Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity

AbstractThe spread of multidrug-resistance in Gram-negative bacterial pathogens presents a major clinical challenge, and new approaches are required to combat these organisms. Nitric oxide (NO) is a well-known antimicrobial that is produced by the immune system in response to infection, and numerous studies have demonstrated that NO is a respiratory inhibitor with both bacteriostatic and bactericidal properties. However, given that loss of aerobic respiratory complexes is known to diminish antibiotic efficacy, it was hypothesised that the potent respiratory inhibitor NO would elicit similar effects. Indeed, the current work demonstrates that pre-exposure to NO-releasers elicits a > tenfold increase in IC50 for gentamicin against pathogenic E. coli (i.e. a huge decrease in lethality). It was therefore hypothesised that hyper-sensitivity to NO may have arisen in bacterial pathogens and that this trait could promote the acquisition of antibiotic-resistance mechanisms through enabling cells to persist in the presence of toxic levels of antibiotic. To test this hypothesis, genomics and microbiological approaches were used to screen a collection of E. coli clinical isolates for antibiotic susceptibility and NO tolerance, although the data did not support a correlation between increased carriage of antibiotic resistance genes and NO tolerance. However, the current work has important implications for how antibiotic susceptibility might be measured in future (i.e. ± NO) and underlines the evolutionary advantage for bacterial pathogens to maintain tolerance to toxic levels of NO.

Download Full-text

Isolation of a respiratory inhibitor from alfalfa

Archives of Biochemistry and Biophysics ◽

10.1016/0003-9861(59)90602-2 ◽

1959 ◽

Vol 84 (2) ◽

pp. 405-410 ◽

Cited By ~ 10

Author(s):

Ralph A. Shaw ◽

Horace D. Jackson

Keyword(s):

Respiratory Inhibitor

Download Full-text

Transcriptome Changes in Mycoplasma hyopneumoniae during Infection

Infection and Immunity ◽

10.1128/iai.01291-07 ◽

2007 ◽

Vol 76 (2) ◽

pp. 658-663 ◽

Cited By ~ 34

Author(s):

Melissa L. Madsen ◽

Supraja Puttamreddy ◽

Eileen L. Thacker ◽

Michael D. Carruthers ◽

F. Chris Minion

Keyword(s):

Elongation Factor ◽

Mycoplasma Hyopneumoniae ◽

Trna Synthetase ◽

Messenger Rnas ◽

Reading Frame ◽

Polymerase Beta ◽

Glycerol Transport ◽

Transcriptional Changes ◽

Bronchial Alveolar Lavage

ABSTRACT Mycoplasma hyopneumoniae causes swine pneumonia and contributes significantly to the porcine respiratory disease complex. The mechanisms of pathogenesis are difficult to address, since there is a lack of genetic tools, but microarrays are available and can be used to study transcriptional changes that occur during disease as a way to identify important virulence-related genes. Mycoplasmas were collected from bronchial alveolar lavage samples and compared to broth-grown cells using microarrays. Bronchial alveolar lavage was performed on pigs 28 days postinfection, and mycoplasmas were isolated by differential centrifugation. Mycoplasma RNA-enriched preparations were then obtained from total RNA by subtracting eucaryotic ribosomal and messenger RNAs. Labeled cDNAs were generated with mycoplasma open reading frame-specific primers. Nine biological replicates were analyzed. During lung infection, our analysis indicated that 79 M. hyopneumoniae genes were differentially expressed (P < 0.01), at a false-discovery rate of <2.7%. Of the down-regulated genes, 28 of 46 (61%) lacked an assigned function, in comparison to 21 of 33 (63%) of up-regulated genes. Four down-regulated genes and two up-regulated genes encoded putative lipoproteins. secA (mhp295) (P = 0.003) and two glycerol transport permease genes (potA [mhp380; P = 0.006] and ugpA [mhp381; P = 0.003]) were up-regulated in vivo. Elongation factor EF-G (fusA [mhp083]) (P = 0.002), RNA polymerase beta chain (rpoC [mhp635]) (P = 0.003), adenylate kinase (adk [mhp208]) (P = 0.001), prolyl aminoacyl tRNA synthetase (proS [mhp397]) (P = 0.009), and cysteinyl-tRNA synthetase (cysS [mhp661]) (P < 0.001) were down-regulated in vivo.

Download Full-text

Inhibition of aquaporin-3 in macrophages by a monoclonal antibody as potential therapy for liver injury

Nature Communications ◽

10.1038/s41467-020-19491-5 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Mariko Hara-Chikuma ◽

Manami Tanaka ◽

Alan S. Verkman ◽

Masato Yasui

Keyword(s):

Monoclonal Antibody ◽

Liver Injury ◽

Macrophage Activation ◽

Cell Activation ◽

Stellate Cell ◽

Nuclear Factor Κb ◽

Activated Macrophages ◽

Aquaporin 3 ◽

Glycerol Transport ◽

Water Glycerol

Abstract Aquaporin 3 (AQP3) is a transporter of water, glycerol and hydrogen peroxide (H2O2) that is expressed in various epithelial cells and in macrophages. Here, we developed an anti-AQP3 monoclonal antibody (mAb) that inhibited AQP3-facilitated H2O2 and glycerol transport, and prevented liver injury in experimental animal models. Using AQP3 knockout mice in a model of liver injury and fibrosis produced by CCl4, we obtained evidence for involvement of AQP3 expression in nuclear factor-κB (NF-κB) cell signaling, hepatic oxidative stress and inflammation in macrophages during liver injury. The activated macrophages caused stellate cell activation, leading to liver injury, by a mechanism involving AQP3-mediated H2O2 transport. Administration of an anti-AQP3 mAb, which targeted an extracellular epitope on AQP3, prevented liver injury by inhibition of AQP3-mediated H2O2 transport and macrophage activation. These findings implicate the involvement of macrophage AQP3 in liver injury, and provide evidence for mAb inhibition of AQP3-mediated H2O2 transport as therapy for macrophage-dependent liver injury.

Download Full-text

The thermodynamics of water and glycerol transport in biological cells during freezing

Cryobiology ◽

10.1016/0011-2240(75)90142-x ◽

1975 ◽

Vol 12 (6) ◽

pp. 585-586

Author(s):

W.M. Toscano ◽

E.G. Cravalho ◽

C.E. Huggins

Keyword(s):

Biological Cells ◽

Glycerol Transport

Download Full-text

Purification and Functional Reconstitution of Soybean Nodulin 26. An Aquaporin with Water and Glycerol Transport Properties†

Biochemistry ◽

10.1021/bi982110c ◽

1999 ◽

Vol 38 (1) ◽

pp. 347-353 ◽

Cited By ~ 119

Author(s):

Robert M. Dean ◽

Ricky L. Rivers ◽

Mark L. Zeidel ◽

Daniel M. Roberts

Keyword(s):

Transport Properties ◽

Glycerol Transport

Download Full-text

Genetic basis of dormancy and differential response to sodium azide in Avena fatua seeds

Canadian Journal of Botany ◽

10.1139/b88-089 ◽

1988 ◽

Vol 66 (4) ◽

pp. 635-641 ◽

Cited By ~ 12

Author(s):

S. Jana ◽

M. K. Upadhyaya ◽

S. N. Acharya

Keyword(s):

Sodium Azide ◽

Time Course ◽

Genetic Basis ◽

Differential Response ◽

Avena Fatua ◽

Maternal Influence ◽

Maternal Parent ◽

Wild Oats ◽

Respiratory Inhibitor ◽

Pure Lines

Seven crosses, involving either nondormant × dormant or dormant × dormant pure lines of wild oats (Avena fatua L.), were made. Selfing of the hybrid and further hybridization were carried out to produce the F2 and reciprocal backcross generations. The seed germination time-course curves of the parents, their F1, and segregating generations over a 20-week period were studied. Differences in time course of germination in these generations were interpreted in terms of a minimum of three interacting loci. Two pure lines, AN51 and MO73, differed in their response to sodium azide, a respiratory inhibitor, with the former being more responsive. In crosses between these lines, the F1 seeds were also more responsive when AN51 was used as the maternal parent. This differential response of two dormant pure lines and their reciprocal F1s suggests maternal influence in germination response to sodium azide.

Download Full-text

Evidence that the blockade of mitochondrial respiration by the neurotoxin 1-methyl-4-phenylpyridinium (MPP+) involves binding at the same site as the respiratory inhibitor, rotenone

Biochemical and Biophysical Research Communications ◽

10.1016/0006-291x(90)91442-u ◽

1990 ◽

Vol 169 (1) ◽

pp. 123-128 ◽

Cited By ~ 57

Author(s):

Matthew J. Krueger ◽

Thomas P. Singer ◽

John E. Casida ◽

Rona R. Ramsay

Keyword(s):

Mitochondrial Respiration ◽

Respiratory Inhibitor

Download Full-text

The Induction of Lysosomal Enzyme Release from Leucocytes of Normal and Emphysematous Subjects and the Effects of Tobacco Smoke upon Phagocytosis

Clinical Science ◽

10.1042/cs0580403 ◽

1980 ◽

Vol 58 (5) ◽

pp. 403-409 ◽

Cited By ~ 2

Author(s):

D. C. S. Hutchison ◽

R. Desai ◽

D. Bellamy ◽

H. Baum

Keyword(s):

Cigarette Smoke ◽

Lysosomal Enzyme ◽

Lysosomal Enzymes ◽

Soluble Fraction ◽

Normal Subjects ◽

Polymorphonuclear Leucocytes ◽

Enzyme Release ◽

Elastic Tissue ◽

Latex Particles ◽

Respiratory Inhibitor

1. The lysosomal enzymes of circulating polymorphonuclear leucocytes contain a potent elastase; release of this enzyme within the lung is thought to be responsible for the destruction of elastic tissue in pulmonary emphysema. 2. The release of lysosomal enzymes from blood leucocytes of normal and emphysematous subjects during phagocytosis of particulate material was studied In vitro. Acid phosphatase and acid ribonuclease were used as markers of lysosomal enzyme release, no sufficiently sensitive assay for elastase being available. Cigarette smoke was separated into ‘particulate’ and ‘soluble’ fractions. In a preliminary study, the particulate fraction stimulated enzyme release; in the experiments reported here, latex particles were used to produce this effect. 3. Approximately one-third of the total lysosomal enzyme content was released to the exterior of the cell during phagocytosis of latex particles. In this respect there was no difference between normal and emphysematous subjects. 4. The effects of the non-particulate soluble fraction of cigarette smoke on phagocytosis-induced enzyme release were studied. This fraction inhibited enzyme release from polymorphonuclear leucocytes of normal subjects but not from those of emphysematous patients. When the ‘cigarette-smoke solution’ was replaced by the respiratory inhibitor, antimycin A, a similar inhibition of enzyme release occurred. The inhibition of phagocytosis in cells of normal subjects is presumed to be due to a respiratory inhibitor such as carbon monoxide in the soluble fraction of the smoke. We postulate that the polymorphonuclear leucocytes of emphysematous patients are adapted to hypoxic conditions so that inhibition of enzyme release does not occur.

Download Full-text