Antagonistic Activity of Antimicrobial Metabolites Produced from Seaweed-Associated Bacillus amyloliquefaciens MTCC 10456 Against Malassezia spp

Efficacy of probiotics in hair growth and dandruff control: A systematic review and meta-analysis

Background

Probiotics are intellectually rewarding for the discovery of their potential as a source of functional food. Investigating the economic and beauty sector dynamics, this study conducted a comprehensive review of scholarly articles to evaluate the capacity of probiotics to promote hair growth and manage dandruff.

Methods

We used the PRISMA 2020 with Embase, Pubmed, ClinicalTrials.gov, Scopus, and ICTRP databases to investigate studies till May 2023. Meta-analyses utilizing the random effects model were used with odds ratios (OR) and standardized mean differences (SMD).

Result

Meta-analysis comprised eight randomized clinical trials and preclinical studies. Hair growth analysis found a non-significant improvement in hair count (SMD = 0.32, 95 % CI -0.10 to 0.75) and a significant effect on thickness (SMD = 0.92, 95 % CI 0.47 to 1.36). In preclinical studies, probiotics significantly induced hair follicle count (SMD = 3.24, 95 % CI 0.65 to 5.82) and skin thickness (SMD = 2.32, 95 % CI 0.47 to 4.17). VEGF levels increased significantly (SMD = 2.97, 95 % CI 0.80 to 5.13), while IGF-1 showed a non-significant inducement (SMD = 0.53, 95 % CI -4.40 to 5.45). For dandruff control, two studies demonstrated non-significant improvement in adherent dandruff (OR = 1.31, 95 % CI 0.13-13.65) and a significant increase in free dandruff (OR = 5.39, 95 % CI 1.50-19.43). Hair follicle count, VEGF, IGF-1, and adherent dandruff parameters were recorded with high heterogeneity. For the systematic review, probiotics have shown potential in improving hair growth and controlling dandruff through modulation of the immune pathway and gut-hair axis. The Wnt/β-catenin pathway, IGF-1 pathway, and VEGF are key molecular pathways in regulating hair follicle growth and maintenance.

Conclusions

This review found significant aspects exemplified by the properties of probiotics related to promoting hair growth and anti-dandruff effect, which serve as a roadmap for further in-depth studies to make it into pilot scales.

An Investigation of Quorum Sensing Inhibitors against Bacillus cereus in The Endophytic Fungus Pithomyces sacchari of the Laurencia sp

Bacillus cereus, a common food-borne pathogen, forms biofilms and generates virulence factors through a quorum sensing (QS) mechanism. In this study, six compounds (dankasterone A, demethylincisterol A3, zinnimidine, cyclo-(L-Val-L-Pro), cyclo-(L-Ile-L-Pro), and cyclo-(L-Leu-L-Pro)) were isolated from the endophytic fungus Pithomyces sacchari of the Laurencia sp. in the South China Sea. Among them, demethylincisterol A3, a sterol derivative, exhibited strong QS inhibitory activity against B. cereus. The QS inhibitory activity of demethylincisterol A3 was evaluated through experiments. The minimum inhibitory concentration (MIC) of demethylincisterol A3 against B. cereus was 6.25 μg/mL. At sub-MIC concentrations, it significantly decreased biofilm formation, hindered mobility, and diminished the production of protease and hemolysin activity. Moreover, RT-qPCR results demonstrated that demethylincisterol A3 markedly inhibited the expression of QS-related genes (plcR and papR) in B. cereus. The exposure to demethylincisterol A3 resulted in the downregulation of genes (comER, tasA, rpoN, sinR, codY, nheA, hblD, and cytK) associated with biofilm formation, mobility, and virulence factors. Hence, demethylincisterol A3 is a potentially effective compound in the pipeline of innovative antimicrobial therapies.

Natural Products and Pharmacological Properties of Symbiotic Bacillota (Firmicutes) of Marine Macroalgae

The shift from the terrestrial to the marine environment to discover natural products has given rise to novel bioactive compounds, some of which have been approved for human medicine. However, the ocean, which makes up nearly three-quarters of the Earth's surface, contains macro- and microorganisms whose natural products are yet to be explored. Among these underexplored marine organisms are macroalgae and their symbiotic microbes, such as Bacillota, a phylum of mostly Gram-positive bacteria previously known as Firmicutes. Macroalgae-associated Bacillota often produce chemical compounds that protect them and their hosts from competitive and harmful rivals. Here, we summarised the natural products made by macroalgae-associated Bacillota and their pharmacological properties. We discovered that these Bacillota are efficient producers of novel biologically active molecules. However, only a few macroalgae had been investigated for chemical constituents of their Bacillota: nine brown, five red and one green algae. Thus, Bacillota, especially from the marine habitat, should be investigated for potential pharmaceutical leads. Moreover, additional diverse biological assays for the isolated molecules of macroalgae Bacillota should be implemented to expand their bioactivity profiles, as only antibacterial properties were tested for most compounds.

Characterization of Bacillus pumilus Strains with Targeted Gene Editing for Antimicrobial Peptides and Sporulation Factor

Due to their capacity to produce antimicrobial peptides that can prevent the growth of diseases, many Bacillus spp. are beneficial to plants. In this study, we looked into the antagonistic activity of the B. pumilus 3-19 strain and its derivatives following targeted genome editing. Two peptide genes with antibacterial action, bacilysin (bac) and bacteriocin (bact), and the sigF gene, which encodes the sigma factor of sporulation, were specifically inactivated using the CRISPR-Cas9 system in the genome of B. pumilus 3-19. Antibacterial activity against B. cereus and Pantoea brenneri decreased as a result of the inactivation of target genes in the B. pumilus 3-19 genome, with a noticeable effect against bacilysin. The growth dynamics of the culture changed when the bac, bact, and sigF genes were inactivated, and the altered strains had less proteolytic activity. An asporogenic mutant of B. pumilus 3-19 was obtained by inactivating the sigF gene. It has been proven that bacilysin plays a unique part in the development of B. pumilus 3-19's antagonistic action against soil microorganisms.

The Role of the Cutaneous Mycobiome in Atopic Dermatitis

Atopic dermatitis is a chronic inflammatory skin disorder characterized by eczematous lesions, itch, and a significant deterioration in the quality of life. Recently, microbiome dysbiosis has been implicated in the pathogenesis of atopic dermatitis. Changes in the fungal microbiome (also termed mycobiome) appear to be an important factor influencing the clinical picture of this entity. This review summarizes the available insights into the role of the cutaneous mycobiome in atopic dermatitis and the new research possibilities in this field. The prevalence and characteristics of key fungal species, the most important pathogenesis pathways, as well as classic and emerging therapies of fungal dysbiosis and infections complicating atopic dermatitis, are presented.

Secondary Metabolites from Marine-Derived Bacillus: A Comprehensive Review of Origins, Structures, and Bioactivities

The marine is a highly complex ecosystem including various microorganisms. Bacillus species is a predominant microbialflora widely distributed in marine ecosystems. This review aims to provide a systematic summary of the newly reported metabolites produced by marine-derived Bacillus species over recent years covering the literature from 2014 to 2021. It describes the structural diversity and biological activities of the reported compounds. Herein, a total of 87 newly reported metabolites are included in this article, among which 49 compounds originated from marine sediments, indicating that marine sediments are majority sources of productive strains of Bacillus species Therefore, marine-derived Bacillus species are a potentially promising source for the discovery of new metabolites.

Antimicrobial Bacillus: Metabolites and Their Mode of Action

The agricultural industry utilizes antibiotic growth promoters to promote livestock growth and health. However, the World Health Organization has raised concerns over the ongoing spread of antibiotic resistance transmission in the populace, leading to its subsequent ban in several countries, especially in the European Union. These restrictions have translated into an increase in pathogenic outbreaks in the agricultural industry, highlighting the need for an economically viable, non-toxic, and renewable alternative to antibiotics in livestock. Probiotics inhibit pathogen growth, promote a beneficial microbiota, regulate the immune response of its host, enhance feed conversion to nutrients, and form biofilms that block further infection. Commonly used lactic acid bacteria probiotics are vulnerable to the harsh conditions of the upper gastrointestinal system, leading to novel research using spore-forming bacteria from the genus Bacillus. However, the exact mechanisms behind Bacillus probiotics remain unexplored. This review tackles this issue, by reporting antimicrobial compounds produced from Bacillus strains, their proposed mechanisms of action, and any gaps in the mechanism studies of these compounds. Lastly, this paper explores omics approaches to clarify the mechanisms behind Bacillus probiotics.

An investigation of antibacterial activity of New Zealand seaweed-associated marine bacteria

Aim: To explore seaweed-associated bacteria as prospective producers of bioactive material with antibacterial properties. Materials & methods: 143 bacterial species were isolated from the surface of 15 New Zealand marine macroalgae. Bacterial extracts obtained using dimethyl sulfoxide and ethyl acetate were screened for antagonistic activities against three antimicrobial susceptibility indicators: Kocuria rhizophila, Staphylococcus epidermidis and Escherichia coli, using well-diffusion method. For selected species, minimum inhibitory concentration was determined, followed by a phylogenetic identification based on 16S rRNA gene sequences. Results: Among all bacteria screened, seven that belonged to the genera Vibrio, Pseudoalteromonas, Psychromonas and Cobetia, showed antagonistic activity against all three indicators. Conclusion: Seaweed-associated bacteria produce bioactive compounds with antimicrobial potential and possible biomedical application in aquatic habitats.

Marine Bacterial Secondary Metabolites: A Treasure House for Structurally Unique and Effective Antimicrobial Compounds

The prevalence of antimicrobial resistance reduces the effectiveness of antimicrobial drugs in preventing and treating infectious diseases caused by pathogenic organisms, such as bacteria, fungi, and viruses. Because of the burgeoning growth of microbes with antimicrobial-resistant traits, there is a dire need to identify and develop novel and effective antimicrobial agents to treat infections from antimicrobial-resistant strains. The marine environment is rich in ecological biodiversity and can be regarded as an untapped resource for prospecting novel bioactive compounds. Therefore, exploring the marine environment for antimicrobial agents plays a significant role in drug development and biomedical research. Several earlier scientific investigations have proven that bacterial diversity in the marine environment represents an emerging source of structurally unique and novel antimicrobial agents. There are several reports on marine bacterial secondary metabolites, and many are pharmacologically significant and have enormous promise for developing effective antimicrobial drugs to combat microbial infections in drug-resistant pathogens. In this review, we attempt to summarize published articles from the last twenty-five years (1996–2020) on antimicrobial secondary metabolites from marine bacteria evolved in marine environments, such as marine sediment, water, fauna, and flora.