摘要:

The nuclei in the vegetative mycelium ofGelasinospora tetraspermado not divide in a manner directly comparable to ordinary mitosis. They divide without the aid of a spindle and individually recognizable chromosomes do not appear to align themselves on a metaphase plate. It is suggested that the dividing central body may function as a mechanical device to separate the divided chromatin and that the densely stained granule present in the chromatin of these nuclei is important to the division of both the chromatin and the central body.

ISSN:0008-4166    

DOI:10.1139/m59-016

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Cells ofRhizobium meliloticontained an intracellular pool of amino acids. The passage of C14-histidine or C14-glutamate into this pool apparently occurred against a concentration gradient and was energy dependent, being inhibited by azide and dinitrophenol. An internal bound form of C14, containing a number of radioactive amino acids, was synthesized at the expense of radioactive pool components. This bound C14consisted predominantly of several proteins whose syntheses were inhibited by chloramphenicol. Added histidine was not incorporated directly into this protein since the protein histidine was nonradioactive. When C14-labelled cells were suspended in glucose-containing basal medium there was an efflux of pool amino acids into the extracellular environment. This leakage presumably was the result of simple diffusion since it was energy independent, occurred with the concentration gradient, and was appreciable at 5 °C. Rapid leakage occurred at 30 °C in the presence and absence of dinitrophenol for an initial period of 6 hours, after which time growth occurred in the absence of this inhibitor. During growth leakage ceased, and a considerable quantity of material passed back into the cells and was incorporated into a bound form. In the presence of dinitrophenol no growth occurred, and the outflow continued after the 6th hour, but at a much reduced rate. X irradiation increased the efflux of pool constituents, but the reason for this is conjectural.

ISSN:0008-4166    

DOI:10.1139/m59-017

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Studies were made on the oxidative metabolism of stem rust uredospores under self-inhibited conditions and when self-inhibition was removed. The oxidative metabolism of self-inhibited spores is characterized by the following features: the oxygen uptake declines rapidly; the respiration is mainly based on a fatty acid oxidation apparently bypassing the Krebs cycle (malonate insensitivity); and the enzymes of carbohydrate breakdown are more or less inactive. Compounds that are able to overcome self-inhibition stimulated oxygen consumption. Simultaneously an intensified utilization of endogenous fatty acids was initiated and also an increased malonate sensitivity. Longer incubation periods with stimulants resulted in germination and in a concomitant activation of carbohydrate metabolism. The catalytic effect of pelargonaldehyde or other stimulants in overcoming self-inhibition was reproduced by the administration in substrate concentrations of suitable respiratory material such as butyrate and propionate. The stimulated respiration induced by these substances appears to be a prerequisite for germination.The possible significance of the above findings from the point of view of host–parasite relations is discussed.

ISSN:0008-4166    

DOI:10.1139/m59-018

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Cells from growth medium had a strong endogenous respiration under aerobic conditions with a respiratory quotient of approximately unity. InM/300 glucose, their oxygen uptake was somewhat greater than the endogenous, but the aerobic carbon dioxide output was approximately twice the oxygen uptake. When such cells were incubated in buffer no change in their respiration in glucose was noted in 2 days, but when incubated in 0.3% acetate the respiratory quotient declined to 1.3–1.5. This decline was evident within six hours of the time the cells were placed in acetate. Glucose (0.1%) also depressed the respiratory quotient. With two other sporulation substrates, sodium pyruvate (0.13%) and lactic acid (0.1%), the effect was not so pronounced, and a fifth, dihydroxyacetone (0.1%), seemed to have little or no effect. Spores developed more rapidly and became more abundant in the acetate than in any of the other compounds. The changes in the respiratory quotient did not show a clear correlation with either the amount or the rapidity of sporulation in the five sporulation substrates. When cells were incubated in acetate or in glucose for a day under anaerobic conditions their respiratory quotient did not decline. Some success was obtained in separating sporulated from non-sporulated cells by centrifuging. No difference was noted in the respiration of sporulated and non-sporulated cells. The respiratory quotient of cells from sporulated cultures returned to values characteristic of growing cells after 2 to 4 hours in growth medium.

ISSN:0008-4166    

DOI:10.1139/m59-019

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Bacillus thuringiensisBerliner produces in vitro a heat-stable, dialyzable substance which is toxic for insects when injected. The same or a similar substance is produced in vivo. The toxic principle is of unknown composition. It is heat-stable, water-soluble, dialyzable, and resistant to low temperatures. It is probably neither a protein nor a lipid. Clearly it is distinct from the heat-labile inclusion bodies and from lecithinase. Growth-curve studies showed that the heat-stable toxin appeared in liver broth cultures during the active growth phase, prior to the formation of spores or inclusion bodies. An attempt to produce the toxic principle from culture media in the absence of bacteria was unsuccessful from sterile inocula both from in vivo and in vitro sources. The LD50for larvae ofGalleria mellonellainjected with autoclaved supernatant from a 10-day-old liver broth culture ofB.thuringiensiswas determined to be 0.00036 ml per larva or 0.002 ml per gram of larvae. Approximately the same level of toxicity was found for another caterpillar, a fly larva, and cockroaches. After larvae ofGalleriaorPyrauslahave been dead for more than 2 days from infection withB.thuringiensisthe bacillus could no longer be recovered. A sublethal amount of the heat-stable toxin injected into old larvae ofGalleriadelayed emergence of the adults by 30 to 40%. The non-pathogenicBacillus cereuswas found to produce a similar-acting, heat-stable toxin under the same conditions that one is produced byB.thuringiensis.

ISSN:0008-4166    

DOI:10.1139/m59-020

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Five of seven bacterial cultures received in this laboratory asBacillus apisepticusandBacillus sphingidisand producing a fatal septicemia in honeybees have been shown upon morphological and cultural examination to belong more properly to the family Pseudomonaceae, genusPsctidomonas. It is suggested that such organisms now be regarded asPseudomonas apiseptica(Burnside), rather thanBacillus apiseplicusas originally proposed. The status of the two remaining cultures representing a singleAeromonasspecies requires additional investigation.

ISSN:0008-4166    

DOI:10.1139/m59-021

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

β-D-1,3 Glucanases are of common occurrence in fungi, being detected in the culture nitrates of 96% of the organisms tested in shake flasks and in the sporophores of six basidiomycetcs. The enzyme is constitutive. Basidiomycete QM 806 andSporotrichum pruinosumQM 826 are excellent sources of β-D-1,3 glucanase of the exo-type giving glucose as the sole reducing product of laminarin hydrolysis.Rhizopus arrhizusQM 1032 produces a β-D-1,3 glucanase of the endo-type giving laminaribiose and higher oligosaccharides as the products of hydrolysis of β-D-1,3 glucans. By controlling the conditions of growth β-D-1,3 glucanases can be produced free of β-1,4 glucanase (cellulase).

ISSN:0008-4166    

DOI:10.1139/m59-022

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Two simultaneous pathways for the fixation of carbon from one-carbon compounds by aPseudomonassp. (PRL-W4) are postulated. Carbonate and formate form parts of one pathway and methanol and formaldehyde the other. It is presumed that both the formate and formaldehyde are incorporated as serine by the organism. The energy necessary for the incorporation of carbonate carbon can be supplied by the oxidation of methanol or of formate but not formaldehyde. No formaldehyde dehydrogenase activity was found.

ISSN:0008-4166    

DOI:10.1139/m59-023

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

All of the free amino acids and calcium dipicolinate are released from disrupted spores ofBacillus megateriumto a hot water extract. Chromatographic resolution of the extract reveals six free amino acid spots and the dipicolinate running as a two-limbed band through the chromatogram. Overlapped by the alanine spot, the dipicolinate area can be recognized by its strong absorption in the ultraviolet region and the slow development of a permanent blue color with ninhydrin. Acid hydrolysis of an eluate from the ultraviolet-absorbing area releases five other amino acids. These can be separated chromatographically from the dipicolinate which now no longer migrates as a band but moves as a discrete spot. Calcium appears to be essential for the maintenance of this "complex" between dipicolinate and amino acids. The possible significance of such a combination in the spore is discussed.

ISSN:0008-4166    

DOI:10.1139/m59-024

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Pseudomonas aeruginosa(Schroeter) Migula antigen remained in the blood of larvae of the wax moth,Galleria mellonella(L.), during the resistant period of the insect. Bacterial antigen present in the immune blood produces agglutinating titers in rabbits about 10 times as great as those produced by an approximately equal volume of standardP.aeruginosavaccine. Attempts to demonstrate the mechanism that enhances the antigen showed that the active portion was contained in the serum, that the action occurred within several hours in vivo and only reached the same level after 3 days in vitro mixture, and that the action was probably not caused by lysis of the bacterial cells and the consequent liberation of more antigen in the blood. Electrophoretic studies on the blood mixture indicated that the altered or enhanced antigen may be bound to a blood fraction, the exact nature of which was not determined. The larvae were actively or passively immunized against lethal doses ofP.aeruginosawithin 20 to 24 hours. Concentration of vaccine had little effect upon the degree of immunity conferred upon the larvae. The immunity lasted about three days and was more specific than nonspecific. The larvae were not actively protected againstP.aeruginosaby introduction of albuminous foreign material into the body cavity. True antibodies were not detectable in the immune blood though the bactericidal action of immune blood was at least twice as great as that of normal blood. Preliminary investigations on immune responses of other lepidopterous insects toP.aeruginosaantigen and of the wax moth to antigens of some other Gram-negative bacteria indicated similar results.

ISSN:0008-4166    

DOI:10.1139/m59-025

出版商:NRC Research Press    

年代:1959

数据来源: NRC