This study describes computer simulations of carbonization and graphite formation, including the effects of hydrogen, nitrogen, oxygen, and sulfur. We introduce a novel technique to simulate carbonization, 'Simulation of Thermal Emission of Atoms and Molecules (STEAM)', designed to elucidate volatile outgassing and density variations in the intermediate material during carbonization. The investigation analyzes the functional groups that endure through high-temperature carbonization and examines the graphitization processes in carbon-rich materials containing non-carbon impurity elements.
View Article and Find Full Text PDFRegulatory T (T) cell modulation of adaptive immunity and tissue homeostasis is well described; however, less is known about T cell-mediated regulation of the innate immune response. Here we show that deletion of ST2, the receptor for interleukin (IL)-33, on T cells increased granulocyte influx into the lung and increased cytokine production by innate lymphoid and γδ T cells without alteration of adaptive immunity to influenza. IL-33 induced high levels of the interleukin-1 receptor antagonist (IL-1Ra) in ST2 T cells and deletion of IL-1Ra in T cells increased granulocyte influx into the lung.
View Article and Find Full Text PDFBackground: Acute respiratory infections (ARIs) are one of the most common causes of mortality and morbidity worldwide. Every year millions of children suffer from viral respiratory tract infections (RTIs) ranging from mild to severe illnesses. Human Metapneumovirus (HMPV) is among the most frequent viruses responsible for RTIs.
View Article and Find Full Text PDFThis study introduces a new approach for constructing atomistic models of nanoporous carbon by randomly distributing carbon atoms and pore volumes in a periodic box and then using empirical and molecular simulation tools to find the suitable energy-minimum structures. The models, consisting of 5000, 8000, 12000, and 64000 atoms, each at mass densities of 0.5, 0.
View Article and Find Full Text PDFIntroduction: Purpura fulminans is an acute and fatal condition presenting with acute progressive hemorrhagic infarction of the skin and disseminated intravascular coagulation. Scrub typhus, is an emerging disease of Nepal, despite being a rickettsioses has been rarely associated with Purpura fulminans. The non-specific clinical presentation and limited diagnostic facility make it difficult for clinicians to diagnose the disease.
View Article and Find Full Text PDFInvertebrates, particularly sponges, have been a dominant source of new marine natural products. For example, lasonolide A (LSA) is a potential anticancer molecule isolated from the marine sponge sp., with nanomolar growth inhibitory activity and a unique cytotoxicity profile against the National Cancer Institute 60-cell-line screen.
View Article and Find Full Text PDFAn amorphous graphite material has been predicted from molecular dynamics simulation using ab initio methods. Carbon materials reveal a strong proclivity to convert into a sp^{2} network and then layer at temperatures near 3000 K within a density range of ca. 2.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
April 2022
Rare actinomycetes represent an underexploited source of new bioactive compounds. Here, we report the use of a targeted metabologenomic approach to identify piperazyl compounds in the rare actinomycete Lentzea flaviverrucosa DSM 44664. These efforts to identify molecules that incorporate piperazate building blocks resulted in the discovery and structural elucidation of two dimeric biaryl-cyclohexapeptides, petrichorins A and B.
View Article and Find Full Text PDFACS Chem Biol
September 2021
Nonribosomal peptide synthetase and polyketide synthase systems are home to complex enzymology and produce compounds of great therapeutic value. Despite this, they have continued to be difficult to characterize due to their substrates remaining enzyme-bound by a thioester bond. Here, we have developed a strategy to directly trap and characterize the thioester-bound enzyme intermediates and applied the strategy to the azinomycin biosynthetic pathway.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
August 2021
genomes harbor numerous, biosynthetic gene clusters (BGCs) encoding for drug-like compounds. While some of these BGCs readily yield expected products, many do not. Biosynthetic crypticity represents a significant hurdle to drug discovery, and the biological mechanisms that underpin it remain poorly understood.
View Article and Find Full Text PDFMicrobiol Resour Announc
December 2020
Here, we report the draft genome sequences of two related sp. strains, JV180 and SP18CM02. Despite their isolation from soils in Connecticut and Missouri (USA), respectively, they are strikingly similar in gene content.
View Article and Find Full Text PDFBackground: Antibiotic resistance mediated by the production of extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases is posing a serious threat in the management of the infections caused by Gram-negative pathogens. The aim of this study was to determine the prevalence of two AmpC β-lactamases genes, and , in Gram-negative bacterial isolates.
Materials And Methods: A total of 1151 clinical samples were obtained and processed at the microbiology laboratory of Annapurna Neurological Institute and Allied Science, Kathmandu between June 2017 and January 2018.
Foxp3 regulatory T (T) cells expressing the interleukin (IL)-33 receptor ST2 mediate tissue repair in response to IL-33. Whether T cells also respond to the alarmin IL-33 to regulate specific aspects of the immune response is not known. Here we describe an unexpected function of ST2 T cells in suppressing the innate immune response in the lung to environmental allergens without altering the adaptive immune response.
View Article and Find Full Text PDFMemory CD4+ T helper type 2 (Th2) cells drive allergic asthma, yet the mechanisms whereby tissue-resident memory Th2 (Th2 Trm) cells and circulating memory Th2 cells collaborate in vivo remain unclear. Using a house dust mite (HDM) model of allergic asthma and parabiosis, we demonstrate that Th2 Trm cells and circulating memory Th2 cells perform nonredundant functions. Upon HDM rechallenge, circulating memory Th2 cells trafficked into the lung parenchyma and ignited perivascular inflammation to promote eosinophil and CD4+ T cell recruitment.
View Article and Find Full Text PDFMarine natural products have become an increasingly important source of new drug leads during recent years. In an attempt to identify novel anti-microbial natural products by bioprospecting deep-sea Actinobacteria, three new angucyclines, nocardiopsistins A-C, were isolated from sp. strain HB-J378.
View Article and Find Full Text PDFDue to the worldwide prevalence of multidrug-resistant pathogens and high incidence of diseases such as cancer, there is an urgent need for the discovery and development of new drugs. Nearly half of the FDA-approved drugs are derived from natural products that are produced by living organisms, mainly bacteria, fungi, and plants. Commercial development is often limited by the low yield of the desired compounds expressed by the native producers.
View Article and Find Full Text PDFBackground: Extended spectrum beta-lactamase (ESBL) and metallo beta-lactamase (MBL) production in Klebsiella pneumoniae and Escherichia coli are the commonest modes of drug resistance among these commonly isolated bacteria from clinical specimens. So the main purpose of our study was to determine the burden of ESBL and MBL production in E. coli and K.
View Article and Find Full Text PDFBackground: The increasing drug resistance along with inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of Staphylococcus aureus are present as the serious problems to the successful treatment of the infections caused by S. aureus. So, the main objectives of this study were to determine the antimicrobial susceptibility patterns along with the rates of inducible clindamycin resistance, methicillin resistance and biofilm production among the strains of S.
View Article and Find Full Text PDFThe Japanese encephalitis virus (JEV) infection is one of the major public health problems in Nepal because of its increasing disease morbidity and mortality. The main purpose of this study was to determine the anti-JEV IgM positivity among acute encephalitis syndromic cases from all over Nepal. The present study was conducted at National Public Health Laboratory, Kathmandu, Nepal from April 2015 to October 2015.
View Article and Find Full Text PDFThe biosynthesis of the azabicyclic ring system of the azinomycin family of antitumor agents represents the "crown jewel" of the pathway and is a complex process involving at least 14 enzymatic steps. This study reports on the first biosynthetic step, the inroads, in the construction of the novel aziridino [1,2-a]pyrrolidine, azabicyclic core, allowing us to support a new mechanism for azabicycle formation.
View Article and Find Full Text PDFDiffusion at solid-liquid interfaces is crucial in many technological and biophysical processes. Although its behavior seems to be deceivingly simple, recent studies showing passive superdiffusive transport suggest that diffusion on surfaces may hide rich complexities. In particular, bulk-mediated diffusion occurs when molecules are transiently released from the surface to perform three-dimensional excursions into the liquid bulk.
View Article and Find Full Text PDFMembrane-targeting domains play crucial roles in the recruitment of signalling molecules to the plasma membrane. For most peripheral proteins, the protein-to-membrane interaction is transient. After proteins dissociate from the membrane they have been observed to rebind following brief excursions in the bulk solution.
View Article and Find Full Text PDF