THE RELATIONS OF TEMPERATURE TO THE POTASSIUM EFFECT AND THE BIOELECTRIC POTENTIAL OF VALONIA

The effect of temperature upon the bioelectric potential across the protoplasm of impaled Valonia cells is described. Over the ordinary tolerated range, the P.D. is lowest around 25°C., rising both toward 15° and 35°. The time curves are characteristic also. The magnitude of the temperature effect can be controlled by changing the KCl content of the sea water (normally 0.012 M): the magnitude is greatly reduced at 0.006 M KCl, enhanced at 0.024 M, and greatly exaggerated at 0.1 M KCl. Conversely, temperature controls the magnitude of the potassium effect, which is smallest at 25°, with a cusped time course. It is increased, with a smoothly rising course, at 15°, and considerably enhanced, with only a small cusp, at 35°. A temporary "alteration" of the protoplasmic surface by the potassium is suggested to account for the time courses. This alteration does not occur at 15°; the protoplasm recovers only slowly and incompletely at 25°, but rapidly at 35°, in such fashion as to make the P.D. more negative than at 15°. This would account for the temperature effects observed in ordinary sea water.     

THE VARIATION OF ELECTRICAL RESISTANCE WITH APPLIED POTENTIAL : III. IMPALED VALONIA VENTRICOSA

Electrical resistance and polarization were measured during the passage of direct current across a single layer of protoplasm in the cells of Valonia ventricosa impaled upon capillaries. These were correlated with five stages of the P.D. existing naturally across the protoplasm, as follows: 1. A stage of shock after impalement, when the P.D. drops from 5 mv. to zero and then slowly recovers. There is very little effective resistance in the protoplasm, and polarization is slight. 2. The stage of recovery and normal P.D., with values from 8 to 25 mv. (inside positive). The average is 15 mv. At first there is little or no polarization when small potentials are applied in either direction across the protoplasm, nor when very large currents pass outward (from sap to sea water). But when the positive current passes inward there is a sudden response at a critical applied potential ranging from 0.5 to 2.0 volts. The resistance then apparently rises as much as 10,000 ohms in some cases, and the rise occurs more quickly in succeeding applications after the first. When the potential is removed there is a back E.M.F. displayed. Later there is also an effect of such inward currents which persists into the first succeeding outward flow, causing a brief polarization at the first application of the reverse potential. Still later this polarization occurs at every exposure, and at increasingly lower values of applied potentials. Finally there is a "constant" state reached in which the polarization occurs with currents of either direction, and the apparent resistance is nearly uniform over a considerable range of applied potential. 3. A state of increased P.D.; to 100 mv. (inside positive) in artificial sap; and to 35 or 40 mv. in dilute sea water or 0.6 M MgSO₄. The polarization response and apparent resistance are at first about as in sea water, but later decrease. 4. A reversed P.D., to 50 mv. (outside positive) produced by a variety of causes, especially by dilute sea water, and also by large flows of current in either direction. This stage is temporary and the cells promptly recover from it. While it persists the polarization appears to be much greater to outward currents than to inward. This can largely be ascribed to the reduction of the reversed P.D. 5. Disappearance of P.D. caused by death, and various toxic agents. The resistance and polarization of the protoplasm are negligible. The back E.M.F. of polarization is shown to account largely for the apparent resistance of the protoplasm. Its calculation from the observed resistance rises gives values up to 150 mv. in the early stages of recovery, and later values of 50 to 75 mv. in the "constant" state. These are compared with the back E.M.F. similarly calculated from the apparent resistance of intact cells. The electrical capacitance of the protoplasm is shown by the time curves to be of the order of 1 microfarad per cm.² of surface.     

THE EFFECTS OF CURRENT FLOW ON BIOELECTRIC POTENTIAL : I. VALONIA

The effect of direct current flow upon the potential difference across the protoplasm of impaled Valonia cells was studied. Current density and direction were controlled in a bridge which balanced the ohmic resistances, leaving the changes (increase, decrease, or reversal) of the small, normally negative, bioelectric potential to be recorded continuously, before, during, and after current flow, with a string galvanometer connected into a vacuum tube detector circuit. Two chief states of response were distinguished: State A.—Regular polarization, which begins to build up the instant current starts to flow, the counter E.M.F. increasing most rapidly at that moment, then more and more slowly, and finally reaching a constant value within 1 second or less. The magnitude of counter E.M.F. is proportional to the current density with small currents flowing in either direction across the protoplasm, but falls off at higher density, giving a cusp with recession to lower values; this recession occurs with slightly lower currents outward than inward. Otherwise the curves are much the same for inward and outward currents, for different densities, for charge and discharge, and for successive current flows. There is a slight tendency for the bioelectric potential to become temporarily positive following these current flows. Records in the regular state (State A) show very little effect of increased series resistance on the time constant of counter E.M.F. This seems to indicate that a polarization rather than a static capacity is involved. State B.—Delayed and non-proportional polarization, in which there is no counter E.M.F. developed with small currents in either direction across the protoplasm, nor with very large outward currents. But with inward currents a threshold density is reached at which a counter E.M.F. rather suddenly develops, with a sigmoid curve rising to high positive values (200 mv. or more). There is sometimes a cusp, after which the P.D. remains strongly positive as long as the current flows. It falls off again to negative values on cessation of current flow, more rapidly after short flows, more slowly after longer ones. The curves of charge are usually quite different in shape from those of discharge. Successive current flows of threshold density in rapid succession produce quicker and quicker polarizations, the inflection of the curve often becoming smoothed away. After long interruptions, however, the sigmoid curve reappears. Larger inward currents produce relatively little additional positive P.D.; smaller ones on the other hand, if following soon after, have a greatly increased effectiveness, the threshold for polarization falling considerably. The effect dies away, however, with very small inward currents, even as they continue to flow. Over a medium range of densities, small increments or decrements of continuing inward current produce almost as regular polarizations as in State A. Temporary polarization occurs with outward currents following soon after the threshold inward currents, but the very flow of outward current tends to destroy this, and to decondition the protoplasm, again raising the threshold, for succeeding inward flows. State A is characteristic of a few freshly gathered cells and of most of those which have recovered from injuries of collecting, cleaning, and separating. It persists a short time after such cells are impaled, but usually changes over to State B for a considerable period thereafter. Eventually there is a reappearance of regular polarization; in the transition there is a marked tendency for positive P.D. to be produced after current flow, and during this the polarizations to outward currents may become much larger than those to inward currents. In this it resembles the effects of acidified sea water, and of certain phenolic compounds, e.g. p-cresol, which produce State A in cells previously in State B. Ammonia on the other hand counteracts these effects, producing delayed polarization to an exaggerated extent. Large polarizations persist when the cells are exposed to potassium-rich solutions, showing it is not the motion of potassium ions (e.g. from the sap) which accounts for the loss or restoration of polarization. It is suggested that inward currents restore a protoplasmic surface responsible for polarization by increasing acidity, while outward currents alter it by increasing alkalinity. Possibly this is by esterification or saponification respectively of a fatty film. For comparison, records of delayed polarization in silver-silver chloride electrodes are included.     

THE ORIGIN OF THE POTENTIAL DIFFERENCES RESPONSIBLE FOR ANOMALOUS OSMOSIS

1. Collodion bags coated with gelatin on the inside were filled with a M/256 solution of neutral salt (e.g., NaCl, CaCl₂, CeCl₃, or Na₂SO₄) made up in various concentrations of HNO₃ (varying from N/50,000 to N/100). Each collodion bag was put into an HNO₃ solution of the same concentration as that inside the bag but containing no salt. In this case water diffuses from the outside solution (containing no salt) into the inside solution (containing the salt) with a relative initial velocity which can be expressed by the following rules: (a) Water diffuses into the salt solution as if the particles of water were negatively charged and as if they were attracted by the cation and repelled by the anion of the salt with a force increasing with the valency of the ion. (b) The initial rate of the diffusion of water is a minimum at the hydrogen ion concentration of about N/50,000 HCl (pH 4.7, which is the point at which gelatin is not ionized), rises with increasing hydrogen ion concentration until it reaches a maximum and then diminishes again with a further rise in the initial hydrogen ion concentration. 2. The potential differences between the salt solution and the outside solution (originally free from salt) were measured after the diffusion had been going on for 1 hour; and when these values were plotted as ordinates over the original pH as abscissae, the curves obtained were found to be similar to the osmotic rate curves. This confirms the view expressed by Girard) Bernstein, Bartell, and Freundlich that these cases of anomalous osmosis are in reality cases of electrical endosmose where the driving force is a P.D. between the opposite sides of the membrane. 3. The question arose as to the origin of these P. D. and it was found that the P.D. has apparently a double origin. Certain features of the P.D. curve, such as the rise and fall with varying pH, seem to be the consequence of a Donnan equilibrium which leads to some of the free HNO₃ being forced from the solution containing salt into the outside solution containing no (or less) salt. This difference of the concentration of HNO₃, on the opposite sides of the membrane leads to a P.D. which in conformity with Nernst''s theory of concentration cells should be equal to 58 x (pH inside minus pH outside) millivolts at 18°C. The curves of the values of (pH inside minus pH outside) when plotted as ordinates over the original pH as abscissae lead to curves resembling those for the P. D. in regard to location of minimum and maximum. 4. A second source of the P.D. seems to be diffusion potentials, which exist even if no membranes are present and which seem to be responsible for the fact that the rate of diffusion of negatively charged water into the salt solution increases with the valency of the cation and diminishes with the valency of the anion of the salt. 5. The experiments suggest the possibility that the establishment of a Donnan equilibrium between membrane and solution is one of the factors determining the Helmholtzian electrical double layer, at least in the conditions of our experiments.     

BIOELECTRIC POTENTIALS IN VALONIA : II. EFFECTS OF ARTIFICIAL SEA WATERS CONTAINING LiCl,CsCl, RbCl,OR NH4Cl

In their influence on the P.D. across the protoplasm of Valonia macrophysa, Kütz., Li⁺ and Cs⁺ resemble Na⁺, while Rb⁺ and NH₄ ⁺ resemble K⁺. The apparent mobilities of the ions in the external surface layer of Valonia protoplasm increase in the order: Cs⁺, Na⁺, Li⁺ < Cl^- < Rb⁺ < K⁺ < NH₄ ⁺.     

CHANGES OF THE MEMBRANE POTENTIAL AT THE TIME OF FERTILIZATION IN THE SEA URCHIN EGG WITH SPECIAL REFERENCE TO THE FERTILIZATION-WAVE

An experimental device was developed from the work of U ehara and S ugiyama (1969), in order to study the electrical phenomena accompanying the fertilization-wave in the sea urchin egg.
The change in membrane potential upon fertilization consists of 2 peaks (I to et al. , 1970), being preceded by a shoulder. The shoulder appears within the "latent period" (A llen and G riffin , 1958), and the 2 peaks correspond to the breakdown of the cortical granules and the formation of the fertilization membrane.
When the equatorial region of the egg surface was exposed to a detergent-sea water, the breakdown of the cortical granules and the formation of the fertilization membrane are induced only in this ring-shaped area. Sperm is then added to one of the polar regions. The fertilization-wave, starting from the point of sperm-entry, propagates across the detergent-treated region, and the membrane is formed on the whole egg surface. During such an experiment, changes of the membrane potential in the detergent-treated region were measured. 1 to 3 sudden transient depolarizations appear, followed by a delayed small depolarization. It is presumed that the initial depolarization corresponds to the fertilization-wave. The pattern of the potential change at normal fertilization may be explained by complexity of the cortical change, and the initial depolarizing shoulder is considered to correspond to the fertilization-wave, which is isolated by the above-mentioned device.     

金门岛北部海域浮游植物的季节变动及与环境的关联

采用2013—2014年四季度月在金门岛北部海域获取的浮游植物及环境因子监测数据, 分析该区浮游植物的群落结构和季节变化及其与温度、盐度、悬浮物、营养盐、叶绿素等的关系, 初步探讨涉海工程建设对浮游植物群落的潜在影响。结果显示, 鉴定出的浮游植物隶属3门43属82种(不含未定种), 群落构成以硅藻为主, 其次是甲藻, 蓝藻仅1种。物种组成的季节差异较大, 3月物种贫乏, 1月次之, 7月和11月最丰富。四季丰度平均为47.09×103 cells/L, 1月丰度最高, 7月次之, 11月最低, 3月高于11月少许。四季优势种均为硅藻, 13个优势种分别为柔弱几内亚藻(Guinardia delicatula)、短角弯角藻(Ecampia zoodicaus)、骨条藻(Skeletonema spp.)、具槽帕拉藻(Paralia sulcata)、微小海链藻(Thalassiosira exigua)、标志星杆藻(Asterionella notula)、旋链角毛藻(Chaetoceros curvisetus)、新月菱形藻(Nitzchia closterium)、派格棍形藻(Bacillaria paxillifera)、异常角毛藻(Chaetoceros abmormis)、小细柱藻(Leptocylindrus minutum)、宽角曲舟藻(Pleurosigma angulatum)和美丽曲舟藻(Pleurosigma formosum)。不同季节优势种有一定程度交错, 仅在单季占优的有6种, 有2/3在3个以上季节出现, 具槽帕拉藻、骨条藻为四季优势种。浮游植物物种多样性和均匀度总体较好, 群落结构稳定。与毗邻海区相比, 本区物种丰富度偏低, 丰度高于毗邻海区, 种类组成相似, 优势种却有较大差别。Pearson相关分析表明, 溶解无机氮及活性磷酸盐仅在1月与丰度存在极显著的正相关, 是促使丰度为四季最高的原因。涉海工程施工产生的悬浮物和冲击波是影响浮游植物群落的主要因素, 大量海洋工程建设案例表明, 施工期造成的浮游植物丰度下降趋势和优势种更替混乱在工程结束后能得以恢复。     

EFFECT OF TRYPSIN ON THE FERTILIZING CAPACITY OF SEA URCHIN SPERMATOZOA TREATED WITH EGG-WATER*

The effect of trypsin on the fertilizing capacity of spermatozoa was studied with 6 species of sea urchins. Trypsin has no harmful effect on intact spermatozoa. However, spermatozoa which have undergone the acrosome reaction in egg-water lose the fertilizing capacity when treated with trypsin-sea water. Electron- microscopical examination revealed that trypsin does not produce any morphologically noticeable effect on intact spermatozoa, but does dissolve the material covering the acrosomal tubule of the spermatozoa which have undergone the acrosome reaction. It is likely that the loss of this material is closely correlated with the loss of fertilizing capacity of spermatozoa by the trypsin treatment.     

南海断面春季放射虫残骸的空间分布及其与表层沉积记录对比

放射虫是揭示古海洋环境信息的重要载体。本文采用虎红染色方法,首次揭示了南海典型断面现代放射虫残骸群的空间分布特征,并比较分析现代水体中放射虫残骸群与海底表层沉积物中放射虫化石群的相互关系。结果表明:南海春季放射虫残骸群比较丰富,其丰度一般呈现出随深度增加而增高的趋势,最高值主要出现在75—300m深即位于叶绿素最大值层和活体高峰深度之下;分析发现研究区放射虫残骸丰度的深度分布受到海流的横向输运影响;春季水体和表层沉积物中放射虫属种组成和丰度分布的差异表明,除了现代放射虫具有季节性变化之外,海流的横向传输也是一个很重要的原因。在150—300m水体中除了Cornutella profunda和Cyrtopera laguncula,还发现了Cycladophora davisiana的残骸,推测典型冷水种C.davisiana由于受到径向翻转流的作用,从中深层水被带到了中上层水体中。     

THE WORK POTENTIAL IN PERSONS WITH HEART DISEASE

Data relevant to the decision-making processes of the professional team which comprises the Work Classification Unit of the San Diego County Heart Association were reviewed. The purpose of the unit is to assess the work potential in patients with heart disease.Intercorrelations between a number of physical and psychosocial assessments were noted, with particular attention to the way in which the assessments correlated with the appraisal of the return-to-work potential of the patients.Findings indicated quite clearly that the team employed other than just physical health measures in estimating work potential. Adjustment to the cardiac condition and certain estimates of the home and social environs were used to a significant degree.     

THE EFFECT OF OXIDANTS AND REDUCTANTS UPON THE BIOELECTRIC POTENTIAL OF NITELLA

Nitella cells were exposed to various oxidants and reductants, to determine their effect upon the bioelectric potential. These included five systems, with an E_h range from +0.454 v. to –0.288 v., a total range of 0.742 v. When proper regard was given to buffering against acidity changes, and concentration changes of Na or K ions in the oxidized and reduced forms, no significant effect upon the bioelectric potential was found: 1. When an oxidant or reductant (K ferri- or ferrocyanide) was applied instead of an equivalent normality of an "indifferent" salt (KCl). 2. In changing from a given oxidant to its corresponding reductant (ferri- to ferrocyanide; oxidized to leuco-dye, etc.). 3. When a mixture of 2 dyes, (indophenol with positive E''₀, and safranin with negative E''₀) was oxidized and reduced, to give better poising at the extremes. It is conduded that the outer surface of this cell is not influenced by the state of oxidation or reduction of the systems employed; at least it does not respond with a manifest change of bioelectric potential to changes in oxidation-reduction intensity of the medium. The cells continued to show, however, at all times their usual response to concentration changes of KCl, NaCl, etc., and to electrical stimulation.     

THE EFFECT OF HYDROGEN ION CONCENTRATION UPON THE INDUCTION OF POLARITY IN FUCUS EGGS : III. GRADIENTS OF HYDROGEN ION CONCENTRATION

1. Gradients of hydrogen ion concentration across Fucus eggs growing in sea water determine the developmental polarity of the embryo. 2. Gradients may determine polarity even if removed before the morphological response begins. 3. The rhizoid forms on the acid side of the egg unless this is too acid, in which case it develops on the basic side of the egg. 4. Since gradients of hydrogen ion concentration in sea water produce gradients of CO₂ tension, as a result of chemical action on the carbonate buffer system, it is not proven whether the physiological effects are due to the hydrogen ions, or to the CO₂ which they produce in the medium. 5. The developmental response of the eggs to gradients of hydrogen ion (or CO₂) concentration provides an adequate but not an exclusive explanation of the group effect in Fucus. 6. Hydrogen ions may exert their effect by activating growth substance. Hydrogen ions or CO₂ probably also affect the underlying rhizoid forming processes in other ways as well.     

THE POTENTIAL AND RESPIRATION OF FROG SKIN : I. THE EFFECT OF THE HOMOLOGOUS CARBAMATES. II. THE EFFECT OF CERTAIN LYSINS

Measurements of the O₂ consumption and of the potential of frog skin, made under comparable conditions, show that the homologous carbamates (ethyl, propyl, butyl, and amyl) reduce both the O₂ consumption and the potential, but not in a similar manner. In this respect, the effect of the carbamates is like the effect of reduction in O₂ tension. The simple lysins (saponin and the bile salts), on the other hand, abolish the potential without reducing the O₂ consumption at all. Irrespective of whether one considers the concentration of carbamate in the entire system or the amount of carbamate adsorbed by the frog skin, Traube''s rule relating the effect of a carbamate to its position in the homologous series does not seem to apply.     

PURIFICATION AND EFFECT OF THE NEUROTOXIN FROM THE SEA ANEMONE PARASICYONIS ACTINOSTOLOIDES

— Three toxic components were isolated from the sea anemone, Parasicyonis actinostoloides. Among these components a main component had an effect on the neuromuscular transmission of the crayfish. The component was purified and found to be a basic polypeptide having a molecular weight of about 2000. Amplitudes of excitatory and inhibitory poslsynaptic potentials were increased by the toxin. It was found that the quantum content increased markedly in the excitatory synapse. The action of the toxin remained for a long time after the nerve–muscle preparation was thoroughly washed. These results suggest that the toxin has an effect on the presynaptic nerve.