- Volume 53, Issue 3, 1968

SUMMARY: An Adansonian analysis was made on 100 isolates of Corynebacterium pyogenes with the aid of a digital computer. A wide variety of tests was used to define the isolates. The resulting dendrogram showed that C. pyogenes was a ‘good species’, with the 100 isolates related at high similarity values. No close affinity between biotype and host-species or between biotype and lesion was found, apart from the disposition within two adjacent groups of all of the isolates which originated from Swedish bulls.

SUMMARY: An oligotrich protozoon identified as Eudiplodinium medium was separated in pure culture and inoculated into the rumen of an isolated ciliate-free buffalo (Bos bubalus L.) calf to act as a continuous source of the organism. Analysis of the protozoa showed that a single organism contained on average 3.35 + 0.003 μg. protein; the carbohydrate fraction (49.1% of dry matter) gave on hydrolysis 60.4% glucose. Growth rate of the protozoa in vitro was dependent on food concentration. The number of protozoa was doubled in 2 hr at a substrate concentration of 0.23 mg./protozoon; at lower concentrations the doubling time was greater; at higher concentrations (0.32 mg./protozoon) the organisms burst.

Eudiplodinium medium did not metabolize simple sugars; it utilized starch, amylopectin, amylose and showed highest activity with hemicelluloses. Xylans were degraded faster than arabans; xylans gave relatively lower amounts of volatile acids than did arabans; acetic and butyric acids predominated, formic acid and traces of propionic and lactic acids were found but no succinic acid. No cellulose digestion took place during incubation for 12 hr; with longer periods of incubation with cellulose the organisms died. Ammonium salts, urea and amino acids were not used by the protozoa; proteolytic activity was observed towards gelatin, casein and gluten in descending order of activity. Cell-free extracts of E. medium showed activities towards carbohydrates as did whole organisms; xylanase activity was greatest. This enzyme was purified 28-fold; it had an optimum pH of 7.5 and an optimum temperature of 43°.

SUMMARY: Motility and flagellated sporangiospores are reported for the first time for the type culture (253) of Amorphosporangium auranticolor; microconidia on the substrate mycelia are also reported. Otherwise, the morphological description by Couch (1963) remains unchanged. Tests for utilization of 21 carbon sources, gelatin, starch, casein, tyrosine, and cellulose acetate, and for nitrate reduction have been made and the results are reported.

SUMMARY: Three geographical collections (isolates) of myxomycetes originally identified as Physarum flavicomum were found to be heterothallic and the clones established from each isolate were divided into two mating types. Previous studies of six isolates of P. flavicomum showed that they could be divided into three groups. Mating occurred within groups but not between groups, and within each group there were two or more mating types. When the new isolates were crossed to the original isolates, they conformed to two of these three groups. This study established the existence of multiple alleles at the incompatibility locus in group 3. Mating-type alleles of the F 1 generation of group 3 segregated in a 1:1 ratio at meiosis. Isolates belonging to group 1 were also separated from the other two groups on morphological and physiological bases. The morphological description fits that of P. rigidum more nearly than P. flavicomum and group 1 isolates were placed in the species P. rigidum. Groups 2 and 3 were separated genetically and physiologically but morphologically the separation was not distinct. These groups were referred to as P. flavicomum varieties 1 and 2.

SUMMARY: Physarum rigidum grew and sporulated in pure culture at pH 4.2 on a partially defined medium containing: mineral salts, glucose, yeast extract, haematin, casein hydrolysate. The inoculum equiv. 0.22 mg. protein/25 ml. grew to equiv. 21.5 mg. protein/25 ml. in about 12 days. Physarum flavicomum varieties 1 and 2 also grew and sporulated on this medium. The yeast extract and haematin were essential for growth; the casein hydrolysate was not. Omission of glucose resulted in a 50% decrease in growth yield. Ethanol, galactose, glycerol, lactose, mannitol, mannose, potato starch, raffinose or sorbitol could replace glucose, but the growth yield was decreased. Fructose, inulin, sucrose and the pentoses and carboxylic acids tested did not support growth.

SUMMARY: In axenic medium with TEM-4T (a tartaric acid ester of beef tallow monoglyceride) as a source of fatty acids, regulation of the growth of Paramecium aurelia, stock 299, was achieved by varying the relative amounts of TEM-4T and stigmasterol. Optimal populations were reached in 7 days at 27° when the relative proportion of these lipids was 10:1 (w/w) TEM-4T: stigmasterol. Division was inhibited at ratios of 2:1 (w/w) or less. The inhibition was annulled by restoration of the ‘optimal’ ratios of TEM-4T: stigmasterol to the growth medium even after the protozoa had been exposed to ‘inhibitory’ ratios for periods up to 6 days. Growth was also inhibited when the relative proportions of TEM-4T: stigmasterol were adjusted to 2:1 (w/w) by the addition of TEM-4T to the culture after a 3-day period during which the organisms had been incubated with stigmasterol alone. No inhibition was observed when the TEM-4T: stigmasterol ratio was adjusted to 2:1 (w/w) by adding stigmasterol to the culture after a period of incubation with TEM-4T alone. It is suggested that under conditions of lipid imbalance in the medium stigmasterol interferes with the utilization of TEM-4T for growth.

SUMMARY: Thirteen strains previously assigned to the species Pseudomonas diminuta and P. vesiculare were subjected to detailed characterization. Ten of these strains could be identified as P. diminuta and two as P. vesiculare. These two species can be readily distinguished by differences in their nutritional spectra, their growth factor requirements and their pigmentation. The DNA of the two strains of P. vesiculare contained 65.8 moles% guanine+cytosine (GC), and the DNA of the ten strains of P. diminuta from 66.3 to 67.3 moles%. One of the 13 strains examined had DNA of significantly lower GC content (62.2 moles%) and also differed in several phenotypic respects from both species; it is probably a monotypic representative of a third species, as yet unnamed.

All the strains examined share a series of distinctive properties, which justify their recognition as a special subgroup of aerobic pseudomonads. The defining characters of this subgroup include: monotrichous flagellation, with flagella of very short wavelength; a requirement for pantothenate, biotin and cyanocobalamin; a limited range of carbon sources; production of acid from primary alcohols by all strains that can utilize alcohols; inability to denitrify or to use nitrate as a nitrogen source; and accumulation of poly-β-hydroxybutyrate as an intracellular reserve.

SUMMARY: A selection procedure was developed for the isolation of mutants of Escherichia coli which require lipoic acid, acetate+succinate, or lysine + methionine for aerobic growth with glucose. The properties of the mutants requiring lipoic acid (lip −) were compared with those of suc − mutants which lack α-ketoglutarate dehydrogenase and require succinate or lysine + methionine. Genetic analysis by conjugation with Hfr and F’ donors indicated that the genetic loci of some 36 independently isolated lip − mutants are confined to a small segment of the E. coli chromosome between the purE and suc sites. By using phage P1 no cotransduction of lip with suc, glt A or purE could be demonstrated, but suc, gltA and gal were cotransducible and the relative order of these sites was determined.

SUMMARY: L-Alanine-initiated germination of spores of Bacillus cereus was potentiated by the following structural analogues of alanine: O-carbamyl-D-serine (OCDS), D-cycloserine (DCS), β-alanylhydroxamic acid (βAHA) and glycyl hydroxamic acid (GHA); but not by D-α-alanyl-hydroxamic acid (DAHA). Potentiation of germination resulted from inhibition of alanine racemase in the spores with consequent suppression of the formation of D-alanine, an inhibitor of L-alanine-initiated germination. OCDS was the most effective potentiator of germination and inhibitor of racemase. βAHA and GHA were more effective potentiators of germination than could be explained solely by their weak inhibition of the racemase. The extra effectiveness was associated with slow binding of the analogues to the spores, and possibly also with formation of hydroxylamine which also inhibited alanine racemase and potentiated L-alanine-initiated germination. Germination initiated by ribosides and amino acids other than L-alanine was not strongly potentiated by OCDS, arguing against a role for L-alanine as an intermediate. However, germination initiated by adenosine+D-alanine was strongly inhibited by OCDS, which argues for the role of D-alanine being to supply the L-isomer by racemization. Antibacterial activities of the analogues did not mirror their activities as potentiators of germination.

SUMMARY: The envelope of Escherichia coli B exhibited areas at which cell wall and protoplasmic membrane were intimately associated. These areas became visible in ultrathin sections after the bacteria had been fixed and embedded in plasmolysed state. At numerous areas the protoplasmic membrane was observed to adhere to the wall, while the protoplast had shrunk. Duct-like extensions of the protoplasmic membrane were thus formed. Two hundred to 400 of these wall membrane associations are found per bacterium of E. coli B. In a number of cells the chromosomal material is seen in close proximity or connected to a wall membrane association.

SUMMARY: Electrophoresis patterns of soluble protein of 34 strains and esterases of 113 strains of lactic acid bacteria were determined. Similar protein patterns were obtained for the three species of lactic acid streptococci; with the lactobacilli most species gave constant species-specific patterns, but Lactobacillus acidophilus and L. delbrueckii strains differed markedly among themselves. Esterase patterns of lactic streptococci were generally species specific. Among the lactobacilli the thermobacteria had weak esterase activity which was only species specific for L. lactis, L. leichmanii and L. salivarius; in the streptobacteria, L. casei had a very consistent esterase pattern, whereas L. plantarum had very different patterns within the species; the unclassified strains were different from each other; in the betabacteria activity was weak and no consistent pattern of bands occurred. Leuconostocs grouped in patterns corresponding to their physiological groups. Esterases of a streptococcus and a lactobacillus examined were classified as ali esterases. When ten strains of lactic acid bacteria were tested for substrate specificity, nine of them had a higher activity against α-naphthyl acetate than against the butyrate and caprylate. A rapid test for esterase activity of whole organisms is described.

SUMMARY: A solidified medium (NP medium) was devised which supported luxuriant growth of Clostridium novyi type B. It consists of peptone, extracts of yeast and liver, blood, glucose and certain other compounds essential as nutrients and/or for poising oxidation-reduction potential. The peptone could be replaced by a commercial preparation of acid-hydrolysed casein or a mixture of 18 amino acids, but the presence of cysteine and either ascorbic acid, thioglycollate (mercapto-acetate) or dithiothreitol (DTT) was essential for consistent rapid and luxuriant surface growth. Blood was not essential in media supplemented with cysteine and DTT, although in its presence the number of colonies which developed was maximal and the formation of zones of haemolysis facilitated the location of smaller colonies. When supplemented with cysteine+DTT several other solidified media, none of which contained yeast—or liver—extract, supported good growth. By incorporating antitoxin into certain clear blood-free plating media containing cysteine+DTT it was possible to show that only some bacilli of a culture produced colonies which developed opaque haloes of toxin antitoxin flocculum. A liquid version of the NP medium was also devised.

SUMMARY: A method for the preparation of protoplasts of Bacillus megaterium is described. The protoplasts obtained were very active metabolically and lysates of them were rich in polyribosomes. Methods for the detection of polyribosomes and of nascent peptides are detailed.