The importance of the complex interplay between the microbiome and mucosal immunity, particularly within the respiratory tract, has gained significant attention due to its potential implications for the severity and progression of lung diseases. Therefore, this review summarizes the specific interactions through which the respiratory tract-specific microbiome influences mucosal immunity and ultimately impacts respiratory health. Furthermore, we discuss how the microbiome affects mucosal immunity, considering tissue-specific variations, and its capacity in respiratory diseases containing asthma, chronic obstructive pulmonary disease, and lung cancer. Additionally, we investigate the external factors which affect the relationship between respiratory microbiome and mucosal immune responses. By exploring these intricate interactions, this review provides valuable insights into the potential for microbiome-based interventions to modulate mucosal immunity and alleviate the severity of respiratory diseases.
Colorectal cancer (CRC) is the second-highest cause of cancer-associated mortality among both men and women worldwide. One of the risk factors for CRC is obesity, which is correlated with a high-fat diet prevalent in Western dietary habits. The association between an obesogenic high-fat diet and CRC has been established for several decades; however, the mechanisms by which a high-fat diet increases the risk of CRC remain unclear. Recent studies indicate that gut microbiota strongly infuence the pathogenesis of both high-fat diet-induced obesity and CRC. The gut microbiota is composed of hundreds of bacterial species, some of which are implicated in CRC. In particular, the expansion of facultative anaerobic Enterobacteriaceae, which is considered a microbial signature of intestinal microbiota functional imbalance (dysbiosis), is associated with both high-fat diet-induced obesity and CRC. Here, we review the interaction between the gut microbiome and its metabolic byproducts in the context of colorectal cancer (CRC) during high-fat diet-induced obesity. In addition, we will cover how a high-fat diet can drive the expansion of genotoxin-producing Escherichia coli by altering intestinal epithelial cell metabolism during gut infammation conditions.
To date, all species in the genus Salicibibacter have been isolated
in Korean commercial kimchi. We aimed to describe
the taxonomic characteristics of two strains, NKC5-3T and
NKC21-4T, isolated from commercial kimchi collected from
various regions in the Republic of Korea. Cells of these strains
were rod-shaped, Gram-positive, aerobic, oxidase- and catalase-
positive, non-motile, halophilic, and alkalitolerant. Both
strains, unlike other species of the genus Salicibibacter, could
not grow without NaCl. Strains NKC5-3T and NKC21-4T
could tolerate up to 25.0% (w/v) NaCl (optimum 10%) and
grow at pH 7.0–10.0 (optimum 8.5) and 8.0–9.0 (optimum
8.5), respectively; they showed 97.1% 16S rRNA gene sequence
similarity to each other and were most closely related
to S. kimchii NKC1-1T (97.0% and 96.8% similarity, respectively).
The genome of strain NKC5-3T was nearly 4.6 Mb in
size, with 4,456 protein-coding sequences (CDSs), whereas
NKC21-4T genome was nearly 3.9 Mb in size, with 3,717 CDSs.
OrthoANI values between the novel strains and S. kimchii
NKC1-1T were far lower than the species demarcation threshold.
NKC5-3T and NKC21-4T clustered together to form
branches that were distinct from the other Salicibibacter species.
The major fatty acids in these strains were anteiso-C15:0
and anteiso-C17:0, and the predominant menaquinone was
menaquinone-7. The polar lipids of NKC5-3T included diphosphatidylglycerol
(DPG), phosphatidylglycerol (PG), and
five unidentified phospholipids (PL), and those of NKC21-4T
included DPG, PG, seven unidentified PLs, and an unidentified
lipid. Both isolates had DPG, which is the first case in
the genus Salicibibacter. The genomic G + C content of strains
NKC5-3T and NKC21-4T was 44.7 and 44.9 mol%, respectively.
Based on phenotypic, genomic, phylogenetic, and chemotaxonomic
analyses, strains NKC5-3T (= KACC 22040T
= DSM 111417T) and NKC21-4T (= KACC 22041T = DSM
111418T) represent two novel species of the genus Salicibibacter,
for which the names Salicibibacter cibarius sp. nov.
and Salicibibacter cibi sp. nov. are proposed.
In recent years, the occurrence of antibiotic-resistant pathogens
is increasing rapidly. There is growing concern as
the development of antibiotics is slower than the increase in
the resistance of pathogenic bacteria. Antimicrobial peptides
(AMPs) are promising alternatives to antibiotics. Despite their
name, which implies their antimicrobial activity, AMPs have
recently been rediscovered as compounds having antifungal,
antiviral, anticancer, antioxidant, and insecticidal effects.
Moreover, many AMPs are relatively safe from toxic side effects
and the generation of resistant microorganisms due to
their target specificity and complexity of the mechanisms underlying
their action. In this review, we summarize the history,
classification, and mechanisms of action of AMPs, and
provide descriptions of AMPs undergoing clinical trials. We
also discuss the obstacles associated with the development of
AMPs as therapeutic agents and recent strategies formulated
to circumvent these obstacles.