Publications by authors named "Aaron Au"

Article Synopsis
  • The study highlights the importance of sensing and responding to osmotic changes for cellular integrity and identifies a relationship between the genes TSC22D2, WNK1, and NRBP1 in managing cell volume.
  • It was found that these gene families form biomolecular condensates within seconds of hyperosmotic stress, a process involving certain protein regions known as intrinsically disordered regions (IDRs).
  • The research suggests that co-evolution of these genes across metazoans has led to efficient regulation of rapid cell volume changes in response to osmolarity through new protein interactions.
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Salmonella utilizes a type 3 secretion system to translocate virulence proteins (effectors) into host cells during infection. The effectors modulate host cell machinery to drive uptake of the bacteria into vacuoles, where they can establish an intracellular replicative niche. A remarkable feature of Salmonella invasion is the formation of actin-rich protuberances (ruffles) on the host cell surface that contribute to bacterial uptake.

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Article Synopsis
  • A low-cost, portable telecentric digital holographic microscope (P-TDHM) has been developed using standard components.
  • * The system's hardware and software are designed to image various samples, including live cells, achieving high-quality quantitative phase images.
  • * The microscope offers impressive resolution in a compact design, making it suitable for use in resource-limited or remote settings.*
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Fouling at liquid-solid interfaces is a pernicious problem for a wide range of applications, including those that are implemented by digital microfluidics (DMF). There are several strategies that have been used to combat surface fouling in DMF, the most common being inclusion of amphiphilic surfactant additives in the droplets to be manipulated. Initial studies relied on Pluronic additives, and more recently, Tetronic additives have been used, which has allowed manipulation of complex samples like serum and whole blood.

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Digital holographic microscopy (DHM) has become an attractive imaging tool for the analysis of living cells and histological tissues. Telecentric DHM (TDHM) is a configuration of DHM that reduces the computational demands through a priori aberration corrections. However, TDHM requires a well-aligned optical pipeline to optimize its resolution and image quality (IQ), which has traditionally complicated the alignment process.

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Supercritical angle fluorescence (SAF) microscopy is a novel imaging tool based on the use of distance-dependent fluorophore emission patterns to provide accurate locations of fluorophores relative to a surface. This technique has been extensively used to construct accurate cellular images and to detect surface phenomena in a static environment. However, the capability of SAF microscopy in monitoring dynamic surface phenomena and changes in millisecond intervals is underexplored in the literature.

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NADPH/NADP redox state supports numerous reactions related to cell growth and survival; yet the full impact is difficult to appreciate due to organelle compartmentalization of NADPH and NADP. To study glucose-stimulated NADPH production in pancreatic beta-cell organelles, we targeted the Apollo-NADP sensor by first selecting the most pH-stable version of the single-color sensor. We subsequently targeted mTurquoise2-Apollo-NADP to various organelles and confirmed activity in the cytoplasm, mitochondrial matrix, nucleus, and peroxisome.

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The intercalated disc (ICD) is a unique membrane structure that is indispensable to normal heart function, yet its structural organization is not completely understood. Previously, we showed that the ICD-bound transmembrane protein 65 (Tmem65) was required for connexin43 (Cx43) localization and function in cultured mouse neonatal cardiomyocytes. Here, we investigate the functional and cellular effects of Tmem65 reductions on the myocardium in a mouse model by injecting CD1 mouse pups (3-7 days after birth) with recombinant adeno-associated virus 9 (rAAV9) harboring Tmem65 shRNA, which reduces Tmem65 expression by 90% in mouse ventricles compared to scrambled shRNA injection.

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Nematode parasites of humans, livestock and crops dramatically impact human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we exploit multiple motor outputs of the model nematode C.

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Precision-cut-tissues (PCTs), which preserve many aspects of a tissue's microenvironment, are typically imaged using conventional sample dishes and chambers. These can require large amounts of reagent and, when used for flow-through experiments, the shear forces applied on the tissues are often ill-defined. Their physical design also makes it difficult to image large volumes and repetitively image smaller regions of interest in the living slice.

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Fluorescence standards allow for quality control and for the comparison of data sets across instruments and laboratories in applications of quantitative fluorescence. For example, users of microscopy core facilities can expect a homogenous and time-invariant illumination and an uniform detection sensitivity, which are prerequisites for imaging analysis, tracking or fluorimetric pH or Ca -concentration measurements. Similarly, confirming the three-dimensional (3-D) resolution of optical sectioning microscopes calls for a regular calibration with a standardized point source.

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Article Synopsis
  • Recent advancements in cryo-EM technology have not been matched by improvements in specimen preparation methods, which still waste over 99.9% of the sample while creating thin films unsuitable for rapid studies.
  • New self-wicking EM grids enable quicker sample application and vitrification, reducing the time from seconds to milliseconds and minimizing sample loss.
  • A proposed device, using components from an ultrasonic humidifier and operated by a Raspberry Pi, simplifies the transfer of protein solutions to these grids, making it accessible for labs focused on cryo-EM development and customizable for specific experiments.
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A series of mono- and bis-salicylaldimine ligands and their corresponding Rh(i) complexes were prepared. The compounds were characterised using standard spectroscopic techniques including NMR, IR spectroscopy and mass spectrometry. The salicylaldimine ligands and complexes were screened for antiparasitic activity against two strains of Plasmodium falciparum i.

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New polynuclear organometallic Platinum Group Metal (PGM) complexes containing di- and tripyridyl ester ligands have been synthesised and characterised using analytical and spectroscopic techniques including (1)H, (13)C NMR and infrared spectroscopy. Reaction of these polypyridyl ester ligands with either [Ru(p-cymene)Cl2]2, [Rh(C5Me5)Cl2]2 or [Ir(C5Me5)Cl2]2 dimers yielded the corresponding di- or trinuclear organometallic complexes. The polyaromatic ester ligands act as monodentate donors to each metal centre and this coordination mode was confirmed upon elucidation of the molecular structures for two of the dinuclear complexes.

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A series of mono- and multimeric 4-amino-7-chloroquinoline and ferrocenyl thioureas have been prepared by the reaction of a 7-chloroquinoline methyl ester and a ferrocenylimine methyl ester with various amines. These compounds were characterized using standard spectroscopic and analytical techniques. The compounds were evaluated against the NF54 (CQ-sensitive) and Dd2 (CQ-resistant) strains of Plasmodium falciparum.

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In the present study, we carried out a structure-activity analysis in Trichomonas vaginalis of a series of adenosine and uridine analogues. The most potent compounds were found to be 2' and 3' modified adenosine analogues some of which are potent inhibitors of S-adenosylhomocysteine hydrolase. The 9-(2-deoxy-2-fluoro-β,D-arabinofuranosyl)adenine compound was more potent than metronidazole, a current FDA approved and commonly prescribed drug for treatment of trichomoniasis.

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