摘要:

An active culture of nitrifying bacteria was established by adding moist garden soil to a high-K nutrient solution and incubating the system at room temperature with adequate aeration. By a succession of transfers into a low-K nutrient solution the soil particles were eliminated and the K level reduced to 0.40 p.p.m. Inoculum from this soil-free, low-K nitrifying culture was then used to study nitrification in buffered nutrient solutions that contained even less K.When the nutrient solutions contained 0.40 p.p.m. K or more, there was no effect of the K level on the nitrification of NH4added as (NH4)2SO4. Nitrification was impaired, however, when the K level was less than 0.35 p.p.m. In a solution that contained virtually no K there was negligible nitrification after a second transfer was made to eliminate the K added by the original inoculum. Under these conditions, the number of nitrifying bacteria apparently decreased, but some of them persisted for at least 48 days. Upon the addition of K, nitrification occurred to about the same extent as if ample K had always been present.

ISSN:0008-4166    

DOI:10.1139/m59-053

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Numbers of bacteria and of fungi in a saline soil were about one-fifth of numbers in a Red River clay soil. Bacterial counts on two soil-extract agar media, one prepared from the saline soil and the other from Red River soil, were the same, and the populations on the two were the same as shown by the replica plating technique. They were larger than counts on sodium albuminate agar or on asparagin–mannitol agar. Likewise, fungal counts on either soil-extract agar, with 0.02% dipotassmm phosphate, 0.1% glucose, and 0.1% peptone, were higher than counts on Waksman's acidified medium, or on Martin's medium, or on Smith and Dawson's medium. Interestingly, fungal counts on a medium with the same three chemicals as the soil-extract media but with the soil extract replaced by water were as high as those on the soil-extract media. Different levels of potassium phosphate were tested in each of the above media. In each medium for bacteria, and in each for fungi, counts varied inversely as the amount of potassium phosphate. The same held true when sodium phosphate was used instead of potassium phosphate in each medium.

ISSN:0008-4166    

DOI:10.1139/m59-054

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Methods for estimating the content of ergot alkaloids in cultures ofClaviceps purpureahave been examined to select a simple but reliable assay procedure for evaluating the effects of cultural conditions and strain differences on yield. Modification of a solvent extraction method used for ergot sclerotia gave the most satisfactory results. Disadvantages and limitations of this and other procedures which were explored are described.

ISSN:0008-4166    

DOI:10.1139/m59-055

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Under the conditions of the official Canadian test, it was found that two simultaneous first-order reactions were in competition. Thus, after 4 hours, while 15% of any initial live MEF1 poliovirus present was adsorbed to the monkey kidney cells, 9% of the virus was destroyed by spontaneous inactivation. When the adsorption rate was increased by decreasing the volume of fluid, it was found that significantly more isolations of virus were obtained. Utilizing the method of Baron for the concentration of polio virus it was found possible to maintain a low test volume without making the routine test unduly cumbersome. The modified test is simpler and more sensitive and may be used with undialyzed vaccines.

ISSN:0008-4166    

DOI:10.1139/m59-056

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

After the reproducibility of poliovirus plaque titrations was estimated, the course of specific neutralization of virus by antiserum at 37 °C was investigated and was found to be logarithmic with respect to time and dilution of serum. A method was adopted for titrating poliomyelitis plaque neutralizing antibodies under defined test conditions. The titers obtained by this method were much more reproducible than those found by other methods in current use, but bore fairly constant relationships to the average values found in larger series of titrations by the latter methods.

ISSN:0008-4166    

DOI:10.1139/m59-057

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Techniques are described for lysing cells of the Gram-negative organismXanthomonas phaseoliwith lysozyme and with penicillin. In the presence of a supporting medium 'protoplasts' are formed which may be stabilized by the addition of magnesium ions at the appropriate time. The application of these methods to the preparation of cell-free extracts of this organism is discussed.

ISSN:0008-4166    

DOI:10.1139/m59-058

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The perfusion technique was used to isolate actinophages from soil. It was demonstrated that the perfusate of a specific soil contained more phages for streptomycetes isolated from that soil than for isolates from other sources. Titers as high as 104/ml of perfusate were obtained. In general, the greatest number of actinophages against the majority of isolates was obtained after 48 hours' perfusion. Differences in daily fluctuation in virus titer indicated a degree of specificity in the viruses observed. Bacteriophages were not as readily isolated from perfusates as were actinophages, however, this might be explained on the basis of adsorption to soil since this factor appears, at least in some cases, to be important in limiting the number of phage particles in the perfusate.

ISSN:0008-4166    

DOI:10.1139/m59-059

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The fatty acids of the oil from, the uredospores ofPuccinia graminisvar.tritici, race 15B, have been examined.Cis-9,10-epoxyoctadecanoic acîd, which has not previously been found in natural fats, is present as a glyceride. The fatty acids were analyzed by gas liquid phase chromatography and the percentages are as follows: myristic 2.9, palmitic 47.4, stearic 4.4, oleic 4.8, linoleic 3.3, linolenic 6.3,cis-9,10-epoxyoctadecanoic acid 28.5, and small amounts of lauric, pentadecanoic, and arachidic acids.

ISSN:0008-4166    

DOI:10.1139/m59-060

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The cell-free filtrates from cultures of selected deuteromycetous species, including representatives ofPiricauda,Slachybotrys,Alternaria,Culcitalna,Humicola, andHelicoma, isolated from wood submerged in the sea, exhibited various intensities of cellulolytic activity on carboxymethylcellulose and Walseth cellulose. Cellulolytic activity was noted following growth of the fungi on intact balsa wood in 0.1% yeast extract sea water broth. Individual isolates of certain genera, especially those ofHelicoma, varied considerably in their activity. However all of the species grew and developed cellulolytic activity in media made with distilled water and with sea water. The amount of enzymatic activity, indicated by the production of reducing sugars (RS), and the proportion of glucose in the RS fraction, varied considerably between species and within individual species on media with different salinities.

ISSN:0008-4166    

DOI:10.1139/m59-061

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Inhibitors of influenza virus haemagglutination were completely removed from normal rabbit and ferret sera by purified and concentrated preparations of influenza viruses. Influenza A-prime strains absorbed only the Chu inhibitor and the B/Lee virus the Francis inhibitor. The heat or periodate inactivation of the viruses did not destroy their ability to combine with the inhibitor.The practical application of these experiments in the antibody absorption test for influenza antigenic studies is discussed.

ISSN:0008-4166    

DOI:10.1139/m59-062

出版商:NRC Research Press    

年代:1959

数据来源: NRC