MICRURGICAL STUDIES IN CELL PHYSIOLOGY : I. THE ACTION OF THE CHLORIDES OF NA,K, CA,AND MG ON THE PROTOPLASM OF AM?BA PROTEUS.

By means of micro-dissection and injection Amœba proteus was treated with the chlorides of Na, K, Ca, and Mg alone, in combination, and with variations of pH. I. The Plasmalemma. 1. NaCl weakens and disrupts the surface membrane of the ameba. Tearing the membrane accelerates the disruption which spreads rapidly from the site of the tear. KCl has no disruptive effect on the membrane but renders it adhesive. 2. MgCl₂ and CaCl₂ have no appreciable effect on the integrity of the surface membrane of the ameba when applied on the outside. No spread of disruption occurs when the membrane is torn in these salts. When these salts are introduced into the ameba they render the pellicle of the involved region rigid. II. The Internal Protoplasm. 3. Injected water either diffuses through the protoplasm or becomes localized in a hyaline blister. Large amounts when rapidly injected produce a \"rushing effect\". 4. HCl at pH 1.8 solidifies the internal protoplasm and at pH 2.2 causes solidification only after several successive injections. The effect of the subsequent injections may be due to the neutralization of the cell-buffers by the first injection. 5. NaCl and KCl increase the fluidity of the internal protoplasm and induce quiescence. 6. CaCl₂ and MgCl₂ to a lesser extent solidify the internal protoplasm. With CaCl₂ the solidification tends to be localized. With MgCl₂ it tends to spread. The injection of CaCl₂ accelerates movement in the regions not solidified whereas the injection of MgCl₂ induces quiescence. III. Pinching-Off Reaction. 7. A hyaline blister produced by the injection of water may be pinched off. The pinched-off blister is a liquid sphere surrounded by a pellicle. 8. Pinching off always takes place with injections of HCl when the injected region is solidified. 9. The injection of CaCl₂ usually results in the pinching off of the portion solidified. The rate of pinching off varies with the concentration of the salt. The injection of MgCl₂ does not cause pinching off. IV. Reparability of Torn Surfaces. 10. The repair of a torn surface takes place readily in distilled water. In the different salt solutions, reparability varies specifically with each salt, with the concentration of the salt, and with the extent of the tear. In NaCl and in KCl repair occurs less readily than in water. In MgCl₂ repair takes place with great difficulty. In CaCl₂ a proper estimate of the process of repair is complicated by the pinching-off phenomenon. However, CaCl₂ is the only salt found to increase the mobility of the plasmalemma, and this presumably enhances its reparability. 11. The repair of the surface is probably a function of the internal protoplasm and depends upon an interaction of the protoplasm with the surrounding medium. V. Permeability. 12. NaCl and KCl readily penetrate the ameba from the exterior. CaCl₂ and MgCl₂ do not. 13. All four salts when injected into an ameba readily diffuse through the internal protoplasm. In the case of CaCl₂ the diffusion may be arrested by the pinching-off process. VI. Toxicity. 14. NaCl and KCl are more toxic to the exterior of the cell than to the interior, and the reverse is true for CaCl₂ and MgCl₂. 15. The relative non-toxicity of injected NaCl to the interior of the ameba is not necessarily due to its diffusion outward from the cell. 16. HCl is much more toxic to the exterior of a cell than to the interior; at pH 5.5 it is toxic to the surface whereas at pH 2.5 it is not toxic to the interior. NaOH to pH 9.8 is not toxic either to the surface or to the interior. VII. Antagonism. 17. The toxic effects of NaCl and of KCl on the exterior of the cell can be antagonized by CaCl₂ and this antagonism occurs at the surface. Although the lethal effect of NaCl is thus antagonized, NaCl still penetrates but at a slower rate than if the ameba were immersed in a solution of this salt alone. 18. NaCl and HCl are mutually antagonistic in the interior of the ameba. No antagonism between the salts and HCl was found on the exterior of the ameba. No antagonism between the salts and NaOH was found on the interior or exterior of the ameba. 19. The pinching-off phenomenon can be antagonized by NaCl or by KCl, and the rate of the retardation of the pinching-off process varies with the concentration of the antagonizing salt. 20. The prevention of repair of a torn membrane by toxic solutions of NaCl or KCl can be antagonized by CaCl₂. These experiments show directly the marked difference between the interior and the exterior of the cell in their behavior toward the chlorides of Na, K, Ca, and Mg.     

MICRURGICAL STUDIES IN CELL PHYSIOLOGY : III. THE ACTION OF CO2AND SOME SALTS OF NA,CA, AND K ON THE PROTOPLASM OF AM?BA DUBIA.

I. Plasmalemma. 1. Of the salts used in these experiments the anions have only a modifying effect on the cations. The dispersive action of Na and, to a lesser extent, of K, predominates. Borate increases the toxicity of Na and acetate decreases it. 2. CO₂ and carbonates dissolve the plasmalemma readily. 3. Na lactate tends to dissolve the surface especially when brought into contact with it from the interior by injection. Lactate antagonizes the stimulating effect of Ca on the plasmalemma. II. The Internal Protoplasm. 4. Acid phosphate of Na and K, when injected, causes a membrane to form around the granular endoplasm within the ameba. 5. Na borate increases the toxicity of Na inside the cell. 6. Bubbles of CO₂, injected into the cell, cause an increase of fluidity of the internal protoplasm. These bubbles shrink and disappear from the cell more readily than air bubbles. 7. The anions modify the typical cation effect. Carbonates accentuate the liquefying and solvent action of Na. Phosphates prevent a complete rounding of the ameba caused by Na. Lactate inhibits the solidification and pinching off effect caused by Ca. III. Physiological Significance of Salts. 8. The buffer salts can be injected in high concentrations without toxic effects but amebæ can be immersed in them only in very dilute solutions without injury. 9. The inhibiting action of lactate and the dispersive effect of CO₂, carbonates, and lactate on the plasma membrane, must be of importance in a consideration of the functions of the organism and perhaps in the production of pathological changes.     

MICRURGICAL STUDIES IN CELL PHYSIOLOGY : II. THE ACTION OF THE CHLORIDES OF LEAD,MERCURY, COPPER,IRON, AND ALUMINUM ON THE PROTOPLASM OF AM?BA PROTEUS.

I. Plasmalemma. 1. The order of toxicity of the salts used in these experiments on the surface membrane of a cell, taking as a criterion viability of amebæ immersed in solutions for 1 day, is HgCl₂, FeCl₃> AlCl₃> CuCl₂> PbCl₂> FeCl₂. Using viability for 5 days as a criterion, the order of toxicity is PbCl₂> CuCl₂> HgCl₂> AlCl₃> FeCl₃> FeCl₂. 2. The rate of toxicity is in the order FeCl₃> HgCl₂> AlCl₃> FeCl₂> CuCl₂> PbCl₂. 3. The ability of amebæ to recover from a marked tear of the plasmalemma in the solutions of the salts occurred in the following order: AlCl₃> PbCl₂> FeCl₂> CuCl₂> FeCl₃> HgCl₂. II. Internal Protoplasm. 4. The relative toxicity of the salts on the internal protoplasm, judged by the recovery of the amebæ from large injections and the range over which these salts can cause coagulation of the internal protoplasm, is in the following order: PbCl₂> CuCl₂> FeCl₃> HgCl₂> FeCl₂> AlCl₃. 5. AlCl₃ in concentrations between M/32 and M/250 causes a marked temporary enlargement of the contractile vacuole. FeCl₂, FeCl₃, and CuCl₃ produce a slight enlargement of the vacuole. 6. PbCl₂, in concentrations used in these experiments, appears to form a different type of combination with the internal protoplasm than do the other salts. III. Permeability. 7. Using the similarity in appearance of the internal protoplasm after injection and after immersion to indicate that the surface is permeable to a substance in which the ameba is immersed, it is concluded that AlCl₃ can easily penetrate the intact plasmalemma. CuCl₂ also seems to have some penetrating power. None of the other salts studied give visible internal evidence of penetrability into the ameba. IV. Toxicity. 8. The toxic action of the chlorides of the heavy metals used in these experiments, and of aluminum, is exerted principally upon the surface of the cell and is due not only to the action of the metal cation but also to acid which is produced by hydrolysis.     

STUDIES ON BLOOD COAGULATION : I. THE R?LE OF PROTHROMBIN AND OF PLATELETS IN THE FORMATION OF THROMBIN

1. A method is described for the preparation and titration of prothrombin and thrombin. 2. Confirming the views of Morawitz, Howell (1916–17, 1925), and Bordet, thrombin cannot be regarded as an artificial by-product of coagulation (Wooldridge, Nolf (both quoted from Morawitz)). Calcium, a platelet factor, and a plasma factor (prothrombin) interact to form thrombin, and this then acts upon fibrinogen to form fibrin. The amount and rate of thrombin formation in the first reaction are independent of the presence or absence of fibrinogen. After a variable latent period, thrombin suddenly appears in large quantities, coincident with or immediately preceding the deposition of fibrin if fibrinogen is present. 3. The amount of thrombin formed in a mixture of prothrombin, Ca and platelets is independent of the platelet or Ca concentration, and depends primarily upon the amount of prothrombin used. The platelets (or cephalin) enormously accelerate the transformation of prothrombin to thrombin, and this acceleration seems to be their physiological rôle in the coagulation process. 4. Contrary to previous reports, platelets have not been demonstrated to contain significant quantities of prothrombin. 5. The available data do not allow any definite decision as to whether the platelet factor actually combines with prothrombin to form thrombin, or merely catalyzes the transformation. The very slow formation of thrombin in the complete absence of platelets may be due to dissolved traces of platelet material released during the physical manipulation of the plasma (centrifuging, Berkefeld filtration). 6. There was no evidence for a species-specific activity of platelets in the transformation of prothrombin to thrombin.     

TAXONOMY, MYCOGEOGRAPHY AND ECTO-MYCORRHIZAL ASSOCIATION OF THE BOLETALES FROM CHINA Ⅰ. FAMILY STROBILOMYCETACEAE

TAXoNOMYSPeciesintheorderBoIetalesisusual1yrnycorrhizalandsaprobic,occasionallyhyperpansihc,mostareedjble,afewpoisonous.ThebasidiocarPsarefleshy,readi1ydecay,withtubularhymenoPhore.CommoulyareaccePted2driilies:inthebolyStrobi1omycetaceae,thesporesareomamentedwithsuperficialsculptUring,orperforate-punctate,oulynalysmoothwhenyoung.InthebolyBoletaCeae,thesporesarealwnyssmooth,onlyrarelyroughinmature.FamilyStrobilomycetaceaeKeytothegeneral.Hymenophorewhite,pallidorgrayishwhenyoung,becoming…     

NOTE ON THE EXCITATION AND INHIBITION OF LUMINESCENCE IN BER?

1. The ions of Ca and K condition general luminescence, and are therefore necessary to the conduction of the impulse. 2. In van''t Hoff''s solution from which Mg is omitted, Berœ shows hyperirritability with respect to luminescence. This is the result of the action of Ca and K ions unantagonized by Mg. 3. The luminescent material spread on filter paper does not show luminescence in sea water, NaCl, MgCl₂, or saccharose solutions isotonic with sea water. In solutions of CaCl₂, SrCl₂, BaCl₂, KCl, and K₂SO₄ the indicator paper glows with a bright luminescence. 4. In dark adapted Berœ, luminescence is inhibited by a certain quantity of light. This quantity has an average value of 57,285 meter-candle-minutes, which is twelve times the value given by Mnemiopsis.     

THE SYNTHESIS OF,AND STUDIES ON, 2′-C-MODIFIED NUCLEOTIDES

The synthesis of uridine monomers containing either a 2′-deoxy-2′-C-methy- lcyano or ethylcyano group is described. These monomers are intended for incorporation into oligonucleotides to investigate a proposed duplex-stabilising effect exerted by 2′-tethered amide groups.