Omics of bifidobacteria: research and insights into their health-promoting activities

2017 ◽  
Vol 474 (24) ◽  
pp. 4137-4152 ◽  
Author(s):  
Francesca Bottacini ◽  
Douwe van Sinderen ◽  
Marco Ventura
Keyword(s):  
Resource Sharing ◽  
Driving Forces ◽  
Acid Stress ◽  
Feeding Strategies ◽  
Surface Layers ◽  
Bacterial Surface ◽  
Genetic Features ◽  
Health Promoting ◽  
Microbe Interactions ◽  
Gastric Barrier

Members of the genus Bifidobacterium include gut commensals that are particularly abundant among the microbial communities residing in the gut of healthy breast-fed infants, where their presence has been linked to many beneficial host effects. Next-generation DNA sequencing and comparative and functional genome methodologies have been shown to be particularly useful in exploring the diversity of this genus. These combined approaches have allowed the identification of genetic features related to bifidobacterial establishment in the gut, involving host–microbe as well as microbe–microbe interactions. Among these, proteinaceous structures, which protrude from the bacterial surface, i.e. pili or fimbriae, and exopolysaccharidic cell surface layers or capsules represent crucial features that assist in their colonization and persistence in the gut. As bifidobacteria are colonizers of the large intestine, they have to be able to cope with various sources of osmotic, oxidative, bile and acid stress during their transit across the gastric barrier and the small intestine. Bifidobacterial genomes thus encode various survival mechanisms, such as molecular chaperones and efflux pumps, to overcome such challenges. Bifidobacteria represent part of an anaerobic gut community, and feed on nondigestible carbohydrates through a specialized fermentative metabolic pathway, which in turn produces growth substrates for other members of the gut community. Conversely, bifidobacteria may also be dependent on other (bifido)bacteria to access host- and diet-derived glycans, and these complex co-operative interactions, based on resource sharing and cross-feeding strategies, represent powerful driving forces that shape gut microbiota composition.

The structure and associations of the double S layer on the cell wall of Aquaspirillum sinuosum

1990 ◽  
Vol 36 (5) ◽  
pp. 327-335 ◽  
Author(s):  
Stephen H. Smith ◽  
Robert G. E. Murray
Keyword(s):  
Cell Wall ◽  
Outer Membrane ◽  
Outer Layer ◽  
Peptide Mapping ◽  
Periodic Acid ◽  
Minor Component ◽  
Membrane Resistance ◽  
Surface Layers ◽  
Periodic Acid Schiff ◽  
Bacterial Surface

Aquaspirillum sinuosum cell walls bear two paracrystalline, proteinaceous surface layers (S layers). Each shows a different symmetry: the inner layer is closely apposed to the outer membrane and is a tetragonal array (90° axes; 5-nm units; repeat frequency 8 nm); the outer layer is a hexagonal array on the external surface (14-nm units; repeat frequency 18 nm) and, although the units have a six-pointed stellate form, the linkage between units is not resolved. The outer layer consists of a major 130-kDa protein and a 180-kDa minor component; these co-extract, co-assemble, and are inseparable by hydroxylapatite chromatography or by recrystallization. The solubilizing effects of reagents suggest stabilization by hydrogen bonding and Ca2+. The two outer layer proteins are serologically related and show partial identity by peptide mapping. Periodic acid – Schiff staining of the 180-kDa band suggests that this may be a glycosylated form of the 130-kDa component. The inner layer components form a doublet of 75- and 80-kDa polypeptides with extreme resistance to extraction. Close apposition to the outer membrane, resistance to chaotropes, aqueous insolubility, and behaviour in charge-shift electrophoresis suggest hydrophobic interaction between subunits and an integral association with the outer membrane. Key words: bacterial surface, cell wall, surface layers, cell-wall proteins, cell-wall assembly.

Effects of health-promoting leadership, employee health on employee engagement: employability as moderating variable

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liping Liu ◽  
Chunyu Zhang ◽  
Chih-Cheng Fang
Keyword(s):  
Employee Engagement ◽  
Driving Forces ◽  
Positive Impact ◽  
Employee Health ◽  
Measurement Instruments ◽  
Cross Sectional Survey ◽  
Core Element ◽  
Cross Sectional ◽  
Content Type ◽  
Health Promoting

PurposeEmployee health is a major challenge for enterprises. Fostering a healthy work environment and promoting employee engagement are key to addressing this challenge. Health-promoting leadership and employee health are the driving forces of corporate development; at the same time, employability is the core element of employee relations. Based on self-determination theory, this study aims to explore the effects of health-promoting leadership and employee health on employee engagement in light of employee employability.Design/methodology/approachThe data of this study encompass 723 valid questionnaires from employees of MSME in China. This study focuses on health-promoting leadership and employee health, engagement relationship and the above relationship moderating by employability.FindingsHealth-promoting leadership plays a key role in the workplace, results show that health-promoting leadership has a positive impact on employee health and employee engagement, while employee health did not have a positive effect on employee engagement. Employability negatively moderated the relationship between employee health and employee engagement.Research limitations/implicationsThis study is based on cross-sectional survey data collected at the COVID-19 pandemic. The pandemic rapidly and continuously changed the organizational responses to employee health. Future studies could utilize longitudinal methods or focus on measurement instruments of the culture of health, to create additional insights about health promoting.Originality/valueThis study adds important knowledge regarding health-promoting leadership and employee health in Chinese MSMEs, an area for which limited research exists. The findings provide insights and knowledge about health-promoting leadership how to affect employee health and to improve engagement outcomes. The findings also identify the moderating role of employability.

scholarly journals Adaptation to pH stress by Vibrio fischeri can affect its symbiosis with the Hawaiian bobtail squid (Euprymna scolopes)

Microbiology ◽  
2020 ◽  
Vol 166 (3) ◽  
pp. 262-277 ◽  
Author(s):  
Meagan Leah Cohen ◽  
Ekaterina Vadimovna Mashanova ◽  
Sveta Vivian Jagannathan ◽  
William Soto
Keyword(s):  
Type Species ◽  
Vibrio Fischeri ◽  
Acid Stress ◽  
Alkaline Stress ◽  
Euprymna Scolopes ◽  
Free Living ◽  
Content Type ◽  
Link Type ◽  
Microbe Interactions ◽  
Host Microbe Interactions

Many microorganisms engaged in host-microbe interactions pendulate between a free-living phase and a host-affiliated stage. How adaptation to stress during the free-living phase affects host-microbe associations is unclear and understudied. To explore this topic, the symbiosis between Hawaiian bobtail squid (Euprymna scolopes) and the luminous bacterium Vibrio fischeri was leveraged for a microbial experimental evolution study. V. fischeri experienced adaptation to extreme pH while apart from the squid host. V. fischeri was serially passaged for 2000 generations to the lower and upper pH growth limits for this microorganism, which were pH 6.0 and 10.0, respectively. V. fischeri was also serially passaged for 2000 generations to vacillating pH 6.0 and 10.0. Evolution to pH stress both facilitated and impaired symbiosis. Microbial evolution to acid stress promoted squid colonization and increased bioluminescence for V. fischeri , while symbiont adaptation to alkaline stress diminished these two traits. Oscillatory selection to acid and alkaline stress also improved symbiosis for V. fischeri , but the facilitating effects were less than that provided by microbial adaptation to acid stress. In summary, microbial adaptation to harsh environments amid the free-living phase may impact the evolution of host-microbe interactions in ways that were not formerly considered.

CRYSTALLINE BACTERIAL SURFACE LAYERS (S-LAYERS) USED IN BIOSENSOR DEVELOPMENT

1992 ◽  
pp. 514
Author(s):  
Dietmar Pum ◽  
Claudia Hödl ◽  
Ursula Kainz ◽  
Angela Neubauer ◽  
Walter Schreier ◽  
...  
Keyword(s):  
Surface Layers ◽  
Bacterial Surface

Unfolding the codes of short-term feed appetence in farm and companion animals. A comparative oronasal nutrient sensing biology review

2008 ◽  
Vol 88 (4) ◽  
pp. 535-558 ◽  
Author(s):  
Eugeni Roura ◽  
Brooke Humphrey ◽  
Gemma Tedó ◽  
Ignacio Ipharraguerre
Keyword(s):  
Driving Forces ◽  
Companion Animals ◽  
Significant Proportion ◽  
Taste Receptor ◽  
Nutrient Sensing ◽  
Feed Consumption ◽  
Sensory Cells ◽  
Feeding Strategies ◽  
Short Term ◽  
Or Genes

The evolution of the chemical senses has resulted in a sensory apparatus for high taste and smell acuity in mammals and birds to ensure self-nourishment. Such peripheral chemosensory systems function as a code to unfold the nutritional value of feedstuffs. Food ingestion simultaneously evokes odor, taste and thermo-mechanical (somatosensing) sensations. Olfaction represents the capacity to identify feed volatiles that are predominantly derived from essential nutrients in plants. Comparative biology of olfaction shows that primates and chickens have a smaller olfactory epithelium and fewer olfactory receptor (OR) genes than non-primate mammals studied to date including farm and companion animals, such as the pig, the cow, the dog, the cat and the horse. A significant proportion of the total OR genes in mammals and birds have lost their functionality (pseudogenes) in a process that seems to reflect a decrease in the animal’s reliance on the sense of smell, particularly in humans and cows. The taste system allows animals to recognize a diverse repertoire of nutrient (sugars, amino acids, salts, acids and fats) or toxic related chemical entities that provide valuable information about the quality of food. Taste senses non-volatile molecules in the oral cavity through taste receptors (TR). The TR are expressed in the sensory cells forming the taste buds of the tongue’s papillae. Taste cells are linked to a network of solitary chemosensory cells diffused through many non-taste tissues involved in metabolic homeostasis. The number of functional taste receptor genes (TASR) in humans is equivalent to that in other mammals and superior to that in chickens. The TASR family 1 (TAS1R coding for umami and sweet TR) is conserved, in number and type, across the species evaluated, with the exception of the sweet receptor in chicken and feline species. The TASR family 2 (TAS2R coding for bitter TR) shows a strong adaptive capacity to dietary sources and digestive physiology across vertebrates. Pseudogenization (loss of gene functionality) in the TAS2R family seems to be a frequent strategy. The implications of oronasal nutrient sensing related to comparative animal feeding strategies and behaviors such as neophobia, feed refusal and hedonic preferences are discussed. Feed palatability and appetence might be one of the main driving forces in short-term feed consumption. Finally, practical applications relevant to animal production are outlined. Key words: Nutrient sensing, taste, olfaction, somatosensing, feed intake, farm, companion animals

Plant Growth and Health Promoting Plant-Microbe Interactions

2019 ◽  
pp. 253-260
Author(s):  
Baby Summuna ◽  
Sachin Gupta ◽  
Parveez Ahmed Sheikh
Keyword(s):  
Plant Growth ◽  
Health Promoting ◽  
Microbe Interactions

Electronic Structure of Regular Bacterial Surface Layers

2004 ◽  
Vol 93 (23) ◽  
Author(s):  
Denis V. Vyalikh ◽  
Steffen Danzenbächer ◽  
Michael Mertig ◽  
Alexander Kirchner ◽  
Wolfgang Pompe ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Surface Layers ◽  
Bacterial Surface

scholarly journals Association of Beta-Glucan Endogenous Production with Increased Stress Tolerance of Intestinal Lactobacilli

2009 ◽  
Vol 76 (2) ◽  
pp. 500-507 ◽  
Author(s):  
Helena M. Stack ◽  
Niamh Kearney ◽  
Catherine Stanton ◽  
Gerald F. Fitzgerald ◽  
R. Paul Ross
Keyword(s):  
Heat Stress ◽  
Recombinant Strain ◽  
Acid Stress ◽  
Fold Increase ◽  
Lactobacillus Paracasei ◽  
Control Strain ◽  
Beta Glucan ◽  
Endogenous Production ◽  
Health Promoting ◽  
Straightforward Approach

ABSTRACT The exopolysaccharide beta-glucan has been reported to be associated with many health-promoting and prebiotic properties. The membrane-associated glycosyltransferase enzyme (encoded by the gtf gene), responsible for microbial beta-glucan production, catalyzes the conversion of sugar nucleotides into beta-glucan. In this study, the gtf gene from Pediococcus parvulus 2.6 was heterologously expressed in Lactobacillus paracasei NFBC 338. When grown in the presence of glucose (7%, wt/vol), the recombinant strain (pNZ44-GTF+) displayed a “ropy” phenotype, while scanning electron microscopy (SEM) revealed strands of polysaccharide-linking neighboring cells. Beta-glucan biosynthesis was confirmed by agglutination tests carried out with Streptococcus pneumoniae type 37-specific antibodies, which specifically detect glucan-producing cells. Further analysis showed a ∼2-fold increase in viscosity in broth media for the beta-glucan-producing strain over 24 h compared to the control strain, which did not show any significant increase in viscosity. In addition, we analyzed the ability of beta-glucan-producing Lactobacillus paracasei NFBC 338 to survive both technological and gastrointestinal stresses. Heat stress assays revealed that production of the polysaccharide was associated with significantly increased protection during heat stress (60-fold), acid stress (20-fold), and simulated gastric juice stress (15-fold). Bile stress assays revealed a more modest but significant 5.5-fold increase in survival for the beta-glucan-producing strain compared to that of the control strain. These results suggest that production of a beta-glucan exopolysaccharide by strains destined for use as probiotics may afford them greater performance/protection during cultivation, processing, and ingestion. As such, expression of the gtf gene may prove to be a straightforward approach to improve strains that might otherwise prove sensitive in such applications.

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