Search Results (86)

Skin photoaging, driven primarily by ultraviolet radiation, remains a critical dermatological concern. Carotenoids, a class of natural pigments with potent antioxidant properties, have emerged as promising agents for preventing and mitigating photoaging. This review comprehensively integrates current understanding regarding the triggers of skin photoaging, oxidative stress and their associated signal pathways, the photoprotective roles and mechanisms of carotenoids, as well as their bioavailability. Common C₄₀ carotenoids, such as β-carotene, lycopene, astaxanthin, lutein, and zeaxanthin demonstrate remarkable antioxidant activity, primarily attributed to their conjugated double bond structures. Many studies have demonstrated that both oral and topical administration of these C₄₀ carotenoids can effectively alleviate skin photoaging. Specifically, they play a crucial role in promoting the formation of a new skin barrier and enhancing the production of collagen and elastin, key structural proteins essential for maintaining skin integrity and elasticity. Mechanistically, these carotenoids combat photoaging by effectively scavenging reactive oxygen species and modulating oxidative stress responsive signal pathways, including MAPK, Nrf2, and NF-κB. Notably, we also anticipate the anti-photoaging potential of novel carotenoids, with a particular emphasis on bacterioruberin, a C₅₀ carotenoid derived from halophilic archaea. Bacterioruberin exhibits a superior radical scavenging capacity, outperforming the conventional C₄₀ carotenoids. Furthermore, when considering the application of carotenoids, aspects such as safe dosage, bioavailability, and possible long term usage issues, including allergies and pigmentation disorders, must be taken into account. This review underscores the anti-photoaging mechanism of carotenoids, providing strategies and theoretical basis for the prevention and treatment of photoaging. Full article

Polyhydroxyalkanoates (PHAs), as biosynthetic and biodegradable polymers, serve as alternatives to petroleum-based plastics, yet face critical cost barriers in large-scale production. While magnetic field (MF) stimulation enhances microbial activity, the optimal MF parameters and metabolic mechanisms for PHA biosynthesis remain unexplored. This study optimized magnetic field parameters to increase PHA biosynthesis in Haloferax mediterranei. A custom-engineered electromagnetic system identified 110 mT of static magnetic field (SMF) as the optimal level for biosynthesis, reaching 77.97 mg/(L·h) PHA volumetric productivity. A pulsed magnetic field caused oxidative stress and impaired substrate uptake despite increasing PHA synthesis. Prolonged SMF exposure (72 h) maximized PHA productivity, while 48 h of exposure attained 90% efficiency. Metabolomics revealed that SMF-driven carbon flux redirection via regulated butanoate metabolism led to a 2.10-fold increase in (R)-3-hydroxybutanoyl-CoA), while downregulating acetoacetate (0.51-fold) and suppressing PHA degradation (0.15-fold). This study pioneers the first application of metabolomics in archaea to decode SMF-induced metabolic rewiring in Haloferax mediterranei. Our findings establish SMF as a scalable bioenhancement tool, offering sustainable solutions for the circular bioeconomy. Full article

The properties of two hybrid nanoarchaeosomes (hybrid nanoARCs) made of archaeolipids extracted from the halophilic archaea Halorubrum tebenquichense and combining the properties of archaeolipid bilayers with metallic nanoparticles are explored here. BS-nanoARC, consisting of a nanoARC loaded with yerba mate (Ilex paraguariensis) extract (YME)-biogenic silver nanoparticles (BSs), and [BS + BS-nanoARC], consistent of a BS-nanoARC core covered by an outer shell of BSs, were structurally characterized and their therapeutic activities screened. By employing 109 ± 5 µg gallic acid equivalents (GAEs) and 73.4 µg chlorogenic acid/ YME mg as a silver reductive agent, spherical, heterogeneously sized (~80 nm diameter), −27 mV ζ potential, 90% Ag⁰ and λ_max 420 nm BSs were obtained. We further prepared ~100–200 nm diameter, −57 mV ζ potential BS-nanoARC and ~300 nm diameter, −37 mV ζ potential [BS + BS-nanoARCs]. Freshly prepared and nebulized BS-nanoARCs reduced the release of TNF-α, IL-6 and IL-8 by LPS-irritated THP-1-macrophages and were highly anti-planktonic against S. aureus (MIC₉₀: 13 ± 0.8 µg Ag/mL). While the nanoARCs and BS-nanoARCs were innocuous, freshly prepared [BS + BS-nanoARCs] magnified the cytotoxicity of BSs (IC₅₀ 12 µg Ag/mL vs. IC₅₀ ~36 µg Ag/mL) on A549 cells. Such cytotoxicity remained after 30 days in the dark at 4 °C, while that of BSs was lost. Freshly prepared BSs also lost activity upon nebulization, whereas freshly prepared [BS + BS-nanoARCs] did not. However, the cytotoxicity of the [BS + BS-nanoARCs] was also lost when nebulized after 30 days of storage. Despite the harmful effects of storage and mechanical stress on the structure of the more active [BS + BS-nanoARCs], hybrid nanoARCs are promising examples of nanomedicines combining the properties of archaeolipids with antimicrobial silver nanoparticles and anti-inflammatory polyphenols that could complement oncologic therapies, reducing the usage of classical antitumoral agents, corticosteroids, and, importantly, of antibiotics, as well as their waste. Full article

Carotenoids from different sources have different structures and functions, and their dietary components benefit the health of various organisms. The effects of halophilic Archaea-derived C50 carotenoids on poultry egg quality and gut microbiota remain largely unexplored. In this study, we isolated a carotenoid-secreting strain of Halalkalicoccus paucihalophilus, TRM89021, from the Pamir Plateau. We characterized the carotenoid pigments produced by this strain; the major components were bacterioruberin and its derivatives. The effects of these carotenoids on the egg quality and cecal microbiota composition of hens were investigated. Compared to the basal diet group (BDG), supplementation with carotenoids in the carotenoids-supplemented diet group (CDG) resulted in significantly lower a* and b* scores at week 5 and lower b* scores and Haugh units at week 2, while egg strength and weight were higher. CDG also showed increased yolk antioxidant capacity, higher glutathione peroxidase levels, and significantly lower catalase levels (p < 0.05). Plasma analysis revealed elevated total bilirubin and aspartate aminotransferase levels, along with reduced inorganic phosphorus levels in the CDG (p < 0.05). No significant differences in cecal microbiota diversity were observed between the groups at any taxonomic level. This result suggests that halophilic archaea-derived carotenoids have the potential to be used as natural feed supplements to improve egg quality. Our study provides a theoretical basis for applying archaea-derived carotenoids in poultry diets. Full article

Haloarchaea are a group of moderate and extreme halophilic microorganisms, belonging to the Archaea domain, that constitute relevant microbial communities in salty environments like coastal and inland salted ponds, marshes, salty lagoons, etc. They can survive in stress conditions such as high salinity and, therefore, high ionic strength, high doses of ultraviolet radiation (UV), high temperature, and extreme pH values. Consequently, most of the species can be considered polyextremophiles owing to their ability to respond to the multiple extreme conditions characterizing their natural habitats. They cope with those stresses thanks to several molecular and metabolic adaptations. Thus, some of the molecules produced by haloarchaea show significantly different biological activities and physicochemical properties compared to their bacterial counterparts. Recent studies have revealed promising applications in biotechnology and medicine for these biomolecules. Among haloarchaeal biomolecules, rare natural pigments (C₅₀ carotenoids) and small peptides called halocins and microhalocins have attracted attention worldwide due to their effects on animal and human commercial tumoral cells, apart from the role as antibiotics described for halocins or the immunomodulatory activity reported from C₅₀ carotenoids like bacterioruberin. This review summarizes recent knowledge on these two types of biomolecules in connection with cancer to shed new light on the design of drugs and new therapies based on natural compounds. Full article

The artificial solar saltworks fields of Hon Khoi are important industrial and biodiversity resources in southern Vietnam. Most hypersaline environments in this area are characterized by saturated salinity, nearly neutral pH, intense ultraviolet radiation, elevated temperatures and fast desiccation processes. However, the extremely halophilic prokaryotic communities associated with these stressful environments remain uninvestigated. To fill this gap, a metabarcoding approach was conducted to characterize these communities by comparing them with solar salterns in northern Vietnam as well as with the Italian salterns of Motya and Trapani. Sequencing analyses revealed that the multiple reuses of crystallization ponds apparently create significant perturbations and structural instability in prokaryotic consortia. However, some interesting features were noticed when we examined the diversity of ultra-small prokaryotes belonging to Patescibacteria and DPANN Archaea. Surprisingly, we found at least five deeply branched clades, two from Patescibacteria and three from DPANN Archaea, which seem to be quite specific to the Hon Khoi saltworks field ecosystem and can be considered as a part of biogeographical connotation. Further studies are needed to characterize these uncultivated taxa, to isolate and cultivate them, which will allow us to elucidate their ecological role in these hypersaline habitats and to explore their biotechnological and biomedical potential. Full article

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas (CRISPR-associated proteins) systems provide acquired heritable protection to bacteria and archaea against selfish DNA elements, such as viruses. These systems must be tightly regulated because they can capture DNA fragments from foreign selfish elements, and also occasionally from self-chromosomes, resulting in autoimmunity. Most known species from the halophilic archaeal genus Haloferax contain type I-B CRISPR-Cas systems, and the strongest hotspot for self-spacer acquisition by H. mediterranei was a locus that contained a putative transposable element, as well as the gene HFX_2341, which was a very frequent target for self-targeting spacers. To test whether this gene is CRISPR-associated, we investigated it using bioinformatics, deletion, over-expression, and comparative transcriptomics. We show that HFX_2341 is a global transcriptional regulator that can repress diverse genes, since its deletion results in significantly higher expression of multiple genes, especially those involved in nutrient transport. When over-expressed, HFX_2341 strongly repressed the transcript production of all cas genes tested, both those involved in spacer acquisition (cas1, 2 and 4) and those required for destroying selfish genetic elements (cas3 and 5–8). Considering that HFX_2341 is highly conserved in haloarchaea, with homologs that are present in species that do not encode the CRISPR-Cas system, we conclude that it is a global regulator that is also involved in cas gene regulation, either directly or indirectly. Full article

Due to the falling water level in the Aral Sea and Muynak Lake, the content of salts dissolved in the water has gradually increased, and toxic elements have been deposited at the lake’s bottom and subsequently washed into the Aral region by the river. Bacteria, archaea and fungi are crucial for the cycling of several important inorganic nutrients in soils. From 15 genera and 31 species of recovered microscopic filamentous fungi, a big group was melanized, of which most of them were also phytopathogenic. The second group consisted of keratinophilic species. Isolated bacteria mainly included members of the genera Arthrobacter, Bacillus, Massilia, Rhodococcus and Nocardiopsis. High-throughput sequencing analysis permitted a better view of the mycobiome and prokaryotic communities (comprising archaea). The cultivation and sequencing approaches were shown to be complementary. The aim of the work was to identify soil microorganisms, including the order Halobacteriales, and to discover the differences in species diversity depending on soil salinity and the presence of PTEs in soil. Full article

Only a few halophilic archaea producing carboxylesterases have been reported. The limited research on biocatalytic characteristics of archaeal esterases is primarily due to their very low production in native organisms. A gene encoding carboxylesterase from Halobacterium salinarum NRC-1 was cloned and successfully expressed in Haloferax volcanii. The recombinant carboxylesterase (rHsEst) was purified by affinity chromatography with a yield of 81%, and its molecular weight was estimated by SDS-PAGE (33 kDa). The best kinetic parameters of rHsEst were achieved using p-nitrophenyl valerate as substrate (K_M = 78 µM, k_cat = 0.67 s⁻¹). rHsEst exhibited great stability to most metal ions tested and some solvents (diethyl ether, n-hexane, n-heptane). Purified rHsEst was effectively immobilized using Celite 545. Esterase activities of rHsEst were confirmed by substrate specificity studies. The presence of a serine residue in rHsEst active site was revealed through inhibition with PMSF. The pH for optimal activity of free rHsEst was 8, while for immobilized rHsEst, maximal activity was at a pH range between 8 to 10. Immobilization of rHsEst increased its thermostability, halophilicity and protection against inhibitors such as EDTA, BME and PMSF. Remarkably, immobilized rHsEst was stable and active in NaCl concentrations as high as 5M. These biochemical characteristics of immobilized rHsEst reveal its potential as a biocatalyst for industrial applications. Full article

Natronorubrum daqingense JX313^T is an extremely halophilic archaea that can grow in a NaCl-saturated environment. The excellent salt tolerance of N. daqingense makes it a high-potential candidate for researching the salt stress mechanisms of halophilic microorganisms from Natronorubrum. In this study, transcriptome analysis revealed that three genes related to the biosynthesis of vitamin B₁₂ were upregulated in response to salt stress. For the wild-type (WT) strain JX313^T, the low-salt adaptive mutant LND5, and the vitamin B₁₂ synthesis-deficient strain ΔcobC, the exogenous addition of 10 mg/L of vitamin B₁₂ could maximize their cell survival and biomass in both optimal and salt stress environments. Knockout of cobC resulted in changes in the growth boundary of the strain, as well as a significant decrease in cell survival and biomass, and the inability to synthesize vitamin B₁₂. According to the HPLC analysis, when the external NaCl concentration (w/v) increased from 17.5% (optimal) to 22.5% (5% salt stress), the intracellular accumulation of vitamin B₁₂ in WT increased significantly from (11.54 ± 0.44) mg/L to (15.23 ± 0.20) mg/L. In summary, N. daqingense is capable of absorbing or synthesizing vitamin B₁₂ in response to salt stress, suggesting that vitamin B₁₂ serves as a specific compatible solute effector for N. daqingense during salt stress. Full article

Halophilic archaea, also termed haloarchaea, are a group of moderate and extreme halophilic microorganisms that constitute the major microbial populations in hypersaline environments. In these ecosystems, mainly aquatic, haloarchaea are constantly exposed to ionic and oxidative stress due to saturated salt concentrations and high incidences of UV radiation (mainly in summer). To survive under these harsh conditions, haloarchaea have developed molecular adaptations including hyperpigmentation. Regarding pigmentation, haloarchaeal species mainly synthesise the rare C₅₀ carotenoid called bacterioruberin (BR) and its derivatives, monoanhydrobacterioruberin and bisanhydrobacterioruberin. Due to their colours and extraordinary antioxidant properties, BR and its derivatives have been the aim of research in several research groups all over the world during the last decade. This review aims to summarise the most relevant characteristics of BR and its derivatives as well as describe their reported antitumoral, immunomodulatory, and antioxidant biological activities. Based on their biological activities, these carotenoids can be considered promising natural biomolecules that could be used as tools to design new strategies and/or pharmaceutical formulas to fight against cancer, promote immunomodulation, or preserve skin health, among other potential uses. Full article

The extremophile Halobacterium salinarum is an aerobic archaeon that has adapted to thrive in high-salt environments such as salted fish, hypersaline lakes, and salterns. Halophiles have garnered significant interest due to their unique interactions with bacteriophages known as haloarchaeophages. Studies have identified and characterized prophages in halophilic archaea, such as Haloferax volcanii, Haloquadratum walsbyi, and Haloarcula marismortui. Still, an investigation has yet to be conducted into the presence of prophage elements on Halobacterium salinarum ATCC 33170. This is of particular interest to us as we are using this strain as a source of archaeol, as one of the components of our sulfated lactosyl archaeol (SLA) archaeosome adjuvant. Genomic contigs of strain 33170 were bioinformatically assessed for prophage-like features using BLAST, PHASTER, InterProScan, and PHYRE2. A 7 kb region encoding six genes was identified as an incomplete prophage, and the proteins were further analyzed, revealing high homology to proteins encoded by bacteria, archaea, and an IS200 transposon. Restricting the BLASTp database to viruses resulted in hits to both myo- and siphoviral proteins, which would be unusual for an intact prophage. Additionally, no known phage structural proteins were identified in the search, suggesting a low chance that H. salinarum ATCC 33170 harbors a latent prophage. Full article

The Dong Taijinar (DT) and Xi Taijinar (XT) Salt Lakes have been extensively researched for their mineral richness. However, the composition and distribution of their microbial communities are still poorly known. In this study, we employed metagenomic sequencing to explore the diversity and potential functions of the microbial populations in DT and XT. Our findings indicate that the salinity levels in DT (332.18–358.30 g/L) were tenfold higher than in XT (20.09–36.83 g/L). Notably, archaea dominated the DT domain at 96.16%, while bacteria prevailed in XT at 93.09%. In DT, the bacterial community comprised 33 phyla and 1717 genera, with Marinobacter emerging as the dominant genus, showing a positive correlation with the total phosphorus content. The archaeal community in DT included four main phyla and 153 genera. The most abundant genera were Natronomonas (24.61%) and Halorubrum (23.69%), which had a strong positive correlation with the concentrations of Na⁺, Ca²⁺, and Cl⁻. Conversely, XT hosted 33 phyla and 1906 bacterial genera, with Loktanella as the dominant genus. The archaeal taxonomy in XT encompassed four phyla and 149 genera. In both salt lakes, Proteobacteria and Euryarchaeota were the most abundant bacterial and archaeal phyla, respectively. Our analysis of the halophilic mechanisms of these microorganisms suggests that the bacteria in XT tend to synthesize compatible solutes, whereas the archaea in DT adopt a ‘salt-in’ strategy, integrating salt into their cellular machinery to cope with the high-salinity environment. Full article

This study aimed to assess the efficacy of a bacterioruberin-rich carotenoid extract (HAE) derived from the halophilic archaea Halorubrum ezzemoulense DSM 19316 in protecting crude fish oil against thermal oxidation. The research used fish oil derived from anchovies, which had a peroxide value (PV) of 6.44 ± 0.81 meq O₂ kg⁻¹. To assess the impact of HAE on the thermal stability and post-oxidation characteristics of fish oil, several concentrations of HAE were added to the fish oil samples: 0 ppm (no additive) (HAE0), 50 ppm (HAE50), 100 ppm (HAE100), 500 ppm (HAE500), and 1000 ppm (HAE1000). Furthermore, a control group was established with the addition of 100 ppm butylated hydroxytoluene (BHT100) in order to evaluate the effectiveness of HAE with a synthetic antioxidant that is commercially available. Prior to the fast oxidation experiment, thermogravimetric analysis was conducted on samples from all experimental groups. At the conclusion of the examination, it was seen that the HAE500 and HAE1000 groups exhibited a delay in the degradation temperature. The experimental groups underwent oxidation at a temperature of 55.0 ± 0.5 °C for a duration of 96 h. The measurement of PV was conducted every 24 h during this time. PV in all experimental groups exhibited a time-dependent rise (p < 0.05). However, the HAE500 group had the lowest PV measurement at the conclusion of the 96 h period (p < 0.05). Significant disparities were detected in the fatty acid compositions of the experimental groups at the completion of the oxidation experiment. The HAE500 group exhibited the highest levels of EPA, DHA, and ΣPUFA at the end of oxidation, with statistical significance (p < 0.05). Through the examination of volatile component analysis, specifically an oxidation marker, it was shown that the HAE500 group exhibited the lowest level of volatile components (p < 0.05). Consequently, it was concluded that the addition of HAE to fish oil provided superior protection compared to BHT at an equivalent rate. Moreover, the group that used 500 ppm HAE demonstrated the highest level of performance in the investigation. Full article

The reserves of light conditional oil in reservoirs with low-salinity formation water are decreasing worldwide, necessitating the extraction of heavy oil from petroleum reservoirs with high-salinity formation water. As the first stage of defining the microbial-enhanced oil recovery (MEOR) strategies for depleted petroleum reservoirs, microbial community composition was studied for petroleum reservoirs with high-salinity formation water located in Tatarstan (Russia) using metagenomic and culture-based approaches. Bacteria of the phyla Desulfobacterota, Halanaerobiaeota, Sinergistota, Pseudomonadota, and Bacillota were revealed using 16S rRNA-based high-throughput sequencing in halophilic microbial communities. Sulfidogenic bacteria predominated in the studied oil fields. The 75 metagenome-assembled genomes (MAGs) of prokaryotes reconstructed from water samples were assigned to 16 bacterial phyla, including Desulfobacterota, Bacillota, Pseudomonadota, Thermotogota, Actinobacteriota, Spirochaetota, and Patescibacteria, and to archaea of the phylum Halobacteriota (genus Methanohalophilus). Results of metagenomic analyses were supported by the isolation of 20 pure cultures of the genera Desulfoplanes, Halanaerobium, Geotoga, Sphaerochaeta, Tangfeifania, and Bacillus. The isolated halophilic fermentative bacteria produced oil-displacing metabolites (lower fatty acids, alcohols, and gases) from sugar-containing and proteinaceous substrates, which testify their potential for MEOR. However, organic substrates stimulated the growth of sulfidogenic bacteria, in addition to fermenters. Methods for enhanced oil recovery should therefore be developed, combining the production of oil-displacing compounds with fermentative bacteria and the suppression of sulfidogenesis. Full article