Franco Dellaglio

Deoxyribonucleic Acid Homology Among Lactobacillus Species of the Subgenus Streptobacterium Orla-Jensen

The deoxyribonucleic acid (DNA) relationship among Lactobacillus species of the subgenus Streptobacterium Orla-Jensen was assessed by means of DNA/DNA hybridization experiments. High genetic homologies were found among Lactobacillus casei subsp. casei, L. casei subsp. alactosus, L. casei subsp. pseudoplantarum, and L. casei subsp. tolerans; however, there was only a low level of homology between the DNA of L. casei subsp. rhamnosus and the DNA of other subspecies of L. casei. The DNAs of Lactobacterium zeae ATCC 15820 and L. casei subsp. casei ATCC 393 were nearly completely homologous. Although the latter strain has been proposed as the neotype for L. casei, it is not related to any of the other strains within the subspecies of L. casei. Lactobacillus plantarum and strains identified as belonging to L. plantarum subsp. rudensis and L. plantarum subsp. arabinosus formed a fairly homogeneous and easily recognized group. The DNA of Lactobacillus pentosus was unrelated to that of any known streptobacteria, and we therefore advocate the recognition of this organism as an independent species. There is a high degree of homology between Lactobacillus sake and Lactobacillus homohiochi; the name L. sake has priority, and L. homohiochi is very probably a synonym; for the same reason, Lactobacillus yamanashiensis has priority over its later subjective synonym, Lactobacillus mali. The general DNA/DNA homology relationships among Lactobacillus casei, L. plantarum, L. coryniformis, L. curvatus, L. xylosus, L. alimentarius, L. farciminis, and Sporolactobacillus inulinus justify their status as separate species.

Taxonomy of Lactobacilli isolated from the alimentary tract of chickens

Summary One hundred and seventy six strains of rod-shaped lactic acid bacteria, 144 homofermentative and 32 heterofermentative, were isolated from different sections of the digestive tracts of 30 chickens. Chemotaxonomic and genetic characteristics revealed that homofermentative strains isolated from crops, belong to Lactobacillus salivarius whereas homofermentative strains from the intestinal tract can be allocated to the different groups of L. acidophilus and to L. salivarius . Of the 32 heterofermentative strains, 30 were assigned to L. reuteri .

Genetic heterogeneity among Lactobacillus acidophilus strains.

Physiological characteristics, DNA base composition (% GC) and DNA-DNA reassociation values were determined for 138 Lactobacillus acidophilus strains. Twenty seven strains were received from various culture collections and 111 strains were freshly isolated during a study on the composition of the intestinal lactic microflora of piglets and suckling calves.All strains had physiological characteristics which were substantially similar. The strains isolated from pigs were unable to ferment trehalose. The % GC ranged from 35.8 to 43.4.On the basis of the results of DNA-DNA hybridization the strains were divided into four genetic groups.

Lactic Acid Bacteria in Ensiled High-Moisture Corn Grain: Physiological and Genetic Characterization

Summary Of 335 lactic acid bacteria, isolated from high-moisture corn grain, 212 were checked for their physiological characteristics and 59 representative strains were chosen for DNA-DNA hybridization. All the homofermentative lactobacilli tested were highly related to the type strain of Lactobacillus plantarum . The pediococci isolated were allotted to Pediococcus pentosaceus . Of the heterofermentative lactic acid bacteria the cocci were classified as Leuconostoc paramesenteroides , the lactobacilli as Lactobacillus brevis . The presence of plasmids was demonstrated in all the species studied.

Classification of Citrate Fermenting Lactobacilli Isolated from Lamb Stomach, Sheep Milk and Pecorino Romano Cheese

Summary Three hundred and thirty strains of citrate-fermenting lactobacilli were isolated from lamb stomach, lamb rennet paste, sheep milk and Pecorino Romano cheese. Fifty-two representative strains belonging to four physiological groups were checked for their genetic relationship using the DNA-DNA hybridization test. Most of the hetero-fermentative strains, isolated from lamb stomach and lamb rennet paste belonged to Lactobacillus reuteri , while the others were found to be related to L. fermentum . The homofermentative citrate-fermenting lactobacilli, isolated mainly from Pecorino Romano cheese, shared high levels of genetic homology with L. plantarum . Only one strain was found to be similar to L. casei .

DNA-DNA homology among representative strains of the genus Pediococcus

Summary About sixty strains of Pediococcus received from different collections were studied by means of DNA-DNA hybridization using the filter competition method and employing eight reference strains. Seven homology groups (78 to 107 per cent homology) were distinguished showing negligible deoxyribonucleic acid interrelatedness among each other (zero to 20 per cent). Five of these groups correspond to the five named species reported in Kitaharas system in the 8 th edition of Bergeys Manual (Buchanan and Gibbons, 1974), namely Pediococcus cerevisiae (= P. damnosus), P. acidilactici, P. pentosaceus, P. halophilus and P. urinae-equi. A sixth group consists of the strains isolated and named P. parvulus by Gunther et al. (1962). The seventh homology group consists of only two strains, ATCC 10400 and NCIB 9208, representative of Aerococcus viridans (Williams et al., 1953).

Presence of Lactobacillus helveticus and an L(+)-lactic acid former in Bulgarian sour milk

Summary Some strains of “thermophilic” lactic acid bacteria isolated from Bulgarian Sour Milk were assigned to the biotype jugurti of Lactobacillus helveticus on account of their physiological and genetical characteristics. One of these strains produces only L(+)-lactic acid.

DNA-DNA homology of Pediococcus strains isolated from some Italian cheeses

Summary The DNA-DNA homology of 71 strains of Pediococcus isolated from Italian cheeses with Pediococcus pentosaceus NCDO 1220 and P. acidilactici ATCC 25742 was determined. Twenty-seven of the 34 strains isolated from Grana are affiliated to P. acidilactici but only 7 to P. pentosaceus . Of the 24 strains isolated from Pecorino Romano 5 strains showed a high percentage of DNA-DNA homology with P. acidilactici and 19 with P. pentosaceus . All the other strains isolated from Provolone, Casera Valsassina and Canestrato Siciliano Pepato belong to the species P. pentosaceus .