bluuebunny/crossref_metadata_2025 huggingface dataset:
Giardia lamblia attenuation of proinflammatory signaling in intestinal epithelial cells is partially dependent on parasitic modulations to the NF‐κB pathway
Authors: Cotton James A , Sayer Heather L , Buret Andre G
Published: June 2021

Giardia lamblia is a non‐invasive, protozoan parasite that causes diarrheal disease in humans. Intestinal epithelial cells (IECs) do not release proinflammatory mediators, such as interleukin (IL)‐8, following exposure to G. lamblia trophozoites. The nuclear factor κB (NF‐κB) pathway regulates the expression of proinflammatory factors, such as IL‐8, and its inhibition reduces the expression of these mediators.

Aims

To determine if human adenocarcinoma (Caco‐2) monolayers, incubated with G. lamblia trophozoites, reduce secreted levels of IL‐8, following stimulation with proinflammatory IL‐1β, and if this reduction occurs through modulations to the NF‐κB pathway.

Results

Caco‐2 monolayers secreted significantly lower levels of IL‐8 when incubated with G. lamblia for 24 hours prior to stimulation with IL‐1β; this result did not require physical contact between trophozoites and monolayers. G. lamblia reduced total levels of the NF‐κB p65 subunit in a strain dependent manner. All strains induced cleavage of p65 into a fragment approximately 37 kDa in size that translocated to the nucleus following IL‐1β stimulation. NF‐κB p65 cleavage requires physical contact between trophozoites and monolayers.

Conclusion

Attenuation of proinflammatory signaling in IECs incubated with G. lamblia is at least partially dependent on parasitic modulations to the NF‐κB pathway. Funding was provided by NSERC.
Introduction of protein transduction domains to the N‐terminus of β‐defensins influences microbicidal activity
Authors: Tai Kenneth Patrick , Le Valerie V. , Ouellette Andre J.
Published: June 2021

Protein transduction domains (PTDs) enable protein fusion partners to transmigrate the cell membrane of mammalian cell lines to the cytosol. To test whether conjugation of PTDs to α‐defensins enhances microbicidal activity by membrane disruptive mechanisms, we prepared recombinant α‐defensins modified with N terminal PTDs. Rhesus myeloid α‐defensin‐4 (RMAD‐4) and mouse Paneth cell α‐defensin cryptdin‐4 (Crp4) were expressed in E. coli, introducing TAT (YGRKKRRQRRR) and nona‐Arg (9R) at both peptide N‐termini. In in vitro bactericidal peptide assays against E. coli, L. monocytogenes, V. cholerae, S. Typhimurium and S. aureus, both PTD‐conjugated peptides exhibited markedly increased activities when compared to the parent molecules. For example, at 0.75 μM, TAT‐RMAD‐4 effectively killed 99.9% of S. Typhimurium CS022 in contrast to RMAD‐4 which had no microbicidal effect at this concentration. Measurements of induced permeabilization of live E. coli cells showed that PTD‐modified peptides were significantly more membrane disruptive. Cytotoxicity assays on RAW264.7 cells showed that PTD fusion to RMAD‐4 and Crp4 imparted cytotoxic activity to the peptides at levels >10 μM. β‐Defensins with N‐terminal PTDs have enhanced antibacterial activities, suggesting potential applications against intracellular infections. Supported by NIH grants AI059346 and DK044632.
Embryonic origins of avian and mammalian laryngeal musculoskeletal structures
Authors: Noden Drew M , Epstein Miles L
Published: June 2021

The larynx forms at the boundary of neural crest‐ and mesoderm‐derived tissues, but the interface site in relation to laryngeal cartilages is uncertain. Our research identifies crest and mesoderm contributions to laryngeal cartilages and muscles in the chick, which has only cricoid and arytenoid cartilages, and in mice with thyroid and epiglottal elements. This was done using quail‐chick transplants and LacZ‐retroviral labeling; for mice labeling of crest‐derived tissues used the Wnt1‐cre/R26R reporter. Chick laryngeal cartilages are derived from lateral mesoderm beside the first somite; intrinsic muscles are from this somite. Mouse epiglottis and thyroid cartilages derive from crest cells; arytenoids do not. The cricoid is mesodermal, but a few crest‐derived chondrocytes may be present in its dorsal plate. Fetal thyroid and cricoid cartilages transiently fuse, and secondarily form a joint whose location does not precisely correspond to the original crest:mesoderm interface. Additional crest labeling is present in the perichondrium at sites of cranially‐oriented extrinsic laryngeal muscle attachment. Crest‐derived Schwann cells and ganglia were widely dispersed beneath the laryngeal mucosa. These studies show that neural crest contributes to the larynx only in those cartilages that are located rostrally and are unique to mammals. Supported by NIH grants EY015917 to DMN and DK081634‐01 MLE.
Immunolocalization of VEGF and VEGFR 1 & 2 in embryonic lung tissues
Authors: McNeil Rosie Thecla , Maina John N , Kramer Beverly
Published: June 2021

Eb 2010 Abstract

The role of vascular endothelial growth factor (VEGF) and its receptors 1 and 2 (flt and flk) have been identified in mammalian lung development but there are few studies concerning their role in avian lung. The objective of this study was to determine whether VEGF, flt and flk are expressed in the developing avian lung between stages 20 to 40.

Sections, 4 micrometers thick from 4% paraformaldehyde‐fixed, paraffin‐embedded embryonic lung buds and were immunolocalized for the growth factors using standard avidin‐biotin peroxidase immunohistochemical techniques. Mouse kidney and lung were used as positive control tissues.

Positive staining for VEGF presented as diffuse cytoplasmic staining which was first observed at stage 27 with the intensity increasing towards stage 40. Staining for flt and flk were however less intense than that of VEGF. We concluded that VEGF, VEGFR1 and VEGFR2 may play significant roles in avian lung development.

Grant Funding Source: Faculty Research Grant
Regulation of Wnt‐mediated developmental competency by Pygo‐Bcl9 during body axis specification in Xenopus
Authors: Kao Kenneth , Kennedy Mark W , Andrews Phillip
Published: June 2021

The early Xenopus embryo responds to the Wnt/β‐catenin intracellular signaling pathway by specifying dorsoanterior body structures. The loss of competence to specify the dorsal side at midblastula is followed closely by commitment to the dorsal lineage by transcriptional activation of dorsoanterior genes. The objective of our study is to determine the role of a core component duet of the β‐catenin transcription complex, made up of Pygopus and Legless/Bcl9 (Pygo‐Bcl9) during body axis specification in Xenopus embryos. Pygo‐Bcl9 recruits chromatin‐remodeling factors to the complex located at promoters of actively transcribing Wnt target genes. Maternal depletion of Bcl9 mRNA prevents body axis formation while co‐expression of Pygo‐Bcl9 ectopically activates dorsoanterior gene expression, inducing a supernumerary embryonic axis. Interestingly Bcl9 mRNA is present in the embryo during the period of Wnt/β‐catenin competence, but is rapidly translated at the end of the competency period, when dorsoanterior gene transcription occurs. We hypothesize that translation of Bcl9 defines the end of the period of competency. We propose that the identification of the factors that regulate Bcl9 translation will provide further insight into the molecular mechanisms of developmental competence.
Regulation of spinal neuron axon outgrowth by calcium influx through mechanosensitive TrpC channels
Authors: Gomez Timothy M , Jaques‐Fricke Bridget , Kerstein Patrick , Rengifo Juliana , Bobel Matt
Published: June 2021

Intracellular calcium signals regulate the development and regeneration of spinal axons downstream of chemical and mechanical cues. Previously, we identified a novel calcium influx pathway through stretch‐activated channels (SACs) that inhibits spinal neuron axon outgrowth. Here we show that TRPC1 functions as a SAC on growth cones, which constitutively suppresses neurite outgrowth. Reducing TRPC1 expression with anti‐sense morpholinos prevents changes in the rate of axon outgrowth in response to stimuli that activate or inhibit calcium influx through mechanosensitive ion channels. Further, activating SACs increases calcium signals in nerve growth cones that are dependent on TRPC1 expression. The elastic properties of the substratum also modulate calcium signaling in growth cones and the extension of spinal axons in a TRPC1‐dependent manner. Downstream of calcium signals, we find that the protease Calpain is activated by calcium influx through TRPC1 containing channels, which likely inhibits the growth promoting effects of the non‐receptor tyrosine kinase Src. Together our results suggest that calcium influx through mechanosensitive channels containing TRPC1 subunits activates calpain, which in turn cleaves Src family kinases to restrict neurite outgrowth by developing spinal cord neurons.
Potential for treatment of age‐related muscle atrophy by exogenous nitric oxide and exercise
Authors: Leiter Jeff R.S. , Janke Alyssa , Ong Melody , Lenoski Stephane , Upadhaya Ritika , Anderson Judy E
Published: June 2021

In adult muscle, activation of satellite cells (SCs) is required for muscle maintenance, growth and repair. SCs are activated in response to exercise, stretch, trauma, denervation and nitric oxide (NO). The muscle response to exercise is age‐dependant and muscle‐specific and may be a factor in age‐related muscle atrophy. The purpose of this experiment was to determine the effects of treatment with an NO‐donor isosorbide dinitrate (ISDN) and exercise on muscle mass, SC activation (DNA synthesis), NOS‐I and β‐dystroglycan and fiber cross‐sectional area (CSA) on muscle in 18‐month‐old mice. Mice between 18–19 mo of age were divided into 6 groups to study effects of ISDN (0, 3 and 6 weeks) with and without exercise for the first 3 weeks of the experiment. Groups had 4–8 mice. Results in quadriceps muscle showed that ISDN treatment combined with exercise increased muscle mass, fiber CSA, and the protein‐expression ratio of NOS‐I/β‐dystroglycan. ISDN for 6 wks also produced the greatest increase in SC activation. These findings show that combining NO treatment and exercise has the potential to combat age‐related muscle atrophy. Supported by the Canadian Space Agency: Life Sciences
Anatomy table conference assessments in place of cadaver practical exams
Authors: Morton David A , Moyle Kimberly A , Livdahl Nicholas S , Albertine Kurt H
Published: June 2021

A new curriculum was implemented in 2009 at the University of Utah, School of Medicine. Cadaver practical exams were eliminated because of schedule constraints. We replaced those exams with oral assessments performed during weekly table conferences. Learning objectives were provided for each weekly dissection period, detailing the content for which the students were responsible during table conference assessment. Weekly, six dissection groups (4–5 students/group) were randomly selected for a table conference, during which each student was assessed. Each student was assessed four times during the course. The same faculty did the assessments, to increase consistency among assessments. Students were graded on accuracy, depth of understanding, clarity of explanation, and use of the cadaver. Results demonstrate that student participation increased, as did the level of understanding of the objectives and retention of material. In addition, communication skills and use of anatomical terminology improved. We suggest that anatomy table conferences increase student engagement, demonstration of anatomic knowledge, and integration of that knowledge with pathology and physiology.

Grant Funding Source: AAA
A Novel Use of Second Life (SL) Technology to Teach the Pterygopalatine Fossa to Medical Students
Authors: Richardson April Dawn , Brueckner Jennifer , Hazzard Matt
Published: June 2021

Second Life™ (SL) technology is a web‐based, 3‐D virtual world that has great potential for anatomy education due its immersive environment in 3‐D structures and highly interactive atmosphere among avatars, or virtual representations of real people. The objective of this study was to introduce SL to medical students and to determine its usefulness as a novel supplemental teaching tool for conceptually challenging anatomical regions, including the pterygopalatine fossa (PPF). A 3D replica of the PPF was constructed in SL, including an illustration of the relevant divisions of the trigeminal nerve that pass through the PPF. The SL virtual tour was demonstrated during lecture in combination with an inverted cone model that was used in previous class sessions to illustrate the various openings through which nerves traverse the PPF. The SL approach was used to build upon the PPF cone model, so that students may be able to experience the organization of the PPF virtually, maneuvering in and out of the PPF boundaries and following the course of the nerves through the fossa. Preliminary qualitative data suggest the students view this new technology as a valid method for studying anatomical arrangements, and that this novel approach enhanced their understanding of the pterygopalatine fossa. Students embraced the idea of SL, and it is our goal to incorporate more anatomy themes in the SL context for future medical courses.
The Future of Medical Education Research: A Different Way to Analyze Data to Produce More Valid Results/Conclusions
Authors: Lufler Rebecca , Zumwalt Ann , Hoagland Todd
Published: June 2021

Medical education research has been criticized for producing less than robust results. Perhaps in these studies significant differences exist, but they are being masked by the statistical analyses used. Typical analyses (t‐test, ANOVA) may not be appropriate in medical education research and may be disguising valid results or producing invalid results by not adjusting for confounding variables. Our purpose is to apply two different statistical analyses to the same set of medical education data and compare the outcomes. Using data from a previous study completed by the authors, analysis was completed in two ways: using ANOVA (assumes students are a homogeneous population) and using regression analyses (adjusting for variables that vary among students). ANOVA results showed no differences in practical exam averages across groups of students with different visual‐spatial abilities (VSA). Using regression analysis and adjusting for gender, learning preference, and MCAT scores, there was a significant difference between the performance of students with highest vs. lowest VSA, with adjusted practical exam average scores of 88.4 and 81.9, respectively (p=0.03). These data demonstrate that controlling for characteristic variables of the study population reveal confounding effects otherwise hidden by typical statistical analysis.

Grant Funding Source: None
Wnt Target Genes in CNS Development
Authors: Dorsky Richard Ian
Published: June 2021

We are interested in the function of Wnt signaling and Lef/Tcf factors in the developing zebrafish central nervous system. In the spinal cord we have evidence that Tcf3 acts to maintain the multipotent progenitor state, both through direct transcriptional regulation and through a novel post‐transcriptional pathway. In the hypothalamus we have identified a role for Tcf7 and Lef1 as Wnt‐mediated activators regulating the development and maintenance of committed neural precursors. We have also identified Lef/Tcf target genes in both processes. Together our data fit with established roles for Lef/Tcf factors in other epithelial tissues, where Tcf3‐mediated repression acts to maintain the stem cell state, while Wnt‐mediated activation supports the progression of cells into a differentiation pathway.
The genesis of the popliteal tendon and the ‘climb’ of the popliteus muscle
Authors: Ghosh Tamojit
Published: June 2021

Object of Study

The genesis of the popliteal tendon and the ‘climb’ of the popliteus muscle

Summary of Results

The present adult morphology of the postero‐lateral aspect of the knee joint requires a good understanding of the evolutionary origin of the popliteal tendon. The popliteus muscle and its tendon originate separately. During evolution they get connected in the way that they are seen in humans. This tendon is not present in reptiles. This work provides proof of the genesis of the popliteus tendon and delineates which of its surrounding structures it evolved from. Origins of the arcuate popliteal ligament and the short lateral ligament are also discussed.

Statement of Conclusions

In lower vertebrates (birds, reptiles and amphibians) there are separate femorotibial and femorofibular joints with separate femorofibular and femorotibial menisci. Both menisci have corresponding meniscal ligaments to the femur above and the fibula and tibia below. The popliteus muscle exists in these lower vertebrates but has no femoral attachment.

As evolution progresses the femorofibular joint and its related structures disappear and the fibula recedes from its femoral attachment to a newer and lower attachment on the upper tibia through the proximal tibiofibular joint. The femorofibular meniscus and it's meniscofemoral ligament (which are remnants of the primitive femorofibular joint) get connected as a continuous tendon to the main body of the popliteus muscle. Thus the popliteus gets a new femoral attachment it did not have initially. The popliteus ‘climbs up’ from a sub‐genual position to a newer supra‐genual one aiding upright walking in humans. Crucially, the formation of its tendon is aided by remnants of the femorofibular joint structures which undergo evolutionary recession.

Grant Funding Source: Self
FGF regulation of myocardial integrity and angiogenesis
Authors: Murakami Masahiro , Simons Michael
Published: June 2021

Integrity of cardiac architecture is crucial to normal cardiac physiology. Cardiac remodeling resulting from impairment of myocardial integrity leads to heart failure, through still incompletely understood mechanisms.

We have recently described a new role of fibroblast growth factor (FGF) signaling in the adult vasculature: inhibition of vascular FGF signaling leads to disassembly of endothelial junctions, progressing to severe deterioration of vascular integrity. Similarly, using a mouse model of cardiomyocyte‐specific inhibition of FGF signaling, our studies showed that the FGF system controls cardiac junction stability by modifying Connexin 43 and N‐cadherin localization and expression. Concomitantly, these mice presented cardiac hypertrophy and later developed heart failure, leading to premature death. Moreover, in the same mouse model, inhibition of FGF signaling in myocytes also caused decreased capillary density prior to the development of heart failure.

Together with recent evidence suggesting that microvascular rarefaction is partly causative to heart failure progression, we concluded that cardiomyocyte FGF signaling is required for the maintenance of cardiac homeostasis through an angiogenesis dependent mechanism. The lack of basal FGF signaling in cardiac myocytes causes a microvessel dropout, thereby leading to the development of heart failure.

Supported by NIH HL‐53793
Mechanistic Perspective of Early Vertebrate Cardiogenesis
Authors: Yang Jennifer , Fraser Scott , Lansford Rusty
Published: June 2021

Vertebrate heart morphogenesis is a complex process that integrates different structures and cell types driven to interact by genetic and epigenetic factors. We have taken an interdisciplinary approach to studying heart formation by combining the power of molecular genetics with advanced optical imaging within living embryos. We have developed multiple transgenic quail lines and novel imaging methods that permit dynamic observation and manipulation of vascular development. Avian embryos are ideal for imaging due to the accessibility at all stages of development outside the vertebrate mother. These embryos also develop hearts with four chambers, allowing for comparative anatomy to study human hearts. Our primary goal is to analyze heart morphogenesis and determine the mechanisms of heart tube formation and the underlying features of heart tube looping.

Grant Funding Source: NIH
Antioxidants Increased In Vitro Wound Healing of Nicotine‐Treated Oral Fibroblasts
Authors: Miguel Symone M San , Opperman Lynne A. , Svoboda Kathy K.
Published: June 2021

Objectives

Smoking is associated with increased risk for oral health and dental problems. Treatment with antioxidants (AO) can block the production of reactive oxygen species or block its effects, and might be therapeutically valuable in reducing the risk for many dental maladies. The aim of this study is to address the hypothesis that nicotine impairs wound healing by inhibiting cell migration, and that AOs may counteract nicotine effects.

Methods

To test the effects of nicotine and AO compounds on cell migration, the cells were grown to confluence. Cells were pretreated with 6 mM nicotine for two hours and then treated with AOs. Two hours later, a scratch wound assay was performed. The migratory behavior of the wounded cells was recorded every hour for ten hours, using a Nikon‐Biostation. Analysis of the levels of RAC‐GTP at the leading edge of the wound were determined using confocal microscopy.

Results

AO treatment counteracted the inhibitory effects of nicotine and increased migration rates in human gingival fibroblasts and human periodontal ligament cells, the former to a greater extent than the latter. AO compounds increased the level of RAC activation at the leading edge of cells around the wound margin.

Conclusions

Nicotine impairs migration of gingival and periodontal fibroblasts. Treatment with combinations of antioxidants showed synergistic effects in restoring cell migration after wound creation.

Grant Funding Source: Periosciences
The anatomy and histology of wound healing following tail loss in the leopard gecko Eublepharis macularius
Authors: Vickaryous Matthew Kenneth , Delorme Stephanie , McLean Katherine E , Zweerman Christopher L
Published: June 2021

Many lizards are able to voluntarily self‐detach (autotomize) a portion of the tail and then regenerate a functional replacement. Autotomy occurs at an intravertebral fracture plane and ruptures all the major tissue types of the tail, resulting in an open wound with various tissues exposed. The objectives of this study were to investigate the anatomy and histology of tail loss and wound healing in the leopard gecko, Eublepharis macularius. Microcomputed tomography and serial histology reveals the structure of the fracture plane and associated tissues, including a persistent notochord and sphincter muscles of the caudal artery. Following tail loss the remaining skin collapses over the wound site, the spinal cord is retracted into the original tail stump, and a clot is formed. Epithelial cells adjacent to the wound site begin to proliferate and migrate deep to the clot. Once the wound epithelium completely spans the wound site the clot drops off to reveal the developing blastema. Unlike most invasive wounds, fibrous scar tissue is not formed. Ongoing studies of wound healing studies in Eublepharis provide an important complement for ongoing regenerative research by expanding the comparative framework.
Biotechnology at James Madison University (VA): A tale of two programs ‐ pitfalls and opportunities.
Authors: Monroe Jonathan DeVoss , McKown Robert L.
Published: June 2021

James Madison University (JMU) is a predominately undergraduate University in the Shenandoah Valley of Virginia. Founded in the 1990s, the Integrated Science and Technology (ISAT) Program at JMU identified seven strategic sectors for new curriculum development, one of which was Biotechnology. The ISAT program is a broad‐based science and technology major with an emphasis on scientific breadth, business applications and problem solving. The Biotechnology (now called Biosystems) concentration in the ISAT Program prepared students to enter the workforce in a variety of non‐research oriented roles. Later, faculty in ISAT, Biology and Chemistry developed a more traditional Biotechnology major to offer students a rigorous background in biology, chemistry, physics, mathematics, and applied sciences that prepared students to attend graduate or professional schools. Both majors offer students opportunities to gain skills and experiences through independent study. This presentation will include 1) a description of these two programs including examples of curriculum and student outcomes and 2) our recommendations on the development and administration of such programs.
Embracing the Information Age: The Science Informatics Major at Montclair State University
Authors: Deremer Dorothy
Published: June 2021

Innovative computing tools and computational thinking support the information needs for theoretical and applied life sciences. Advances in computer hardware/software, biochemistry, molecular biology, geosciences and mathematical modeling have added computing to the laboratory and field‐based sciences creating interdisciplinary collaborations of science, computer science, and mathematics, that is, science informatics. Bioinformatics in The Human Genome project is perhaps the best known science informatics.

Montclair State's B.S. in Science Informatics began in 2002. With biweekly meetings for 1.5 years, 10 faculty members from Computer Science, Biology/Molecular Biology, Chemistry/Biochemistry, and Mathematical Sciences developed the degree. It includes courses in supporting disciplines, a concentration for depth in one of the disciplines, and 16 credits in interdisciplinary Science Informatics courses. The interdisciplinary courses permeate the program from freshman to the senior years. They include internal and external internships, ethics, and research. A faculty Coordinating Council and the Dean of the College oversee the program.

The presentation includes a history of Science Informatics development, the content of the concentrations, the details of the interdisciplinary Science Informatics courses, experiences of the Coordinating Council and other faculty, lesson learned, concerns, and future directions for Science Informatics at Montclair State University.
Building A Replication Fork: Structural Synergy And Molecular Crosstalk Between Bacterial Initiators And Helicase Loaders
Authors: Berger James M , Mott Melissa , Duderstadt Karl , Erzberger Jan
Published: June 2021

The proper initiation of DNA replication is critical to all cells. Dedicated initiation factors belonging to the AAA+ ATPase superfamily are essential regulators of this process. In bacteria, ATP binding activates the DnaA initiator to trigger DNA melting and facilitate replisome assembly. Using structural approaches, we show that ATP induces conformational changes in DnaA that lead to the formation of a right‐handed, helical initiator assembly. This quaternary arrangement wraps origin DNA into a positive supercoil, and frees catalytic ATPase motifs for interacting with other proteins at filament ends. Parallel work on DnaC, the loading factor for the DnaB helicase, shows that this protein is close structural homolog of DnaA that also assembles into a helical structure, and that engages the initiator in an ATP‐dependent manner. Our findings provide a molecular framework for understanding how prokaryotic initiators transition between inactive monomer and functional multimer states, and implicate DnaC as an adaptor that helps ensure the proper spatial deposition of replicative hexameric helicases onto a replication origin.
Structural mechanisms of ssDNA/SSB‐processing enzymes
Authors: Keck James L , Marceau Aimee , George Nicholas P
Published: June 2021

Unwinding genomic DNA to form single‐stranded (ss) DNA is an obligatory step in many DNA replication, recombination, and repair pathways. However, because ssDNA is sensitive to chemical and nucleolytic attack and can self‐associate to form structures that impede genome maintenance, DNA unwinding also presents a potential threat to genomic integrity. To help mediate this risk, cells have evolved ssDNA‐binding proteins (SSBs) that bind and protect ssDNA from biochemical attacks and maintain its single stranded structure. SSB/ssDNA nucleoprotein complexes thus form a common substrate utilized in genome maintenance reactions. Defining how DNA replication, recombination, and repair enzymes recognize and process SSB/ssDNA structures is key to understanding cellular genome maintenance mechanisms.

Bacterial SSBs facilitate DNA replication, recombination, and repair processes in part by recruiting diverse genome maintenance enzymes to ssDNA. This function utilizes the C‐terminus of SSB (SSB‐Ct) as a common binding site for SSB's protein partners. The SSB‐Ct is a highly conserved, amphipathic sequence, comprising acidic and hydrophobic elements. I will present our most recent studies that examine the structural mechanisms that support protein interaction with the SSB‐Ct element, focusing on the roles of these interactions in DNA replication.
Crystal Structures of Translation Termination Complexes
Authors: Noller Harry F. , Korostelev Andrei , Laurberg Martin , Zhu Jianyu , Asahara Haruichi , Lancaster Laura , Hirschi Alexander , Donohue John Paul
Published: June 2021

Recognition of stop codons depends on the release factors RF1 and RF2 instead of tRNA. Yet the following basic questions have gone unanswered for more than 40 years: (i) Are the stop codons recognized directly by the release factors or indirectly through the ribosome? (ii) Is peptidyl‐tRNA hydrolysis catalyzed by the release factors or by the ribosome? (iii) How is stop codon recognition coupled to peptidyl‐tRNA hydrolysis with an error frequency as small as ~10−5in the absence of GTP‐dependent proofreading? We have solved the structures of ribosome termination complexes containing release factors RF1 (bound with UAG or UAA) and RF2 (bound with UAA) at resolutions between 3.0 and 3.2 Å. Together with the structure of an RF2 complex bound with a UGA codon from the Ramakrishnan laboratory, the structures of all of the four possible termination complexes are now known. We can now propose a mechanism for translation termination that provides answers to the three key questions.
Is the future of metagenomics, genomics?
Authors: Hugenholtz Philip
Published: June 2021

Metagenomics, the application of high throughput sequencing to environmental samples, has the great advantage over genomics that it bypasses the cultivation bottleneck and provides access to the largely unexplored microbial world. On the downside, metagenomes are usually aggregates of numerous microbial genomes that need to be informatically separated to facilitate analysis. Moreover, most members of a microbial community are not sampled sufficiently to produce even low‐quality draft genomes. An alternative approach to analyzing communities without the need for cultivation is flow sorting constituent members and obtaining genomic data from sorted cells or populations. Although this is not a new approach, several recent advances have brought us to the point where it may be possible to sort and sequence representatives of most dominant populations (>0.5%) in a given community, essentially turning comparative metagenomics into comparative genomics. An additional benefit of this approach is the potential to obtain a phylogenetically‐balanced genomic representation of the microbial tree of life.
Imaging Brain Chemistry in Diseases of Addiction
Authors: Fowler Joanna S , Wang Gene‐Jack , Volkow Nora D
Published: June 2021

Molecular imaging utilizing positron emission tomography (PET) and labeled compounds continues to provide new knowledge of brain circuits which are altered in disease and by drugs. This can provide unique new knowledge of biological pathways directly in the living human brain. The advancement of PET for medical applications requires innovation in radiotracer chemistry, particularly in the development of rapid synthetic methods for introducing the short‐lived isotopes, carbon‐11 (t1/2: 20.4 min) and fluorine‐18 (t1/2: 110 min) into chemical compounds and which are targeted to different cellular elements. In this presentation, we highlight some examples of development and applications selective radiotracers and labeled drugs for imaging the brain dopamine system and for measuring the pharmacokinetics and pharmacodynamics of drugs of abuse in the human brain. We will also highlight recent advances on the development of new radiotracers and imaging instrumentation which will serve as scientific tools to advance our knowledge of the human brain. Supported by the U. S. Department of Energy, Office of Biological and Environmental Research (for infrastructure support) and the National Institutes of Health (NIDA, K05 DA 020001) and GCRC grant 5‐MO1‐RR‐10710.
Correcting for the influence of inflammation improves the accuracy for estimation of iron status among preschoolers in western Kenya
Authors: Grant Frederick , Suchdev Parmi , Cole Conrad R , Ramakrishnan Usha , Flores‐Ayala Rafael , Martorell Reynaldo
Published: June 2021

Iron status (IS) estimation in high infection areas is difficult due to the effects of infection on indicators of IS. Using data on indicators of IS [(hemoglobin (Hb), zinc protoporphyrin (ZP), ferritin (Ft), transferrin receptors (TfR), and TfR/Ft index)] and subclinical infection [(acute phase proteins; C‐reactive protein (CRP) and alpha glycoprotein (AGP)] on preschoolers, we examined if the use of a correction factor (CF) will improve the accuracy of estimations of iron deficiency (ID).

Methods

We recruited 2340 children (aged 6–59 mos) in cross sectional surveys and obtained blood for Hb, Ft, TfR, ZP, CRP, and AGP measurements.

Results

CRP correlated with AGP (r=0.62; p<0.001), Ft (r=0.40; p<0.001), Hb (r=−0.21; p<0.001) and ZP (r=0.17; p<0.001); AGP correlated with Ft (r= 0.38; p<0.001), Hb (r=−0.2; p<0.001) and ZP (r=0.16; p<0.001). Use of CFs (ratios of median for reference group over each inflammatory group) improved the estimation of IS of the population (p<0.001) when median iron indicators [Hb (108 vs. 111g/L), Ft (19.4 vs. 13.9μg/L), and ZP (142 vs. 126μmol/mol)] and estimated anemia (Hb<110g/L: 54 vs. 45%) and ID prevalences [(Ft<12 μg/L: 32 vs. 43%), (ZP>80μmol/mol: 89 vs. 83%)] of uncorrected and corrected IS indicators were compared.

Conclusion

CRP and AGP have an impact on the estimation of IS among preschoolers, but the use of a CF is indicated to improve the accuracy for diagnosis of ID.

Sources of research support: CDC, Atlanta, GA; and International Nutrition Foundation, Boston, MA.

Grant Funding Source: NUTRITION (ASN)
Postnatal impairments of auditory acuity and neural transmission times induced by maternal iron deficiency
Authors: Jougleux Jean‐Luc , Rioux France , Church Michael , Fiset Sylvain , Surette Marc
Published: June 2021

Iron deficiency (ID) is believed to affect central nervous system (CNS) on several aspects such as myelinogenesis, neurotransmitter synthesis and brain fatty acid metabolism. While most findings in humans investigated ID during post natal periods, our study aimed to evaluate consequences of moderate maternal ID on CNS development in guinea pig offspring. We used auditory brainstem response (ABR) to assess neurophysiologic auditory function and neural transmission times (NTT). Females were fed an iron sufficient (IS) or deficient (ID) diet during the gestation and lactation periods. ID appeared in the third trimester of pregnancy for the ID group. On post natal day 9 (PND9), an IS diet was introduced to wean offspring from both groups. ABR was measured on PND24 using descending intensities and various frequencies (2 to 32 kHz). ID pups had significantly elevated ABR thresholds (hearing loss) at 2, 16 and 32 kHz. NTT seemed to demonstrate shorter inter peak latencies for offspring born to ID dams. A delay in the appearance of the first neural nucleus is likely to be the explanation, whereas later relays did not differ among the two groups. Our study demonstrates that a moderate maternal ID adversely impairs the auditory functions of pups born to ID females. These results suggest that maternal ID may alter the CNS myelinogenesis in the progeny. Support: Canadian Institutes of Health Research and the Canada Research Chairs.
Maternal and Neonatal Iron Status Impact the Expression of the Heme Transporter, FLVCR, in the Placenta
Authors: Jaacks Lindsay Marie , Young Melissa F. , Essley Bridget V. , McNanley Thomas J. , Cooper Elizabeth M. , Pressman Eva K. , Mcintyre Allison W. , Orlando Mark S. , Abkowitz Janis L. , Guillet Ronnie , O'Brien Kimberly O.
Published: June 2021

Mechanisms of placental heme iron transport are largely unknown. To address this, expression of the heme transporter Feline Leukemia Virus, Subgroup C, Receptor (FLVCR) was measured in placental tissue from 84 pregnant teens (13–18 y). Iron (Fe) status indicators, serum ferritin (SF) and serum transferrin receptor (sTfR), were measured at mid‐gestation (25.1±3.5 wks) and in maternal/cord blood at delivery (39.8±1.1 wks). At delivery, 33% (18/54) of teens were anemic (Hb<11 g/dL); hemoglobin (Hb) averaged 11.6±1.5 g/dL (n=54). Maternal SF at delivery was 21.8±13.3 μg/L (n=67); 52% (35/67) had depleted Fe stores (SF<20 μg/L). Neonatal SF averaged 140.8±79.9 μg/L (n=65). At delivery, maternal and neonatal sTfR averaged 5.8±3.7 mg/L (n=66) and 8.0±2.4 mg/L (n=65), respectively. A significant relationship was observed between maternal mid‐gestation SF and neonatal SF (p<0.05, n=52) and between placental FLVCR expression and the maternal delivery: neonatal SF ratio (p<0.01, n=43). Although FLVCR expression was regulated in response to maternal and neonatal Fe status, up‐regulation of this protein was not sufficient to normalize ferritin stores in neonates born to teens with depleted Fe stores. Funded by: NRI Grants 2008‐01857 & 2005‐35200, USDA HATCH (2006‐07‐160), and HHMI.
Bioavailability of grape‐derived polyphenolics and implications in Alzheimer's disease prevention and therapy
Authors: Ho Lap , Ferruzzi Mario G. , Janle Elsa M. , Lobo Jessica , Chen Tzu‐Ying , Talcott Stephen T. , Simon Jim , Wu Qing Li , Wang Jun , Cheng Alice , Weaver Connie M. , Percival Susan S. , Pasinetti Giulio Maria
Published: June 2021

The production and accumulation of β‐amyloid (Aβ) peptides is central to the pathogenesis of Alzheimer's disease (AD). Accumulating evidence suggests that selective bioactive grape‐derived polyphenols may protect against the AD‐type cognitive deterioration, in part, by interfering with Aβ‐mediated neuropathologic mechanisms. Results from our in vitro and in vivo studies suggest that select polyphenolics from red wines and Concord grape juice may inhibit the generation of Aβ peptides and/or the assembly of Aβ peptides into neurotoxic oligomeric Aβ aggregate species. We next explored the pharmacokinetic and bioavailability of red wine and grape juice polyphenolics to gather insights on the identity and bioactivity of specific polyphenolic components that might exert beneficial AD disease‐modifying activity in vivo. Specific polyphenolic derivatives that are bioavailable in the blood and/or in the brain have been identified. Ongoing studies are now exploring the potential role of these bioavailable polyphenolics in mitigating AD‐type neuropathologic and neurodegenerative mechanisms. Results from our studies provide further support for the inclusion of polyphenolics in the diet and the impetus to develop selective polyphenolic compounds for AD prevention and/or therapy.

Supports: 1PO1AT004511‐01 Proj.‐1 (LH), 1PO1AT004511‐01 Proj.‐3 (GMP), J.J. Peters VA GRECC Program (GMP).
Predicting intention to eat breakfast among adolescents using the theory of planned behavior
Authors: Carson Diane E , Sharkey Joseph R , McIntosh Wm. Alex , Kubena Karen S , Goodson Patricia
Published: June 2021

Purpose

To test the effectiveness of a nutrition education intervention based on the Theory of Planned Behavior (TPB) on intention to eat breakfast.

Settings/Participants

A sample of 106 primarily Hispanic adolescents aged 12‐ to 14‐years was recruited from an after‐school program in Los Angeles County, CA. Youth were randomly assigned to the treatment or control group. One hundred‐six adolescents completed the pre‐intervention questionnaire, 75 completed the post‐intervention questionnaire,

Design

Participants were assigned by after‐school site to either the treatment group (n = 57) or control group (n = 49). Within the treatment group, participants were assigned to groups based on grade to facilitate discussion and to allow for easy group interaction. Each group met for 60 minutes, once weekly, for seven weeks. The curriculum focused on the benefits of eating breakfast and in identifying the influences of attitude, subjective norms, and perceived behavioral control.

Results

Fifty‐five percent of participants were girls and 88% were Hispanic. Attitude and perceived behavioral control were significant in predicting intention to eat breakfast after controlling for gender and age. Subjective norms had no effect in predicting intention. Behavioral belief was significant in predicting attitude toward eating breakfast.

Conclusions

These results show incorporating interventions based on the TPB may improve breakfast behavior and habits among adolescents.
Genetic Variation in Selenoenzymes and Their Activity
Authors: Takata Yumie , Kristal Alan R , Burk Raymond F , Hill Kristina E , Santella Regina M , King Irena B , Duggan David J , Lampe Johanna W , Blount Patricia L , Reid Brian J , Vaughan Thomas L , Peters Ulrike
Published: June 2021

Selenium may protect against various diseases through the activity of selenoenzymes. However, little is known of the effect of genetic variation in selenoenzymes on their activity. We tested 37 tagging single nucleotide polymorphisms (SNPs) in the selenoenzyme genes, glutathione peroxidase1–4 (GPX1–4), selenoprotein P (SEPP1), and 15 kDa selenoprotein (SEP15), with regard to activity of lymphocyte GPX1 and plasma GPX3, plasma SEPP1 concentration (conc), plasma malondialdehyde and protein carbonyl content. We included 195 participants of a cohort of Barrett's esophagus who were free of esophageal cancer at the time of blood draw. Genetic variation in the GPX1 gene as measured by 3 SNPs (rs3448, rs8179164 and rs1987628) was significantly associated with GPX1 activity (p global = .02), with each of the latter 2 SNPs being suggestively associated (p trend = .10 and .08, respectively). Moreover, we found that 2 GPX2 SNPs (rs4902346 and rs2071566) and a GPX3 SNP (rs3763011) were significantly associated with SEPP1 conc (p trend = .004, .002, and .02, respectively). Our suggestive association of GPX1 rs1987628 with the GPX1 activity is consistent with previous studies. To our knowledge, this is the first study that observed associations of SNPs in GPX2 and GPX3 genes with SEPP1 conc, which need a replication in future studies. Our study supports that common genetic variants in selenoenzymes affect their activity.

Grant Funding Source: National Cancer Institute
Activating ERK Signaling enhances 1alpha,25(OH)2D3‐regulated 25‐hydroxyvitamin D‐24‐hydroxylase (CYP24) gene expression through the transcription factor Sp3 pathway in Caco‐2 cells.
Authors: Jiang Yan , Fleet James C
Published: June 2021

CYP24 is an enzyme critical for degradation of 1, 25 dihydroxyvitamin (1,25D) and its gene is strongly regulated by 1,25D. Multiple signaling pathways have been shown to modulate 1,25D‐mediated CYP24 gene expression. Phorbol ester (PMA) treatment activates PKC, as well as ERK1/2 and p38 MAP kinase signaling pathways. In addition, PMA treatment enhances 1,25D‐induced CYP24 gene transcription (mRNA, 180%; reporter gene 150–250%) in Caco‐2 cells. Inhibition of PKC, ERK, and p38 kinase signaling pathways each reduced PMA enhanced and 1,25D induced CYP24 mRNA and reporter genes by 20–40%. Mithramycin A, an inhibitor of Sp protein binding to DNA, dose‐dependently reduced both 1,25D‐induced and PMA‐enhanced CYP24 promoter activity. Bioinformatics revealed 11 putative Sp1/Sp3 sites in the −298 to +74 bp region of the human CYP24 promoter. siRNA knockout of Sp1 reduced 1,25D action by only 30% but had no effect on PMA‐mediated enhancement of CYP24 induction. In contrast, Sp3 siRNA decreased both 1,25D‐mediated CYP24 induction and PMA enhancement of that effect by 20%. Immunoprecipitation showed that PMA can phosphorylate a serine residue on Sp3 and that this is blocked by inhibition of MEK1 with U0126. These data show that a portion of the impact that PMA has on 1,25D‐mediated CYP24 induction is due to activation of ERK1/2 and subsequent phosphorylation/activation of the Sp3 transcription factor. Supported by NIDDK Award DK054111 to JCF.

Grant Funding Source: NIDDK Award DK054111 to JCF
Genome‐wide identification of vitamin D receptor (VDR) binding sites in DNA from prostate epithelial cells (PEC) by chromatin immunoprecipitation‐sequencing (ChIP‐seq)
Authors: Cui Min , Fang Youhan , Qi Yuan , Fleet James
Published: June 2021

The 1,25 dihydroxyvitamin D (1,25D) activates the VDR to bind DNA and initiate gene transcription. While microarray studies show 1,25D regulates expression of many transcripts, few of these genes have been examined for VDR binding. Using ChIP‐seq, we mapped VDR binding sites in DNA from the human PEC line, RWPE1. Cells were treated with vehicle or 1,25D (10 nM, 3 h) and subjected to ChIP using either VDR antibody or IgG. Using IgG as the reference, 1236 and 1175 VDR binding peaks were found in 1,25D and vehicle‐treated cells, respectively (0.1 FDR, 200 bp window, Cisgenome). Genes with known VDREs were confirmed e.g. CYP24 and IGFBP3. Correlation between ChIP‐seq peaks and a previous microarray study found that only 39% were associated with 1,25D‐regulated transcripts, including novel peaks close to the transcription factors (TF) JunB, FOS and TBP. Also only 5% of VDR peaks were found within 5 kb of the transcription start site of a gene and the known DR3 VDR binding motif was found in just 15% of the peaks. However, several other DNA‐binding motifs were enriched under the peaks suggesting indirect DNA association of VDR through other TF. Our data suggest the relationship between VDR binding and transcription is more complex that previously reported.

Grant Funding Source: Showalter Trust to JCF
Supplement of an egg‐containing formula in Thai elderly does not adversely affect blood lipid profiles
Authors: Mayurasakorn Korapat , Srichayet Phisamai , Mingpakanee Raveenan , Dahlan Winai
Published: June 2021

We developed (low carbohydrate, egg‐containing) formulas in a blended diet (BD) and determined their effects on blood lipoproteins and proteins after continuous six‐week feeding. 51 older participants (mean age 70.7±1.8 years), living at an elderly care center were randomly assigned into 3 groups: control (N=11), low‐carbohydrate‐low‐cholesterol‐formula group (LCL; n=25) and low‐carbohydrate‐high‐cholesterol‐formula group (LCH; n=15) Anthropometric and laboratory measurements were performed at wk‐1, wk‐3, wk‐6 with 8‐week‐run‐in period. Our data showed that 100 ml of BD in LCL arm provided 80.57 kcal (45%carb, 27%prot and 28%fat) with 17.01 mg of dietary cholesterol (dC), while the LCH arm provided 73.04 kcal (44%carb, 27%prot and 29% fat) with 50.87 mg of dC. When other items of daily dC were added, LCL received up to 223 mg/day while LCH received 373 mg/day, equivalent to 1–1.5 egg/day. There were no statistical differences in blood level of total cholesterol, triacylglycerol, LDL‐C, albumin and prealbumin (p >0.05) after BD diet. There were no differences in lipid and protein levels between LCL and LCH formula. However, BD diet continuously increased HDL levels by 1.38 mg every 3 weeks (95% CI: 0.204, 2.561). We conclude that in Thai elderly, addition of egg‐containing, low‐carbohydrate blenderized supplement improves HDL cholesterol levels without affecting LDL levels.

Supported by NRCT Grant No. 2550‐299

No conflict of interest.

Email: Drkorapat@hotmail.com