Publications by authors named "Naomi E Kramer"

Brominated flame retardants are used in many household products to reduce flammability, but often leach into the surrounding environment over time. Hexabromocyclododecane (HBCD) is a brominated flame retardant detected in human blood across the world. HBCD exposure can result in neurological problems and altered lipid metabolism, but to date, the two remain unlinked.

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Brominated flame retardants (BFRs) reduce flammability in a wide range of products including electronics, carpets, and paint, but leach into the environment to result in continuous, population-level exposure. Epidemiology studies have correlated BFR exposure with neurological problems, including alterations in learning and memory. This study investigated the molecular mechanisms mediating BFR-induced cell death in hippocampal cells and clarified the impact of hexabromocyclododecane (HBCD) exposure on gene transcription in the hippocampus, dorsal striatum, and frontal cortex of male mice.

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Article Synopsis
  • Over the last 20 years, two dangerous viruses (SARS-CoV-1 and SARS-CoV-2) were discovered to jump from animals to humans, causing serious illness and highlighting the need for new medicines to fight them.
  • Scientists studied a specific part of a bat coronavirus (PLpro) to understand how these viruses work and what makes them different, which could help in creating better treatments.
  • They developed 30 new drug-like compounds that could block the action of PLpro in these viruses and ran tests to see how effective and safe these new medicines might be.
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Brominated flame retardants (BFRs) are environmentally persistent, are detected in humans, and some have been banned due to their potential toxicity. BFRs are developmental neurotoxicants and endocrine disruptors; however, few studies have explored their potential nephrotoxicity. We addressed this gap in the literature by determining the toxicity of three different BFRs (tetrabromobisphenol A (TBBPA), hexabromocyclododecane (HBCD), and tetrabromodiphenyl ether (BDE-47)) in rat (NRK 52E) and human (HK-2 and RPTEC) tubular epithelial cells.

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Like other epithelial cells, taste bud cells have a short life span and undergo continuous turnover. An active stem or progenitor cell niche is essential for taste bud formation and maintenance. Early taste bud cells have a life span of ~4 days on average in chicken hatchlings when taste buds grow rapidly and undergo maturation.

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Article Synopsis
  • Taste is super important because it helps us choose what foods to eat and feel hungry.
  • Chickens might not have as many taste buds as we thought, but new studies show they actually have a pretty good taste system.
  • Understanding how chickens taste food can help farmers make better feeding practices for raising livestock.
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Nisin is a post-translationally modified antimicrobial peptide produced by Lactococcus lactis which binds to lipid II in the membrane to form pores and inhibit cell-wall synthesis. A nisin-resistant (Nis(R)) strain of L. lactis, which is able to grow at a 75-fold higher nisin concentration than its parent strain, was investigated with respect to changes in the cell wall.

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Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II-targeted lantibiotics are too short to be able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis.

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Article Synopsis
  • Nisin is a type of peptide made by a bacteria called Lactococcus lactis and is used to keep food fresh.
  • Some bacteria are becoming resistant to nisin, but scientists don’t fully understand how this happens.
  • Researchers studied the genes of different L. lactis strains and found that changes in certain genes help bacteria resist nisin in different ways, like keeping it from entering their cells or making their surroundings less acidic.
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Background: In research laboratories using DNA-microarrays, usually a number of researchers perform experiments, each generating possible sources of error. There is a need for a quick and robust method to assess data quality and sources of errors in DNA-microarray experiments. To this end, a novel and cost-effective validation scheme was devised, implemented, and employed.

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Lipid II is essential for nisin-mediated pore formation at nano-molar concentrations. We tested whether nisin resistance could result from different Lipid II levels, by comparing the maximal Lipid II pool in Micrococcus flavus (sensitive) and Listeria monocytogenes (relatively insensitive) and their nisin-resistant variants, with a newly developed method. No correlation was observed between the maximal Lipid II pool and nisin sensitivity, as was further corroborated by using spheroplasts of nisin-resistant and wild-type strains of M.

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Several complete genome sequences of Lactococcus lactis and their annotations will become available in the near future, next to the already published genome sequence of L. lactis ssp. lactis IL 1403.

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