Effect of Feeding Lactobacilli on the Coliform and Lactobacillus Flora of Intestinal Tissue and Feces from Piglets .

Development of fecal Lactobacillus and coliform in healthy newborn pigs during the first 48 h after birth was studied. Lactobacilli were detected (10 per g) in the feces of newborn pigs as early as 4 h after birth and colifroms by 8 h (10 per g). By 24 h the two types were present in near equal numbers (10 to 10/g).

Preparation and storage of high-titer lactic streptococcus bacteriophages.

Various techniques were employed for preparation of high-titer bacteriophage lysates of Streptococcus lactis, S. cremoris, and S. diacetilactis strains.

Carbohydrate metabolism in lactic streptococci: fate of galactose supplied in free or disaccharide form.

Phosphorylation of free galactose by lactic streptococci was mediated by an adenosine triphosphate (ATP)-dependent kinase. The phosphoenolpyruvate (PEP) phosphotransferase system (PTS) was involved to a limited extent in transport of the sugar. The conversion of free galactose to glucose also was demonstrated, and uridine diphosphogalactose-4-epimerase was demonstrated to account for this change.

Cytological and deoxyribonucleic acid-deoxyribonucleic acid hybridization studies on lactobacillus isolates from San Francisco sourdough.

Molecular taxonomic and electron microscopy studies were performed on four bacterial isolates obtained from different sources of San Francisco sourdough (SD). These bacteria were first isolated by Kline and Sugihara who tentatively described them as a previously unreported species of heterofermentative Lactobacillus; they suggested the name Lactobacillus sanfrancisco. The guanine plus cytosine base composition (%GC) of the deoxyribonucleic acid (DNA) ranged from 38 to 40%.

-D-phosphogalactoside galactohydrolase of lactic streptococci.

beta-D-Phosphogalactoside galactohydrolase (beta-Pgal) was examined in a number of lactic streptococci by use of the chromogenic substrate o-nitrophenyl-beta-D-galactopyranoside-6-phosphate. Specific activity of beta-Pgal ranged from 0.563 units/mg of protein in Streptococcus lactis UN, to 0.

Lactose-hydrolyzing enzymes of Lactobacillus species.

beta-Galactosidase (beta-gal, EC 3.2.1.

Involvement of sulfhydryl groups in the -galactosidase of Streptococcus lactis.

Sulfhydryl oxidants and stabilizers caused changes demonstrating the sulfhydryl content of beta-galactosidase for Streptococcus lactis 7962. Ammonium sulfate (0.85 m) rendered the enzyme insensitive to the oxidants.

Extracellular nuclease in the genus Lactobacillus.

Several species and strains of lactobicilli, Bacillus coagulans, and Sporolactobacillus inulinus produced detectable amounts of extracellular nuclease which hydrolyzed ribonucleic acid and deoxyribonucleic acid.

Mechanisms of lactose utilization by lactic acid streptococci: enzymatic and genetic analyses.

The apparent instability of beta-galactosidase in toluene-treated cells or cell-free extracts of lactic streptococci is explained by the fact that these organisms do not contain the expected enzyme. Instead, various strains of Streptococcus lactis, S. cremoris, and S.

Enzymatic removal of diacetyl from beer. 3. Enzyme protection and regeneration of cofactor.

Use of diacetyl reductase, a reduced nicotinamide adenine dinucleotide (NADH)-requiring enzyme, to eliminate diacetyl off-flavor in beer was studied. The crude enzyme was extracted from Aerobacter aerogenes and partially purified by ammonium sulfate precipitation or Sephadex chromatography. In the semipure state, the enzyme was inactivated by lyophilization; in a crude state, the lyophilized extract remained stable for at least 4 months at - 20 C.

Deoxyribonucleic acid base composition of lactobacilli determined by thermal denaturation.

Moles per cent guanine plus cytosine content of 16 lactobacilli provided three taxonomic groups: I, 32.4 to 38.3% with five species; II, 42.

Enzymatic removal of diacetyl from beer. II. Further studies on the use of diacetyl reductase.

Diacetyl removal from beer was studied with whole cells and crude enzyme extracts of yeasts and bacteria. Cells of Streptococcus diacetilactis 18-16 destroyed diacetyl in solutions at a rate almost equal to that achieved by the addition of whole yeast cells. Yeast cells impregnated in a diatomaceous earth filter bed removed all diacetyl from solutions percolated through the bed.

Involvement of phosphoenolpyruvate in lactose utilization by group N streptococci.

The effect of sodium fluoride on lactose metabolism and o-nitrophenyl-beta-d-galactopyranoside (ONPG) hydrolysis by Streptococcus lactis strains 7962 and C(2)F suggested that different mechanisms of lactose utilization existed in the two strains. Sodium fluoride prevented lactose utilization and ONPG hydrolysis by whole cells of S. lactis C(2)F but had no effect on S.

Some factors influencing carbon dioxide production by Leuconostoc citrovorum.

This study was undertaken to determine whether Leuconostoc citrovorum plays a role in carbon dioxide production in milk. The ability of L. citrovorum strains to produce gas was studied by two methods.

Microbial destruction by low concentrations of hypochlorite and iodophor germicides in alkaline and acidified water.

Hypochlorite and iodophor germicides were evaluated for their ability to destroy a variety of organisms at levels approximating those used for final sanitizing rinse for dairy and food equipment and beverage bottles (3 to 50 ppm). Test organisms included Escherichia coli, Streptococcus lactis, Lactobacillus plantarum, Pediococcus cerevisiae, and Saccharomyces cerevisiae. The hypochlorites and iodophors demonstrated approximate rates of destruction at equivalent concentrations for the bacterial species tested, except where the hypochlorite contained excess alkalinity.

Purification and properties of Streptococcus lactis beta-galactosidase.

beta-Galactosidase of Streptococcus lactis 7962 was partially purified, and its properties were studied. Enzyme from only this strain of numerous lactic streptococci tested was stable in cell exudates prepared by various means. Cell-free extracts of the 7962 strain were prepared by sonic treatment of washed cells previously grown in presence of lactose to fully induce enzyme synthesis.

Influence of culture media on the radiation resistance of Micrococcus radiodurans.

The addition of NZ-case (a tryptic digest of casein) to a growth medium (PC) consisting of tryptone, glucose, and yeast extract caused a significant decrease in gamma radiation resistance of Micrococcus radiodurans. The level of radiation resistance was inversely related to the concentration of NZ-case. The ld(50) for this organism was approximately 700 krad when grown in tryptone, glucose, yeast extract, and dl-methionine (TGYM) broth, but it was approximately one-half as resistant when grown in a PC medium containing 0.

Evaluation of filters for removal of bacteriophages from air.

Glass wool, nonabsorbent cotton, fiberglass filter medium, and a commercial absolute filter were tested for effectiveness in removing aerosolized bacterial viruses under low flow rate (1 ft(3)/min) and high flow rate (10 to 25 ft(3)/min) air-flow conditions. Special equipment was designed for measurement of filter efficiencies under the two air-flow conditions. Under low air-flow rate test conditions, glass wool was only 98.