scholarly journals ABC transporter content diversity inStreptococcus pneumoniaeimpacts competence regulation and bacteriocin production

2018 ◽  
Vol 115 (25) ◽  
pp. E5776-E5785 ◽  
Author(s):  
Charles Y. Wang ◽  
Nisha Patel ◽  
Wei-Yun Wholey ◽  
Suzanne Dawid
Keyword(s):  
Abc Transporters ◽  
Opportunistic Pathogen ◽  
Bacteriocin Production ◽  
Genetic Competence ◽  
Full Extent ◽  
Sensing Systems ◽  
Kinetics Of ◽  
Transporter Expression ◽  
Natural Genetic Competence ◽  
Dna Acquisition

The opportunistic pathogenStreptococcus pneumoniae(pneumococcus) uses natural genetic competence to increase its adaptability through horizontal gene transfer. One method of acquiring DNA is through predation of neighboring strains with antimicrobial peptides called “bacteriocins.” Competence and production of the major family of pneumococcal bacteriocins, pneumocins, are regulated by the quorum-sensing systemscomandblp, respectively. In the classical paradigm, the ABC transporters ComAB and BlpAB each secretes its own system’s signaling pheromone and in the case of BlpAB also secretes the pneumocins. While ComAB is found in all pneumococci, only 25% of strains encode an intact version of BlpAB [BlpAB(+)] while the rest do not [BlpAB(−)]. Contrary to the classical paradigm, it was previously shown that BlpAB(−) strains can activateblpthrough ComAB-mediated secretion of theblppheromone during brief periods of competence. To better understand the full extent ofcom-blpcrosstalk, we examined the contribution of each transporter to competence development and pneumocin secretion. We found that BlpAB(+) strains have a greater capacity for competence activation through BlpAB-mediated secretion of thecompheromone. Similarly, we show that ComAB and BlpAB are promiscuous and both can secrete pneumocins. Consequently, differences in pneumocin secretion between BlpAB(+) and BlpAB(−) strains derive from the regulation and kinetics of transporter expression rather than substrate specificity. We speculate that BlpAB(−) strains (opportunists) use pneumocins mainly in a narrowly tailored role for DNA acquisition and defense during competence while BlpAB(+) strains (aggressors) expand their use for the general inhibition of rival strains.

Effect of Neuroinflammation on ABC Transporters: Possible Contribution to Refractory Epilepsy

2018 ◽  
Vol 17 (10) ◽  
pp. 728-735 ◽  
Author(s):  
Xiaolin Deng ◽  
Yangmei Xie ◽  
Yinghui Chen
Keyword(s):  
Antiepileptic Drugs ◽  
Abc Transporters ◽  
Refractory Epilepsy ◽  
Vascular Endothelial Cells ◽  
Efflux Transporters ◽  
Vascular Endothelial ◽  
Intracellular Signalling Pathways ◽  
The Brain ◽  
Transporter Expression

Background & Objective: Epilepsy is a common and serious chronic neurological disorder that is mainly treated with antiepileptic drugs. Although current antiepileptic drugs used in clinical practice have advanced to the third generation, approximately one-third of patients are refractory to these treatments. More efficacious treatments for refractory epilepsy are therefore needed. A better understanding of the mechanism underlying refractory epilepsy is likely to facilitate the development of a more effective therapy. The abnormal expression and/or dysfunction of efflux transporters, particularly ABC transporters, might contribute to certain cases of refractory epilepsy. Inflammation in the brain has recently been shown to regulate the expression and/or function of ABC transporters in the cerebral vascular endothelial cells and glia of the blood-brain barrier by activating intracellular signalling pathways. Conclusion: Therefore, in this review, we will briefly summarize recent research advances regarding the possible role of neuroinflammation in regulating ABC transporter expression in epilepsy.

scholarly journals Identification and Characterization of Quorum-Quenching Activity of N-Acylhomoserine Lactonase from Coagulase-Negative Staphylococci

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 483
Author(s):  
Tomohiro Morohoshi ◽  
Yaoki Kamimura ◽  
Nobutaka Someya
Keyword(s):  
Quorum Sensing ◽  
Opportunistic Pathogen ◽  
Quorum Quenching ◽  
Coagulase Negative Staphylococci ◽  
Sensing Systems ◽  
Genes Encoding ◽  
Acyl Chains ◽  
Gene Homologue ◽  
Identification And Characterization

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signals in Gram-negative bacteria. Many genes encoding AHL-degrading enzymes have been cloned and characterized in various microorganisms. Coagulase-negative staphylococci (CNS) are present on the skin of animals and are considered low-virulent species. The AHL-lactonase gene homologue, ahlS, was present in the genomes of the CNS strains Staphylococcus carnosus, Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus sciuri. We cloned the candidate ahlS homologue from six CNS strains into the pBBR1MCS5 vector. AhlS from the CNS strains showed a higher degrading activity against AHLs with short acyl chains compared to those with long acyl chains. AhlS from S. sciuri was expressed and purified as a maltose-binding protein (MBP) fusion. Pseudomonas aeruginosa is an opportunistic pathogen that regulates several virulence factors such as elastase and pyocyanin by quorum-sensing systems. When MBP-AhlS was added to the culture of P. aeruginosa PAO1, pyocyanin production and elastase activity were substantially reduced compared to those in untreated PAO1. These results demonstrate that the AHL-degrading activity of AhlS from the CNS strains can inhibit quorum sensing in P. aeruginosa PAO1.

scholarly journals Regulation of Quorum Sensing by RpoS inPseudomonas aeruginosa

2000 ◽  
Vol 182 (15) ◽  
pp. 4356-4360 ◽  
Author(s):  
Marvin Whiteley ◽  
Matthew R. Parsek ◽  
E. P. Greenberg
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Gene Transcription ◽  
Opportunistic Pathogen ◽  
Null Mutant ◽  
Global Regulators ◽  
Acylhomoserine Lactone ◽  
Sensing Systems

ABSTRACT The LasR-LasI and RhlR-RhlI quorum-sensing systems are global regulators of gene expression in the opportunistic pathogenPseudomonas aeruginosa. Previous studies suggest that the RhlR-RhlI system activates expression of rpoS. We constructed merodiploid strains of P. aeruginosa containing the native rpoS gene and an rpoS-lacZ fusion. Studies of lacZ transcription in these strains indicated that rpoS was not regulated by RhlR-RhlI. We also generated an rpoS null mutant. This rpoS mutant showed elevated levels of rhlI (but not rhlR) transcription, elevated levels of the RhlI-generated acylhomoserine lactone quorum-sensing signal, and elevated levels of RhlR-RhlI-regulated gene transcription. These findings indicate that there is a relationship between RpoS and quorum sensing, but rather than the RhlR-RhlI system influencing the expression ofrpoS, it appears that RpoS regulates rhlI.

scholarly journals Tension-activated channels in the mechanism of osmotic fitness in Pseudomonas aeruginosa

2017 ◽  
Vol 149 (5) ◽  
pp. 595-609 ◽  
Author(s):  
Uğur Çetiner ◽  
Ian Rowe ◽  
Anthony Schams ◽  
Christina Mayhew ◽  
Deanna Rubin ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Opportunistic Pathogen ◽  
High Rate ◽  
Cloning And Expression ◽  
Osmotic Swelling ◽  
Excised Patches ◽  
Dilution Experiments ◽  
Kinetics Of ◽  
Flow Experiments ◽  
Mechanical Rupture

Pseudomonas aeruginosa (PA) is an opportunistic pathogen with an exceptional ability to adapt to a range of environments. Part of its adaptive potential is the ability to survive drastic osmolarity changes. Upon a sudden dilution of external medium, such as during exposure to rain, bacteria evade mechanical rupture by engaging tension-activated channels that act as osmolyte release valves. In this study, we compare fast osmotic permeability responses in suspensions of wild-type PA and Escherichia coli (EC) strains in stopped-flow experiments and provide electrophysiological descriptions of osmotic-release channels in PA. Using osmotic dilution experiments, we first show that PA tolerates a broader range of shocks than EC. We record the kinetics of cell equilibration reported by light scattering responses to osmotic up- and down-shocks. PA exhibits a lower water permeability and faster osmolyte release rates during large osmotic dilutions than EC, which correlates with better survival. To directly characterize the PA tension-activated channels, we generate giant spheroplasts from this microorganism and record current responses in excised patches. Unlike EC, which relies primarily on two types of channels, EcMscS and EcMscL, to generate a distinctive two-wave pressure ramp response, PA exhibits a more gradual response that is dominated by MscL-type channels. Genome analysis, cloning, and expression reveal that PA possesses one MscL-type (PaMscL) and two MscS-type (PaMscS-1 and 2) proteins. In EC spheroplasts, both PaMscS channels exhibit a slightly earlier activation by pressure compared with EcMscS. Unitary currents reveal that PaMscS-2 has a smaller conductance, higher anionic preference, stronger inactivation, and slower recovery compared with PaMscS-1. We conclude that PA relies on MscL as the major valve defining a high rate of osmolyte release sufficient to curb osmotic swelling under extreme shocks, but it still requires MscS-type channels with a strong propensity to inactivation to properly terminate massive permeability response.

Growth and bacteriocin production kinetics of Leuconostoc mesenteroides E131

2005 ◽  
Vol 99 (6) ◽  
pp. 1314-1323 ◽  
Author(s):  
E.H. Drosinos ◽  
M. Mataragas ◽  
P. Nasis ◽  
M. Galiotou ◽  
J. Metaxopoulos
Keyword(s):  
Leuconostoc Mesenteroides ◽  
Bacteriocin Production ◽  
Production Kinetics ◽  
Kinetics Of

Biphasic kinetics of growth and bacteriocin production with Lactobacillus amylovorus DCE 471 occur under stress conditions

Microbiology ◽  
2003 ◽  
Vol 149 (4) ◽  
pp. 1073-1082 ◽  
Author(s):  
Patricia Neysens ◽  
Winy Messens ◽  
Dirk Gevers ◽  
Jean Swings ◽  
Luc De Vuyst
Keyword(s):  
Bacteriocin Production ◽  
Stress Conditions ◽  
Biphasic Kinetics ◽  
Lactobacillus Amylovorus ◽  
Kinetics Of

scholarly journals Natural Competence in Thermoanaerobacter and Thermoanaerobacterium Species

2010 ◽  
Vol 76 (14) ◽  
pp. 4713-4719 ◽  
Author(s):  
A. Joe Shaw ◽  
David A. Hogsett ◽  
Lee R. Lynd
Keyword(s):  
Genetic Engineering ◽  
Exponential Growth Phase ◽  
Genetic Competence ◽  
Natural Competence ◽  
Relative Ease ◽  
Type Iv ◽  
Thermoanaerobacterium Saccharolyticum ◽  
Foreign Dna ◽  
Natural Genetic Competence ◽  
Dna Incorporation

ABSTRACT Low-G+C thermophilic obligate anaerobes in the class Clostridia are considered among the bacteria most resistant to genetic engineering due to the difficulty of introducing foreign DNA, thus limiting the ability to study and exploit their native hydrolytic and fermentative capabilities. Here, we report evidence of natural genetic competence in 13 Thermoanaerobacter and Thermoanaerobacterium strains previously believed to be difficult to transform or genetically recalcitrant. In Thermoanaerobacterium saccharolyticum JW/SL-YS485, natural competence-mediated DNA incorporation occurs during the exponential growth phase with both replicating plasmid and homologous recombination-based integration, and circular or linear DNA. In T. saccharolyticum, disruptions of genes similar to comEA, comEC, and a type IV pilus (T4P) gene operon result in strains unable to incorporate further DNA, suggesting that natural competence occurs via a conserved Gram-positive mechanism. The relative ease of employing natural competence for gene transfer should foster genetic engineering in these industrially relevant organisms, and understanding the mechanisms underlying natural competence may be useful in increasing the applicability of genetic tools to difficult-to-transform organisms.

scholarly journals Inflammation Induces Changes in the Functional Expression of P-gp, BCRP, and MRP2: An Overview of Different Models and Consequences for Drug Disposition

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1544
Author(s):  
Sonia Saib ◽  
Xavier Delavenne
Keyword(s):  
Abc Transporters ◽  
Drug Exposure ◽  
Drug Disposition ◽  
Therapeutic Index ◽  
Functional Expression ◽  
In Vivo Models ◽  
Inflammatory Conditions ◽  
Transporter Expression

The ATP-binding cassette (ABC) transporters play a key role in drug pharmacokinetics. These membrane transporters expressed within physiological barriers can be a source of pharmacokinetic variability. Changes in ABC transporter expression and functionality may consequently affect the disposition of substrate drugs, resulting in different drug exposure. Inflammation, present in several acute and chronic diseases, has been identified as a source of modulation in drug transporter expression leading to variability in drug response. Its regulation may be particularly dangerous for drugs with a narrow therapeutic index. In this context, numerous in vitro and in vivo models have shown up- or downregulation in the expression and functionality of ABC transporters under inflammatory conditions. Nevertheless, the existence of contradictory data and the lack of standardization for the models used have led to a less conclusive interpretation of these data.

scholarly journals Natural Genetic Competence in Bacillus subtilis Natto OK2

2000 ◽  
Vol 182 (9) ◽  
pp. 2411-2415 ◽  
Author(s):  
Sayaka Ashikaga ◽  
Hideaki Nanamiya ◽  
Yoshiaki Ohashi ◽  
Fujio Kawamura
Keyword(s):  
Bacillus Subtilis ◽  
Base Change ◽  
Competence Development ◽  
Transformation Frequency ◽  
Genetic Competence ◽  
Natural Competence ◽  
Bacillus Subtilis Natto ◽  
High Transformation ◽  
Single Base Change ◽  
Natural Genetic Competence

ABSTRACT We isolated a Bacillus subtilis natto strain, designated OK2, from a lot of commercial fermented soybean natto and studied its ability to undergo natural competence development using acomG-lacZ fusion at the amyE locus. Although transcription of the late competence genes was not detected in theB. subtilis natto strain OK2 during competence development, these genes were constitutively transcribed in the OK2 strain carrying either the mecA or the clpC mutation derived from B. subtilis 168. In addition, both OK2 mutants exhibited high transformation frequencies, comparable with that observed for B. subtilis 168. Moreover, as expected from these results, overproduction of ComK derived from strain 168 in strain OK2 resulted in a high transformation frequency as well as in induction of the late competence genes. These results clearly indicated that ComK produced in both the mecA and clpC mutants of strain OK2 (ComKOK2) could activate the transcription of the whole set of late competence genes and suggested that ComKOK2 was not activated in strain OK2 during competence development. We therefore sequenced the comS gene of OK2 and compared it with that of 168. The comS OK2had a single-base change, resulting in the replacement of Ser (strain 168) by Cys (strain OK2) at position 11.

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