Explore the vast range of titles available.

X-ray single-crystal diffraction (SCD) analysis has the intrinsic limitation that the target molecules must be obtained as single crystals. Here we report a protocol for SCD analysis that does not require the crystallization of the sample. In our method, tiny crystals of porous complexes are soaked in a solution of the target, such that the complexes can absorb the target molecules. Crystallographic analysis clearly determines the absorbed guest structures along with the host frameworks. Because the SCD analysis is carried out on only one tiny crystal of the complex, the required sample mass is of the nanogram–microgram order. We demonstrate that as little as about 80 nanograms of a sample is enough for the SCD analysis. In combination with high-performance liquid chromatography, our protocol allows the direct characterization of multiple fractions, establishing a prototypical means of liquid chromatography SCD analysis. Furthermore, we unambiguously determined the structure of a scarce marine natural product using only 5 micrograms of the compound. Absorption of target molecules into a porous matrix permits single-crystal X-ray diffraction analysis of the ‘guest’ molecules, avoiding the need to obtain them in single-crystal form and making analysis possible using as little as 80 nanograms of sample. Crystal structure without the crystals X-ray single crystal diffraction provides direct structural information of molecules at the atomic level and is recognized as a reliable structure determination method. However, as its name implies, the technique has a limitation, the sample needs to be available as a single crystal, the growth of which can be a time consuming process of trial-and-error. This paper describes a new X-ray analysis protocol that does not require crystallization of the sample itself. Instead, crystalline 'sponges' known as metal organic frameworks are used to soak up a drop of a liquid guest containing the target molecule. The sponges contain pores that recognize the target molecules and bind them in an ordered array, enabling the crystallographic structure analysis of the absorbed guest along with the host framework. The method is demonstrated with the absolute structure determination of a scarce natural product, miyakosyne A, using little more than a trace, 5 μg of sample. Corrected 8 April 2013

Aggregated mass spectral data by consortia such as the Global Natural Products Social (GNPS) molecular networking infrastructure enable natural product discovery. DEREPLICATOR, validated on peptidic natural products, is a computational tool to identify known metabolites in complex samples. Peptidic natural products (PNPs) are widely used compounds that include many antibiotics and a variety of other bioactive peptides. Although recent breakthroughs in PNP discovery raised the challenge of developing new algorithms for their analysis, identification of PNPs via database search of tandem mass spectra remains an open problem. To address this problem, natural product researchers use dereplication strategies that identify known PNPs and lead to the discovery of new ones, even in cases when the reference spectra are not present in existing spectral libraries. DEREPLICATOR is a new dereplication algorithm that enables high-throughput PNP identification and that is compatible with large-scale mass-spectrometry-based screening platforms for natural product discovery. After searching nearly one hundred million tandem mass spectra in the Global Natural Products Social (GNPS) molecular networking infrastructure, DEREPLICATOR identified an order of magnitude more PNPs (and their new variants) than any previous dereplication efforts.

Pufferfish belonging to Lagocephalus are composed of several species, some of which have been recognized to be non-toxic. Although fish belonging to this genus inhabit a wide variety of seawaters from temperate to tropical, toxin distribution has remained unclear. The present study was conducted to thoroughly survey the presence of tetrodotoxin (TTX) and its analogs (TTXs) in the extracts from various tissues of Lagocephalus pufferfish, including L. spadiceus, L. cheesemanii, L. lunaris, and L. inermis collected in Vietnam, by using the TTX enzyme-linked immunosorbent assay (ELISA) kit. Analyses using the TTX-ELISA kit demonstrated the presence of a considerable amount of TTXs in the extracts prepared from various tissues and organs of Lagocephalus pufferfish. TTX was detected in gonads and intestine of L. cheesemanii as well as L. lunaris by high performance liquid chromatography with fluorescence detection, but not in any tissues and organs of L. spadiceus. The extract from muscle of L. spadiceus was further subjected to liquid chromatography-mass spectrometry analyses to investigate toxin components, revealing the presence of a high amount of 5,6,11-trideoxyTTX (TDT), but no TTX. Since the toxicity of TDT is very weak, L. spadiceus muscle was regarded to be non-toxic as far as samples collected in the present study are concerned.

BackgroundWe previously identified hypopharyngeal cancer as an independent risk factor for the incidence of newly diagnosed secondary cancers after the treatment of early-stage laryngeal, oropharyngeal, and hypopharyngeal cancers. We subsequently used a different patient cohort to validate the usefulness of this factor during the follow-up period in these patients.MethodsPatients who underwent transoral surgery (TOS) as a definitive treatment between April 1, 2016, and September 30, 2020, were included. The incidence of secondary cancer was evaluated in hypopharyngeal and other cancers. Overall survival (OS), recurrence-free survival (RFS), and disease-free survival (DFS) outcomes were evaluated. Statistical analyses based on the risk factors were also performed.ResultsIncidence of new secondary cancer was 30% in hypopharyngeal cancer patients as compared to 11% in other cancer patients, and the risk was 3.60-fold (95% confidence interval 1.07–12.10) higher after definitive treatment for initial head and neck cancers. The 3-year OS, RFS, and DFS rates were 98%, 86%, and 67%, respectively.ConclusionsAmong patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma, who were initially treated with TOS, hypopharyngeal cancer patients had a higher risk of newly diagnosed secondary cancers as observed during the follow-up period.

BackgroundOur prospective study of patients with early T-stage head and neck cancer indicated a high incidence of newly diagnosed secondary malignancies during the follow-up period. We aimed to determine the incidence rate and risk factors of secondary malignancies in early-stage head and neck cancer patients.MethodsWe sub-analyzed the patient data of a previous study focusing on secondary cancer incidence. The endpoints were statistical analyses of risk factors and survival and incidence rates.ResultsThe incidence rate of secondary cancer was 37%, the crude incidence of second primary cancers was 10.6 per 100 person-years, and the 5 year secondary cancer-free survival rate was 63%. The hypopharynx as the primary site was an independent significant predictive factor (odds ratio 3.96, 95% confidence interval 1.07–14.6, p = 0.039).ConclusionsEarly stages of laryngeal, oropharyngeal, and hypopharyngeal cancer had a risk of secondary cancer, especially hypopharyngeal cancer. Attention to the secondary cancer has to be paid during the follow-up period after controlling the early-stage disease. These findings highlight the need for awareness of the incidence of secondary cancer in cases of early-stage primary head and neck cancer.

BackgroundWe had previously identified the following risk factors for insufficient control of early T-stage head and neck cancer by transoral surgery (TOS): (1) tumor thickness > 7 mm on enhanced computed tomography (CT), and (2) poor differentiation in pathological examination. We subsequently used a different patient cohort to validate the usefulness of these factors in determining the need for adaptation of TOS.Study settingA prospective observational studyMethodsPatients who received TOS as a definitive treatment between April 1, 2016 and September 30, 2020 were included. Primary control rates (by single TOS and TOS alone) in relation to the above-mentioned risk factors were calculated. Overall (O), recurrence-free (RF), and disease-free (DF) survival (S) outcomes were evaluated. A combination analysis based on the number of risk factors was also performed.ResultsPatients with tumor thickness > 7 mm had a 2.88-fold [95% confidence interval (CI) 1.01–8.51] higher risk of incomplete primary resection by single TOS, while patients who showed poor differentiation on pathological assessments had a 13.14-fold (95% CI 3.66–47.14) higher risk of insufficient primary control by TOS alone. The 3 year OS, RFS, and DFS rates were 99%, 83%, and 63%, respectively. Patients with both risk factors had a 93.00-fold (95% CI 4.99–1732.00) higher risk of incomplete primary control by TOS alone.ConclusionsAmong patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma, primary control by TOS alone may not be achieved in patients with both risk factors, that is, tumor thickness > 7 mm as measured by enhanced CT and poor differentiation on pathological examination.

The green microalga Botryococcus braunii is considered a promising biofuel feedstock producer due to its prodigious accumulation of hydrocarbon oils that can be converted into fuels. B. braunii Race L produces the C 40 tetraterpenoid hydrocarbon lycopadiene via an uncharacterized biosynthetic pathway. Structural similarities suggest this pathway follows a biosynthetic mechanism analogous to that of C 30 squalene. Confirming this hypothesis, the current study identifies C 20 geranylgeranyl diphosphate (GGPP) as a precursor for lycopaoctaene biosynthesis, the first committed intermediate in the production of lycopadiene. Two squalene synthase ( SS )-like complementary DNAs are identified in race L with one encoding a true SS and the other encoding an enzyme with lycopaoctaene synthase (LOS) activity. Interestingly, LOS uses alternative C 15 and C 20 prenyl diphosphate substrates to produce combinatorial hybrid hydrocarbons, but almost exclusively uses GGPP in vivo . This discovery highlights how SS enzyme diversification results in the production of specialized tetraterpenoid oils in race L of B. braunii . The green microalga Botryococcus braunii is a promising biofuel producer due to its ability to produce large amounts of hydrocarbon oils that can be converted into fuels. Here the authors implicate lycopaoctaene synthase, a squalene synthases-like enzyme, in the first step towards the biosynthesis of the C40 tetraterpenoid hydrocarbon lycopadiene.

Background/Aim: We evaluated the impact of FosL1, a member of the activated protein-1 family, on the pathways leading to regional metastasis of head and neck squamous cell carcinoma (HNSCC). Materials and Methods: We examined the influence of small interfering RNA (siRNA) and short heparin RNA (shRNA) mediated knockdown of FosL1 on cell migration, invasion, and proliferation in vitro as well as on regional metastasis in vivo. The prognostic significance of FosL1 was also analyzed using the Kaplan– Meier plotter using data from an HNSCC patient database. Results: Down-regulation of FosL1 inhibited cell migration, invasion, and proliferation in vitro, decreased the incidence of regional metastases, and prolonged the survival of mice in vivo. We also determined that HNSCC patients with higher expression levels of FosL1 had a significantly shorter survival time than those with low expression of FosL1. Conclusion: FosL1 plays a crucial role in promoting cell migration, invasion, and proliferation in HNSCC.

Purpose Depending on its histological subtype, salivary gland carcinoma (SGC) may have a poor prognosis. Due to the scarcity of preclinical experimental models, its molecular biology has so far remained largely unknown, hampering the development of new treatment modalities for patients with these malignancies. The aim of this study was to generate experimental human SGC models of multiple histological subtypes using patient-derived xenograft (PDX) and organoid culture techniques. Methods Tumor specimens from surgically resected SGCs were processed for the preparation of PDXs and patient-derived organoids (PDOs). Specimens from SGC PDXs were also processed for PDX-derived organoid (PDXO) generation. In vivo tumorigenicity was assessed using orthotopic transplantation of SGC organoids. The pathological characteristics of each model were compared to those of the original tumors using immunohistochemistry. RNA-seq was used to analyze the genetic traits of our models. Results Three series of PDOs, PDXs and PDXOs of salivary duct carcinomas, one series of PDOs, PDXs and PDXOs of mucoepidermoid carcinomas and PDXs of myoepithelial carcinomas were successfully generated. We found that PDXs and orthotopic transplants from PDOs/PDXOs showed similar histological features as the original tumors. Our models also retained their genetic traits, i.e., transcription profiles, genomic variants and fusion genes of the corresponding histological subtypes. Conclusion We report the generation of SGC PDOs, PDXs and PDXOs of multiple histological subtypes, recapitulating the histological and genetical characteristics of the original tumors. These experimental SGC models may serve as a useful resource for the development of novel therapeutic strategies and for investigating the molecular mechanisms underlying the development of these malignancies.

Marine sponges harbor diverse secondary metabolites with a variety of biological activity, many of which are considered as chemical defense substances for the sponges themselves. Recently, we observed that Thromidia catalai, one of the largest species of starfish, feeds on the sponge Theonella swinhoei (chemotype Y), known to contain diverse biologically active metabolites. Here we report the isolation of three novel brominated indole alkaloids, catalindoles A–C, from the arms of T. catalai as well as the elucidation of their structures. Their structures were determined by a combination of spectroscopic data analyses and chemical methods, and they were further confirmed by chemical syntheses of the molecules. Moreover, we revealed the predator–prey relationship between T. catalai and Theonella sponges in terms of chemical components, noting that T. catalai feeds not only on T. swinhoei (chemotype Y) but also on T. swinhoei (chemotype W).