Extracellular vesicles (EVs) are produced by all domains of life. In Gram-negative bacteria, EVs are produced by the pinching off of the outer membrane; however, how EVs escape the thick cell walls ...of Gram-positive bacteria, mycobacteria and fungi is still unknown. Nonetheless, EVs have been described in a variety of cell-walled organisms, including Staphylococcus aureus, Mycobacterium tuberculosis and Cryptococcus neoformans. These EVs contain varied cargo, including nucleic acids, toxins, lipoproteins and enzymes, and have important roles in microbial physiology and pathogenesis. In this Review, we describe the current status of vesiculogenesis research in thick-walled microorganisms and discuss the cargo and functions associated with EVs in these species.
Here, we report a new nanoantenna for surface-enhanced infrared absorption (SEIRA) detection, consisting of a fan-shaped Au structure positioned at a well-specified distance above a reflective plane ...with an intervening silica spacer layer. We examine how to optimize both the antenna dimensions and the spacer layer for optimal SEIRA enhancement of the C–H stretching mode. This tunable 3D geometry yields a theoretical SEIRA enhancement factor of 105, corresponding to the experimental detection of 20–200 zeptomoles of octadecanethiol, using a standard commercial FTIR spectrometer. Experimental studies illustrate the sensitivity of the observed SEIRA signal to the gap dimensions. The optimized antenna structure exhibits an order of magnitude greater SEIRA sensitivity than previous record-setting designs.
Commentary: See one, do one, teach one…not anymore Brown, Lisa M.
The Journal of thoracic and cardiovascular surgery,
June 2020, 2020-Jun, 2020-06-00, 20200601, Letnik:
159, Številka:
6
Journal Article
Restrictions related to the 2019 novel coronavirus (COVID-19) pose unique and significant challenges for community-dwelling caregivers and people with dementia, including disrupted routines, a lack ...of structure, decreased access to respite care, and new or worsening safety issues related to interpersonal violence and hygiene. In addition to identifying issues confronting caregivers, the authors also describe possible ways to address some of these pressing concerns.
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•Toxicity and ubiquity of NAs in OSPW continues to drive concerted research efforts.•Research, monitoring plagued by lack of universal adoption of single analytical method.•NA ...recalcitrance to biodegradation by indigenous microorganisms firmly established.•Treatment strategy has evolved to advanced oxidation, attached growth bioreactors.
The Alberta oil sands contain one of the world’s largest reserves of oil – over 169 billion barrels of bitumen are economically recoverable with current extraction technologies. Surface mining and subsequent hot water extraction of bitumen from the ore generates about nine cubic meters of raw tailings per cubic meter of oil. Oil sands facilities are required to operate under a policy of zero water discharge, resulting in ponds containing more than one billion cubic meters of tailings, a mixture of sand, fines and process-affected water. Process-affected water contains numerous organic compounds, including naphthenic acids (NAs), which have been identified as the primary source of acute toxicity of process-affected water. Developments in analytical techniques, aerobic biodegradability, and treatment via chemical oxidation (ozone) of NAs are reviewed. The field continues to be challenged by the lack of a cost-effective, accurate analytical technique for NAs or an understanding of all the organic constituents in process-affected water that may be contributing to observed toxicity and thus requiring treatment.
Immunity of fleas (Order Siphonaptera) Brown, Lisa D.
Developmental and comparative immunology,
September 2019, 2019-09-00, 20190901, Letnik:
98
Journal Article
Recenzirano
The immune response of arthropod vectors plays a key role in the spread and transmission of vector-borne diseases. Although fleas transmit several human pathogens (e.g., Bartonella henselae, ...Rickettsia felis, R. typhi, and Yersinia pestis), few studies have examined how these vectors respond to infection. In hematophagous arthropods, imbibed pathogens must survive the hostile environment of blood meal digestion, which includes proteolytic digestive enzymes, protease inhibitors and expression of genes associated with protection of epithelial linings. Additionally, insect epithelial cells exhibit local immune defense against ingested pathogens by producing antimicrobial peptides and reactive oxygen species. This review details these and other aspects of insect immunity as it relates to fleas, with an emphasis on the gut immune response to two blood-borne pathogens, R. typhi and Y. pestis.
•The first barrier faced by a pathogen acquired with a blood meal is attachment to the gut to avoid excretion.•Infection modulates the transcription of digestive proteases.•Infection influences the transcription of serine protease inhibitors.•Defense mechanisms in the gut includes local production of AMPs and ROS.•The hemocoel can also be inhabited by pathogens and contains additional immune factors.
The development of antenna structures for surface-enhanced infrared absorption spectroscopy (SEIRA) is a topic of intense and growing interest for extending IR spectroscopy to zeptomolar quantities ...and ultimately to the single-molecule level. Here we show that strong infrared spectroscopic enhancements can be obtained from individual gold nanoantennas using conventional IR spectrometric sources. The antenna structure dimensions can be tuned to enhance the IR modes of specific chemical moieties. Simulations of the electric field intensity in the antenna junction region reveal a maximum SEIRA enhancement factor of more than 12 000. These findings open new opportunities for analyzing IR vibrations of exceptionally small quantities of molecules using widely accessible light sources.
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