Aggregation-based detection of M. smegmatis using<scp>d</scp>-arabinose-functionalized fluorescent silica nanoparticles

Jayawardana, Kalana W.; Wijesundera, Samurdhi A.; Yan, Mingdi

doi:10.1039/c5cc05772h

Cited by 17 publications

(8 citation statements)

References 30 publications

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“…In M. tuberculosis and M. smegmatis , polysaccharides containing arabinose are suggested to be involved in the aggregation of cells via interaction with Antigen 85s, which are homologs for corynomycolyl transferases [ 55 ]. Furthermore, arabinose was shown to promote the cell aggregation of M. smegmatis [ 56 ]. Therefore, excretion of polysaccharides or carbohydrate-containing compounds caused by sigD overexpression may induce cell aggregation also in C. glutamicum .…”

Section: Discussionmentioning

confidence: 99%

Physiological roles of sigma factor SigD in Corynebacterium glutamicum

et al. 2017

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BackgroundSigma factors are one of the components of RNA polymerase holoenzymes, and an essential factor of transcription initiation in bacteria. Corynebacterium glutamicum possesses seven genes coding for sigma factors, most of which have been studied to some detail; however, the role of SigD in transcriptional regulation in C. glutamicum has been mostly unknown.ResultsIn this work, pleiotropic effects of sigD overexpression at the level of phenotype, transcripts, proteins and metabolites were investigated. Overexpression of sigD decreased the growth rate of C. glutamicum cultures, and induced several physiological effects such as reduced culture foaming, turbid supernatant and cell aggregation. Upon overexpression of sigD, the level of Cmt1 (corynomycolyl transferase) in the supernatant was notably enhanced, and carbohydrate-containing compounds were excreted to the supernatant. The real-time PCR analysis revealed that sigD overexpression increased the expression of genes related to corynomycolic acid synthesis (fadD2, pks), genes encoding corynomycolyl transferases (cop1, cmt1, cmt2, cmt3), L, D-transpeptidase (lppS), a subunit of the major cell wall channel (porH), and the envelope lipid regulation factor (elrF). Furthermore, overexpression of sigD resulted in trehalose dicorynomycolate accumulation in the cell envelope.ConclusionsThis study demonstrated that SigD regulates the synthesis of corynomycolate and related compounds, and expanded the knowledge of regulatory functions of sigma factors in C. glutamicum.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-017-1067-6) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Physiological roles of sigma factor SigD in Corynebacterium glutamicum

et al. 2017

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“…Our future work will focus on combining the reported TU activation with optimization of AuNC uptake into bacteria, taking advantage of current work on modification of AuNC surface ligands that can target specific bacteria. 30,31,69…”

Section: Discussionmentioning

confidence: 99%

Activating the potent antimicrobial activities of gold nanoclusters against multidrug resistant Pseudomonas aeruginosa

Ndugire

Truong

Raviranga

et al. 2022

Preprint

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In this work we show that biological inactive gold nanoclusters (AuNCs) capped with D-maltose can be converted to antimicrobial AuI species by the addition of thiourea (TU). The antimicrobial activity mainly arises from the reaction of AuNCs with TU generating [Au(TU)2]Cl and small Au nanoclusters. Excess TU also maintains the oxidation state as AuI (vs. AuIII) which is key in maintaining activity. The AuNCs/TU combination was a powerful bactericidal agent against resistant bacteria, including multidrug-resistant (MDR) clinical isolates of Pseudomonas aeruginosa, and could eradicate S. epidermidis biofilm. It is unaffected by the efflux or bacterial outer membrane. The modes of action are multiple, including inhibition of thioredoxin reductase, CuI regulation interference and depletion of ATP. The formulation was 30-60 times less toxic on mammalian cells. This represents a new strategy enabling the antimicrobial activity of otherwise inactive AuNCs against the most difficult to treat MDR bacteria.

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“…Figure 4(D) shows the same size field-of-view for each imaging set-up, and clumps of M. smegmatis of various sizes are easily distinguishable. Due to the low pathogenicity, but similar cell-wall structure and morphology of M. smegmatis to M. tuberculosis it is widely accepted as an in vitro model for the latter [33], thus it was selected as the model organism within this study, and we anticipate that similar fluorescence intensity and resolution could be achieved in subsequent TB imaging studies, however this warrants further biological evaluation.…”

Section: Imaging With the Pdms Integrated Filtering Lensesmentioning

confidence: 99%

Frugal filtering optical lenses for point-of-care diagnostics

Long¹,

Parker²,

Ehrlich³

et al. 2020

Biomed. Opt. Express

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Infectious diseases are the leading cause of morbidity and mortality in low and middle income countries (LMICs). Rapid diagnosis of infections in LMICs presents many challenges, especially in rural areas where access to health care, including diagnostics, is poor. Microscopy is one of the most commonly used platforms to diagnose bacterial infections on clinical samples. Fluorescence microscopy has high sensitivity and specificity but to date is mostly performed within a laboratory setting due to the high-cost, low portability and highly specialist nature of equipment. Point-of-care diagnostics could offer a solution to the challenge of infection diagnosis in LMICs. In this paper we present frugal, easy to manufacture, doped polydimethylsiloxane filtering optical lenses that can be integrated into smartphone microscopes for immediate detection of fluorescently labelled bacteria. This provides a breakthrough technology platform for point-of-care diagnostics.

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Aggregation-based detection of M. smegmatis usingd-arabinose-functionalized fluorescent silica nanoparticles

Cited by 17 publications

References 30 publications

Physiological roles of sigma factor SigD in Corynebacterium glutamicum

Physiological roles of sigma factor SigD in Corynebacterium glutamicum

Activating the potent antimicrobial activities of gold nanoclusters against multidrug resistant Pseudomonas aeruginosa

Frugal filtering optical lenses for point-of-care diagnostics

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