Genome-wide analysis of in vivo-evolved Candida auris reveals multidrug-resistance mechanisms.

Candida auris, an emerging and multidrug-resistant fungal pathogen, has led to numerous outbreaks in China. While the resistance mechanisms against azole and amphotericin B have been studied, the development of drug resistance in this pathogen remains poorly understood, particularly in in vivo-generated drug-resistant strains. This study employed pathogen whole-genome sequencing to investigate the epidemiology and drug-resistance mutations of C. auris using 16 strains isolated from two patients. Identification was conducted through Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and antimicrobial susceptibilities were assessed using broth microdilution and Sensititre YeastOne YO10. Whole-genome sequencing revealed that all isolates belonged to the South Asian lineage, displaying genetic heterogeneity. Despite low genetic variability among patient isolates, notable mutations were identified, including Y132F in ERG11 and A585S in TAC1b, likely linked to increased fluconazole resistance. Strains from patient B also carried F214L in TAC1b, resulting in a consistent voriconazole minimum inhibitory concentration of 4 µg/mL across all isolates. Furthermore, a novel frameshift mutation in the SNG1 gene was observed in amphotericin B-resistant isolates compared to susceptible ones. Our findings suggest the potential transmission of C. auris and emphasize the need to explore variations related to antifungal resistance. This involves analyzing genomic mutations and karyotypes, especially in vivo, to compare sensitive and resistant strains. Further monitoring and validation efforts are crucial for a comprehensive understanding of the mechanisms of drug resistance in C. auris.

Structural identification of pyridinopyrone compounds with anti-neuroinflammatory activity from streptomyces sulphureus DSM 40104.

This study investigated the chemical composition and biosynthesis pathway of compounds produced by Streptomyces sulphureus DSM 40104. With the guild of molecular networking analysis, we isolated and identified six uncommon structural characteristics of compounds, including four newly discovered pyridinopyrones. Based on genomic analysis, we proposed a possible hybrid NRPS-PKS biosynthesis pathway for pyridinopyrones. Notably, this pathway starts with the use of nicotinic acid as the starting unit, which is a unique feature. Compounds 1-3 exhibited moderate anti-neuroinflammatory activity against LPS-induced BV-2 cell inflammation. Our study demonstrates the diversity of polyene pyrone compounds regarding their chemical structure and bioactivity while providing new insights into their biosynthesis pathway. These findings may lead to the development of new treatments for inflammation-related diseases.

Ambient nitrogen dioxide and cardiovascular diseases in rural regions: a time-series analyses using data from the new rural cooperative medical scheme in Fuyang, East China.

Most of studies relating ambient nitrogen dioxide (NO2) exposure to hospital admissions for cardiovascular diseases (CVDs) were conducted among urban population. Whether and to what extent these results could be generalizable to rural population remains unknown. We addressed this question using data from the New Rural Cooperative Medical Scheme (NRCMS) in Fuyang, Anhui, China. Daily hospital admissions for total CVDs, ischaemic heart disease, heart failure, heart rhythm disturbances, ischaemic stroke, and haemorrhagic stroke in rural regions of Fuyang, China, were extracted from NRCMS between January 2015 and June 2017. A two-stage time-series analysis method was used to assess the associations between NO2 and CVD hospital admissions and the disease burden fractions attributable to NO2. In our study period, the average number (standard deviation) of hospital admissions per day were 488.2 (117.1) for total CVDs, 179.8 (45.6) for ischaemic heart disease, 7.0 (3.3) for heart rhythm disturbances, 13.2 (7.2) for heart failure, 267.9 (67.7) for ischaemic stroke, and 20.2 (6.4) for haemorrhagic stroke. The 10-µg/m3 increase of NO2 was related to an elevated risk of 1.9% (RR: 1.019, 95% CI: 1.005 to 1.032) for hospital admissions of total CVDs at lag0-2 days, 2.1% (1.021, 1.006 to 1.036) for ischaemic heart disease, and 2.1% (1.021, 1.006 to 1.035) for ischaemic stroke, respectively, while no significant association was observed between NO2 and hospital admissions for heart rhythm disturbances, heart failure, and haemorrhagic stroke. The attributable fractions of total CVDs, ischaemic heart disease, and ischaemic stroke to NO2 were 6.52% (1.87 to 10.94%), 7.31% (2.19 to 12.17%), and 7.12% (2.14 to 11.85%), respectively. Our findings suggest that CVD burdens in rural population are also partly attributed to short-term exposure to NO2. More studies across rural regions are required to replicate our findings.

Griseocazines: Neuroprotective Multiprenylated Cyclodipeptides Identified through Targeted Genome Mining.

Prenylation can impart pharmacological advantages to bioactive compounds. Global genome mining for prenylated cyclodipeptides identified a gczABC BGC from Streptomyces griseocarneus 132 containing a cyclodipeptide synthase and two prenyltransferase genes. Subsequent heterologous expression allowed isolation and characterization of griseocazines, which displayed potent neuroprotective activity. Further biotransformation analyses revealed that prenyltransferases GczB and GczC catalyzed the stereospecific prenylation of cWW and attached geranyl and farnesyl groups to a cyclodipeptide scaffold, respectively.

Cassane diterpenoids from the aerial parts of Caesalpinia pulcherrima and their antibacterial and anti-glioblastoma activity.

Sixteen cassane diterpenoids (CAs), including four undescribed lactam-type, four unreported lactone-type, along with eight known ones, were isolated from the aerial parts of Caesalpinia pulcherrima (L.) Sw. Their structures were characterized by comprehensive spectroscopic analyses (including NMR and HRESIMS). The absolute configuration of pulcherritam A was finally established by single-crystal X-ray diffraction with Cu Kα radiation. Notably, pulcherritam s A-D were elucidated as a group of rare CAs bearing an α, ß-unsaturated γ-lactam ring rather than a typical lactone moiety. Almost all compounds were examined for their antibacterial. The results reveal that pulcherritam H exhibited significant antibacterial activities against Bacillus cereus, Staphylococcus aureus, as well as Pseudomonas syringae pv. actinidae (Psa) with the MIC from 6.25 to 12.5 µM, while pulcherritams A and C displayed potent antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). Then, all isolates were evaluated for their anti-glioblastoma activities. Pulcherritam A and Pulcherrimin G illustrated moderate inhibitory activity against glioblastoma multiforme (GBM) U87MG cell, and the other compounds did not show obvious inhibitory activity against GBM U87MG cell. Furthermore, the preliminary structure-activity relationship and their biosynthetic pathway were also discussed.

Combined analysis of C-reactive protein in pleural fluid and serum is effective in the differential diagnosis of exudative pleural effusions.

BACKGROUND: Exudative pleural effusion (EPE) is one of the common pleural manifestations of various diseases. Differential diagnosis of EPE is imperative clinically as it identifies different causes of EPE, thereby, enabling effective treatments. Thoracoscopy is a useful tool for differential diagnosis of EPE; however, some patients refuse thoracoscopic examination due to its invasive nature. In addition, the specificity and sensitivity of existing routine tests of EPE are unsatisfactory. Therefore, there is a great need to establish an effective method for the differential diagnosis of EPE. METHODS: This study was a single-institution retrospective analysis of diagnostic efficiency of C-reactive protein (CRP) and procalcitonin (PCT) between March 2018 and September 2018. A total of 87 patients diagnosed with EPE were enrolled. All participants underwent diagnostic thoracentesis. The EPE was examined using biochemical, routine, microbiological, and cytological methods. Pathological cytology detection was necessary for those suspected of malignant PE. Benign PE originates in patients with pneumonia, empyema, and tuberculosis. The levels of CRP and PCT in EPE and serum were measured before treatment. Correlation analysis and receiver-operating characteristic (ROC) curve analysis were conducted to determine the underlying relationship between levels of CRP and PCT, and for differential diagnosis. RESULTS: The ROC analysis showed that the sensitivity and specificity for the analysis of pleural fluid CRP (p-CRP) were higher (cut-off: 17.55 pg/mL; sensitivity: 75.00%, specificity: 83.90%) than that of serum CRP (s-CRP, cut-off: 23.90 pg/mL; sensitivity: 71.00%, specificity: 80.4%) in the differential diagnosis for EPE. However, the analysis of pleural fluid PCT (p-PCT) and serum PCT (s-PCT) did not demonstrate correlations with EPE. Combined analysis of p-CRP (cut-off: 17.55 mg/dL) with s-CRP (cut-off: 23.9 pg/mL) showed the highest diagnostic accuracy (88.4%) in diagnosing infectious EPE. CONCLUSIONS: The data support the close relationship between combined analysis of p-CRP with s-CRP and effective and accurate differential diagnosis of EPE, due to its higher sensitivity and specificity. However, as a highly sensitive marker for diagnosing bacterial infections, neither s-PCT nor p-PCT, showed correlations with the differential diagnosis of EPE.

Global Genome Mining Reveals the Distribution of Diverse Thioamidated RiPP Biosynthesis Gene Clusters.

Thioamidated ribosomally synthesized and post-translationally modified peptides (RiPPs) are recently characterized natural products with wide range of potent bioactivities, such as antibiotic, antiproliferative, and cytotoxic activities. These peptides are distinguished by the presence of thioamide bonds in the peptide backbone catalyzed by the YcaO-TfuA protein pair with its genes adjacent to each other. Genome mining has facilitated an in silico approach to identify biosynthesis gene clusters (BGCs) responsible for thioamidated RiPP production. In this work, publicly available genomic data was used to detect and illustrate the diversity of putative BGCs encoding for thioamidated RiPPs. AntiSMASH and RiPPER analysis identified 613 unique TfuA-related gene cluster families (GCFs) and 797 precursor peptide families, even on phyla where the presence of these clusters have not been previously described. Several additional biosynthesis genes are colocalized with the detected BGCs, suggesting an array of possible chemical modifications. This study shows that thioamidated RiPPs occupy a widely unexplored chemical landscape.

Global Genome Mining Reveals a Cytochrome P450-Catalyzed Cyclization of Crownlike Cyclodipeptides with Neuroprotective Activity.

We conducted global genome mining of 162,672 bacterial genomes and identified 829 cyclodipeptide (CDP) biosynthesis gene clusters (BGC) containing a cytochrome P450 gene. Heterologous expression of BGC from Saccharopolyspora hirsuta DSM 44795 led to the identification of two novel crownlike CDPs, cyctetryptomycin A (4) and B (5), which possess unprecedented complex macrocycle and show neuroprotective activity. The two cytochrome P450s found in the BGC catalyze sequential reactions leading to the cyclization of diketopiperazine dimers.

Pore Size Distribution Characteristics of High Rank Coal with Various Grain Sizes.

Particle void filling effects (P f) under low pressure and coal matrix compressibility effects (P c) at high pressure should not be ignored when using mercury intrusion porosimetry (MIP) to study the pore size distribution of coal. In this study, two coal samples (FX and HF) collected from western Guizhou were crushed into three different grain sizes; then, the subsamples were analyzed by MIP and low-pressure nitrogen adsorption to study the pore size distribution characteristics. The micro- and transition pore volumes contribute to the total pore volume of the FX and HF subsamples. With decreasing subsample grain sizes, the macropore volume of FX subsamples tends to increase, while mesopore volume decreases; the volumes of micropores and transition pores first increase and then decrease. In regard to the HF subsamples, the volumes of macropores and mesopores do not reveal any distinctive changes, while the 40-60 mesh subsample contains the greatest volume of micropores and transition pores. Fractal theory was introduced to determine P f and P c. P f barely changed as grain size decreased; it ranged from 0.1 to 0.15 MPa. However, P c increased with reduced coal grain sizes. The coal matrix compressibility coefficients of the subsamples were calculated from the cumulative mercury volume curve, and the true pore volume was also modified. The modified volume of macropores does not change markedly, while the volumes of mesopores and transition pores decrease significantly, clearly indicating the coal matrix compressibility under high mercury injection pressure. The modified pore volume shows that the pore (<10,000 nm) still harbors fractal characteristics.

Marine natural products as antifouling molecules - a mini-review (2014-2020).

In the present review, 182 antifouling (AF) natural products from marine microorganisms, algae and marine invertebrates reported from August 2014 to May 2020 are presented. Amongst these compounds, over half were isolated from marine-derived microorganisms, including 70 compounds from fungi and 31 compounds from bacteria. The structure-relationship of some of these compounds is also briefly discussed. Based on the work reported, a general workflow was drafted to refine the procedures for the commercialization of any novel AF compounds. Finally, butenolide, which is considered a potential environmentally friendly antifoulant, is used as a case study to show the procedures involved in AF compound work from the aspect of discovery, structure optimization, toxicity, stability, AF mechanism and coating incorporation, which highlight the current challenges and future perspectives in AF compound research.

Cyathane Diterpenes from Cultures of the Bird's Nest Fungus Cyathus hookeri and Their Neurotrophic and Anti-neuroinflammatory Activities.

Six new cyathane diterpenoids, cyahookerins A-F (1-6), as well as nine known analogues (7-15), were isolated from the liquid culture of the basidiomycete Cyathus hookeri. Their structures were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, and ECD), and the absolute configurations of compounds 1 and 4 were determined by single-crystal X-ray crystallography. Compounds 1 and 2 represent the first unusual cyathane acetals featuring a dioxolane ring. Compounds 1-6 displayed differential nerve growth factor-induced neurite outgrowth-promoting activity in PC-12 cells at concentrations of 10 µM. In addition, cyahookerin B (2), cyathin E (9), cyathin B2 (12), and cyathin Q (13) showed significant nitric oxide production inhibition in Lipopolysaccharide (LPS)-activated BV-2 microglial cells with IC50 values of 12.0, 6.9, 10.9, and 9.1 µM, respectively. Similar binding modes of the four compounds were indicated by molecular-docking studies, and structure-activity relationships are discussed.

Genome-based analysis of the type II PKS biosynthesis pathway of xanthones in Streptomyces caelestis and their antifungal activity.

The ethyl acetate extract from the liquid fermentation of S. caelestis Aw99c exhibited high and broad antifungal activities against plant pathogenic fungi. Bioassay guide fractionation led to the discovery of two xanthones, citreamicin ε and θ. The draft genome sequence of S. caelestis Aw99c was analyzed by a similarity-based approach to elucidate the pathway for the citreamicins. A 48 kb citreamicin (cit) gene cluster with 51 open reading frames encoding type II polyketide synthases and unique polyketide tailoring enzymes was proposed based on the genome analysis and the chemical structure derivation. In vitro antifungal assay showed that citreamicin ε exhibited significant growth inhibition against the plant pathogenic fungi with MIC values ranging from 1.56 to 12.5 µM. The cellular structural change of M. grisea treated with citreamicin ε was detected by SEM and the result showed that citreamicin ε caused disruptive surface of the mycelia.

Ansamycins with Antiproliferative and Antineuroinflammatory Activity from Moss-Soil-Derived Streptomyces cacaoi subsp. asoensis H2S5.

Three new 21-membered macrocyclic benzenoid ansamycins, trienomycins J-L (1-3), together with seven known analogues, trienomycins A-G (4-10), were isolated from liquid culture of the moss soil-derived actinomycete Streptomyces cacaoi subsp. asoensis H2S5. The structures of the new compounds were elucidated by extensive NMR spectroscopic analysis and HRESIMS data. The absolute configurations of trienomycins were established by Marfey's method. Antiproliferative assays showed that compound 1 had the greatest activity against HepG2 cells, with an IC50 value of 0.1 µM. The induction of apoptosis of HepG2 cells by 1 was investigated by flow cytometry and evaluation of nuclear morphology. In addition, all of the compounds inhibited nitric oxide production with IC50 values of 0.02 to 8.3 µM, and compounds 1, 4, and 7 were the most potent inhibitors. These findings will facilitate the development of new antineuroinflammatory agents.

Stoichiometric and polymorphic salt of imidazolium picrate monohydrate.

The asymmetric unit of the title co-crystal salt, 1H-imidazol-3-ium 2,4,6-tri-nitro-phenolate monohydrate, C4H7N2+·C6H2N3O7-·H2O, contains one imidazolium cation, one picrate anion and one solvent water mol-ecule of crystallization. The phenolic proton has been transferred to an imidazole N atom. In the crystal, the components are linked by N-H⋯O and O-H⋯O hydrogen bonds into a three-dimensional network which is further consolidated by weak C-H⋯O hydrogen bonds. In addition, π-π stacking inter-actions occur between pairs of imidazolium cations and picrate anions. If only the classical N-H⋯O and O-H⋯O hydrogen bonds are considered, the component ions are linked into a three-dimensional threefold inter-penetrating network of the topological type utp [or (10,3)-d]. Hirshfeld surface analysis indicates the crystal structure is mainly stabilized by H⋯·O contacts of the hydrogen bonds.

Thielavins W-Z7, New Antifouling Thielavins from the Marine-Derived Fungus Thielavia sp. UST030930-004.

Eleven new depsides-thielavins W-Z (1-4) and thielavins Z1-Z7 (5-11)-and also four known thielavins-A, H, J, and K (12-15)-were isolated from the ethyl acetate extract of a marine-derived fungal strain Thielavia sp UST030930-004. All of these compounds were evaluated for antifouling activity against cyprids of the barnacle Balanus (=Amphibalanus) amphitrite. The results showed that compounds 1-3 and 6-13 were active, with EC50 values ranging from 2.95 ± 0.59 to 69.19 ± 9.51 µM, respectively. The inhibitive effect of compounds 1-3 and 7 was reversible. This is the first description of the antifouling activity of thielavins against barnacle cyprids.

Gabosines P and Q, new carbasugars from Streptomyces sp. and their α-glucosidase inhibitory activity.

Two new polyoxygenated cyclohexenone 'ketocarbasugars', named gabosines P and Q (1 and 2), were isolated from the culture of the actinomycete Streptomycetes strain no. 8, along with two known cyclic dipeptides. The structures and absolute configurations of the new metabolites were determined by spectroscopic data (1D- and 2D-NMR, HR-ESI-MS, and IR), chemical transformation, and electronic circular dichroism (ECD). These compounds were evaluated for α-glucosidase inhibitory activity in vitro. Only compound 1 exhibited IC50 values of 9.07µM, with potency higher than that of the control acarbose. Molecular docking studies revealed the existence of hydrogen bonding and hydrophobic interaction between the enzyme and gabosine P. The results will be useful in designing new anti-diabetes control agents.

Multilocus Sequence Typing of Clinical Isolates of Burkholderia pseudomallei Collected in Hainan, a Tropical Island of Southern China.

Burkholderia pseudomallei is a gram-negative bacterium that causes melioidosis. In this study, we examined the sequence types (STs) of 60 clinical isolates from patients with melioidosis in Hainan, a tropical island in southern China. The 60 clinical isolates were resolved into 30 STs. Among the STs, ST562 was also reported in Australia, and ST90 was also reported in the United States, probably from a traveler who had previously visited Asia. In addition, six novel STs were found in this study, including ST1395, ST1396, ST1397, ST1398, ST1399, and ST1443, whereas the remaining STs were mostly shared with other southeast Asian regions. Phylogenetic analysis of 60 isolates conducted using the eBURST v3 software segregated the 30 STs into three groups and 18 singletons. Our study shows genetic diversity of 60 clinical isolates of B. pseudomallei in Hainan Island.

Cochliomycin A inhibits the larval settlement of Amphibalanus amphitrite by activating the NO/cGMP pathway.

Cochliomycin A is a compound with anti-barnacle settlement activity and low toxicity, but the molecular mechanism of the compound is unknown. Here, isobaric tags for the relative or absolute quantitation (iTRAQ) labeling proteomic method were applied to analyze changes in the proteome of Amphibalanus (=Balanus) amphitrite cyprids in response to cochliomycin A treatment. Cochliomycin A affected the cytochrome P450, glutathione S-transferase (GST) and NO/cGMP pathways, among which the NO/cGMP pathway was considered to play a key role in barnacle larval settlement, while the cytochrome P450 and the GST pathways are mainly for detoxification. The results of real-time PCR further suggested the NO/cGMP pathway was activated in response to cochliomycin A. Larval settlement assays revealed that S-methylisothiourea sulfate (SMIS) and 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) rescued cyprids from cochliomycin A-induced inhibition of larval settlement. The findings supported the hypothesis that cochliomycin A inhibited barnacle larval settlement by stimulating the NO/cGMP pathway.

9,11-Secosteroids with cytotoxic activity from the South China Sea gorgonian coral Subergorgia suberosa.

Nine new 9,11-secosterols (1-9), containing the same 3ß,6α,11-trihydroxy-9,11-seco-5α-cholest-7-en-9-one steroidal nucleus, whereas possessing an array of structurally diverse side chains, along with fourteen known 9,11-secosterol compounds (10-23), were isolated from the South China Sea gorgonian coral Subergorgia suberosa, of which 3/4, 5/6, 7/8, and the known compounds 11/12, 20/21 were five pairs of inseparable C-24 epimers. Their structures were established by the extensive analyses of 1D and 2D NMR spectra, high-resolution chemical ionization mass spectrometry (HRCIMS), and by the comparison with literature data. Cytotoxic effect of these metabolites against the growth of HeLa cell lines was evaluated. The result showed that the inhibitory effect of compounds 1-23 varied considerably depending on the nature of the side chain in spite of sharing the same steroidal nucleus. Compound 19, featuring both the absence of hydroxyl group and the presence of double bond in the stigmasterol side chain, exhibited the most potent cytotoxicity with IC50 being 15.1 µM. The preliminary structure activity relationship studies identified some important structural features considerably influencing the biological effect deserved, providing valuable information for chemists and pharmacologists to design and synthesize more effective antitumor agents bearing the 9,11-secosteroid framework.

Characterization of the antigenicity of Cpl1, a surface protein of Cryptococcus neoformans var. neoformans.

Cryptococcus neoformans var. neoformans is an important fungal pathogen. The capsule is a well established virulence factor and a target site for diagnostic tests. The CPL1 gene is required for capsular formation and virulence. The protein product Cpl1 has been proposed to be a secreted protein, but the characteristics of this protein have not been reported. Here we sought to characterize Cpl1. Phylogenetic analysis showed that the Cpl1 of C. neoformans var. neoformans and the Cpl1 orthologs identified in C. neoformans var. grubii and C. gattii formed a distinct cluster among related fungi; while the putative ortholog found in Trichosporon asahii was distantly related to the Cryptococcus cluster. We expressed Cpl1 abundantly as a secreted His-tagged protein in Pichia pastoris. The protein was used to immunize guinea pigs and rabbits for high titer mono-specific polyclonal antibody that was shown to be highly specific against the cell wall of C. neoformans var. neoformans and did not cross react with C. gattii, T. asahii, Aspergillus spp., Candida spp. and Penicillium spp. Using the anti-Cpl1 antibody, we detected Cpl1 protein in the fresh culture supernatant of C. neoformans var. neoformans and we showed by immunostaining that the Cpl1 protein was located on the surface. The Cpl1 protein is a specific surface protein of C. neoformans var. neoformans.