Lactobacillus là gì? Các công bố khoa học về Lactobacillus
Lactobacillus thuộc họ Lactobacillaceae là vi khuẩn lợi khuẩn quan trọng, chuyển hóa đường thành axit lactic, thường có trong môi trường lên men, thực phẩm và hệ vi sinh vật đường ruột. Các chủng như Lactobacillus acidophilus, casei, rhamnosus, và plantarum có tác dụng tăng cường sức khỏe tiêu hóa và miễn dịch, ngăn ngừa các bệnh như tiêu chảy, viêm ruột. Lactobacillus còn có ứng dụng trong công nghiệp thực phẩm như sản xuất sữa chua, phô mai, giúp cải thiện hương vị và bảo quản thực phẩm. Ứng dụng trong y học và dinh dưỡng vẫn là lĩnh vực nghiên cứu hấp dẫn.
Lactobacillus: Tổng Quan Về Vi Khuẩn Lợi Khuẩn
Lactobacillus là một chi tiêu biểu thuộc họ Lactobacillaceae, được biết đến rộng rãi như một loại lợi khuẩn quan trọng có khả năng chuyển hóa đường thành axit lactic. Chúng chủ yếu tồn tại trong môi trường lên men, thực phẩm và hệ vi sinh vật đường ruột của con người và động vật.
Đặc Điểm Sinh Học Của Lactobacillus
Lactobacillus là vi khuẩn gram dương, không hình thành bào tử, thường xuất hiện như các que mỏng và không di động. Đặc trưng nổi bật của chi này là khả năng lên men ở điều kiện yếm khí, mặc dù một số chủng có thể phát triển trong môi trường hiếu khí. Quá trình lên men của chúng tạo ra axit lactic, từ đó giúp ức chế sự phát triển của vi khuẩn gây hại khác trong cùng môi trường.
Các Chủng Lactobacillus Quan Trọng
Có hơn 200 chủng Lactobacillus, nhưng một số chủng phổ biến và có lợi ích chế phẩm sinh học bao gồm:
- Lactobacillus acidophilus: Giúp duy trì sức khỏe tiêu hóa và cân bằng vi khuẩn trong đường ruột.
- Lactobacillus casei: Nổi tiếng với khả năng tăng cường hệ miễn dịch và cải thiện tiêu hóa.
- Lactobacillus rhamnosus: Được sử dụng rộng rãi trong các sản phẩm probiotic vì tính hiệu quả trong việc ngăn ngừa tiêu chảy và các bệnh nhiễm trùng khác.
- Lactobacillus plantarum: Đóng vai trò quan trọng trong việc cải thiện thực phẩm và giúp duy trì hệ vi sinh vật đường ruột.
Lợi Ích Của Lactobacillus Đối Với Sức Khỏe
Lactobacillus được sử dụng chủ yếu trong các sản phẩm chế phẩm sinh học (probiotics) vì khả năng thúc đẩy sức khỏe tiêu hóa, cải thiện hệ miễn dịch và ngăn ngừa một số bệnh lý như tiêu chảy, viêm ruột và hội chứng ruột kích thích.
Một số nghiên cứu cũng cho thấy Lactobacillus có khả năng làm giảm triệu chứng của các bệnh dị ứng, hỗ trợ giảm cân và cải thiện tâm trạng nhờ vào khả năng tác động lên hệ thần kinh trung ương thông qua trục thần kinh-ruột.
Ứng Dụng Trong Công Nghiệp Thực Phẩm
Lactobacillus là thành phần quan trọng trong quá trình sản xuất nhiều loại thực phẩm lên men như sữa chua, phô mai, dưa chua và kimchi. Chúng không chỉ giúp cải thiện hương vị mà còn kéo dài thời gian bảo quản thực phẩm và tăng giá trị dinh dưỡng.
Kết Luận
Lactobacillus là một chi vi khuẩn có vai trò quan trọng không chỉ trong ngành công nghiệp thực phẩm mà còn trong y học và chăm sóc sức khỏe. Với những lợi ích đa dạng mà chúng mang lại, vi khuẩn này vẫn là một đề tài nghiên cứu hấp dẫn trong cộng đồng khoa học và dinh dưỡng.
Danh sách công bố khoa học về chủ đề "lactobacillus":
Ingestion of <i>Lactobacillus</i> strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve
There is increasing, but largely indirect, evidence pointing to an effect of commensal gut microbiota on the central nervous system (CNS). However, it is unknown whether lactic acid bacteria such as
Lactobacillus rhamnosus
could have a direct effect on neurotransmitter receptors in the CNS in normal, healthy animals. GABA is the main CNS inhibitory neurotransmitter and is significantly involved in regulating many physiological and psychological processes. Alterations in central GABA receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with functional bowel disorders. In this work, we show that chronic treatment with
L. rhamnosus
(
JB-1
) induced region-dependent alterations in GABA
B1b
mRNA in the brain with increases in cortical regions (cingulate and prelimbic) and concomitant reductions in expression in the hippocampus, amygdala, and
locus coeruleus
, in comparison with control-fed mice. In addition,
L. rhamnosus
(
JB-1
) reduced GABA
Aα2
mRNA expression in the prefrontal cortex and amygdala, but increased GABA
Aα2
in the hippocampus. Importantly,
L. rhamnosus
(
JB-1
) reduced stress-induced corticosterone and anxiety- and depression-related behavior. Moreover, the neurochemical and behavioral effects were not found in vagotomized mice, identifying the vagus as a major modulatory constitutive communication pathway between the bacteria exposed to the gut and the brain. Together, these findings highlight the important role of bacteria in the bidirectional communication of the gut–brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression.
Proceedings of the National Academy of Sciences of the United States of America - Tập 108 Số 38 - Trang 16050-16055 - 2011
Complete genome sequence of <i>Lactobacillus plantarum</i> WCFS1
The 3,308,274-bp sequence of the chromosome of
Lactobacillus plantarum
strain WCFS1, a single colony isolate of strain NCIMB8826 that was originally isolated from human saliva, has been determined, and contains 3,052 predicted protein-encoding genes. Putative biological functions could be assigned to 2,120 (70%) of the predicted proteins. Consistent with the classification of
L. plantarum
as a facultative heterofermentative lactic acid bacterium, the genome encodes all enzymes required for the glycolysis and phosphoketolase pathways, all of which appear to belong to the class of potentially highly expressed genes in this organism, as was evident from the codon-adaptation index of individual genes. Moreover,
L. plantarum
encodes a large pyruvate-dissipating potential, leading to various end-products of fermentation.
L. plantarum
is a species that is encountered in many different environmental niches, and this flexible and adaptive behavior is reflected by the relatively large number of regulatory and transport functions, including 25 complete PTS sugar transport systems. Moreover, the chromosome encodes >200 extracellular proteins, many of which are predicted to be bound to the cell envelope. A large proportion of the genes encoding sugar transport and utilization, as well as genes encoding extracellular functions, appear to be clustered in a 600-kb region near the origin of replication. Many of these genes display deviation of nucleotide composition, consistent with a foreign origin. These findings suggest that these genes, which provide an important part of the interaction of
L. plantarum
with its environment, form a lifestyle adaptation region in the chromosome.
Proceedings of the National Academy of Sciences of the United States of America - Tập 100 Số 4 - Trang 1990-1995 - 2003
Bacteriocin production as a mechanism for the antiinfective activity of <i>Lactobacillus salivarius</i> UCC118
The mechanisms by which probiotic strains enhance the health of the host remain largely uncharacterized. Here we demonstrate that
Lactobacillus salivarius
UCC118, a recently sequenced and genetically tractable probiotic strain of human origin, produces a bacteriocin
in vivo
that can significantly protect mice against infection with the invasive foodborne pathogen
Listeria monocytogenes
. A stable mutant of
Lb. salivarius
UCC118 that is unable to produce the Abp118 bacteriocin also failed to protect mice against infection with two strains of
L. monocytogenes
, EGDe and LO28, confirming that bacteriocin production is the primary mediator of protection against this organism. Furthermore,
Lb. salivarius
UCC118 did not offer any protection when mice were infected with a strain of
L. monocytogenes
expressing the cognate Abp118 immunity protein AbpIM, confirming that the antimicrobial effect is a result of direct antagonism between
Lb. salivarius
and the pathogen, mediated by the bacteriocin Abp118.
Proceedings of the National Academy of Sciences of the United States of America - Tập 104 Số 18 - Trang 7617-7621 - 2007
Detection of <i>Lactobacillus, Pediococcus, Leuconostoc</i> , and <i>Weissella</i> Species in Human Feces by Using Group-Specific PCR Primers and Denaturing Gradient Gel Electrophoresis ABSTRACT
Denaturing gradient gel electrophoresis (DGGE) of DNA fragments generated by PCR with 16S ribosomal DNA-targeted group-specific primers was used to detect lactic acid bacteria (LAB) of the genera
Lactobacillus, Pediococcus, Leuconostoc
, and
Weissella
in human feces. Analysis of fecal samples of four subjects revealed individual profiles of DNA fragments originating not only from species that have been described as intestinal inhabitants but also from characteristically food-associated bacteria such as
Lactobacillus sakei, Lactobacillus curvatus, Leuconostoc mesenteroides
, and
Pediococcus pentosaceus
. Comparison of PCR-DGGE results with those of bacteriological culture showed that the food-associated species could not be cultured from the fecal samples by plating on Rogosa agar. On the other hand, all of the LAB species cultured from feces were detected in the DGGE profile. We also detected changes in the types of LAB present in human feces during consumption of a milk product containing the probiotic strain
Lactobacillus rhamnosus
DR20. The analysis of fecal samples from two subjects taken before, during, and after administration of the probiotic revealed that
L. rhamnosus
was detectable by PCR-DGGE during the test period in the feces of both subjects, whereas it was detectable by culture in only one of the subjects.
Applied and Environmental Microbiology - Tập 67 Số 6 - Trang 2578-2585 - 2001
Crystal structures of Escherichia coli and Lactobacillus casei dihydrofolate reductase refined at 1.7 A resolution. I. General features and binding of methotrexate.
Journal of Biological Chemistry - Tập 257 Số 22 - Trang 13650-13662 - 1982
Development and application of an in vitro methodology to determine the transit tolerance of potentially probiotic Lactobacillus and Bifidobacterium species in the upper human gastrointestinal tract
Journal of Applied Microbiology - Tập 84 Số 5 - Trang 759-768 - 1998
Enhancement of the Circulating Antibody Secreting Cell Response in Human Diarrhea by a Human Lactobacillus Strain
Pediatric Research - Tập 32 Số 2 - Trang 141-144 - 1992
Molecular Diversity of <i>Lactobacillus</i> spp. and Other Lactic Acid Bacteria in the Human Intestine as Determined by Specific Amplification of 16S Ribosomal DNA ABSTRACT
A
Lactobacillus
group-specific PCR primer, S-G-Lab-0677-a-A-17, was developed to selectively amplify 16S ribosomal DNA (rDNA) from lactobacilli and related lactic acid bacteria, including members of the genera
Leuconostoc
,
Pediococcus
, and
Weissella.
Amplicons generated by PCR from a variety of gastrointestinal (GI) tract samples, including those originating from feces and cecum, resulted predominantly in
Lactobacillus
-like sequences, of which ca. 28% were most similar to the 16S rDNA of
Lactobacillus ruminis
. Moreover, four sequences of
Leuconostoc
species were retrieved that, so far, have only been detected in environments other than the GI tract, such as fermented food products. The validity of the primer was further demonstrated by using
Lactobacillus
-specific PCR and denaturing gradient gel electrophoresis (DGGE) of the 16S rDNA amplicons of fecal and cecal origin from different age groups. The stability of the GI-tract bacterial community in different age groups over various time periods was studied. The
Lactobacillus
community in three adults over a 2-year period showed variation in composition and stability depending on the individual, while successional change of the
Lactobacillus
community was observed during the first 5 months of an infant’s life. Furthermore, the specific PCR and DGGE approach was tested to study the retention in fecal samples of a
Lactobacillus
strain administered during a clinical trial. In conclusion, the combination of specific PCR and DGGE analysis of 16S rDNA amplicons allows the diversity of important groups of bacteria that are present in low numbers in specific ecosystems to be characterized, such as the lactobacilli in the human GI tract.
Applied and Environmental Microbiology - Tập 68 Số 1 - Trang 114-123 - 2002
Detection and activity of lactacin B, a bacteriocin produced by Lactobacillus acidophilus A total of 52 strains of Lactobacillus acidophilus were examined for production of bacteriocins. A majority (63%) demonstrated inhibitory activity against all members of a four-species grouping of Lactobacillus leichmannii, Lactobacillus bulgaricus, Lactobacillus helveticus, and Lactobacillus lactis. Four L. acidophilus strains with this activity also inhibited Streptococcus faecalis and Lactobacillus fermentum, suggesting a second system of antagonism. Under conditions eliminating the effects of organic acids and hydrogen peroxide, no inhibition of other gram-positive or -negative genera was demonstrated by L. acidophilus. The agent produced by L. acidophilus N2 and responsible for inhibition of L. leichmannii, L. bulgaricus, L. helveticus, and L. lactis was investigated. Ultrafiltration studies indicated a molecular weight of approximately 100,000 for the crude inhibitor. The agent was sensitive to proteolytic enzymes and retained full activity after 60 min at 100 degrees C (pH 5). Activity against sensitive cells was bactericidal but not bacteriolytic. These characteristics identified the inhibitory agent as a bacteriocin, designated lactacin B. Examination of strains of L. acidophilus within the six homology groupings of Johnson et al. (Int. J. Syst. Bacteriol. 30:53-68, 1980) demonstrated that production of the bacteriocin lactacin B could not be used in classification of neotype L. acidophilus strains. However, the usefulness of employing sensitivity to lactacin B in classification of dairy lactobacilli is suggested.
Applied and Environmental Microbiology - Tập 45 Số 6 - Trang 1808-1815 - 1983
<i>Lactobacillus reuteri</i> induces gut intraepithelial CD4 <sup>+</sup> CD8αα <sup>+</sup> T cells Tolerogenic T cells need probiotics
CD4
+
CD8αα
+
double-positive intraepithelial lymphocytes (DP IELs) are a recently discovered class of intestinal T cells believed to take part in a variety of immune responses, including oral tolerance. These cells are absent in germ-free mice, but the mechanisms driving their development are unclear. Cervantes-Barragan
et al.
found that a particular species of probiotic bacteria,
Lactobacillus reuteri
, induces DP IELs. This does not occur by stimulating the immune system directly. Instead,
L. reuteri
generates a specific derivative of dietary tryptophan that promotes differentiation of DP IEL precursors. These findings underscore the delicate interplay between benign bacteria, diet, and gut health.
Science
, this issue p.
806
American Association for the Advancement of Science (AAAS) - Tập 357 Số 6353 - Trang 806-810 - 2017
Tổng số: 5,837
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