COMPARATIVE STUDIES ON RESPIRATION : VIII. THE RESPIRATION OF BACILLUS SUBTILIS IN RELATION TO ANTAGONISM.

1. In relatively low concentrations of NaCl, KCl, and CaCl₂ the rate of respiration of Bacillus subtilis remains fairly constant for a period of several hours, while in the higher concentrations, there is a gradual decrease in the rate. 2. NaCl and KCl increase the rate of respiration of Bacillus subtilis somewhat at concentrations of 0.15 M and 0.2 M respectively; in sufficiently high concentrations they decrease the rate. CaCl₂ increases the rate of respiration of Bacillus subtilis at a concentration of 0.05 M and decreases the rate at somewhat higher concentrations. 3. The effects of salts upon respiration show a well marked antagonism between NaCl and CaCl₂, and between KCl and CaCl₂. The antagonism between NaCl and KCl is slight and the antagonism curve shows two maxima.     

COMPARATIVE STUDIES ON RESPIRATION : IV. THE EFFECT OF ETHER ON THE RESPIRATION OF WHEAT.

These experiments show that 7.3 and 3.65 per cent ether solutions cause an increase in respiration followed by a decrease. The results agree with those of Haas on Laminaria, of Gustafson on higher fungi, and of Mrs. Brooks on bacteria. They do not agree with the theory of Verworn that anesthesia is a kind of asphyxia and that it decreases respiration.     

COMPARATIVE STUDIES ON RESPIRATION : X. TOXIC AND ANTAGONISTIC EFFECTS OF MAGNESIUM IN RELATION TO THE RESPIRATION OF BACILLUS SUBTILIS.

1. Concentrations of MgCl₂ up to 0.01 M have little effect upon the rate or respiration of Bacillus subtilis; at 0.03 M there is an increase in the rate, while in the higher concentrations there is a gradual decrease. 2. There is a well marked antagonism between MgCl₂ and NaCl, and a very slight antagonism between MgCl₂ and CaCl₂.     

COMPARATIVE STUDIES ON RESPIRATION : V. THE EFFECT OF ETHER ON THE PRODUCTION OF CARBON DIOXIDE BY ANIMALS.

1. The experiments on frog tadpoles show that with 0.15, 0.37, and 0.55 per cent ether solutions there is a decrease in CO₂ output. The effect is reversible. With these concentrations the breathing movements and body movements remained normal during the experiment. In 3.65 and 7.3 per cent ether there is a decrease of respiration followed by an increase which in turn is followed by a decrease. The increase may reach about three times the normal rate. The increase in the CO₂ output is accompanied by the peeling of the skin. The effect is irreversible. 2. Experiments on an aquatic insect, Dineutes assimilis Aube, show that in 7.3 per cent ether there is a decrease followed by an increase which in turn is followed by a decrease. There is no apparent disintegration of structures in the organism accompanying the increase. The effect is irreversible. 3. The experiments on frog eggs with 7.3 per cent ether show a result similar to that found in aquatic insects. 4. Experiments on Fundulus embryos show that with 0.73 per cent ether there is a reversible decrease in the rate of CO₂ production. In 3.65 per cent ether there is a temporary decrease followed by an increase, after which the rate begins to fall off. In 7.3 per cent ether there is an immediate increase amounting to 307 per cent which is followed by a decrease. The increase in the 3.65 and 7.3 per cent ether is accompanied by irreversible changes leading to death. The decrease found in 0.73 per cent ether is not sufficient to cause narcosis, as is shown by experiments on which the same decrease is produced by lowering the temperature. 5. These experiments show that narcosis is not due to asphyxia. The action of anesthetics is due to some other cause than the effect on respiration. There is a difference between the animals studied and the plants described in this series of articles, since in animals the increase in the CO₂ output is accompanied by irreversible changes leading to death, while this is not necessarily the case in plants. The reversible (narcotic) action of ether on the animals studied was accompanied by a decrease in the carbon dioxide output; in plants this is not ordinarily the case. These facts are of considerable interest, but their interpretation must be left to future investigation.     

COMPARATIVE STUDIES ON RESPIRATION : XV. THE EFFECT OF BILE SALTS AND OF SAPONIN UPON RESPIRATION.

1. The addition of Na taurocholate produces an increase in the rate of respiration at a concentration of 0.0000125 M, and a decrease at 0.001 M and in higher concentrations. 2. NaCl is antagonized by Na taurocholate, the most favorable proportion being 14,375 parts of NaCl to 1 part of Na taurocholate (molecular proportions). 3. Solutions of saponin, at concentrations from 0.00005 M to 0.001 M, decrease the rate of respiration: lower concentrations produce no effect.     

COMPARATIVE STUDIES ON RESPIRATION : II. THE EFFECT OF ANESTHETICS AND OTHER SUBSTANCES ON THE RESPIRATION OF ASPERGILLUS NIGER.

1. In concentrations which are high enough to produce any effect, formaldehyde, ether, and acetone cause an increase, followed by a decrease, in the rate of respiration. 2. 3.65 per cent ether, which causes an increase with certain cultures, produces only a decrease with others. 3. The reaction producing an increase in the respiration with 7.3 per cent ether is a reversible process, while the reaction producing the decrease is not reversible. 4. 0.5 per cent caffeine produces only a decrease in respiration while a saturated solution causes an increase, which is followed by a decrease.     

COMPARATIVE STUDIES ON RESPIRATION : XI. THE EFFECT OF HYDROGEN ION CONCENTRATION ON THE RESPIRATION OF PENICILLIUM CHRYSOGENUM.

1. Variations in pH value between 4 and 8 produce practically no effect on the normal rate of respiration (the rate at neutrality is called normal). 2. Increasing the pH value to 8.80 causes respiration to fall to 60 per cent of the normal, after which it remains stationary for the duration of the experiment. 3. Decreasing the pH value to 2.65 causes a gradual rise and a gradual return to normal; at pH 1.10 to 1.95 the preliminary rise amounts to 20 per cent and is followed by a fall to below the normal. 4. The decrease in respiration brought about by solutions of a pH value of 1.95 or less are irreversible, while a similar decrease which occurs at pH 8.80 is reversible, the rate coming back to practically normal after the material is replaced in a neutral solution. 5. Determinations by means of Winkler''s method showed an increase in the consumption of oxygen in acid solutions and a decrease in alkaline solutions.     

COMPARATIVE STUDIES ON RESPIRATION : XIX. A PRELIMINARY STAGE IN THE PROGRESS OF ETHER ANESTHESIA.

Using these concentrations of ether (1 per cent, 3.65 per cent, 7.3 per cent), the following conclusions may be drawn. 1. The first effect of ether is to cause a depression in the rate of respiration. This is followed by a rapid rise above normal, which in turn is succeeded by a fall. 2. With all these concentrations the respiration is ultimately reduced to approximately the same level; the stronger the ether, the less time required to produce this result. 3. Even when the respiration has been reduced below normal, recovery is possible on removal from the ether, and appears to be complete, if sufficient time is allowed. If, however, the rate has been too far depressed, no recovery is possible. 4. These results extend those of Irwin on frog eggs and Fundulus embryos.     

COMPARATIVE STUDIES ON RESPIRATION : XXIV. THE EFFECTS OF CHLOROFORM ON THE RESPIRATION OF DEAD AND OF LIVING TISSUE.

1. Chloroform in low concentration (0.25 per cent) causes an increase in the rate of production of CO₂ in Ulva; this is followed by a decrease. In higher concentration (0.5 per cent) only a decrease is observed. 2. Assuming that the normal oxidation depends on the action of peroxide and peroxidase, experiments were made by placing Ulva in 1.0 per cent H₂O₂ and in Fe₂(SO₄)₃ (which acts like a peroxidase). The former diminishes the rate, the latter increases and subsequently decreases it. 3. When Ulva is killed in such a manner as to destroy the oxidizing enzymes, no CO₂ is produced unless H₂O₂ and Fe₂(SO₄)₃ are present. If to this mixture chloroform is added, the effect depends on the concentration of the iron. If the concentration is low there is an increase in the production of CO₂ followed by a decrease. If the concentration is high the rate appears to decrease from the start.     

COMPARATIVE STUDIES ON RESPIRATION : IX. THE EFFECTS OF ANTAGONISTIC SALTS ON THE RESPIRATION OF ASPERGILLUS NIGER.

1. In the presence of 0.05 per cent dextrose the respiration of Aspergillus niger is increased by NaCl in concentrations of 0.25 to 0.5M, and by 0.5M CaCl₂. 2. Stronger concentrations, as 2M NaCl and 1.25M CaCl₂, decrease the respiration. The decrease in the higher concentrations is probably an osmotic effect of these salts. 3. A mixture of 19 cc. of NaCl and 1 cc. of CaCl₂ (both 0.5M) showed antagonism, in that the respiration was normal, although each salt alone caused an increase. 4. Spores of Aspergillus niger did not germinate on 0.5M NaCl (plus 0.05 per cent dextrose) while they did on 0.5M CaCl₂ (plus 0.05 per cent dextrose) and on various mixtures of the two. This shows that a substance may have different effects on respiration from those which it has upon growth.     

THE EFFECT OF HYDROGEN ION CONCENTRATION ON THE PRODUCTION OF CARBON DIOXIDE BY BACILLUS BUTYRICUS AND BACILLUS SUBTILIS

1. The maximum rate of CO₂ production of Bacillus butyricus was found to be at a pH value of 7; of Bacillus subtilis at pH 6.8. If the pH value be raised or lowered there is a progressive decrease in the rate of production of CO₂. 2. Spontaneous recovery follows the addition of alkali to either organism, while addition of acid is followed by recovery only upon addition of an equivalent amount of alkali, and is not complete except when the amount of acid is very small.     

COMPARATIVE STUDIES ON RESPIRATION : XVI. EFFECTS OF HYPOTONIC AND HYPERTONIC SOLUTIONS UPON RESPIRATION.

1. In highly hypertonic solutions of sea water the rate of respiration of Laminaria agardhii is rapidly reduced. 2. In highly hypotonic solutions the rate of respiration of Laminaria agardhii is reduced somewhat less rapidly than in the case of hypertonic solutions. 3. Hypertonic solutions of NaCl, CaCl₂, and of mixtures of NaCl, and CaCl₂ in the proportion of 50:1, all caused a decrease in the rate of respiration of wheat seedlings.     

COMPARATIVE STUDIES ON RESPIRATION : XX. THE CAUSE OF PARTIAL RECOVERY.

The respiration of Chlorella is diminished by exposure to hypertonic salt solutions. After a short exposure there is complete recovery when the algæ are removed to the normal medium. After a longer exposure recovery may be incomplete, as shown by the fact that the rate of respiration fails to rise to the normal level. Staining with methylene blue indicates that few, if any, of the cells are killed as the result of the exposure. It would therefore seem that the treatment produces a persistent lowering of the rate of metabolism. Such a condition of metabolism is also found after exposure to chloroform.     

芽孢杆菌原生质体的形成,再生及种间融合的研究

原生质体融合技术不仅能使遗传基因高频率重组,而且可以集双亲优良遗传性状为一体.自Schaeffer等人成功地进行了微生物原生质体融合以来,这项技术便广为人们所接受.枯草芽孢杆菌分泌的抗菌蛋白能抑制多种植物病原菌的生长,苏云金芽孢杆菌生成的伴孢晶体蛋白可毒杀植物害虫.利用原生质体融合技术将这两种芽孢杆菌抑菌杀虫的遗传特性融为一体,选育出防治植物病虫害的新一代生防菌株成为可能,有关这方面的研究国内外尚未见报道.本文报道了抗菌蛋白产生菌TG26-10和晶体蛋白产生菌AS1.904-17原生质体的形成,再生及种间融合的影响因素,为进一步筛选目的融合子提供基础.