HPLC-MS Analysis Research Articles

Biodegradation of Crude Oil and Aniline by Heavy Metal-Tolerant Strain Rhodococcus sp. DH-2

Aniline and crude oil are common environmental pollutants that present a significant risk to both the ecological and human health environments. The implementation of efficacious bioremediation strategies is imperative for the elimination of these contaminants. In this study, a bacterial strain designated DH-2 was isolated from soil contaminated with aniline. The strain was identified as belonging to the genus Rhodococcus. The optimal conditions for the growth and aniline degradation by strain DH-2 were determined to be pH 8.0 and 35 °C, respectively. Under these conditions, the degradation rate of aniline at a concentration of 1000 mg/L exceeded 90% within 36 h. Even in the presence of 4% NaCl, the degradation rate remained above 60%. HPLC–MS analysis revealed that the aniline degradation pathway of strain DH-2 follows the catechol pathway. Additionally, strain DH-2 is capable of utilizing crude oil as the sole carbon source, achieving a degradation rate of 91.0% for 2% crude oil concentration within 4 days. In soil modeling experiments, strain DH-2 was observed to degrade aniline and crude oil under triple stress conditions, including 1000 mg/L aniline, 2% crude oil, and 20 mg/L Fe(II) or Pb(II). Complete degradation of aniline and crude oil was achieved after 3 days and 12 days, respectively. The addition of Fe(II) or Pb(II) ions was found to enhance the degradation ability of DH-2. These results demonstrate that strain DH-2 is an extremely effective biodegradable strain, with potential applications in the remediation of environments contaminated with aniline and crude oil, even in the presence of heavy metals.

Synthesis and antimycotic activity of new derivatives of imidazo[1,2-a]pyrimidines.

The heterocyclic core of imidazo[1,2-a]pyrimidine was formed in satisfactory yields as a result of the interaction of the readily available 2-aminoimidazole with N-substituted maleimides or N-arylitaconimides. The mechanism of the studied processes was postulated basing on experimental data, HPLC-MS analysis of reaction mixtures, and quantum chemical calculations. Molecular docking results of the obtained imidazo[1,2-a]pyrimidines, when compared with voriconazole, a drug already in clinical use, suggest that they may possess antifungal activity against Candida albicans.

Antiproliferative and biochemical evaluation of rose extracts: impact on tumor and normal skin cells.

Rose petals (Rosa L.) are rich sources of phenolic compounds, including anthocyanins. Anthocyanins and anthocyanidins are associated with multiple health benefits due to their antioxidant properties. In this study, eighteen rose cultivars were comparatively analyzed to determine their total polyphenol and flavonoid content, as well as their antioxidant activity using the 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging method. The extracts were purified using Amberlite XAD-7 and Sephadex LH-20 columns to obtain anthocyanin-rich fractions. Individual anthocyanins were separated and identified using high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS). The three cultivars with the highest anthocyanin content were further examined for cytotoxic effects on cell cultures at various extract concentrations (200-1000 µg/mL) using two skin cell lines: a melanoma cell line (A375) and a normal skin cell line (Hs27). The HPLC-MS analysis identified nine different anthocyanin compounds, with the total anthocyanin content in the rose cultivars varying from 12.42 to 331.95 mg of cyanidin-3-glucoside equivalent/100g of fresh weight. The total polyphenol and total flavonoid contents ranged from 289 to 2703 mg gallic acid equivalent/100g fresh weight and 102 to 603 mg catechin equivalent/100g fresh weight, respectively. Antioxidant activity ranged from 450 to 1304 µmol trolox equivalent/g fresh weight. A significant correlation was observed between antioxidant activity and the content of anthocyanins (R = 0.875, p < 0.001), flavonoids (R = 0.982, p < 0.001), and polyphenols (R = 0.991, p < 0.001). Furthermore, principal component analysis, along with dendrograms and heatmaps, illustrated the relationships among these key compounds and their association with antioxidant activity. The MTT assay showed a substantial suppression of A375 cancer skin cells, while simultaneously exhibiting cell proliferation in Hs27 normal skin cells in a concentration-dependent manner. Altogether, results suggest that the anthocyanins from these rose cultivars could be considered as a promising agent for adjuvant treatment of skin melanoma.

Enhanced Cu-EDTA degradation with trace Cu(II) in limestone via activating PMS

Effective removal of heavy metal complexes from contaminated water remains a challenging task. In this work, a limestone/PMS system was constructed for the efficient degradation of Cu-EDTA. Under the conditions of 3.0 g/L limestone and 1.0 mM PMS, the degradation efficiency of 10.0 mg/L Cu-EDTA reached 99.0 % in 60 min, and the removal efficiency of Cu ions approached 50.0 %. The main active specie revealed by quenching and EPR experiments was the singlet oxygen (1O2). Interestingly, Trace amounts of Cu(II) in limestone react with PMS enhancing the degradation of Cu-EDTA. The results of the HPLC-MS analysis showed that the reactive species attacked the Cu–O and Cu–N bonds, as well as triggered a decarboxylation process, resulting in the decomposition of Cu-EDTA into six intermediates. Meanwhile, SEM and XPS analyses revealed that Cu ions released during the degradation of Cu-EDTA are deposited on the limestone surface as Cu(OH)2 and Cu2(OH)2CO3. In addition, the initial pH and co-existing ions have a weak effect on the system. Finally, a one-month continuous flow experiment showed that the degradation efficiency of Cu-EDTA was about 95.0 % and the removal efficiency of Cu ions was 40.0 %. In conclusion, this study provides a new approach for the destruction of metal complexes and the removal of heavy metals.

Mechanisms and degradation pathways of tetracycline by Co7Fe3 nanoparticles anchored porous carbon activated peroxymonosulfate

In recent years, catalysts based on transition metals have been extensively employed for the activation of peroxymonosulfate (PMS) in the removal of tetracycline (TC) from aquatic environments. However, the efficiency of single transition metals and heterogeneous transition metals as catalysts has been somewhat limited. In this study, different bimetallic Co-Fe catalysts embedded in a porous carbon (Co7Fe3-500/600/700/800) were synthesized using a straightforward single-step calcination process at varying temperatures, addressing the issues of poor activation performance of single transition metals and low dispersion of active components in heterogeneous transition metals. The Co7Fe3-500/600/700/800 enhanced the electronic configuration, establishing electron-rich and highly active zones that promoted electron transfer between the Co and Fe transition metals. The results showed that Co7Fe3-600, exhibited excellent PMS activation performance, removing 95.1 % of TC from the solution within 10 min. Additionally, Co7Fe3-600 showed strong adaptability and resistance to interference under various environmental conditions. DFT calculations, HPLC-MS analysis and T.E.S.T analysis were used to predict potential degradation intermediates during TC degradation and assess their biological toxicity. This research introduces an innovative strategy for formulating sophisticated bimetallic alloy catalysts and contributes fresh perspectives on the mechanisms involved in the PMS activation process by bimetallic catalysts.

Biodegradation of imidacloprid and diuron by Simplicillium sp. QHSH-33

Imidacloprid (IMI) and diuron (DIU) are widely used pesticides in agricultural production. However, their excessive use and high residues have caused harm to the ecological environment and human health. Microbial remediation as an efficient and low-toxic method has become a research hotspot for controlling environmental pollutants. A fungus QHSH-33, identified as Simplicillium sp., has the ability to degrade neonicotinoids IMI and phenylurea DIU. When QHSH-33 and pesticide were co-cultured in liquid medium for 7 days, the degradation rates of IMI and DIU by QHSH-33 in simulated field soil microenvironment were 50.19 % and 70.57 %, respectively. Through HPLC-MS analysis, it was found that the degradation of IMI mainly involved nitro reduction, hydroxylation and other reactions. Three degradation pathways and eight degradation products were identified, among which two metabolites were obtained by microbial transformation of IMI for the first time. The degradation of DIU mainly involved demethylation and dehalogenation reactions, and two degradation pathways and four degradation products were identified, one of which was a new degradation product of DIU. Toxicity assessment demonstrated that most of the degradation products might be considerably less harmful than IMI and DIU. Whole genome sequencing of QHSH-33 revealed a genome size of 33.2 Mbp with 11,707 genes. The genome of QHSH-33 was annotated by KEGG to reveal 128 genes related to exogenous degradation and metabolism. After local blast with reported IMI and DIU degrading enzymes, seven IMI-degrading related genes and seven DIU-degrading related genes were identified in the QHSH-33 genome. The results of this study will help to expand our knowledge on the microbial decomposition metabolism of IMI and DIU, and provide new insights into the degradation mechanism of IMI and DIU in soil and pure culture system, laying a foundation for QHSH-33 strain applied to the removal, biotransformation or detoxification of IMI and DIU.

Construction of C3N4/Ag2S p-n semiconductor heterojunction coupled with Ag-induced SPR effect on CF cloth for improving photocatalytic activity

C3N4/Ag2S p-n semiconductor heterojunction coupled with Ag-induced SPR effect on carbon fiber cloth with large macroscopic area, recyclability and excellent photocatalytic performance was prepared by thermal condensation-chemical precipitation. CF/C3N4/Ag/Ag2S cloth showed strong Vis-NIR light absorption and outstanding separation efficiency of photo-generated electron and hole pairs. CF/C3N4/Ag/Ag2S cloth displayed a markedly enhanced catalytic activity (94 % of TC, 85 % of Cr(VI)) compared with CF/C3N4 cloth (52 % of TC, 50 % of Cr(VI)) or CF/Ag/Ag2S cloth (34 % of TC, 19 % of Cr(VI)), attributing to the establishment of p-n junction along with Ag SPR effect. Moreover, degradation pathways for TC were proposed utilizing HPLC-MS and Fukui index analysis, and photocatalytic mechanism was confirmed by active species experiments and DFT computations. This facile strategy provides novel approach to the synthesis of material with large macroscopic areas, recyclability, and excellent photocatalytic property for degrading contaminants from wastewater.

Novel dual-photoelectrode Z-scheme PEC system for efficient TBBPA removal and debromination: Performance and promoting mechanism

Herein, a novel dual-photoelectrode Z-scheme photoelectrocatalytic system is created to achieve efficient synergistic anodic oxidation and cathodic reduction for TBBPA degradation and debromination. Based on the polydopamine-modified N-doped TiO2 nanotubes (PN-TNTs) photoanode and polydopamine-modified Cu2O nanowires (PC-CNWs) photocathode, the degradation, debromination and mineralization were 99.4%, 77.7% and 52.1% at 0.7 V under visible light for 2 h. The introduction of PDA enhances the visible light absorption by the TiO2 photoanode and protects the Cu2O photocathode from photocorrosion. The main active species identified by electron paramagnetic resonance (EPR) and scavenger experiments as •OH and e− were found to promote the degradation and debromination of TBBPA by oxidation and reduction, respectively. The degradation pathway of TBBPA was determined by Density Functional Theory (DFT) calculations and HPLC-MS analyses. Comparing the intermediates of single and dual chambers, it demonstrated that the photocathode was able to achieve the continuous debromination of TBBPA and intermediates, which reduced the toxicity. Finally, the stability, reusability and energy consumption were evaluated, confirming the feasibility of the system.

Rapeseed cake meal extract as an eco-friendly green sustainable inhibitor for the corrosion of cold rolled steel in trichloroacetic acid solution

The inhibitory properties of rapeseed cake meal extract (RCME) on the corrosion of cold rolled steel (CRS) in trichloroacetic acid (TCA) were systematically investigated using gravimetric, electrochemical, surface characterizations and theoretical calculations. The results demonstrate that RCME exhibits excellent inhibitory performance with a maximum inhibition efficiency of 92.7% for 100 mg L−1 RCME at 20°C. The adsorption of RCME obeys Langmuir isotherm at 20 and 30°C, Temkin isotherm at 40°C, and Freundlich isotherm at 50°C. RCME acts as a cathodic inhibitor. The charge transfer resistance is increased with the addition of RCME, while the double-layer capacitance decreases. SEM, AFM, CLSM, XPS, XRD and TOF-SIMS analyses confirm that the active components in RCME adsorb onto the surface of CRS, forming a protective film that effectively inhibits the corrosion of CRS by TCA. Along with the increase in the concentration of RCME, the surface tension of the inhibited solution gradually decreases, while the electrical conductivity increases before stabilizing. HPLC-MS and FTIR analyses reveal rutin, linolenic acid, linoleic acid and adenine are the effective substances in RCME. Quantum chemical (QC) calculations and molecular dynamic (MD) simulations indicate that the active centers of the effective inhibitor molecules are predominantly located on benzene rings, O- or N-containing heterocyclic rings, and functional groups such as C=O and C=C. Additionally, their main chains adsorb onto the Fe (001) surface in an approximately flat manner, involving both chemical and physical adsorption processes.

Electrochemical potential enhanced EC-SERS sensor for sensitive and label-free detection of acetamiprid

Label-free surface-enhanced Raman spectroscopy (SERS) holds promise for detecting pesticide residues, yet its broader application in food safety is limited by the weak affinity between pesticides and SERS substrates. This study introduces an electrochemical surface-enhanced Raman spectroscopy (EC-SERS) sensor that utilizes potential strengthened molecular interactions and Ag@SiO2 nanospheres as SERS substrates, significantly enhancing the detection sensitivity for acetamiprid (AAP). The dense distribution of silver nanoparticles (Ag NPs) on the SiO2 surfaces creates numerous “hot spots,” significantly improving the SERS performance for AAP detection. A potential of −0.5 V substantially boosts the SERS signal intensity for AAP compared to without applied potential, notably achieving a 4.3-fold increase at the 631 cm−1 signal peak. Under optimal conditions, the EC-SERS method achieved a limit of detection (LOD) for AAP at 0.046 μM, spanning a linear range from 0.05 μM to 0.1 mM, which is 185 times more sensitive than conventional SERS approaches. When applied to vegetable samples, the method showed recoveries between 95.56 % and 109.33 %, with results corroborated by HPLC-MS analysis. Thus, this study provides an effective and facile strategy for the detection of AAP in the food safety field.

Green surfactant and circulating ultrasound coupling extraction of total flavonoids from Cynanchum auriculatum leaves: Parameter optimization, extraction mechanism, and HPLC-MS analysis

This study aimed to devise an integrated green surfactant and circulating ultrasound coupling extraction (GSCUE) approach for extracting the total flavonoids from Cynanchum auriculatum leaves. Single-factor optimization combined with a Box–Behnken design was used to determine the optimal technological conditions, which included an APG0814/MES amount of 5 % (w/v), extraction temperature of 46 °C, ultrasound irradiation power of 509 W, liquid–solid ratio of 30 mL/g, mixing speed of 1000 r/min, and extraction time of 50 min. Under these conditions, the extraction yield of the total flavonoids reached 7.83 mg/g. The HPLC-MS was applied to identify the flavonoid compositions in Cynanchum auriculatum leaves extract. The results showed that flavonoid composition included Gardenin B, Luteolin, Kaempferol, Quercetin, 4′-Methoxy-7-O-beta-D-glucopyranosyl-8,3′-dihydroxyflavanone, Astragalin, Spiraeoside, Rutin, and Kaempferol 3-gentiobioside. Further, to investigate the GSCUE mechanism, plant samples before and after extraction were analyzed by fourier transform infrared spectroscopy, scanning electron microscopy, and contact angle analysis. The results indicate that the functional groups, surface microstructure, and surface wettability of the plant samples all affect the yield of the target active ingredients. The hydrophilic group content on the plant sample surface after GSCUE treatment was higher compared to the case of the untreated samples. Additionally, there was evidence of surface structural collapse and shrinkage, increased surface roughness, and a decreased contact angle due to GSCUE treatment. These results highlight the greater surface wettability of the plant samples, faster solvent penetration, and an effective increase in the total flavonoid yield, indicating the synergistic effect of combining ultrasound with green surfactants for total flavonoid extraction. Overall, GSCUE technology provided a sustainable and efficient approach for extracting the total flavonoids from plant materials.

Changes in Phenolic Composition and Bioactivities of Ayocote Beans under Boiling (Phaseolus coccineus L.).

Ayocote beans (Phaseolus coccineus L.) are a rich source of some bioactive molecules, such as phenolic compounds that exhibit antioxidant capacity that promote health benefits. Ayocote is mainly consumed after cooking, which can impact the antioxidant characteristics of the phenolic compounds responsible for some of its health benefits. Therefore, this study investigated the effects of boiling on the phenolic composition and bioactivities of ayocote beans before and after boiling. Boiling decreased the total phenolic content (70.2, 60.3, and 58.2%), total anthocyanin (74.3, 80.6, and 85.7%), and antioxidant activity (DPPH: 41.2, 46.9, and 59.1%; ORAC: 48.23, 53.6 and 65.7%) of brown, black, and purple ayocote beans, respectively. All the extracts also inhibited the activity of α-glucosidase with efficacy values from 29.7 to 87.6% and α-amylase from 25.31 to 56.2%, with moderate antiglycation potential (15.2 to 73.2%). Phenolic acids, anthocyanins, and flavonoid decreases were detected in boiled samples by HPLC-MS analysis. Although boiling reduced the phenolic compounds, bioactive compounds remained in a considerable content in boiled ayocote.

Photocatalytic degradation of tetracycline by g-C3N4/stilbite under visible light: Mechanistic insights and degradation pathways

In this study, the g-C3N4/stilbite composite was fabricated by the in-situ synthesis method, and the photocatalytic performance was investigated by degrading tetracycline (TC) under visible light. The results indicated that the photocatalytic degradation efficiency of g-C3N4/stilbite-6 (86.8 %) was about 2.7 times higher than that of pure g-C3N4 (31.8 %). The introduction of the stilbite carrier effectively resolved the issues of g-C3N4 such as easy self-agglomeration and the difficulty in separating photo-generated carriers, thereby improving the photocatalytic activity of g-C3N4. From the quenching experiment, it was found that h+ and •O2− were main active species for TC degradation. By HPLC-MS analysis, TC degradation products were identified, and three degradation pathways were proposed. In addition, the impacts of solution pH, light intensity, and catalyst dosage on TC degradation performance were also evaluated. Overall, a simple and successful strategy has been proposed to synthesize high-performing visible-light-driven photocatalysts for efficiently eliminating organic contaminants from wastewater.

Enhanced activation of persulfate by bimetal and nitrogen co-doped biochar for efficient degradation of refractory organic contaminants: The role of the second metal

The leaching of metal ions limits the application of Fe-biochar catalyst in activating persulfate (PS). In this work, Fe-M (M = Co, Cu) and nitrogen co-doped biochar (Fe-M@N-BC) were synthesized through impregnating bio-waste soybean straw to activate PS for the removal of various refractory organic contaminants (tetracycline (TC), oxytetracycline (OTC), methyl orange (MO) and rhodamine B (RhB)). The catalysts were characterized by XRD, XPS, Raman, BET, TEM, SEM, and the degradation mechanism was investigated through quenching experiments and EPR. The results indicated that the doping of second metal (Co, Cu) has a strong promoting effect on catalytic activity with the order of Co > Cu. Surprisingly, the removal rates of TC, OTC, RhB, MO by Fe–Co@N-BC reached 84.7 %, 90.3 %, 89.4 %, and 91 %, respectively. The excellent catalytic performance of Fe–Co@N-BC was mainly attributed to abundant pyridinic-N, larger specific surface area (270 m2 g−1) and the Co(II)/Co(III) redox cycle promoting the regeneration of Fe(II). Notably, the formation of Co7Fe3 alloy could inhibit the leaching of iron ions and Fe–Co@N-BC possessed excellent reusability. Additionally, non-radical (1O2) was the main active species in the Fe–Co@N-BC/PS system. Finally, the degradation pathway of MO was proposed by HPLC-MS analysis. This research work provided an insight into how to reasonably utilize biological waste to construct highly efficient and stable catalysts for pollutants degradation.

Rejuvenation of Meropenem by Conjugation with Tilapia Piscidin-4 Peptide Targeting NDM-1 Escherichia coli.

Gram-negative pathogens that produce β-lactamases pose a serious public health threat as they can render β-lactam antibiotics inactive via hydrolysis. This action contributes to the waning effectiveness of clinical antibiotics and creates an urgent need for new antimicrobials. Antimicrobial peptides (AMPs) exhibiting multimodal functions serve as a potential source in spite of a few limitations. Thus, the conjugation of conventional antibiotics with AMPs may be an effective strategy to leverage the advantages of each component. In this study, we conjugated meropenem to the AMP Tilapia piscidin 4 (TP4) using a typical coupling reaction. The conjugate was characterized by using HPLC-MS, HR-MS, and MS-MS fragmentation analysis. It was then evaluated in terms of antibacterial potency, hemolysis, and cytotoxicity toward RAW264.7 and CCD-966SK cell lines. The conjugation of meropenem with TP4 significantly reduced the cytotoxicity compared to TP4. Conjugation of unprotected TP4 with meropenem resulted in cross-linking at the N-terminal and lysine sites. The structural activity relationship of the two isomers of the TP4-meropenem conjugate was investigated. Both the isomers showed notable antibacterial activities against NDM-1 Escherichia coli and reduced red blood cell hemolysis as compared to TP4. Lysine conjugate (TP4-K-Mero) showed lesser hemolysis than the N-terminal conjugate (TP4-N-Mero). Molecular modeling further revealed that the conjugates can bind to lipopolysaccharides and inhibit NDM-1 β-lactamase. Together, these data show that conjugation of antibiotics with AMP can be a feasible approach to increase the therapeutic profile and effectively target multidrug-resistant pathogens. Furthermore, antibiotic conjugation at different AMP sites tends to show unique biological properties.

Synergistic adsorption-photocatalytic degradation of tetracycline by S-scheme InVO4/ZnIn2S4 heterojunction: mechanism, toxicity assessment, and potential applications

The development of materials with dual adsorption/photocatalytic functions for the removal of difficult-to-degrade organics is a very promising and challenging strategy. In this paper, a novel S-scheme heterojunction photocatalyst, InVO4/ZnIn2S4, was successfully synthesized with a unique hierarchical structure, which provides plenty of accessible adsorption/photocatalytic sites with a high light-harvesting rate (by multiple reflections). The experimental results show that optimized InVO4/ZnIn2S4 (5-IV/ZIS) has superior removal performance, whose adsorption-photocatalytic synergistic removal of tetracycline (TET) can reach 69.31 % after 15 min and 90.69 % after 45 min. Based on the analysis of the mechanism, the excellent removal performance can be attributed to the adsorption of the target onto the material by hydrogen bonding, followed by the degradation of the adsorbed target by active substances (h+ > O2•− > e- >1O2 >•OH) generated by the S-scheme heterojunction. In addition, the possible pathways for the photocatalytic removal of TET on 5-IV/ZIS were investigated by HPLC-MS analysis. T.E.S.T. and E. coli inhibition experiments demonstrated a significant reduction in the toxicity of TET after the photocatalytic reaction. In conclusion, the novel multifunctional photocatalyst 5-IV/ZIS prepared in this study can be used for the efficient treatment of organic compounds in wastewater with a bright application prospect.

Controlled humidity synthesis of surface sulfate functionalized CdS for enhanced visible light photocatalysis

At present, the pollution of antibiotic wastewater is serious, which has a potential impact on the survival of organisms. In this study, SO42- functionalized small-sized flower-like CdS is successfully synthesized by utilizing H2S at various levels of relative humidity. The CdS catalyst is then employed for the degradation of tetracycline hydrochloride (TC) through photocatalytic processes. Experimental findings indicate that CdS-8 %RH exhibits the highest photocatalytic efficiency, degrading 98.6 % of TC within 80 min, which is 1.5 times more efficient than CdS alone. HPLC-MS analysis is used to identify degradation intermediates and pathways, and to evaluate the toxicity and mutagenicity of these intermediates. The photocatalytic mechanism is elucidated through species capture experiments, electrochemical tests, KPFM tests, and conduction valence band position analysis.

Chemical Composition and Protective Possibilities of Juglans Nigra Leaves and Green Husks Extracts: DNA Binding and Micronucleus Assay in Human Lymphocytes.

To better understand the mechanism of action of the compounds in the ethanolic extracts of J. nigra leaves and green husks, their binding to CT-DNA was investigated. This study was conducted to elucidate the in vitro protective effect of extracts against chromosomal damage in mitogen-induced human lymphocytes and investigate the possible application of selec+ted extracts as a natural source of polyphenolic compounds. Using HPLC-MS analysis, 103 different compounds were identified as having a higher number of active species, which is consistent with their activity. The frequency of micronuclei (MN) was scored in binucleated cells, and the nuclear proliferation index was calculated. Cyclic voltammetry experiments demonstrate that the nature of the interaction between extracts and CT-DNA is a synergy of electrostatic and intercalative modes, where leaves extracts showed a higher ability to bind to DNA. Extracts showed excellent antioxidant activity. At a concentration of only 4 µg/mL, extract of J. nigra leaves and the green husks reduced the incidence of MN by 58.2% and 64.5%, respectively, compared to control cell cultures.

Ancient and remote quartzite caves as a novel source of culturable microbes with biotechnological potential

Quartzite caves located on table-top mountains (tepuis) in the Guyana Shield, are ancient, remote, and pristine subterranean environments where microbes have evolved peculiar metabolic strategies to thrive in silica-rich, slightly acidic and oligotrophic conditions. In this study, we explored the culturable fraction of the microbiota inhabiting the (ortho)quartzite cave systems in Venezuelan tepui (remote table-top mountains) and we investigated their metabolic and enzymatic activities in relation with silica solubilization and extracellular hydrolytic activities as well as the capacity to produce antimicrobial compounds. Eighty microbial strains were isolated with a range of different enzymatic capabilities. More than half of the isolated strains performed at least three enzymatic activities and four bacterial strains displayed antimicrobial activities. The antimicrobial producers Paraburkholderia bryophila CMB_CA002 and Sphingomonas sp. MEM_CA187, were further analyzed by conducting chemotaxonomy, phylogenomics, and phenomics. While the isolate MEM_CA187 represents a novel species of the genus Sphingomonas, for which the name Sphingomonas imawarii sp. nov. is proposed, P. bryophila CMB_CA002 is affiliated with a few strains of the same species that are antimicrobial producers. Chemical analyses demonstrated that CMB_CA002 produces ditropolonyl sulfide that has a broad range of activity and a possibly novel siderophore. Although the antimicrobial compounds produced by MEM_CA187 could not be identified through HPLC-MS analysis due to the absence of reference compounds, it represents the first soil-associated Sphingomonas strain with the capacity to produce antimicrobials. This work provides first insights into the metabolic potential present in quartzite cave systems pointing out that these environments are a novel and still understudied source of microbial strains with biotechnological potential.

Gonadal efficacy of Thymus quinquecostatus Celakovski: Regulation of testosterone levels in aging mouse models

Late-onset hypogonadism (LOH) is an age-related disease in men characterized by decreased testosterone levels with symptoms such as decreased libido, erectile dysfunction, and depression. Thymus quinquecostatus Celakovski (TQC) is a plant used as a volatile oil in traditional medicine, and its bioactive compounds have anti-inflammatory potential. Based on this knowledge, the present study aimed to investigate the effects of TQC extract (TE) on LOH in TM3 Leydig cells and in an in vivo aging mouse model. The aqueous extract of T. quinquecostatus Celakovski (12.5, 25, and 50 µg/mL concentrations) was used to measure parameters such as cell viability, testosterone level, body weight, and gene expression, via in vivo studies. Interestingly, TE increased testosterone levels in TM3 cells in a dose-dependent manner without affecting cell viability. Furthermore, TE significantly increased the expression of genes involved in the cytochrome P450 family (Cyp11a1, Cyp17a1, Cyp19a1, and Srd5a2), which regulate testosterone biosynthesis. In aging mouse models, TE increased testosterone levels without affecting body weight and testicular tissue weight tissue of an aging animal group. In addition, the high-dose TE-treated group (50 mg/kg) showed significantly increased expression of the cytochrome p450 enzymes, similar to the in vitro results. Furthermore, HPLC-MS analysis confirmed the presence of caffeic acid and rosmarinic acid as bioactive compounds in TE. Thus, the results obtained in the present study confirmed that TQC and its bioactive compounds can be used for LOH treatment to enhance testosterone production.