Visible light-induced reductive aza-6π electrocyclization access to phenanthridines.

Visible light-induced aza-6π electrocyclization was developed for the synthesis of aza-arenes from nitroarenes with diverse aldehydes. This protocol allows the reduction of nitroarenes by B2nep2 and subsequent 6π-electrocyclization of the in situ formed imine under visible light. An array of 6- and multi-substituted phenanthridines were constructed in moderate to good yields under purple LEDs at room temperature. A wide scope of substrates with diverse functional groups were well tolerated. In addition, the synthetic utility of this methodology was further demonstrated in the late-stage functionalization of celecoxib.

Iridium-Catalyzed Direct Ortho-C-H Amidation of α-Ketoesters with Sulfonyl Azides Using a Transient Directing Group Strategy.

Direct C-H amidation of α-ketoesters was accomplished using various organic azides as the amino source through the combination of transient directing group strategy and iridium catalysis. Excellent functional group tolerance and wide substrate scope were explored under simple and mild conditions. Importantly, it was found that the steric hindrance of the ester moiety played a pivotal role for the reaction efficacy. In addition, the reaction could be enlarged to gram scale, and several useful heterocycles were readily constructed via one-step late-stage derivatization.

Direct Assembly of Diverse Unsymmetrical Tertiary 9-Fluorenols via Transient Directing Group-Enabled Palladium-Catalyzed Dual C-H Bond Activation of α-Ketoesters.

An expeditious construction of an unsymmetrical tertiary 9-fluorenol skeleton was accomplished starting from readily available α-ketoester and aryl iodide. Inexpensive commercially available substituted aniline was utilized as a potent monodentate transient directing group (TDG) to assist palladium-catalyzed direct ortho-C-H arylation and tandem dual C-H activation of α-ketoesters to form two carbon-carbon bonds. To demonstrate practical applications, the reaction was enlarged to the gram scale, and subsequent one-step derivatization allowed facile access to structurally diversified useful derivatives. A series of control experiments were carried out to shed light on the possible catalytic mechanism.

A Metal-Free Visible-Light Photoredox Construction and Direct C-H Functionalization of Pyridines: Green Synthesis of Polysubstituted Picolinaldehydes.

The development of a novel environmental benign and sustainable synthetic method for highly efficient construction and direct C-H functionalization of N-heterocycles remains a pivotal central research topic for organic and medicinal chemistry. Herein, a novel visible-light-enabled biomimetic aza-6π electrocyclization for efficient assembly of diverse pyridines and further tandem Minisci-type reaction were developed. A broad spectrum of polysubstituted picolinaldehydes were readily constructed with high efficacy and good functional group tolerance under metal- and oxidant-free conditions.

Comprehensive Mechanism of CO2 Electroreduction on Non-Noble Metal Single-Atom Catalysts of Mo2 CS2 -MXene.

In this work, a series of non-noble metal single-atom catalysts of Mo2 CS2 -MXene for CO2 reduction were systematically investigated by well-defined density-functional-theory (DFT) calculations. It is found that nine types of transitional metal (TM) supported Mo2 CS2 (TM-Mo2 CS2 ) are very stable, while eight can effectively inhibit the competitive hydrogen evolution reaction (HER). After comprehensively comparing the changes of free energy for each pathway in CO2 reduction reaction (CO2 RR), it is found that the products of TM-Mo2 CS2 are not completely CH4 . Furthermore, Cr-, Fe-, Co- and Ni-Mo2 CS2 are found to render excellent CO2 RR catalytic activity, and their limiting potentials are in the range of 0.245-0.304 V. In particular, Fe-Mo2 CS2 with a nitrogenase-like structure has the lowest limiting potential and the highest electrocatalytic activity. Ab initio molecular dynamics (AIMD) simulations have also proven that these kinds of single-atom catalysts with robust performance could exist stably at room temperature. Therefore, these single TM atoms anchored on the surface of MXenes can be profiled as a promising catalyst for the electrochemical reduction of CO2 .

Monodentate Transient Directing Group Assisted Ruthenium(II)-Catalyzed Direct ortho-C-H Imidation of Benzaldehydes for Diverse Synthesis of Quinazoline and Fused Isoindolinone.

2-Fluoro-5-(trifluoromethyl)aniline was found to be a suitable monodentate transient directing group (MonoTDG) to enable Ru(II)-catalyzed intermolecular direct ortho-C(sp2)-H imidation of benzaldehydes. N-Tosyloxyphthalimide was used as an alternative azide-free amidation reagent to achieve high efficiency and good functional group tolerance. Moreover, the reaction could be enlarged to gram scale, and the amidated product could be readily converted into useful quinazoline and fused isoindolinone scaffolds by one-step derivatization.

Disseminated sporotrichosis following iatrogenic immunosuppression for suspected pyoderma gangrenosum.

Sporotrichosis is an infection caused by the dimorphic fungus Sporothrix schenckii and related species that often arises from traumatic inoculation of inhabited soil and organic debris into skin. The infection is usually limited to the skin in immunocompetent patients, usually as lymphocutaneous sporotrichosis. Accurate diagnosis rests on clinical data and culture, and might be facilitated by biopsy identification of suppurative and granulomatous inflammation with fungal elements. In this Grand Round, we present a dramatic case of cutaneous sporotrichosis initially presented with an atypical large ulcer without associated lymphocutaneous spread, clinically mimicking pyoderma gangrenosum, and subsequently progressed to disseminated sporotrichosis in the setting of iatrogenic immunosuppression. We further review the clinical features, risk factors, and treatment of these disseminated sporotrichosis cases, and discuss the need for improved awareness of this fungus' potential link to cause disseminated and invasive fungal infections.

Rapid and Simple Detection of Trichosporon asahii by Optimized Colony PCR.

Trichosporon asahii is the major pathogen causing invasive trichosporonosis. Conventional methods of its detection are time-consuming or costly and often require complex DNA extraction and purification steps, which hinders rapid clinical diagnosis. In this study, we evaluated colony PCR, which directly uses colonies or trace clinical samples as the template for amplification, for rapid detection of T. asahii infection. Four methods, namely, direct colony, freeze-thaw, glass beads, and enzymolysis, were compared to select the best DNA extraction strategy. We subsequently designed and screened species-specific primers targeting the intergenic spacer 1 (IGS1) of the ribosomal DNA of T. asahii and used them to detect mock infection clinical samples. The species-specific colony PCR based on glass beads proved advantageous, with short procedure time (154.8 ± 0.6 min), good sensitivity (detection limit, 102 CFU/mL), and specificity for T. asahii, indicating that this method can be used for the rapid and simple identification of clinical samples of T. asahii infection.

In Vitro Interactions between Non-Steroidal Anti-Inflammatory Drugs and Antifungal Agents against Planktonic and Biofilm Forms of Trichosporon asahii.

Increasing drug resistance has brought enormous challenges to the management of Trichosporon spp. infections. The in vitro antifungal activities of non-steroidal anti-inflammatory drugs (NSAIDs) against Candida spp. and Cryptococcus spp. were recently discovered. In the present study, the in vitro interactions between three NSAIDs (aspirin, ibuprofen and diclofenac sodium) and commonly used antifungal agents (fluconazole, itraconazole, voriconazole, caspofungin and amphotericin B) against planktonic and biofilm cells of T. asahii were evaluated using the checkerboard microdilution method. The spectrophotometric method and the XTT reduction assay were used to generate data on biofilm cells. The fractional inhibitory concentration index (FICI) and the ΔE model were compared to interpret drug interactions. Using the FICI, the highest percentages of synergistic effects against planktonic cells (86.67%) and biofilm cells (73.33%) were found for amphotericin B/ibuprofen, and caspofungin/ibuprofen showed appreciable percentages (73.33% for planktonic form and 60.00% for biofilm) as well. We did not observe antagonism. The ΔE model gave consistent results with FICI (86.67%). Our findings suggest that amphotericin B/ibuprofen and caspofungin/ibuprofen combinations have potential effects against T. asahii. Further in vivo and animal studies to investigate associated mechanisms need to be conducted.

Epidemiology and Outcome of Trichosporon Fungemia: A Review of 185 Reported Cases From 1975 to 2014.

Background. Trichosporon species have emerged as an important non-Candida spp yeast pathogen in immunocompromised patients in recent decades; however, the systemic analysis of Trichosporon epidemiology has seldom been reported. Methods. We reviewed 185 reported cases of Trichosporon fungemia from 1975 to 2014 in the English-language literature, and the epidemiology and prognostic factors of the included cases are described. Results. The number of cases reported has increased with time, especially over the past decade. During the 3 decades from 1975 to 2004, the most commonly used antifungal compounds were amphotericin B/liposomal amphotericin B; however, in recent decades (2005-2014), triazoles (especially voriconazole) have become the most widely used agents, significantly improving outcome in the reported cases. Correlation analysis revealed that negative outcome is associated with several prognostic factors, including a history of antimicrobial use, bacterial bloodstream coinfection, prophylactic/empirical antifungal therapy, Trichosporon beigelii infection, and receiving the antifungal regimen of amphotericin B/liposomal amphotericin B. In addition, a significantly greater proportion of patients with a positive outcome had fungemia without invasive tissue infection and received a voriconazole regimen or an AmB-triazole combined regimen. Significant positive outcome was also associated with patients who had recovered from neutropenia or after central venous catheter removal. Conclusions. Voriconazole can be recommended as a first-line antifungal compound to treat Trichosporon fungemia; the immune status of the host plays a crucial role in the outcome of this infection, and the removal of vascular catheters should be considered if feasible.

Efficacy of Ethanol against Trichosporon asahii Biofilm in vitro.

Trichosporon asahii (T. asahii) can cause invasive infections, particularly catheter-related bloodstream infections (CR-BSIs). T. asahii biofilm, which is resistant to the most common clinical antifungal agents, may play an important role in these life-threatening infections. This study focused on the effects of ethanol on the different phases of T. asahii biofilm formation. At the concentrations clinically used, ethanol killed T. asahii planktonic cells (MIC90 = 15% and m-MIC90 = 15%) and biofilm (SMIC90 = 50%), and exposure to 25% ethanol for 12 h or to 50% ethanol for 8 h completely inhibited biofilm development and eradicated mature T. asahii biofilm. Thus, our results showed that ethanol effectively inhibited the main phases of T. asahii biofilm formation. This study reveals a new potential strategy to prevent and treat T. asahii biofilm-related CR-BSIs.

Development of a loop-mediated isothermal amplification assay for rapid detection of Trichosporon asahii in experimental and clinical samples.

Invasive trichosporonosis is a deep mycosis found mainly in immunocompromised hosts, and the major pathogen is Trichosporon asahii. We detected the species-specific intergenic spacers (IGS) of rRNA gene of T. asahii using a loop-mediated isothermal amplification (LAMP) assay in 15 isolates with 3 different visualization methods, including SYBR green detection, gel electrophoresis, and turbidimetric methods. The LAMP assay displayed superior rapidity to other traditional methods in the detection time; that is, only 1 h was needed for detection and identification of the pathogen DNA. Furthermore, the detection limit of the LAMP assay was more sensitive than the PCR assay. We also successfully detect the presence of T. asahii in samples from experimentally infected mice and samples from patients with invasive trichosporonosis caused by T. asahii, suggesting that this method may become useful in clinical applications in the near future.

Early transcriptional response of human monocyte-like THP-1 cells in response to Trichosporon asahii infection.

Trichosporon asahii is the major cause of invasive trichosporonosis, but little is known about the host immune response to this pathogen. In this study, the early transcriptional response of human monocyte-like THP-1 cells to T. asahii infection was evaluated using cDNA microarray and 1,315 differentially expressed genes were identified. The up-regulated genes were mostly involved in both innate and adaptive immune responses, as well as apoptosis and anti-apoptosis processes. Genes encoding the pro-inflammatory cytokines TNF-α, IL-1ß, IL18 and IL-23α, along with the both C-C motif and C-X-C motif chemokines were strongly up-regulated, suggesting that THP-1 cells can mount a powerful inflammatory response to T. asahii infection. Genes encoding pattern recognition receptors were found up-regulated, such as dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin, cluster of differentiation 36 and the long pentraxin 3. Genes encoding members of the dual-spasticity phosphates family were up-regulated, and these genes were considered as a negative feedback mechanism to prevent excessive inflammatory response. The down-regulated genes in T. asahii-infected THP-1 cells were predominantly associated with cell cycle, mitosis, cell division and DNA repair. Thus, our study defines the early transcriptional response of monocyte-like THP-1 cells to T. asahii infection and provides a foundation for further investigations into the pathogenesis of T. asahii infection.

Higher concentration of CO2 and 37°C stabilize the less virulent opaque cell of Candida albicans.

BACKGROUND: Candida albicans (C. albicans) strains can spontaneously switch at a very low frequency from white to opaque phase. The ability to switch reversibly between white and opaque phenotype and contributes to the pathogenicity of C. albicans. White and opaque switching can be induced by various environmental signals. Previous study showed that opaque cells switch en masse to white when transferred in vitro to 37°C, the temperature of their animal host. The objective of the present study was to determine the effect of different concentration of carbon dioxide and temperature on white-opaque switching, and to determine the different anti-candida killing activity of white and opaque form by human monocyte-macrophage cell line THP-1. METHODS: White-opaque switching and opaque-white switching were assayed. Modified Lee's medium supplemented with phloxine B was used to detect white and opaque forms of C. albicans under 0.03% CO2 at 25°C, 0.03% CO2 at 37°C and 5% CO2 at 37°C. Growth curve of C. albicans was monitored using OD value at 630 nm simultaneously. White and opaque forms of C. albicans and THP-1 cells were cocultured at ratio of 1:10. Colony serial dilutions were used to assay for intracellular candidacidal activity. MTT assay was used to measure the extracellular candidacidal activity. RESULTS: Phenotype switching was successfully induced in vitro in all three strains of C. albicans. When evaluating white to opaque switching, opaque colony proportion of all colonies was 0.572 ± 0.087, 0.920 ± 0.030 and 0.985 ± 0.026 exposure of white cells to 0.03% CO2 at 25°C, 0.03% CO2 at 37°C and 5% CO2 at 37°C. When evaluating opaque to white switching, opaque colony proportion of all colonies was 0.600 ± 0.114, 0.983 ± 0.003 and 0.998 ± 0.003 exposure of white cells to 0.03% CO2 at 25°C, 0.03% CO2 at 37°C and 5% CO2 at 37°C. No significant difference of white or opaque form growth rate was found among three conditions (P > 0.05). THP-1 mediated extracellular anti-candida activity in white form was (79.80 ± 3.71)% and (56.28 ± 19.12)% at different dilution ratio, which were significantly lower than that in opaque form (100%, P < 0.01). THP-1 mediated intracellular anti-candida activity in white form ((62.98 ± 5.02)%) was significantly lower than that in opaque form ((87.07 ± 1.80)%, P < 0.01). CONCLUSIONS: Our results showed that opaque form is more vulnerable and less virulent than that in white form. It suggested that higher concentration of CO2 and 37°C in host niches stabilize the less virulent opaque cell of C. albicans, which might have implications for pathogenesis, commensalism and mating.

Primary cutaneous zygomycosis caused by rhizomucor variabilis: a new endemic zygomycosis? A case report and review of 6 cases reported from China.

We report a case of primary cutaneous zygomycosis caused by Rhizomucor variabilis and review 6 cases reported from China that share similar features and are different from those cases caused by other species of Mucorales. It is noteworthy that all 6 of the cases were observed in 3 adjacent provinces of eastern China.

Insoluble beta-glucan from the cell wall of Candida albicans induces immune responses of human THP-1 monocytes through Dectin-1.

BACKGROUND: beta-glucan is the major structure component of Candida albicans (C. albicans) cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor (PRR) can recognize fungal beta-glucan and induce immune responses. In this study, we sought to clarify whether insoluble beta-glucan from the cell wall of C. albicans (CaIG) could induce immune responses in human THP-1 monocytes (a human acute monocytic leukemia cell line) and to determine the underlying mechanisms. METHODS: Human THP-1 monocytes were challenged with CaIG in vitro. The mRNA expression of Dectin-1, Toll-like receptors (TLR2), proinflammatory cytokine (TNF-alpha) and chemokine (IL-8) was assayed by real-time reverse transcription polymerase chain reaction (RT-PCR). The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). H(2)O(2) release was determined by microplate fluorescent assay. Western blotting was used to analyze IkappaB-a phosphorylation and degradation. RESULTS: Exposure of THP-1 monocytes to CaIG led to increased gene expression and secretion of TNF-alpha and IL-8. CaIG induced H(2)O(2) release in a time-dependent manner. CaIG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-alpha, IL-8 and H(2)O(2) release. CaIG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CaIG resulted in the activation of NF-kappaB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CaIG-induced production of TNF-alpha and H(2)O(2) in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor (polymyxin B). CONCLUSION: CaIG may play a role in activation of immune responses in human THP-1 cells through Dectin-1, not TLR2.

Pyoderma gangrenosum with pulmonary involvement?

Pyoderma gangrenosum is a rare, painful, noninfectious, ulcerative, reactive neutrophilic skin condition. It is characterized by ulcers that can spread quickly showing undermined violaceous borders. Since there is no single diagnostic test, early diagnosis is always challenging. The aggressive nature of classical pyoderma gangrenosum may become apparent only with time. Pulmonary involvement of pyoderma gangrenosum maybe underreported. We describe a case of classical pyoderma gangrenosum in a 65-year-old man with pulmonary involvement, who presented with a painful fluctuate nodule and ulcer with mucopurulent and hemorrhagic exudates, and with a monoclonal gammopathy, IgA type. One month later the ulcer and hemoptysis all disappeared after treatment with glucocorticosteroids. The pulmonary manifestations of pyoderma gangrenosum were also reviewed.