Showing papers in "Applied and Environmental Microbiology in 1965"
TL;DR: Cell-wall preparations were made from more than 140 strains of aerobic actinomycetes representing most of the form-genera that have been proposed and contained as major constituents glucosamine, muramic acid, alanine, and glutamic acid.
Abstract: Cell-wall preparations were made from more than 140 strains of aerobic actinomycetes representing most of the form-genera that have been proposed. All cell-wall preparations contained as major constituents glucosamine, muramic acid, alanine, and glutamic acid. In addition, cell-wall preparations from various types of streptomycetes and strains of Microellobosporia contained glycine and ll-α,e-diaminopimelic acid; those from strains of most Actinoplanaceae and micromonosporae contained glycine and meso-α-e-diaminopimelic acid; those from strains of Thermoactinomyces, Microbispora, Dermatophilus, and nocardiae of the madurae-pelletieri group contained meso-α,e-diaminopimelic acid; and those from strains of Thermomonospora, Micropolyspora, and most nocardiae contained meso-α,e-diaminopimelic acid, arabinose, and galactose. All the strains used were also studied morphologically.
475 citations
TL;DR: Geosmin, an earthy-smelling substance, has been isolated from several actinomycetes and has been used to produce 1 mg per liter of whole broth from Streptomyces griseus LP-16.
Abstract: Geosmin, an earthy-smelling substance, has been isolated from several actinomycetes. Production of 1 mg per liter of whole broth was obtained from Streptomyces griseus LP-16. After preliminary separations, pure geosmin was isolated in milligram amounts by gas chromatography. Geosmin is a neutral oil, with an approximate boiling point of 270 C, which contains carbon and hydrogen, but no nitrogen. It undergoes a reaction with acid to give odorless argosmin, a neutral oil, with an approximate boiling point of 230 C, which contains only carbon and hydrogen. Specific rotation and ultraviolet- and infrared-absorbtion spectra were determined for both.
356 citations
TL;DR: The potential utility of this medium as a basis for controlled studies of a live bacterial vaccine in terms of growth characteristics, dissociation, virulence, and immunogenicity is indicated.
Abstract: A chemically defined medium was prepared which adequately supported growth of a vaccine strain of Pasteurella tularensis. This medium differed from those previously described in: (i) concentration of components, (ii) a requirement for calcium pantothenate to obtain increased growth, and (iii) a low initial pH. Varying the concentration of individual components up to 10 times the standard amount did not increase the viable population or affect dissociation. The vaccine strain grown in this chemically defined medium, although lower in viable population, appears to retain its identity and to be equal in potency to that prepared by the conventional method. This preliminary study indicates the potential utility of this medium as a basis for controlled studies of a live bacterial vaccine in terms of growth characteristics, dissociation, virulence, and immunogenicity.
263 citations
TL;DR: Chlorine dioxide was found to be a more effective disinfectant than chlorine in sewage effluent at pH 8.5 and a more stable bactericide in relation to pH in the range studied.
Abstract: We found chlorine dioxide to be a more effective disinfectant than chlorine in sewage effluent at p H 85 Chlorine dioxide was also found to be a more stable bactericide in relation to p H in the range studied Images
190 citations
TL;DR: Concentrations of aflatoxin of 60 to 80 mg per liter can readily be obtained in indented shake flasks; somewhat lower yields were obtained in 5-liter fermentors.
Abstract: Aflatoxins can be produced on a synthetic medium in submerged culture. Glucose, sucrose, or fructose are the preferred carbon sources, and Casamino Acids are the preferred nitrogen source. Ammonia is almost as good a nitrogen source. Zinc is required at levels of at least 0.4 mg per liter. Concentrations of aflatoxin of 60 to 80 mg per liter (as determined by optical-density measurements of a chloroform extract of the unfiltered broth) can readily be obtained in indented shake flasks; somewhat lower yields were obtained in 5-liter fermentors.
177 citations
TL;DR: Evans blue dye employed as a counterstain eliminated the nonspecific background staining and increased the reliability of the direct FA procedure for Neisseria gonorrhoeae detection.
Abstract: Direct smears from female patients have been considered unreliable for the detection of Neisseria gonorrhoeae by fluorescent-antibody (FA) methods because of inadequate background contrast of the fluorescent-stained smears and a scarcity of organisms on the smear. Evans blue dye employed as a counterstain eliminated the nonspecific background staining and increased the reliability of the direct FA procedure. Direct smears demonstrating positive fluorescence were obtained from 86% of a group of culturally positive named female contacts. The FA-counterstain technique is as sensitive as the presently recommended cultural procedures.
164 citations
TL;DR: The validity and reliability of the microtechnique suggests that it can be used as a valuable screening procedure for the microscopic agglutination test for preliminary cross agglUTination studies on unknown strains and for the detection of leptospiral antibodies in human and animal sera.
Abstract: A microtechnique has been developed and adapted successfully to the microscopic agglutination test with live antigens for detection of leptospiral antibodies. Simultaneous titrations were performed by the conventional microscopic agglutination test and the microtechnique. When the microtechnique was used to screen 50 unknown leptospiral strains with a battery of hyperimmune sera, 98% agreement was obtained with the conventional procedure. Comparative data on 635 tests on these 50 cultures established the reliability of the microtechnique. Results with the two tests on 46 human sera revealed 93% agreement in the detection of leptospiral antibodies. The validity and reliability of the microtechnique obtained in these comparative studies suggests that it can be used as a valuable screening procedure for the microscopic agglutination test for preliminary cross agglutination studies on unknown strains and for the detection of leptospiral antibodies in human and animal sera.
147 citations
TL;DR: Isolation and purification procedures are given for the new antitumor agent, alpha sarcin, and an unknown amino acid was present in the acid hydrolysate, which has been named "sarcinine," is extremely stable in 6 n hydrochloric acid in the absence of air, and is unstable in alkali.
Abstract: Isolation and purification procedures are given for the new antitumor agent, alpha sarcin. These procedures include the use of column ion exchange with a carboxylic resin (Amberlite IRC50), dialysis, decolorization with activated charcoal, gradient salt chromatography, salt removal, and drying from the frozen state. The final product has an activity of 800 sarcoma 180 mouse dilution units per mg. The amino acid composition of the purified material is reported. All of the usual amino acids found in proteins were present except methionine. In addition to the usual amino acids, an unknown amino acid was present in the acid hydrolysate. The latter was isolated, and was found to yield phenylalanine and kynurenine. This compound, which has been named “sarcinine,” is extremely stable in 6 n hydrochloric acid in the absence of air, and is unstable in alkali. Sarcinine has also been found in two other antitumor peptides produced by aspergilli, and so may relate significantly to the antitumor properties of these peptides.
146 citations
TL;DR: In the CaCO(3)-containing media, Schizophyllum commune, Merulius tremellosus, and Porodisculus pendulus were found to produce substantial amounts of L-malic acid as a main metabolic product, along with small quantities of oxalic and other acids in shake cultures.
Abstract: Sixty-seven strains belonging to 47 species of Basidiomycetes were examined for their acid-producing abilities in glucose media, in both the presence and absence of CaCO(3), in stationary and shake cultures. Some strains were found to produce large quantities of oxalic acid. The oxalic acid-producing strains could be separated into two groups. Strains of one group (mostly brown-rot fungi) were able to produce oxalic acid, regardless of whether CaCO(3) was present in the medium. Strains of the other group (mostly white-rot fungi) were characterized by their ability to produce oxalic acid only when CaCO(3) was added to the medium. With the latter group, shake-culturing was generally more effective than stationary culturing in respect to acid production. In the CaCO(3)-containing media, Schizophyllum commune, Merulius tremellosus, and Porodisculus pendulus were found to produce substantial amounts of L-malic acid as a main metabolic product, along with small quantities of oxalic and other acids in shake cultures. Especially, S. commune and M. tremellosus may be employed as malic acid-producing species.
137 citations
TL;DR: Methods are described for the extraction and serological detection of trace amounts of enterotoxins A and B in foods incriminated in outbreaks of staphylococcal food poisoning.
Abstract: Methods are described for the extraction and serological detection of trace amounts of enterotoxins A and B in foods incriminated in outbreaks of staphylococcal food poisoning. Evidence is presented for the probable applicability of the methods for the detection of unidentified enterotoxins.
135 citations
TL;DR: The fermentation of idli demonstrates a leavening action caused by the activity of the heterofermentative lactic acid bacterium, L. mesenteroides, which is the first record of a le avenging action produced exclusively by theActivity of a lactic Acid bacterium.
Abstract: The fermentation of the batter of idli, a fermented food of India, was studied. The microorganisms responsible for the characteristic changes in the batter were isolated and identified. Although there is a sequential change in the bacterial flora, the predominant microorganism responsible for souring, as well as for gas production, was found to be Leuconostoc mesenteroides. In the later stages of fermentation, growth of Streptococcus faecalis and, still later, of Pediococcus cerevisiae becomes significant. The fermentation of idli demonstrates a leavening action caused by the activity of the heterofermentative lactic acid bacterium, L. mesenteroides. As far as is known, this is the first record of a leavening action produced exclusively by the activity of a lactic acid bacterium.
TL;DR: Aspergillus giganteus MDH 18894 was found to produce alpha sarcin, a new antitumor agent inhibitory to a number of different animal tumors, which produced culture filtrates that inhibited mouse sarcoma 180 at dilutions up to 1:32.
Abstract: Aspergillus giganteus MDH 18894 was found to produce alpha sarcin, a new antitumor agent inhibitory to a number of different animal tumors. This culture produced culture filtrates that inhibited mouse sarcoma 180 at dilutions up to 1:32. Optimal fermentation conditions were established for shake flasks and 30-liter and 100-gal (378.5-liter) fermentors. Results from a variety of media were reported; however, the medium which yielded the most reproducible filtrates consisted of 2% corn starch, 1.5% beef extract (Difco), 2% peptone (Difco), and 0.5% sodium chloride. Purified preparations of 800 sarcoma 180 dilution units per mg were inactive against bacteria, yeasts, molds, actinomycetes, and protozoa, but were cytotoxic to several strains of mammalian cells. Alpha sarcin inhibited sarcoma 180 in mice at a dose of 62.5 μg per kg per day. A variety of other animal tumors were also inhibited by this compound.
TL;DR: Both CIPC- and CEPC-effective isolates degraded isopropyl N-phenylcarbamate (IPC) more rapidly than either C IPC or CEPC.
Abstract: Microbial degradation of isopropyl-N-3-chlorophenylcarbamate (CIPC) and 2-chloroethyl-N-3-chlorophenylcarbamate (CEPC) was observed in a soil perfusion system. Degradation in perfused soils, and by pure cultures of effective bacterial isolates, was demonstrated by the production of 3-chloroaniline and the subsequent liberation of free chloride ion. Identified isolates effective in degrading and utilizing CIPC as a sole source of carbon included Pseudomonas striata Chester, a Flavobacterium sp., an Agrobacterium sp., and an Achromobacter sp. Identified isolates, effective in degrading and utilizing CEPC as a sole source of carbon, included an Achromobacter sp. and an Arthrobacter sp. CIPC-effective isolates degraded CEPC more slowly than CIPC, whereas CEPC-effective isolates degraded CIPC more rapidly than CEPC. Both CIPC- and CEPC-effective isolates degraded isopropyl N-phenylcarbamate (IPC) more rapidly than either CIPC or CEPC.
TL;DR: F fungi isolated from prepared feed and from corn collected on farms were grown separately in moist autoclaved corn and caused increases of five to eight times in weight of the uterus as compared with controls that were fed sound corn.
Abstract: Eighty-five fungi isolated from prepared feed and from corn collected on farms were grown separately in moist autoclaved corn. The corn was fed to virgin weanling rats for 5 to 12 days; the rats were then killed, and their uteri were removed and weighed. Twelve isolates of Fusarium from corn and one from poinsettias caused increases of five to eight times in weight of the uterus as compared with controls that were fed sound corn. The greatest increase in weight of the uterus was caused by corn inoculated with Fusarium No. 5 incubated for 21 days at 20 to 25 C followed by 14 days at 12 C. Extraction of this corn with methylene chloride, separation into fractions by means of a silicic acid column, and further purification by thin-layer chromatography yielded a compound with ultraviolet-absorption maxima at 314, 274, and 236 mmu.
TL;DR: Findings indicate that outbreaks of C. perfringens food-borne disease in the Cincinnati area are caused principally by the contamination of the food with vegetative cells or spores of the organism after cooking.
Abstract: A total of 262 specimens of meat and meat dishes were examined for the presence of Clostridium perfringens. Of this total, 161 were raw, unprocessed beef, veal, lamb, pork, or chicken; 101 were processed meats and meat dishes. C. perfringens was isolated from 113 (43.1%) of these specimens. The highest percentage of contamination (82%) was found in veal cuts, and the lowest (4.7%) in sliced sandwich meats and spreads. Only 2 of the 113 isolates were shown to produce heat-resistant spores, which indicates a very low incidence (0.8%) of contamination. These findings indicate that outbreaks of C. perfringens food-borne disease in the Cincinnati area are caused principally by the contamination of the food with vegetative cells or spores of the organism after cooking. Studies of the effects of various holding temperatures on the growth of C. perfringens indicated that, in the range of 5 to 15 C, no multiplication would occur, but that viable cells would still be present at the end of a 5-day holding period. Extremely rapid growth occurred at temperatures around 45 C, and complete inhibition of growth was accomplished between 49 and 52 C.
TL;DR: A simple technique for measuring the rate of fermentation of rumen microorganisms allows quick preparation and handling of the rumen sample immediately after collection and indicates a net average growth of 8% per hr, or 192% per day, in approximate agreement with rumen turnover time.
Abstract: A simple technique for measuring the rate of fermentation of rumen microorganisms is described. It allows quick preparation and handling of the rumen sample immediately after collection. The average rate of fermentation of rumen samples collected from a lactating cow fed on alfalfa hay and concentrate in the ratio of 2:1 was very similar to the rate obtained by other methods. On the assumption that when substrate is in excess, the fermentation rate is proportional to the total microbial cells, the method was used to estimate the net growth of rumen microorganisms. The maximal fermentation rate of subsamples, taken at the beginning and after 1 hr of incubation of a sample, was measured. The results indicate a net average growth of 8% per hr, or 192% per day, in approximate agreement with rumen turnover time. The highest net growth does not necessarily coincide with the highest gas-production rate in the rumen, in part because the bicarbonate concentration in the rumen contents varies. In a cow fed on hay and concentrate, the net growth was lowest before feeding and immediately after feeding.
TL;DR: For the physical set-up used in this work and with the biological system employed, Bellco 598 flasks and flasks fitted with Biotech stainless-steel baffles gave satisfactory results at workable broth volumes; unbaffled and Bellco 600 flasks did not.
Abstract: The effect of oxygen-supply rates on bacterial growth was studied in commercially available unbaffled and baffled flasks with the use of Escherichia coli in a synthetic medium as a test system. The amount of growth obtained depended on the oxygen-supply rate. Based on oxygen-absorption rates (OAR) measured by the rate of sulfite oxidation, equal OAR values in different types of flasks did not give equal amounts of growth. However, growth was essentially equal at the equal sulfite-oxidation rates when these were determined in the presence of killed whole cultures. Specific growth rates were reduced only at oxygen-supply rates much lower than those at which the total amount of growth was reduced. For the physical set-up used in this work and with the biological system employed, Bellco 598 flasks and flasks fitted with Biotech stainless-steel baffles gave satisfactory results at workable broth volumes; unbaffled and Bellco 600 flasks did not.
TL;DR: These studies indicate the quantitative and selective superiority of TSN agar, incubated at 46 C, over SPS agar.
Abstract: A new medium, Tryptone-sulfite-neomycin (TSN) agar, and an incubation procedure for the enumeration of Clostridium perfringens are described. Tolerance to neomycin, optimal growth at 46 C, and sulfite-reducing properties of C. perfringens were used as a basis for development of the medium. Comparisons were made between sulfite-polymyxin-sulfadiazine (SPS) agar and TSN agar at 37 and 46 C with C. perfringens and other organisms. These studies indicate the quantitative and selective superiority of TSN agar, incubated at 46 C, over SPS agar.
TL;DR: Organisms isolated from activated sludge and identified as Zoogloea ramigera accumulated large amounts of sudanophilic granules as the cultures flocculated, noting as a possible mechanism of flocculation the accumulation of PHB.
Abstract: Organisms isolated from activated sludge and identified as Zoogloea ramigera accumulated large amounts of sudanophilic granules as the cultures flocculated The granules were extracted by chloroform and precipitated with ether from acid-hydrolyzed cells Identification of the sudanophilic granules as poly-beta-hydroxybutyric acid (PHB) was confirmed by physical, chemical, and infrared spectral analyses The isolated polymer accounted for 120 to 505% of the dry weight of the cells The polymer was not synthesized when the culture was grown in a growth-limiting concentration of organic substrate; it did accumulate when the culture was grown in medium enriched with carbon and energy sources An increase in concentration of intracellular PHB was directly proportional to optical density and uptake of glucose Aside from intracellular storage of PHB as endogenous metabolite, the accumulation of PHB is noted as a possible mechanism of flocculation
TL;DR: This article corrects the article on p. 249 in vol.
Abstract: Two new antibiotics, structurally related to cephalothin, have been given the generic names cephaloglycin and cephaloridine. Cephaloglycin is the dipolar ion of 7-(d-alpha-aminophenylacetamido)-cephalosporanic acid. Cephaloridine is 7-[alpha-(2-thiophene)acetamido]-3-(1-pyridylmethyl)-3-cephem-4-carboxylic acid betaine. These new compounds were evaluated simultaneously. The broad spectrum of activity observed in vitro and in vivo with both antibiotics, the good oral absorption obtained with cephaloglycin, and the stability of cephaloridine are emphasized. The data suggest that both antibiotics merit clinical trial in humans.
TL;DR: The thermal inactivation characteristics of Bacillus subtilis A spores suspended in skim milk with the use of large-scale ultrahigh temperature (UHT) processing equipment were investigated in terms of survival as measured with two plating media.
Abstract: The thermal inactivation characteristics of Bacillus subtilis A spores suspended in skim milk with the use of large-scale ultrahigh temperature (UHT) processing equipment were investigated in terms of survival as measured with two plating media. Data on survival immediately after UHT treatments were recorded in temperature-survivor curves, time-survivor curves, and decimal reduction time (DRT) curves. The temperature-survivor curves emphasized that inactivation is accelerated more by increases in the treatment temperature than by increases in the exposure time. Time-survivor curves and DRT curves were not linear. Generally, exceedingly concave time-survivor curves were observed with the standard plating medium; however, only slightly concave curves were observed when CaCl(2) and sodium dipicolinate were added to the medium. For a given UHT sample, larger D values were obtained by use of the medium with the added CaCl(2) and sodium dipicolinate. The DRT curves of all data were concave and appeared to have two discrete slopes (z(D) values). The z(D) values observed in the upper UHT range (above 260 F; 127 C) were twice those observed at lower test temperatures.
TL;DR: A comparative estimation of the coliform population of raw sewage, activated sludge, and the effluent derived therefrom revealed that raw sewage had a preponderance of Escherichia coli (75%), as compared with 25 and 30%, respectively, in sludge and effluent.
Abstract: A comparative estimation of the coliform population of raw sewage, activated sludge, and the effluent derived therefrom revealed that raw sewage had a preponderance of Escherichia coli (75%), as compared with 25 and 30%, respectively, in sludge and effluent. Nitrogen-free mannitol-sucrose enrichments of activated sludge resulted in the isolation of Azotobacter agilis, Aerobacter aerogenes, Corynebacterium laevaniformans, and an Achromabacter species. Sludge had a large population of C. laevaniformans and A. aerogenes but not of Azotobacter. The bacterial parasites, Bdellovibrio and bacteriophages, were not active during activated-sludge treatment. A 10-fold reduction in phage content occurred after 2 hr of aeration, but the Bdellovibrio population was unaffected.
TL;DR: The inhibitory effects of carob pod extract upon the cellulolysis and deamination were correlated mainly with its sugar, rather than its tannin components, and proteolytic activity and protein biosynthesis were more significantly affected by the tannIn fraction.
Abstract: Carob pod extract and its tannin and sugar fractions were compared with gallotannic acid and sucrose for their effect on the cellulolytic, proteolytic, protein biosynthetic, and deaminative activities of rumen microorganisms The inhibitory effects of carob pod extract upon the cellulolysis and deamination were correlated mainly with its sugar, rather than its tannin components On the other hand, proteolytic activity and protein biosynthesis were more significantly affected by the tannin fraction In contrast to the tannin fraction of carob pod extract, gallotannic acid inhibited cellulolytic activity The harmful effect of a low concentration of tannins on protein biosynthesis could be prevented by the addition of carbohydrates to the reaction mixture At high tannin concentration (40 μg/ml), however, the addition of carbohydrates did not prevent the inhibition
TL;DR: It was shown that extensive or total losses of virus may attend filtration at these porosities, apparently owing to adsorption of the virus to the membrane matrix, and the degree to which these factors were critical was found to decrease with increasing pore diameter.
Abstract: The filtration of two species of enteroviruses through membranes of porosity ranging from 50 to 220 mmu was studied. It was shown that extensive or total losses of virus may attend filtration at these porosities, apparently owing to adsorption of the virus to the membrane matrix. This could be minimized by the incorporation of serum into the virus suspension at the time of filtration, or by pretreating the membrane with serum or with a gelatin solution. It was also found that the first few drops of filtrate, even under optimal conditions, were likely to be virus-free, so that the filtration of too small a volume of virus suspension would result in a relatively great loss of titer. The degree to which these factors were critical was found to decrease with increasing pore diameter.
TL;DR: Investigation revealed that factors present in Yeast Nitrogen Base medium could reverse the inhibition which was due to antagonism, and the major factor found was nicotinamide, and further study revealed that the biological availability of this compound was influenced by the pH of the medium.
Abstract: The growth of Staphylococcus aureus MF 31 was suppressed when grown in association with Streptococcus diacetilactis and other lactic streptococci. The data indicated that the initial proportion of staphylococci present in the medium was of less importance than the depletion of vital nutrients. Investigation revealed that factors present in Yeast Nitrogen Base medium could reverse the inhibition which was due to antagonism. The major factor found was nicotinamide, and further study revealed that the biological availability of this compound was influenced by the pH of the medium. The addition of nicotinamide to depleted media with careful control of the pH resulted in increased growth of S. aureus in the test system. Further data indicated that additional factors may affect the degree of growth by S. aureus in depleted media.
TL;DR: Erwinia-like microorganisms were isolated from the vital organs of a large deer population examined as well as from 13% of a small random sampling and from throat cultures of children and one adolescent.
Abstract: Erwinia-like microorganisms were isolated from the vital organs of more than 40% of a large deer population examined as well as from 13% of a small random sampling. Over a brief period of observation, a similar isolate was recovered from throat cultures of two children and one adolescent. There is no obvious explanation of the presence of the plant pathogen or its significance under these circumstances.
TL;DR: It was concluded that a method is now available to determine directly and unequivocally the role played in spoilage by various bacterial groups and that it is no longer necessary to rely on indirect evidence.
Abstract: A total of 807 bacterial isolates from fresh and spoiling fillets of English sole (Parophrys vetulus) stored at 5 C were classified as to genus and tested for various biochemical activities, including the ability to spoil sterile muscle press juice at 5 C. Production of off-odor, volatile reducing substances, and trimethylamine was used to estimate spoilage. It was found that (i) spoilers could be distinguished from nonspoilers on the basis of the juice spoilage test, (ii) differentiation between spoilers and nonspoilers could not be achieved by means of the usual biochemical tests, (iii) no micrococci, flavobacteria, and “coryneforms” were spoilers, (iv) certain specific subgroups of the genus Pseudomonas consisted exclusively of spoilers whereas others were inactive, (v) the genus Achromobacter likewise consisted of spoilers and nonspoilers, and (vi) “coliforms” could produce spoilage. It was concluded that a method is now available to determine directly and unequivocally the role played in spoilage by various bacterial groups and that it is no longer necessary to rely on indirect evidence.
TL;DR: The results suggest that the color systems which seem most practically appealing and effective to specialists on actinomycetes are those embracing a limited number of color names and groups, including the color-wheel system of Tresner and Backus.
Abstract: A report summarizing the results of an international workshop on determination of color of streptomycetes is presented. The results suggest that the color systems which seem most practically appealing and effective to specialists on actinomycetes are those embracing a limited number of color names and groups. The broad groupings allow placement of isolates into reasonably well-defined categories based on color of aerial mycelium. Attempts to expand such systems (more color groups) lead to difficulties. It is common knowledge that many, if not all, of the individual groups would in these broad systems contain strains that differ in many other respects, e.g., spore-wall ornamentation, color of vegetative (substratal) mycelium, morphology of chains of spores, and numerous physiological criteria. Also, cultures of intermediate color can be found, which makes placement difficult. As it now stands, color as a criterion for characterization of streptomycetes and streptoverticillia is in questionable status. Although much useful color information can be obtained by an individual, the application of this information to that in the literature or its use in communication with other individuals leaves much to be desired. More objective methods of color determination are needed. At present, the most effective method that could be used internationally is the color-wheel system of Tresner and Backus. Furthermore, the significance of color in speciation of these organisms is an open question. Obviously, more critical work on the color problem is needed.