1,721,166 research outputs found
Related Genera Within the Family Bifidobacteriaceae
No full textWithin the class of Actinobacteria, Stackebrandt et al. (1997) proposed the new order Bifidobacteriales with the
family Bifidobacteriaceae as type family of the order. At that time only two genera were described to be members of
the Bifidobacteriaceae (i.e., the genus Bifidobacterium as a type genus and the genus Gardnerella). Following the new
classification system, phylogenetically closely related genera are clustered into the family Bifidobacteriaceae on the
basis of 16S rRNA/DNA sequences analysis; this is of paramount importance in the new taxonomic vision if compared
to the more traditional chemotaxonomic, morphological, and physiological properties. In the following years
the family Bifidobacteriaceae was expanded so that at present in addition to Bifidobacterium (Orla-Jensen, 1924) with
54 validated species and ten subspecies, and Gardnerella (Greenwood and Pickett, 1980) with the species Gardnerella
vaginalis, another seven genera were allocated in the family. This chapter will be devoted to the so-called scardovial
genera, since the genus Bifidobacterium will be treated in a separate chapter while the genus Gardnerella is marginal
for the scope of the present book and is already well represented in the literature. The new taxa belonging to the
scardovial genera were isolated from a variety of habitats: Aeriscardovia aeriphila from a porcine cecum, Alloscardovia
omnicolens from human clinical samples, Alloscardovia macacae from the milk of a macaque, Alloscardovia criceti from
dental plaque of golden hamsters, Bombiscardovia coagulans from the digestive tract of bumblebees, Neoscardovia arbecensis
from porcine slurries, Parascardovia denticolens from human dental caries, Pseudoscardovia suis and P. radai from
the digestive tract of wild pigs, Scardovia inopinata from human dental caries, and S. wiggsiae from a wound infection
in the arm of an intravenous drug user. Considering the use of beneficial bacteria in different applications, one aspect
of great importance refers to their classification into risk groups. Most countries use a four-level risk group system
according to their virulence and potential danger to humans. Almost all the species belonging to scardovial genera
are classified in risk group 1 that refers to organisms that generally do not cause disease in healthy adult humans.
Only Alloscardovia omnicolens is classified into risk group 2, which refers to microorganisms with a moderate risk for
humans. The data on the risk level were obtained from Deutsche Sammlung von Mikroorganismen und Zellkulturen
and are partially based on the list from Technical Rules for Biological Agents. Within the family Bifidobacteriaceae the
major genera include Bifidobacterium and Gardnerella. Bifidobacteria are playing an important role in the development
of new concepts related to beneficial bacteria found in human and animal intestinal tracts. Their use in food
and pharmaceutical preparations as probiotics is a fast-growing business. Gardnerella vaginalis is the only species
of this genus. Isolated from the human genital and urinary tracts, it is classified in risk group 2. For a long time it
has been considered as the etiological agent of bacterial vaginosis. Nowadays it is assumed that bacterial vaginosis
is associated with a large spectrum of anaerobic bacteria. The role of G. vaginalis in this disease is controversial, as
demonstrated in recent studies that demonstrated a high rate of detection of G. vaginalis in subjects without bacterial
vaginosis (Fredricks et al., 2007)
Bifidobacterium ruminantium sp. nov. and Bifidobacterium merycicum sp. nov. from the rumens of cattle
No full textAmong several hundred bifidobacteria isolated from bovine rumens, eight strains were recognized primarily on the basis of DNA-DNA hybridization results as members of two new distinct DNA homology groups. We studied the morphology, oxygen, carbon dioxide, temperature, and pH requirements, fermentation patterns, end products of glucose fermentation, biochemical reactions, protein electrophoretic patterns, isozyme patterns, DNA homology relationships, and guanine-plus-cytosine contents of these organisms, and we propose that these two groups of strains should be considered new species, Bifidobacterium ruminantium (type strain, strain ATCC 49390) and Bifidobacterium merycicum (type strain, strain ATCC 49391)
Influence of aminoacid requirement on the growth of Bifidobacterium globosum strains
No full textA general procedure has been devised for the determination of aminoacid requirements in Bifidobacterium globosum strains, based upon identification of individual aminoacids singularly deprived of the defined synthetic medium. In the plasmid-positive and plasmid-negative clones of RU 809 and T 19 strains, we found a correlation between the presence of plasmid and L-leucine auxotrophy. This characteristic is not shared by the other 145 strains, 26 of which are plasmid-positive, of the B. globosum species
L-leucine auxotrophy in Bifidobacterium globosum
No full textThe enzymes involved in the biosynthetic pathway of L-leucine were studied in plasmid-negative and plasmid-positive clones derived from the RU 809 strain of the Bifidobacterium globosum species. The growth of plasmid-positive clones in synthetic medium required L-leucine. We have shown that no detectable activity of the β-isopropylmalate dehydrogenase enzyme was present in plasmid-positive clones, whereas detectable and significant activity of this enzyme was found in plasmid-negative clones. The lack of activity of the β-isopropylmalate dehydrogenase enzyme is considered responsible for the L-leucine auxotrophy in the plasmid-positive clones
Probiotics and prebiotics in animal health and food safety
No full textThis book discusses the role of probiotics and prebiotics in maintaining the health status of a broad range of animal groups used for food production. It also highlights the use of beneficial microorganisms as protective agents in animal derived foods. The book provides essential information on the characterization and definition of probiotics on the basis of recently released guidelines and reflecting the latest trends in bacterial taxonomy. Last but not least, it discusses the concept of “dead” probiotics and their benefits to animal health in detail. The book will benefit all professors, students, researchers and practitioners in academia and industry whose work involves biotechnology, veterinary sciences or food productio
Identification of bifidobacteria from fermented milk products
No full textSix samples of fermented milk preparations were examined for the presence of bifidobacteria. Identification was based on fermentation tests, genetic relatedness studies and electrophoretic analysis. Contrary to label information, Bifidobacterium animalis was the only species present
Bifidobacterium saeculare: a New Species Isolated from Feces of Rabbit
No full textIn a previous investigation, some bifidobacteria isolated from rabbit feces were characterized as “unassigned homology group I”. New evidence derived from studies on DNA-DNA homology, phenotypic characters and electrophoretic patterns of proteins and of isozymes suggests that “unassigned homology group I” represents a new species of the genus Bifidobacterium, described in this paper as Bifidobacterium saeculare (type strain ATCC 49392). © 1991, Gustav Fischer Verlag, Stuttgart · New York. All rights reserved
Species in the Genus Bifidobacterium
No full textBifidobacteria were first described at the beginning of 1900 by the French paediatrician Tissier (Tissier, 1900), who
observed a low number of bacteria characterized by a peculiar Y-shaped morphology in stools of infants with gastrointestinal
disturbances when compared with those from healthy infants. He suggested that these bacteria could be administered
to patients with diarrhea to help to restore a healthy gut microbiota. At the same time Metchnikoff, a Russian
zoologist, pioneer researcher on immunology, correlated the potential life-lengthening properties of lactic acid bacteria
with the longevity of Bulgarian peasants consuming large amounts of yogurt (Metchnikoff, 1908). This intuition has
been the basis of the current concept that bifidobacteria are often associated with health-promoting activities, either as
an endogenous member of the gut microbiota (immunomodulation, antagonistic activity toward pathogens, etc.) or as
allochthonous probiotics species (restoring healthy gut microbiota). The intestinal microbiota studies started to reveal
the great influence of bifidobacteria, which are considered helpful not only in the gastrointestinal apparatus but also in
other systems, such as nervous [e.g., depression (Savignac et al., 2015)] and bone [e.g., arthritis reumatoides (Zamani
et al., 2016)] systems. The current extensive genomic analyses will allow a deeper understanding of bifidobacterial
diversity and will reveal host–bifidobacterial interactions in a more precise manner that could help in maintaining human
and animal health. At the basis of all these studies, there is the knowledge of bifidobacterial species features and
occurrence and the discovery of new species, obtaining new isolates that could be investigated for beneficial propertie
Characterization of the plasmid pVS809 from Bifidobacterium globosum
No full textA plasmid from a B. globosum strain was cut with 38 restriction enzymes and a physical map was constructed. Out of a total of 121 clones from curing experiments, plasmid was lost in 58% and 100% for acridine orange and ethidium bromide curing agent respectively. The plasmid does not exist as a chromosomal integrated form. An attempt to determine phenotypic characters encoded by the plasmid was made by electrophoretic analyses of the total proteins
Effect of growth temperature on the biosynthesis of cell wall proteins from Bifidobacterium globosum
No full textSeventy strains of Bifidobacterium globosum isolated from gastrointestinal tracts of different animals were studied. Strains were grown at temperatures ranging from 25 to 46.5°C in order to examine changes both in the expression of bifidobacterial outer proteins (BIFOPs) and in their hydrophobic properties. It was observed that the expression of BIFOPs found on the cell-surface changes according to growth temperature, with quantitative and/or qualitative variations. Generally speaking, it was observed that BIFOP expression at low-growth temperature was considerably attenuated, while at medium- and high-growth temperature it increased. Furthermore, at high-growth temperatures, the presence of a new common protein was detected in all the strains studied. Cells from B. globosum strains grown under different temperature conditions were studied in terms of their cellular hydrophobicity properties. At medium-growth temperature, the cell hydrophobicity was strictly correlated with BIFOP expression, while at low and high-growth temperatures, the presence of BIFOP only partially influenced the hydrophobic features
- …
