- Volume 23, Issue 3, 1973

Relatedness among soft-rot-producing organisms of the genus Pectobacterium Waldee was assessed by means of interspecific deoxyribonucleic acid reassoci-ation followed by chromatography on hydroxyapatite. Relatedness was also determined between pectobacteria and representatives from all other established genera of the family Enterobacteriaceae. The results indicate five distinct groups of pectobacteria: (i) Pectobacterium carotovorum (Jones) Waldee, including Erwinia aroideae (Townsend) Holland, E. atroseptica (van Hall) Jennison, E. solanisapra (Harrison) Holland, and Bacillus oleraceae Harrison; (ii) P. carnegieana (Lightle et al.) comb, nov.; (iii) cornstalk-rot bacterium and P. chrysanthemi (Burkholder et al.) comb. nov. (including E. dieffenbachiae McFadden, E. cytolytica Chester, and P. carotovorum f. sp. parthenii); (iv) P. cypripedii (Hori) comb, nov.; and (v) P. rhapontici (Millard) Patel and Kulkarni. Relatedness between groups of pectobacteria is 20 to 50% except between the P. carotovorum group and strains of P. carnegieana, which exhibit 60 to 70% relatedness. With few exceptions, the pectobacteria are 20 to 50% related to other members of the family Enterobacteriaceae. The data presented support the inclusion of pectobacteria in the family Enterobacteriaceae.

A study was made of the biochemical reactions of 109 strains of Enterobacter liquefaciens (Grimes and Hennerty) Ewing and 49 isolants resembling Bacterium rubidaeum Stapp. The results supported the recent transfer of E. liquefaciens to the genus Serratia Bizio by Bascomb et al. and indicated that Bacterium rubidaeum Stapp should also be transferred to Serratia as Serratia rubidaea (Stapp) comb, nov., the previous use of the name Serratia rubidaea by Stapp not having constituted valid publication of this name. According to proposals made, three species are recognized in the genus Serratia: S. marcescens, S. liquefaciens, and S. rubidaea. Means for differentiating the three species are provided. Strains 1284-57 (=ATCC 27592) and 2199-72 (= ATCC 27593) are proposed as the type and neotype strains, respectively, of S. liquefaciens and S. rubidaea.

Deoxyribonucleic acid hybridization among three immunological types of Corynebacterium renale (Migula) Ernst was carried out. The data indicated that hybridizations between the different types were lower than those obtained in the homologous systems and that the three types of C. renale are not too closely related.

Deoxyribonucleic acids (DNAs) from an unnamed species of microorganism (bovine encephalitis isolate) previously placed in the family Brucellaceae and from representative species of this family were thermally denatured to determine mole percentages of guanine plus cytosine (mol %G+C). The results established that DNA from the bovine encephalitis isolate had a mol %G+C of 37.3 ± 0.2, which was between values for Haemophilus influenzae and Francisella tularensis. Values for mol %G+C of the other microorganisms in this family agreed with previously reported data. A heterogenous group of microorganisms composed of six different overlapping genera and the BEI were in the range of 33 to 46 mol %G+C. Because the mol %G+C of the genera in this group did not differ statistically, the proper taxonomic position of recognized members of the family Brucellaceae was questioned.

An alkaline-amylase-producing, alkalophilic bacillus, NRRL B-3881, was characterized and compared with Bacillus sp. ATCC 21591 and Bacillus alcalophilus Vedder strain NCTC 4553 (=ATCC 27647), which is here designated as the type strain of B. alcalophilus. All three strains contained. motile, gram-positive rods with rounded ends and swollen, clavate sporangia with oval, terminal to subterminal endospores. All three strains grew in soybean broth; were facultatively anaerobic; hydrolyzed starch, gelatin, and casein; reduced methylene blue; and fermented the following carbohydrates without gas production: sucrose, D-glucose, lactose, maltose, D-mannitol, D-xylose, L-arabinose, glycerol, sorbitol, and salicin. None produced acetylmethylcarbinol, indole, urease, or crystalline dextrins. Bacillus sp. ATCC 21591 and Bacillus sp. NRRL B-3881, but not NCTC 4553, reduced nitrate to nitrite, utilized citrate, and grew well in 12% NaCl and slowly in 15% NaCl. B. alcalophilus NCTC 4553 did not grow in 5% NaCl. In our opinion, these differences are sufficient to justify the establishment of a separate subspecies for ATCC 21591, NRRL B-3881, and similar strains. We propose the name B. alcalophilus subsp. halodurans as the name for this new subspecies. The name of the type subspecies, which contains the type strain, NCTC 4553, is B. alcalophilus subsp. alcalophilus Vedder. NRRL B-3881 is designated as the type strain of B. alcalophilus subsp. halodurans and is available from the Northern Regional Research Laboratory. It has also been deposited in the American Type Culture Collection under the number 27557.

The use of whole mounts in the electron microscope study of Micromonospora chalcea is a rapid and simple method for obtaining morphologic information about both the spore and sporophore. Spore anomalies were observed by this method, and their anatomical basis was confirmed by thin sections. Spore shape and surface ornamentation varied with the age of the spore and should be taken into consideration when characterizing and comparing the spores of various isolates. The spore of M. chalcea is not an endospore as found either in the bacilli or in the thermoactinomycetes; it lacks the multilaminar inner coat found in these thermoresistant spores. The spore of M. chalcea appears to contain an outer coat, or possibly coats, and a less electron-dense, thick inner coat or cortex. The spore of M. chalcea differs from the spore of streptomycetes in lacking a sheath around the hyphal wall. This sheath surrounding the hyphal wall in streptomycetes contains the spore ornamentation such as spines or hairs, but in M. chalcea spore ornamentation arises in the outer portion of the spore wall as wart-like protuberances. The spore of M. chalcea appears to develop its coats in a centripetal fashion similar to streptomycetes. Cross walls in M. chalcea are double and appear to develop in a manner similar to streptomycetes in which the hyphal wall appears to “peel apart,” the inner portions being continuous with the cross walls. Mesosomes and nuclei found in thin sections of M. chalcea appear similar to those found in streptomycetes and other gram-positive bacteria. The electron microscope data obtained for M. chalcea ATCC 12452 in this study appear to be representative of the morphologic and anatomical features found in other species of Micromonospora that we have studied.

Cultures of Chloropseudom onas ethylica strain 2-K obtained from several laboratories were examined. All cultures examined to date in this laboratory contained nonmotile, green, photosynthetic bacteria (Chlorobiaceae) identical to published descriptions of Chlorokium limicola and at least one colorless, motile bacterium. All attempts to isolate motile photosynthetic bacteria corresponding to published descriptions of C. ethylica from such cultures have been unsuccessful. Several physiological characteristics previously ascribed to C. ethylica 2-K are expressions of mixed cultures rather than the property of a single species.

A bacterium with the general properties of a member of the family Pseudomonadaceae has been isolated from infusions of decaying marine algae (Nova Scotia). The organism possesses rigid, randomly arranged appendages that are nonprosthecate and can best be described as “echinuliform” (spinelike)..

The deoxyribonucleic acid base compositions of 14 newly isolated strains and the type strains of Prosthecomicrobium enhydrum, P. pneumaticum, and Ancalomicrobium adetum are reported. The guanine plus cytosine values of these strains range from 66.1 to 71.4 mol %.

Hydrolysates and cell extracts of 23 strains of Nocardia pellegrino were analyzed chemically. The components of the cell extracts indicated that the strains cannot be regarded as members of the genus Mycobacterium but that they belong to the genus Nocardia. Moreover, it is concluded that the strains of N. pellegrino constitute a uniform taxon and produce an LCN-A (lipid characteristic for Nocardia) similar to that produced by N. calcarea.

Forty-six strains of serratiae, including 10 strains of Serratia liquefaciens (syn.: Enterobacter liquefaciens) hydrolyzed chitin in a chitin-salts-Casamino Acids agar medium. Strains which were tested on chitin-salts agar were able to use chitin as a sole source of carbon, nitrogen, and energy. None of the other members of the family Enterobacteriaceae studied produced chitinase. The ability to hydrolyze chitin may be a useful characteristic in differentiating serratiae from other Enterobacteriaceae. However, many more strains will have to be tested for chitinase synthesis before the usefulness of the test can be determined.

In 269 parallel acetoin tests upon 212 strains of staphylococci and micrococci, 227 were positive by the 14-day tube method and 213 by a 2-day paper-disk method. Both tests showed the same percentage error in primary results.