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Thomas A Tompkins - One of the best experts on this subject based on the ideXlab platform.
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bifidobacterium longum and Lactobacillus helveticus synergistically suppress stress related visceral hypersensitivity through hypothalamic pituitary adrenal axis modulation
Journal of Neurogastroenterology and Motility, 2018Co-Authors: Afifa Aitbelgnaoui, Isabelle Payard, Claire Rolland, Cherryl Harkat, Viorica Braniste, V Theodorou, Thomas A TompkinsAbstract:Background/aims Visceral pain and hypothalamic-pituitary-adrenal axis (HPA) dysregulation is a common characteristic in irritable bowel syndrome (IBS) patients. Previously, we reported that a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) prevents chronic stress-mediated brain function abnormalities by attenuating the HPA axis response. Here, we compared the effect between different probiotic treatments on the perception of visceral pain during colorectal distension (CRD) following a chronic stress and the consequences to the activity of the HPA axis. Methods After a 2-week treatment with a combined probiotic formulation, or L. helveticus or B. longum alone in stressed mice, the visceral pain in response to CRD was recorded. The expression of glucocorticoid receptors was determined in the different brain areas involved in the stress response (hypothalamus, hippocampus, and prefrontal cortex). The plasma levels of stress hormones were also measured. Results A pretreatment using the combination of probiotic formulation significantly reduces the chronic stress-induced visceral hypersensitivity respectively at 0.06, 0.08, and 0.10 mL CRD volume. However, a single probiotic (B. longum or L. helveticus) administration is less effective in reducing visceral pain in stressed mice. Moreover, the expression of the glucocorticoid receptor mRNA was consistently up-regulated in several brain areas after pretreatment with a combined probiotic, which correlated with the normalization of stress response compared to the inconsistent effects of a single probiotic. Conclusion The combination of L. helveticus and B. longum is more effective in regulating glucocorticoid negative feedback on the HPA axis than probiotic alone and subsequently in treating stress-induced visceral pain.
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Bifidobacterium longum and Lactobacillus helveticus synergistically suppress stress-related visceral hypersensitivity through hypothalamic-pituitary-adrenal axis modulation
Journal of Neurogastroenterology and Motility, 2018Co-Authors: Afifa Ait-belgnaoui, Isabelle Payard, Claire Rolland, Cherryl Harkat, Viorica Braniste, V Theodorou, Thomas A TompkinsAbstract:Visceral pain and hypothalamic-pituitary-adrenal axis (HPA) dysregulation is a common characteristic in irritable bowel syndrome (IBS) patients. Previously, we reported that a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) prevents chronic stress-mediated brain function abnormalities by attenuating the HPA axis response. Here, we compared the effect between different probiotic treatments on the perception of visceral pain during colorectal distension (CRD) following a chronic stress and the consequences to the activity of the HPA axis. After a 2-week treatment with a combined probiotic formulation, or L. helveticus or B. longum alone in stressed mice, the visceral pain in response to CRD was recorded. The expression of glucocorticoid receptors was determined in the different brain areas involved in the stress response (hypothalamus, hippocampus, and prefrontal cortex). The plasma levels of stress hormones were also measured. A pretreatment using the combination of probiotic formulation significantly reduces the chronic stress-induced visceral hypersensitivity respectively at 0.06, 0.08, and 0.10 mL CRD volume. However, a single probiotic (B. longum or L. helveticus) administration is less effective in reducing visceral pain in stressed mice. Moreover, the expression of the glucocorticoid receptor mRNA was consistently up-regulated in several brain areas after pretreatment with a combined probiotic, which correlated with the normalization of stress response compared to the inconsistent effects of a single probiotic. The combination of L. helveticus and B. longum is more effective in regulating glucocorticoid negative feedback on the HPA axis than probiotic alone and subsequently in treating stress-induced visceral pain.
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complete genome sequence for Lactobacillus helveticus cnrz 32 an industrial cheese starter and cheese flavor adjunct
Genome Announcements, 2013Co-Authors: Jeff R Broadbent, Joanne E Hughes, Dennis L Welker, Thomas A Tompkins, James L SteeleAbstract:ABSTRACT Lactobacillus helveticus is a lactic acid bacterium widely used in the manufacture of cheese and for production of bioactive peptides from milk proteins. We present the complete genome sequence for L. helveticus CNRZ 32, a strain particularly recognized for its ability to reduce bitterness and accelerate flavor development in cheese.
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genetic diversity in proteolytic enzymes and amino acid metabolism among Lactobacillus helveticus strains
Journal of Dairy Science, 2011Co-Authors: Jeffery R Broadbent, Joanne E Hughes, Dennis L Welker, Thomas A Tompkins, Ylva Ardo, H Cai, Rebecca Larsen, V G De Carvalho, Finn K Vogensen, A De LorentiisAbstract:Lactobacillus helveticus CNRZ 32 is recognized for its ability to decrease bitterness and accelerate flavor development in cheese, and has also been shown to release bioactive peptides in milk. Similar capabilities have been documented in other strains of Lb. helveticus, but the ability of different strains to affect these characteristics can vary widely. Because these attributes are associated with enzymes involved in proteolysis or AA catabolism, we performed comparative genome hybridizations to a CNRZ 32 microarray to explore the distribution of genes encoding such enzymes across a bank of 38 Lb. helveticus strains, including 2 archival samples of CNRZ 32. Genes for peptidases and AA metabolism were highly conserved across the species, whereas those for cell envelope-associated proteinases varied widely. Some of the genetic differences that were detected may help explain the variability that has been noted among Lb. helveticus strains in regard to their functionality in cheese and fermented milk.
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surface layer protein extracts from Lactobacillus helveticus inhibit enterohaemorrhagic escherichia coli o157 h7 adhesion to epithelial cells
Cellular Microbiology, 2007Co-Authors: Kathene C Johnsonhenry, Thomas A Tompkins, Karen E Hagen, Mahsa Gordonpour, Philip M ShermanAbstract:Adherence of intestinal pathogens, including Escherichia coli O157:H7, to human intestinal epithelial cells is a key step in pathogenesis. Probiotic bacteria, including Lactobacillus helveticus R0052 inhibit the adhesion of E. coli O157:H7 to epithelial cells, a process which may be related to specific components of the bacterial surface. Surface-layer proteins (Slps) are located in a paracrystalline layer outside the bacterial cell wall and are thought to play a role in tissue adherence. However, the ability of S-layer protein extract derived from probiotic bacteria to block adherence of enteric pathogens has not been investigated. Human epithelial (HEp-2 and T84) cells were treated with S-layer protein extract alone, infected with E. coli O157:H7, or pretreated with S-layer protein extract prior to infection to determine their importance in the inhibition of pathogen adherence. The effects of S-layer protein extracts were characterized by phase-contrast and immunofluorescence microscopy and measurement of the transepithelial electrical resistance of polarized monolayers. Pre-treatment of host epithelial cells with S-layer protein extracts prior to E. coli O157:H7 infection decreased pathogen adherence and attaching-effacing lesions in addition to preserving the barrier function of monolayers. These in vitro studies indicate that a non-viable constituent derived from a probiotic strain may prove effective in interrupting the infectious process of an intestinal pathogen.
Toshiaki Takano - One of the best experts on this subject based on the ideXlab platform.
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oral intake of Lactobacillus helveticus fermented milk whey decreased transepidermal water loss and prevented the onset of sodium dodecylsulfate induced dermatitis in mice
Bioscience Biotechnology and Biochemistry, 2010Co-Authors: Hidehiko Baba, Chiaki Yoshimura, Yoshiko Aoyama, Akihiro Masuyama, Toshiaki Takano, Kohji OhkiAbstract:We investigated the effects of oral intake of Lactobacillus helveticus-fermented milk whey on the intact and sodium dodecylsulfate (SDS)-exposed skin of Hos:HR-1 hairless mice. The mice were allowed to drink 10% L. helveticus-fermented milk whey in distilled water ad libitum for 5 weeks. SDS solution was topically applied to the dorsal skin at 4 weeks, leading to the development of dermatitis. The skin moisture content, transepidermal water loss, and sizes of the dermatitis areas were periodically measured. Compared with oral intake of water alone, oral intake of water containing L. helveticus-fermented milk whey for 4 weeks significantly lowered transepidermal water loss from intact skin, significantly reduced in size the areas of early SDS-induced dermatitis, and ameliorated both the SDS-induced decrease in moisture content and the increase in transepidermal water loss. These results suggest that oral intake of L. helveticus-fermented milk whey might be effective in promoting the epidermal barrier function and in preventing the onset of dermatitis.
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purification and characterization of an antihypertensive peptide from a yogurt like product fermented by Lactobacillus helveticus cpn4
Journal of Dairy Science, 1999Co-Authors: Naoyuki Yamamoto, Masafumi Maeno, Toshiaki TakanoAbstract:Abstract Whey peptides in a yogurt-like product fermented by Lactobacillus helveticus CPN4 were fractionated by a Sep-pak C-18 cartridge followed by two-step reverse-phase HPLC. The antihypertensive activity was measured by systolic blood pressure in spontaneously hypertensive rats after oral administration of each fraction. Five major peptides in the final fraction were further purified by reverse-phase HPLC and were measured for these antihypertensive activities in spontaneously hypertensive rats. The only peptide in the final fraction that showed strong antihypertensive activity had a sequence of Tyr-Pro, which is found in α s1 -casein (CN), β -CN, and κ -CN. The synthetic peptide Tyr-Pro yielded significant antihypertensive activity from 2 to 8h after oral administration of 1mg of peptide/kg of body weight, and the effect was maximal at 6h after oral administration. The antihypertensive effect of the peptide was dependent on the peptide dosage from 0.1 to 10mg of peptide/kg of body weight. The concentration of Tyr-Pro peptide increased during fermentation and reached about 8.1 μ g/ml of whey in the pH 4.3 yogurt-like product. The antihypertensive peptide had a low inhibitory activity against angiotensin I-converting enzyme. The inhibition of 50% of the angiotensin I-converting enzyme (IC 50 ) was 720 μM .
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purification and characterization of an antihypertensive peptide from a yogurt like product fermented by Lactobacillus helveticus cpn4
Journal of Dairy Science, 1999Co-Authors: Naoyuki Yamamoto, Masafumi Maeno, Toshiaki TakanoAbstract:Whey peptides in a yogurt-like product fermented by Lactobacillus helveticus CPN4 were fractionated by a Sep-pak C-18 cartridge followed by two-step reverse-phase HPLC. The antihypertensive activity was measured by systolic blood pressure in spontaneously hypertensive rats after oral administration of each fraction. Five major peptides in the final fraction were further purified by reverse-phase HPLC and were measured for these antihypertensive activities in spontaneously hypertensive rats. The only peptide in the final fraction that showed strong antihypertensive activity had a sequence of Tyr-Pro, which is found in alpha s1-casein (CN), beta-CN, and kappa-CN. The synthetic peptide Tyr-Pro yielded significant antihypertensive activity from 2 to 8 h after oral administration of 1 mg of peptide/kg of body weight, and the effect was maximal at 6 h after oral administration. The antihypertensive effect of the peptide was dependent on the peptide dosage from 0.1 to 10 mg of peptide/kg of body weight. The concentration of Tyr-Pro peptide increased during fermentation and reached about 8.1 micrograms/ml of whey in the pH 4.3 yogurt-like product. The antihypertensive peptide had a low inhibitory activity against angiotensin I-converting enzyme. The inhibition of 50% of the angiotensin I-converting enzyme (IC50) was 720 microM.
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identification of an antihypertensive peptide from casein hydrolysate produced by a proteinase from Lactobacillus helveticus cp790
Journal of Dairy Science, 1996Co-Authors: Masafumi Maeno, Naoyuki Yamamoto, Toshiaki TakanoAbstract:Abstract Casein hydrolysate, produced by an extracellular proteinase from Lactobacillus helveticus CP790, was fractionated by two-step reverse-phase HPLC. Only one fraction showed antihypertensive activity as measured by systolic blood pressure in spontaneously hypertensive rats after oral administration. Ten peptides in the fraction were further purified and identified by analysis of amino acid sequences. Each identified peptide was chemically synthesized, and the antihypertensive activity of each peptide was evaluated in spontaneously hypertensive rats. The synthetic peptide with a sequence of Lys-Val-Leu-Pro-Val-Pro-Gln, found in β -casein, indicated strong anti-hypertensive activity from 2 to 10h after oral administration of 2mg of peptide/kg of BW, and the effect was maximal at 6h after oral administration (−31.5±5.6mm Hg). Moreover, the antihypertensive effect of the peptide was dependent on the dosage of peptide from 0.5 to 2mg of peptide/kg of BW. Interestingly, the antihypertensive peptide showed lower inhibitory activity of angiotensin I-converting enzyme, but the activity was increased after pancreatin digestion.
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antihypertensive effect of the peptides derived from casein by an extracellular proteinase from Lactobacillus helveticus cp790
Journal of Dairy Science, 1994Co-Authors: Naoyuki Yamamoto, Atsuko Akino, Toshiaki TakanoAbstract:Abstract Peptides derived from α s1 - and β -caseins by the Lactobacillus helveticus CP790 proteinase were investigated for their inhibitory activities against angiotensin I-converting enzyme. The antihypertensive effect of casein hydrolysates in strain SHR spontaneously hypertensive rats was also investigated. Both α s1 and β -casein hydrolysates inhibited this enzyme. Some of these peptides showed enzyme inhibitory activity, and one of them from β -casein inhibited the enzyme greatly; the concentration of an angiotensin I-converting enzyme inhibitor needed to inhibit 50% of the enzyme activity was 4 μM. The hydrolysate of casein demonstrated antihypertensive activity in spontaneously hypertensive rats at an orally administered dosage of 15 mg/kg of body weight. Milk fermented with L. helveticus CP790, containing about .3% peptides, also showed antihypertensive activity in SHR rats with 5 ml/kg of body weight (15mg of peptide/kg); however, the milk fermented with L. helveticus CP791, a variant defective for proteinase activity, did not show this activity. Results suggested that the peptides liberated from casein by the proteinase in the culture medium showed antihypertensive effect in SHR rats.
Riitta Korpela - One of the best experts on this subject based on the ideXlab platform.
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long term intervention with Lactobacillus helveticus fermented milk reduces augmentation index in hypertensive subjects
European Journal of Clinical Nutrition, 2010Co-Authors: Tiina Jauhiainen, Mats Ronnback, K Wuolle, Per-henrik Groop, Riitta Korpela, Hannu Kautiainen, Heikki VapaataloAbstract:Long-term intervention with Lactobacillus helveticus fermented milk reduces augmentation index in hypertensive subjects
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Lactobacillus helveticus fermented milk lowers blood pressure in hypertensive subjects in 24 h ambulatory blood pressure measurement
American Journal of Hypertension, 2005Co-Authors: Tiina Jauhiainen, Riitta Korpela, Heikki Vapaatalo, Tuija Poussa, Sinikka Kyronpalo, Martin RasmussenAbstract:Background The present study was carried out to evaluate the blood pressure (BP)-lowering effect and the safety aspects of Lactobacillus helveticus LBK-16H fermented milk with high tripeptide doses on hypertensive subjects using 24-h ambulatory measurements (ABPM). Methods In a randomized, double blinded placebo-controlled parallel group study, 94 hypertensive patients not receiving any drug treatment were given 150 mL twice daily of either L. helveticus LBK-16H fermented milk with a high concentration of tripeptides (Ile-Pro-Pro 7.5 mg/100 g and Val-Pro-Pro 10 mg/100 g) or a control product, for 10 weeks after a 4-week run-in period. Twenty-four-hour ABPM were taken at the beginning and at the end of the intervention period. The average baseline systolic and diastolic BP values were 132.6 ± 9.9/83.0 ± 8.0 mm Hg in the L. helveticus group and 130.3 ± 9.6 /80.2 ± 7.0 mm Hg in the control group. Results There was a mean difference of −4.1 ± 0.9 mm Hg in systolic (P = .001) and a −1.8 ± 0.7 mm Hg in diastolic BP (P = .048) between the L. helveticus group and the control group. There was no difference in the sum of the adverse events (P = .820). Conclusions Lactobacillus helveticus LBK-16H fermented milk containing bioactive peptides, in daily use, does have a BP-lowering effect in hypertensive subjects and is thus a potential for the dietary treatment of hypertension.
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the effect of a Lactobacillus helveticus lbk 16 h fermented milk on hypertension a pilot study on humans
Milchwissenschaft-milk Science International, 2002Co-Authors: Leena Seppo, Outi Kerojoki, Tarja Suomalainen, Riitta KorpelaAbstract:A number of milk-derived peptides have a blood pressure lowering effect based on angiotensin I-converting enzyme (ACE) inhibitory activity. The aim of the present pilot study was to evaluate the effects of Lactobacillus helveticus LBK-16 H fermented milk on hypertension. Seventeen mildly hypertensive volunteers were studied. The study included a 4-week run-in period, 8 weeks of treatment and a 4-week follow-up period. The study group (mean blood pressure 148/94, SEM 4/2) received 150 ml per day of peptide sour milk, and the control group (mean blood pressure 148/93, SEM 5/1) received 150 ml of control sour milk. The peptide sour milk was fermented with L. helveticus LBK-16 H and contained bioactive tripeptides, isoleucyl-prolyl-proline and valyl-prolyl-proline, that were not present in the control milk. During the 8-week treatment period, blood pressure was reduced more in the test milk group than in the control group L. helveticus LBK-16 H fermented milk seems to be a possible means of supporting the treatment of hypertension.
Naoyuki Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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purification and characterization of an antihypertensive peptide from a yogurt like product fermented by Lactobacillus helveticus cpn4
Journal of Dairy Science, 1999Co-Authors: Naoyuki Yamamoto, Masafumi Maeno, Toshiaki TakanoAbstract:Abstract Whey peptides in a yogurt-like product fermented by Lactobacillus helveticus CPN4 were fractionated by a Sep-pak C-18 cartridge followed by two-step reverse-phase HPLC. The antihypertensive activity was measured by systolic blood pressure in spontaneously hypertensive rats after oral administration of each fraction. Five major peptides in the final fraction were further purified by reverse-phase HPLC and were measured for these antihypertensive activities in spontaneously hypertensive rats. The only peptide in the final fraction that showed strong antihypertensive activity had a sequence of Tyr-Pro, which is found in α s1 -casein (CN), β -CN, and κ -CN. The synthetic peptide Tyr-Pro yielded significant antihypertensive activity from 2 to 8h after oral administration of 1mg of peptide/kg of body weight, and the effect was maximal at 6h after oral administration. The antihypertensive effect of the peptide was dependent on the peptide dosage from 0.1 to 10mg of peptide/kg of body weight. The concentration of Tyr-Pro peptide increased during fermentation and reached about 8.1 μ g/ml of whey in the pH 4.3 yogurt-like product. The antihypertensive peptide had a low inhibitory activity against angiotensin I-converting enzyme. The inhibition of 50% of the angiotensin I-converting enzyme (IC 50 ) was 720 μM .
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purification and characterization of an antihypertensive peptide from a yogurt like product fermented by Lactobacillus helveticus cpn4
Journal of Dairy Science, 1999Co-Authors: Naoyuki Yamamoto, Masafumi Maeno, Toshiaki TakanoAbstract:Whey peptides in a yogurt-like product fermented by Lactobacillus helveticus CPN4 were fractionated by a Sep-pak C-18 cartridge followed by two-step reverse-phase HPLC. The antihypertensive activity was measured by systolic blood pressure in spontaneously hypertensive rats after oral administration of each fraction. Five major peptides in the final fraction were further purified by reverse-phase HPLC and were measured for these antihypertensive activities in spontaneously hypertensive rats. The only peptide in the final fraction that showed strong antihypertensive activity had a sequence of Tyr-Pro, which is found in alpha s1-casein (CN), beta-CN, and kappa-CN. The synthetic peptide Tyr-Pro yielded significant antihypertensive activity from 2 to 8 h after oral administration of 1 mg of peptide/kg of body weight, and the effect was maximal at 6 h after oral administration. The antihypertensive effect of the peptide was dependent on the peptide dosage from 0.1 to 10 mg of peptide/kg of body weight. The concentration of Tyr-Pro peptide increased during fermentation and reached about 8.1 micrograms/ml of whey in the pH 4.3 yogurt-like product. The antihypertensive peptide had a low inhibitory activity against angiotensin I-converting enzyme. The inhibition of 50% of the angiotensin I-converting enzyme (IC50) was 720 microM.
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identification of an antihypertensive peptide from casein hydrolysate produced by a proteinase from Lactobacillus helveticus cp790
Journal of Dairy Science, 1996Co-Authors: Masafumi Maeno, Naoyuki Yamamoto, Toshiaki TakanoAbstract:Abstract Casein hydrolysate, produced by an extracellular proteinase from Lactobacillus helveticus CP790, was fractionated by two-step reverse-phase HPLC. Only one fraction showed antihypertensive activity as measured by systolic blood pressure in spontaneously hypertensive rats after oral administration. Ten peptides in the fraction were further purified and identified by analysis of amino acid sequences. Each identified peptide was chemically synthesized, and the antihypertensive activity of each peptide was evaluated in spontaneously hypertensive rats. The synthetic peptide with a sequence of Lys-Val-Leu-Pro-Val-Pro-Gln, found in β -casein, indicated strong anti-hypertensive activity from 2 to 10h after oral administration of 2mg of peptide/kg of BW, and the effect was maximal at 6h after oral administration (−31.5±5.6mm Hg). Moreover, the antihypertensive effect of the peptide was dependent on the dosage of peptide from 0.5 to 2mg of peptide/kg of BW. Interestingly, the antihypertensive peptide showed lower inhibitory activity of angiotensin I-converting enzyme, but the activity was increased after pancreatin digestion.
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antihypertensive effect of the peptides derived from casein by an extracellular proteinase from Lactobacillus helveticus cp790
Journal of Dairy Science, 1994Co-Authors: Naoyuki Yamamoto, Atsuko Akino, Toshiaki TakanoAbstract:Abstract Peptides derived from α s1 - and β -caseins by the Lactobacillus helveticus CP790 proteinase were investigated for their inhibitory activities against angiotensin I-converting enzyme. The antihypertensive effect of casein hydrolysates in strain SHR spontaneously hypertensive rats was also investigated. Both α s1 and β -casein hydrolysates inhibited this enzyme. Some of these peptides showed enzyme inhibitory activity, and one of them from β -casein inhibited the enzyme greatly; the concentration of an angiotensin I-converting enzyme inhibitor needed to inhibit 50% of the enzyme activity was 4 μM. The hydrolysate of casein demonstrated antihypertensive activity in spontaneously hypertensive rats at an orally administered dosage of 15 mg/kg of body weight. Milk fermented with L. helveticus CP790, containing about .3% peptides, also showed antihypertensive activity in SHR rats with 5 ml/kg of body weight (15mg of peptide/kg); however, the milk fermented with L. helveticus CP791, a variant defective for proteinase activity, did not show this activity. Results suggested that the peptides liberated from casein by the proteinase in the culture medium showed antihypertensive effect in SHR rats.
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antihypertensive effect of the peptides derived from casein by an extracellular proteinase from Lactobacillus helveticus cp790
Journal of Dairy Science, 1994Co-Authors: Naoyuki Yamamoto, Atsuko Akino, Toshiaki TakanoAbstract:Peptides derived from alpha s1- and beta-caseins by the Lactobacillus helveticus CP790 proteinase were investigated for their inhibitory activities against angiotensin I-converting enzyme. The antihypertensive effect of casein hydrolysates in strain SHR spontaneously hypertensive rats was also investigated. Both alpha s1- and beta-casein hydrolysates inhibited this enzyme. Some of these peptides showed enzyme inhibitory activity, and one of them from beta-casein inhibited the enzyme greatly; the concentration of an angiotensin I-converting enzyme inhibitor needed to inhibit 50% of the enzyme activity was 4 microM. The hydrolysate of casein demonstrated antihypertensive activity in spontaneously hypertensive rats at an orally administered dosage of 15 mg/kg of body weight. MILK fermented with L. helveticus CP790, containing about .3% peptides, also showed antihypertensive activity in SHR rats with 5 ml/kg of body weight (15 mg of peptide/kg); however, the milk fermented with L. helveticus CP791, a variant defective for proteinase activity, did not show this activity. Results suggested that the peptides liberated from casein by the proteinase in the culture medium showed antihypertensive effect in SHR rats.
Stefan Irmler - One of the best experts on this subject based on the ideXlab platform.
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Population Dynamics of Lactobacillus helveticus in Swiss Gruyère-Type Cheese Manufactured With Natural Whey Cultures.
Frontiers in microbiology, 2018Co-Authors: Aline Moser, Karl Schafroth, Leo Meile, Lotti Egger, René Badertscher, Stefan IrmlerAbstract:Lactobacillus helveticus, a ubiquitous bacterial species in natural whey cultures used for Swiss Gruyere cheese production, is considered to have crucial functions for cheese ripening such as enhancing proteolysis. We tracked the diversity and abundance of L. helveticus strains during six months of ripening in eight Swiss Gruyere-type cheeses using a culture-independent typing method. The study showed that the L. helveticus population present in natural whey cultures persisted in cheese and demonstrated a stable multi-strain coexistence during cheese ripening. With regard to proteolysis, one of the eight L. helveticus populations exhibited less protein degradation during ripening.
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Amplicon Sequencing of the slpH Locus Permits Culture-Independent Strain Typing of Lactobacillus helveticus in Dairy Products
Frontiers Media S.A., 2017Co-Authors: Aline Moser, Leo Meile, Daniel Wüthrich, Rémy Bruggmann, Elisabeth Eugster-meier, Stefan IrmlerAbstract:The advent of massive parallel sequencing technologies has opened up possibilities for the study of the bacterial diversity of ecosystems without the need for enrichment or single strain isolation. By exploiting 78 genome data-sets from Lactobacillus helveticus strains, we found that the slpH locus that encodes a putative surface layer protein displays sufficient genetic heterogeneity to be a suitable target for strain typing. Based on high-throughput slpH gene sequencing and the detection of single-base DNA sequence variations, we established a culture-independent method to assess the biodiversity of the L. helveticus strains present in fermented dairy food. When we applied the method to study the L. helveticus strain composition in 15 natural whey cultures (NWCs) that were collected at different Gruyère, a protected designation of origin (PDO) production facilities, we detected a total of 10 sequence types (STs). In addition, we monitored the development of a three-strain mix in raclette cheese for 17 weeks
