nSMase2-mediated exosome secretion shapes the tumor microenvironment to immunologically support pancreatic cancer.

The pleiotropic roles of nSMase2-generated ceramide include regulation of intracellular ceramide signaling and exosome biogenesis. We investigated the effects of eliminating nSMase2 on early and advanced PDA, including its influence on the microenvironment. Employing the KPC mouse model of pancreatic cancer, we demonstrate that pancreatic epithelial nSMase2 ablation reduces neoplasia and promotes a PDA subtype switch from aggressive basal-like to classical.

Engineered mRNA-ribosome fusions for facile biosynthesis of selenoproteins.

Ribosomes are often used in synthetic biology as a tool to produce desired proteins with enhanced properties or entirely new functions. However, repurposing ribosomes for producing designer proteins is challenging due to the limited number of engineering solutions available to alter the natural activity of these enzymes. In this study, we advance ribosome engineering by describing a novel strategy based on functional fusions of ribosomal RNA (rRNA) with messenger RNA (mRNA).

Pandemic play moderates the relation between caregiver stress and child emotional distress in contexts of economic adversity.

It is well-established that caregiver stress is linked to increased emotional distress among children, and recent evidence highlights similar associations between caregiver and child emotional well-being during the coronavirus (COVID-19) pandemic. Examining protective factors and coping mechanisms that are associated with resiliency in the face of pandemic-related stress can highlight potential strategies that may help children adapt to other unexpected hardships outside of a global pandemic. Previous research found that playing about the pandemic moderated an association between caregiver stress and children's emotional distress.

Recoding UAG to selenocysteine in .

Unique chemical and physical properties are introduced by inserting selenocysteine (Sec) at specific sites within proteins. Recombinant and facile production of eukaryotic selenoproteins would benefit from a yeast expression system; however, the selenoprotein biosynthetic pathway was lost in the evolution of the kingdom Fungi as it diverged from its eukaryotic relatives. Based on our previous development of efficient selenoprotein production in bacteria, we designed a novel Sec biosynthesis pathway in using translation components.

Creating Selenocysteine-Specific Reporters Using Inteins.

The selenium moiety in selenocysteine (Sec) imparts enhanced chemical properties to this amino acid and ultimately the protein in which it is inserted. These characteristics are attractive for designing highly active enzymes or extremely stable proteins and studying protein folding or electron transfer, to name a few. There are also 25 human selenoproteins, of which many are essential for our survival.

Split aminoacyl-tRNA synthetases for proximity-induced stop codon suppression.

Synthetic biology tools for regulating gene expression have many useful biotechnology and therapeutic applications. Most tools developed for this purpose control gene expression at the level of transcription, and relatively few methods are available for regulating gene expression at the translational level. Here, we design and engineer split orthogonal aminoacyl-tRNA synthetases (o-aaRS) as unique tools to control gene translation in bacteria and mammalian cells.

Dual incorporation of non-canonical amino acids enables production of post-translationally modified selenoproteins.

Post-translational modifications (PTMs) can occur on almost all amino acids in eukaryotes as a key mechanism for regulating protein function. The ability to study the role of these modifications in various biological processes requires techniques to modify proteins site-specifically. One strategy for this is genetic code expansion (GCE) in bacteria.

The selenocysteine toolbox: A guide to studying the 21st amino acid.

Selenocysteine (Sec), the 21st genetically encoded amino acid, is structurally similar to cysteine (Cys) but with a sulfur to selenium replacement. This small change confers Sec with related chemical properties to Cys but often with enhanced reactivity. In organisms, Sec is present in selenoproteins taking on various roles such as cellular maintenance, immune response, hormone regulation, and oxidative stress.

Unconventional genetic code systems in archaea.

Archaea constitute the third domain of life, distinct from bacteria and eukaryotes given their ability to tolerate extreme environments. To survive these harsh conditions, certain archaeal lineages possess unique genetic code systems to encode either selenocysteine or pyrrolysine, rare amino acids not found in all organisms. Furthermore, archaea utilize alternate tRNA-dependent pathways to biosynthesize and incorporate members of the 20 canonical amino acids.

Using selenocysteine-specific reporters to screen for efficient tRNA variants.

The unique properties of selenocysteine (Sec) have generated an interest in the scientific community to site-specifically incorporate Sec into a protein of choice. Current technologies have rewired the natural Sec-specific translation factor-dependent selenoprotein biosynthesis pathway by harnessing the canonical elongation factor (EF-Tu) to simplify the requirements for Sec incorporation in Escherichia coli. This strategy is versatile and can be applied to Sec incorporation at any position in a protein of interest.

Multiplex suppression of four quadruplet codons via tRNA directed evolution.

Genetic code expansion technologies supplement the natural codon repertoire with assignable variants in vivo, but are often limited by heterologous translational components and low suppression efficiencies. Here, we explore engineered Escherichia coli tRNAs supporting quadruplet codon translation by first developing a library-cross-library selection to nominate quadruplet codon-anticodon pairs. We extend our findings using a phage-assisted continuous evolution strategy for quadruplet-decoding tRNA evolution (qtRNA-PACE) that improved quadruplet codon translation efficiencies up to 80-fold.

Consensus-Based Recommendations on the Prevention of Squamous Cell Carcinoma in Solid Organ Transplant Recipients: A Delphi Consensus Statement.

Importance: There is a paucity of evidence to guide physicians regarding prevention strategies for cutaneous squamous cell carcinoma (CSCC) in solid organ transplant recipients (SOTRs).

Objective: To examine the development and results of a Delphi process initiated to identify consensus-based medical management recommendations for prevention of CSCC in SOTRs.

Evidence Review: Dermatologists with more than 5 years' experience treating SOTRs were invited to participate.

Intein-based Design Expands Diversity of Selenocysteine Reporters.

The presence of selenocysteine in a protein confers many unique properties that make the production of recombinant selenoproteins desirable. Targeted incorporation of Sec into a protein of choice is possible by exploiting elongation factor Tu-dependent reassignment of UAG codons, a strategy that has been continuously improved by a variety of means. Improving selenoprotein yield by directed evolution requires selection and screening markers that are titratable, have a high dynamic range, enable high-throughput screening, and can discriminate against nonspecific UAG decoding.

Gld2 activity and RNA specificity is dynamically regulated by phosphorylation and interaction with QKI-7.

In the cell, RNA abundance is dynamically controlled by transcription and decay rates. Posttranscriptional nucleotide addition at the RNA 3' end is a means of regulating mRNA and RNA stability and activity, as well as marking RNAs for degradation. The human nucleotidyltransferase Gld2 polyadenylates mRNAs and monoadenylates microRNAs, leading to an increase in RNA stability.

Introducing Selenocysteine into Recombinant Proteins in Escherichia coli.

Selenoproteins contain the 21st amino acid, selenocysteine. Selenocysteine is the only amino acid that is synthesized on its cognate tRNA, and it is inserted at specific recoded UGA stop codons via a complex translation system. Although highly similar to cysteine, selenocysteine has unique properties, including a stronger nucleophilic ability and lower reduction potential.

COVID-19 Case Investigation and Contact Tracing Efforts from Health Departments - United States, June 25-July 24, 2020.

Case investigation and contact tracing are core public health tools used to interrupt transmission of pathogens, including SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19); timeliness is critical to effectiveness (1,2). In May 2020, CDC funded* 64 state, local, and territorial health departments to support COVID-19 response activities. As part of the monitoring process, case investigation and contact tracing metrics for June 25-July 24, 2020, were submitted to CDC by 62 health departments.

Overcoming Obstacles in Protein Expression in the Yeast Pichia pastoris: Interviews of Leaders in the Pichia Field.

The yeast (also known as ) has been used for over 30 years to produce thousands of valuable, heterologous proteins, such as insulin to treat diabetes and antibodies to prevent migraine headaches. Despite its success, there are some common, stubborn problems encountered by research scientists when they try to use the yeast to produce their recombinant proteins. In order to provide those working in this field with strategies to overcome these common obstacles, nine experts in protein expression field were interviewed to create a written review and video (https://www.

Using Genetic Code Expansion for Protein Biochemical Studies.

Protein identification has gone beyond simply using protein/peptide tags and labeling canonical amino acids. Genetic code expansion has allowed residue- or site-specific incorporation of non-canonical amino acids into proteins. By taking advantage of the unique properties of non-canonical amino acids, we can identify spatiotemporal-specific protein states within living cells.

The burden of cutaneous disease in solid organ transplant recipients of color.

Organ transplant recipients (OTRs) are at increased risk of cutaneous malignancy. Skin disorders in OTRs of color (OTRoC) have rarely been systematically assessed. We aimed to ascertain the burden of skin disease encountered in OTRoC by prospectively collecting data from OTRs attending 2 posttransplant skin surveillance clinics: 1 in London, UK and 1 in Philadelphia, USA.

Topical rapamycin reduces markers of senescence and aging in human skin: an exploratory, prospective, randomized trial.

Aging is a major risk factor for the majority of human diseases, and the development of interventions to reduce the intrinsic rate of aging is expected to reduce the risk for age-related diseases including cardiovascular disease, cancer, and dementia. In the skin, aging manifests itself in photodamage and dermal atrophy, with underlying tissue reduction and impaired barrier function. To determine whether rapamycin, an FDA-approved drug targeting the mechanistic target of rapamycin (mTOR) complex, can reduce senescence and markers of aging in human skin, an exploratory, placebo-controlled, interventional trial was conducted in a clinical dermatology setting.

Building Biosafety Capacity in Our Nation's Laboratories.

The 2014 Ebola outbreak revealed biosafety vulnerabilities across the United States. We distributed $24.1 million to health departments to support public health laboratories (PHLs) and sentinel clinical laboratory partners to improve biosafety practices.

Initial skin cancer screening for solid organ transplant recipients in the United States: Delphi method development of expert consensus guidelines.

Skin cancer is the most common malignancy affecting solid organ transplant recipients (SOTR), and SOTR experience increased skin cancer-associated morbidity and mortality. There are no formal multidisciplinary guidelines for skin cancer screening after transplant, and current practices are widely variable. We conducted three rounds of Delphi method surveys with a panel of 84 U.

Gld2 activity is regulated by phosphorylation in the N-terminal domain.

The de-regulation of microRNAs (miRNAs) is associated with multiple human diseases, yet cellular mechanisms governing miRNA abundance remain largely elusive. Human miR-122 is required for Hepatitis C proliferation, and low miR-122 abundance is associated with hepatic cancer. The adenylyltransferase Gld2 catalyses the post-transcriptional addition of a single adenine residue (A + 1) to the 3'-end of miR-122, enhancing its stability.

The Role of 3' to 5' Reverse RNA Polymerization in tRNA Fidelity and Repair.

The tRNA guanylyltransferase (Thg1) superfamily includes enzymes that are found in all three domains of life that all share the common ability to catalyze the 3' to 5' synthesis of nucleic acids. This catalytic activity, which is the reverse of all other known DNA and RNA polymerases, makes this enzyme family a subject of biological and mechanistic interest. Previous biochemical, structural, and genetic investigations of multiple members of this family have revealed that Thg1 enzymes use the 3' to 5' chemistry for multiple reactions in biology.

Cutaneous gummatous tuberculosis in a kidney transplant patient.

Cutaneous gummatous tuberculosis (TB) is an uncommon subtype of cutaneous TB that can be seen in notably immunocompromised individuals. We report a case of cutaneous gummatous TB in an immunosuppressed kidney transplant patient. A 60-year-old Cambodian woman presented with fever attributed to recurrent pyelonephritis while on immunosuppressive medications 7 months after kidney transplant.