingly short interval of the order of magnitude associated with photographic processes. The second is a latent period of about 1.3 seconds, during which Mya need not remain exposed to the stimulating light.

2. The process of dark adaptation in Mya is orderly. Its progress may be represented by the formation of a photosensitive substance according to the dynamics of a bimolecular reaction.

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3. Photosensory equilibrium as represented by the light- and dark-adapted conditions finds a rational explanation in terms of the "stationary state" of a reversible photochemical reaction involving a photosensitive substance and its two precursors.

4. There are two corollaries to this hypothesis. The first requires that the reaction time at sensory equilibrium for a given intensity should vary inversely with the temperature; the second, that the rate of dark adaptation should vary directly with the temperature. Experiments verified both of these requirements.
IODINE AND THE THYROID
Authors: Swingle W. W.
Published: May 2004

1. Amphibian metamorphosis depends upon the amount of iodine secured by the larvæ; the greater the quantity the more rapid the differentiation.

2. Bromine is physiologically inert when fed even in large quantities to frog larvæ, hence it cannot be substituted for iodine. Bromine feeding has no effect on the thyroid.

3. Iodine is the active constituent of the thyroid gland, in the Anura at any rate, and functions within the body by stimulating intracellular oxidations; it is apparently specific in its action.

4. The basal metabolism of patients suffering from athyreosis, whose metabolism is 40 per cent below normal, is very likely held at this figure and prevented from sinking lower to the death point by the introduction of iodine into the body through food and water.

5. The thyroid gland is an organ the function of which is the extraction from the circulation, storage, and supplying to the organism, under the pressure of its needs, the small quantities of iodine taken into the body. The chief function of this gland then is the utilization of iodine in small quantities.
THE EFFECT OF VARIOUS ACIDS ON THE DIGESTION OF PROTEINS BY PEPSIN
Authors: Northrop J. H.
Published: May 2004

1. At equal hydrogen ion concentration the rate of pepsin digestion of gelatin, egg albumin, blood albumin, casein, and edestin is the same in solutions of hydrochloric, nitric, sulfuric, oxalic, citric, and phosphoric acids. Acetic acid diminishes the rate of digestion of all the proteins except gelatin.

2. There is no evidence of antagonistic salt action in the effect of acids on the pepsin digestion of proteins.

3. The state of aggregation of the protein, i.e. whether in solution or not, and the viscosity of the solution have no marked influence on the rate of digestion of the protein.
VERMILION-DEFICIENCY
Authors: Bridges Calvin B.
Published: May 2004

In May, 1916, a culture of Drosophila melanogaster showed that a new sex-linked lethal had arisen. The linkage relations indicated that the position of the lethal was in the neighborhood of the sex-linked recessive "vermilion," whose locus in the X chromosome is at 33.0. When females heterozygous for the lethal were outcrossed to vermilion males, all the daughters that received the lethal-bearing chromosome showed vermilion eye-color, though, from the pedigree, vermilion was known to be absent from the ancestry of the mother. The lethal action and the unexpected appearance of vermilion both suggested that this was another instance of the phenomenon called "deficiency;" that is, the loss or "inactivation" of the genes of a section of the X chromosome. The lethal action would then be due to the deficient region including one or more genes necessary for the life of the individual. The appearance of vermilion in females carrying only one vermilion gene would be explainable on the ground that the deficient-bearing females are virtually haploid for the region including the vermilion locus. Linkage tests showed that the amount of crossing over in the neighborhood of the deficiency was cut down by about five units. Part of this may be attributed to the actual length of the "deficient" region, within which it is probable that no crossing over occurs, and part (probably most) to an alteration in the synaptic relations in the regions immediately adjacent. In more remote regions there was no disturbance or perhaps a slight rise in the frequency of crossing over. Both the local fall and the possible rise in more distant regions would seem to argue that a "pucker" at synapsis had been caused by an actual shortening of the deficient chromosome. That the deficient region extends to the left of the locus of vermilion was indicated by a test in which it was observed that the presence of an extra piece of chromosome including the loci for vermilion and sable ("vermilion-sable duplication") did not neutralize the lethal action of the deficiency. Haploid tests with the other recessive mutations in the neighborhood of vermilion showed that the deficiency was not extensive enough to include their loci. Cytological preparations were made but were unsatisfactory. The stock was finally lost, apparently as the result of injurious action upon viability, fertility, and productivity by the deficiency.
THE INFLUENCE OF ELECTROLYTES ON THE ELECTRIFICATION AND THE RATE OF DIFFUSION OF WATER THROUGH COLLODION MEMBRANES
Authors: Loeb Jacques
Published: May 2004

1. When pure water is separated by a collodion membrane from a watery solution of an electrolyte the rate of diffusion of water is influenced not only by the forces of gas pressure but also by electrical forces.

2. Water is in this case attracted by the solute as if the molecules of water were charged electrically, the sign of the charge of the water particles as well as the strength of the attractive force finding expression in the following two rules, (a) Solutions of neutral salts possessing a univalent or bivalent cation influence the rate of diffusion of water through a collodion membrane, as if the water particles were charged positively and were attracted by the anion and repelled by the cation of the electrolyte; the attractive and repulsive action increasing with the number of charges of the ion and diminishing inversely with a quantity which we will designate arbitrarily as the "radius" of the ion. The same rule applies to solutions of alkalies. (b) Solutions of neutral or acid salts possessing a trivalent or tetravalent cation influence the rate of diffusion of water through a collodion membrane as if the particles of water were charged negatively and were attracted by the cation and repelled by the anion of the electrolyte. Solutions of acids obey the same rule, the high electrostatic effect of the hydrogen ion being probably due to its small "ionic radius."

3. The correctness of the assumption made in these rules concerning the sign of the charge of the water particles is proved by experiments on electrical osmose.

4. A method is given by which the strength of the attractive electric force of electrolytes on the molecules of water can be roughly estimated and the results of these measurements are in agreement with the two rules.

5. The electric attraction of water caused by the electrolyte increases with an increase in the concentration of the electrolyte, but at low concentrations more rapidly than at high concentrations. A tentative explanation for this phenomenon is offered.

6. The rate of diffusion of an electrolyte from a solution to pure solvent through a collodion membrane seems to obey largely the kinetic theory inasmuch as the number of molecules of solute diffusing through the unit of area of the membrane in unit time is (as long as the concentration is not too low) approximately proportional to the concentration of the electrolyte and is the same for the same concentrations of LiCl, NaCl, MgCl2, and CaCl2.
TEMPERATURE CHARACTERISTICS FOR DURATION OF AN INSTAR IN CLADOCERANS
Authors: Brown L. A.
Published: May 2004

1. The temperature characteristics for the rate of development during a well defined instar were determined for three species of Cladocera, and found to be of the same general magnitudes as those obtained for rates of development and of O2 consumption in other arthropods.

2. Critical temperatures were found to occur at points most frequently critical in quite diverse vital phenomena as determined by abrupt changes in the relationship between rate and temperature.

3. A suggestion is made that, since the values of µ and the positions of critical temperatures obtained for the different species are not the same, some relation may exist between the occurrence of these forms in nature and their relative rates of development as controlled by temperatures.
STEREOTROPISM IN RATS AND MICE
Authors: Crozier W. J. , Pincus G.
Published: May 2004

Typical stereotropic orientation toward a lateral surface of contact is obtained in young rats and mice, and with adult mice congenitally blind. Removal of vibrissæ or tail or both does not essentially affect this response.

Equal contact on both sides of the body prevents orientation toward either source of contact. Unequal contact areas on the two sides leads to orientation toward the more extensive contact.

This behavior very exactly parallels the stereotropic conduct of arthropods, and thus provides a fairly complete instance of a tropism in mammals.
INTERPRETATION OF THE LACTATION CURVE
Authors: Gaines W. L.
Published: May 2004

The validity of the assumption of a substance determining the rate of milk secretion and undergoing monomolecular destruction, based on group behavior, is questioned on the evidence from a large number of individual lactation curves. It seems probable that the rate of decrease in the rate of milk secretion with advance in lactation is dependent upon factors of a nutritional nature.
RATE OF RESPIRATION AS RELATED TO AGE
Authors: Hover J. Milton , Gustafson Felix G.
Published: May 2004

In the present paper it is shown that as the leaves of corn, sorghum, wheat, and oats increase in age there is a decrease in rate of respiration; but that as the leaves become still older (past about middle age) the rate gradually increases.