scholarly journals Role of Spore Coat Proteins in the Resistance of Bacillus subtilis Spores to Caenorhabditis elegans Predation

2008 ◽  
Vol 190 (18) ◽  
pp. 6197-6203 ◽  
Author(s):  
Maria-Halima Laaberki ◽  
Jonathan Dworkin
Keyword(s):  
Bacillus Subtilis ◽  
Caenorhabditis Elegans ◽  
Spore Coat ◽  
Coat Proteins ◽  
Host Interaction ◽  
Wide Range ◽  
In The Wild

ABSTRACT Bacterial spores are resistant to a wide range of chemical and physical insults that are normally lethal for the vegetative form of the bacterium. While the integrity of the protein coat of the spore is crucial for spore survival in vitro, far less is known about how the coat provides protection in vivo against predation by ecologically relevant hosts. In particular, assays had characterized the in vitro resistance of spores to peptidoglycan-hydrolyzing enzymes like lysozyme that are also important effectors of innate immunity in a wide variety of hosts. Here, we use the bacteriovorous nematode Caenorhabditis elegans, a likely predator of Bacillus spores in the wild, to characterize the role of the spore coat in an ecologically relevant spore-host interaction. We found that ingested wild-type Bacillus subtilis spores were resistant to worm digestion, whereas vegetative forms of the bacterium were efficiently digested by the nematode. Using B. subtilis strains carrying mutations in spore coat genes, we observed a correlation between the degree of alteration of the spore coat assembly and the susceptibility to the worm degradation. Surprisingly, we found that the spores that were resistant to lysozyme in vitro can be sensitive to C. elegans digestion depending on the extent of the spore coat structure modifications.

scholarly journals SpoVID Guides SafA to the Spore Coat inBacillus subtilis

2001 ◽  
Vol 183 (10) ◽  
pp. 3041-3049 ◽  
Author(s):  
Amanda J. Ozin ◽  
Craig S. Samford ◽  
Adriano O. Henriques ◽  
Charles P. Moran
Keyword(s):  
Direct Interaction ◽  
Spore Coat ◽  
Coat Proteins ◽  
Yeast Two Hybrid System ◽  
Spore Coat Proteins ◽  
Basement Layer ◽  
Two Hybrid ◽  
Spore Coat Protein

ABSTRACT Bacteria assemble complex structures by targeting proteins to specific subcellular locations. The protein coat that encasesBacillus subtilis spores is an example of a structure that requires coordinated targeting and assembly of more than 24 polypeptides. The earliest stages of coat assembly require the action of three morphogenetic proteins: SpoIVA, CotE, and SpoVID. In the first steps, a basement layer of SpoIVA forms around the surface of the forespore, guiding the subsequent positioning of a ring of CotE protein about 75 nm from the forespore surface. SpoVID localizes near the forespore membrane where it functions to maintain the integrity of the CotE ring and to anchor the nascent coat to the underlying spore structures. However, it is not known which spore coat proteins interact directly with SpoVID. In this study we examined the interaction between SpoVID and another spore coat protein, SafA, in vivo using the yeast two-hybrid system and in vitro. We found evidence that SpoVID and SafA directly interact and that SafA interacts with itself. Immunofluorescence microscopy showed that SafA localized around the forespore early during coat assembly and that this localization of SafA was dependent on SpoVID. Moreover, targeting of SafA to the forespore was also dependent on SpoIVA, as was targeting of SpoVID to the forespore. We suggest that the localization of SafA to the spore coat requires direct interaction with SpoVID.

scholarly journals Subinhibitory Antimicrobial Concentrations: A Review of In Vitro and In Vivo Data

1992 ◽  
Vol 3 (4) ◽  
pp. 193-201 ◽  
Author(s):  
George G Zhanel ◽  
Daryl J Hoban ◽  
Godfrey KM Harding
Keyword(s):  
Antimicrobial Activity ◽  
Animal Studies ◽  
Molecular Level ◽  
Bacterial Virulence ◽  
Antibacterial Effects ◽  
Wide Range ◽  
Immune Defences

Antimicrobial activity is not an ‘all or none’ effect. An increase in the rate and extent of antimicrobial action is usually observed over a wide range of antimicrobial concentrations. Subinhibitory antimicrobial concentrations are well known to produce significant antibacterial effects, and various antimicrobials at subinhibitory concentrations have been reported to inhibit the rate of bacterial growth. Bacterial virulence may be increased or decreased by subinhibitory antimicrobial concentrations by changes in the ability of bacteria to adhere to epithelial cells or by alterations in bacterial susceptibility to host immune defences. Animal studies performed in rats, hamsters and rabbits demonstrate decreased bacterial adherence, reduced infectivity and increased survival of animals treated with subinhibitory antimicrobial concentrations compared to untreated controls. The major future role of investigation of subinhibitory antimicrobial concentrations will be to define more fully, at a molecular level, how antimicrobials exert their antibacterial effects.

Correlation between magnesium and potassium contents in muscle: role of Na(+)-K+ pump

1993 ◽  
Vol 264 (2) ◽  
pp. C457-C463 ◽  
Author(s):  
I. Dorup ◽  
T. Clausen
Keyword(s):  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Deficient Diet ◽  
Young Rats ◽  
Wide Range ◽  
86Rb Influx

In young rats fed a Mg(2+)-deficient diet for 3 wk, Mg2+ and K+ contents in soleus and extensor digitorum longus muscles were significantly reduced and closely correlated. In isolated soleus muscles, Mg2+ depletion induced an even more pronounced loss of K+, and Mg2+ and K+ contents were correlated over a wide range (r = 0.95, P < 0.001). Extracellular Mg2+ (0-1.2 mM) caused no change in total or ouabain-suppressible 86Rb influx. After long-term incubation in Ca(2+)-Mg(2+)-free buffer with EDTA and EGTA, cellular Mg2+ and K+ contents were reduced by 35 and 15%, respectively, without any reduction in ATP and total or ouabain-suppressible 86Rb influx. In Mg(2+)-depleted muscles 42K efflux was increased by up to 42%, and repletion with Mg2+ produced a graded decrease. We conclude that Mg2+ and K+ contents are closely correlated in muscles Mg2+ depleted in vivo or in vitro and that neither extracellular nor moderate intracellular Mg2+ depletion affects total or Na(+)-K+ pump-mediated K+ influx. The reduced K+ content may rather be related to increased K+ efflux from the muscles.

scholarly journals A Possible Role of Allatostatin C in Inhibiting Ecdysone Biosynthesis Revealed in the Mud Crab Scylla paramamosain

2021 ◽  
Vol 8 ◽  
Author(s):  
An Liu ◽  
Wenyuan Shi ◽  
Dongdong Lin ◽  
Haihui Ye
Keyword(s):  
Scylla Paramamosain ◽  
Dependent Manner ◽  
Mud Crab ◽  
Methyl Farnesoate ◽  
Independent Manner ◽  
Wide Range ◽  
Negative Effect

C-type allatostatins (C-type ASTs) are a family of structurally related neuropeptides found in a wide range of insects and crustaceans. To date, the C-type allatostatin receptor in crustaceans has not been deorphaned, and little is known about its physiological functions. In this study, we aimed to functionally define a C-type ASTs receptor in the mud crab, Scylla paramamosian. We showed that C-type ASTs receptor can be activated by ScypaAST-C peptide in a dose-independent manner and by ScypaAST-CCC peptide in a dose-dependent manner with an IC50 value of 6.683 nM. Subsequently, in vivo and in vitro experiments were performed to investigate the potential roles of ScypaAST-C and ScypaAST-CCC peptides in the regulation of ecdysone (20E) and methyl farnesoate (MF) biosynthesis. The results indicated that ScypaAST-C inhibited biosynthesis of 20E in the Y-organ, whereas ScypaAST-CCC had no effect on the production of 20E. In addition, qRT-PCR showed that both ScypaAST-C and ScypaAST-CCC significantly decreased the level of expression of the MF biosynthetic enzyme gene in the mandibular organ, suggesting that the two neuropeptides have a negative effect on the MF biosynthesis in mandibular organs. In conclusion, this study provided new insight into the physiological roles of AST-C in inhibiting ecdysone biosynthesis. Furthermore, it was revealed that AST-C family peptides might inhibit MF biosynthesis in crustaceans.

scholarly journals In Vivo Effect of Mutations at the PRPP Binding Site of the Bacillus subtilis Purine Repressor

2003 ◽  
Vol 185 (22) ◽  
pp. 6728-6731 ◽  
Author(s):  
Pekka Rappu ◽  
Terhi Pullinen ◽  
Pekka Mäntsälä
Keyword(s):  
Bacillus Subtilis ◽  
Binding Site ◽  
Binding Motif

ABSTRACT The Bacillus subtilis PurR mediates adenine repression and guanosine induction of purA. PRPP inhibits binding of PurR to DNA in vitro. Mutations in the PRPP binding motif of PurR caused strong repression regardless of purine exclusions or additions, establishing the role of PRPP as regulator of PurR.

scholarly journals Role of Exosomes in Islet Transplantation

2021 ◽  
Vol 12 ◽  
Author(s):  
Jordan Mattke ◽  
Srividya Vasu ◽  
Carly M. Darden ◽  
Kenjiro Kumano ◽  
Michael C. Lawrence ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Graft Function ◽  
Pancreatic Islet Transplantation ◽  
Complex Molecules ◽  
Wide Range ◽  
And Function ◽  
Antigen Presenting

Exosomes are known for their ability to transport nucleic acid, lipid, and protein molecules, which allows for communication between cells and tissues. The cargo of the exosomes can have a variety of effects on a wide range of targets to mediate biological function. Pancreatic islet transplantation is a minimally invasive cell replacement therapy to prevent or reverse diabetes mellitus and is currently performed in patients with uncontrolled type 1 diabetes or chronic pancreatitis. Exosomes have become a focus in the field of islet transplantation for the study of diagnostic markers of islet cell viability and function. A growing list of miRNAs identified from exosomes collected during the process of isolating islets can be used as diagnostic biomarkers of islet stress and damage, leading to a better understanding of critical steps of the isolation procedure that can be improved to increase islet yield and quality. Exosomes have also been implicated as a possible contributor to islet graft rejection following transplantation, as they carry donor major histocompatibility complex molecules, which are then processed by recipient antigen-presenting cells and sensed by the recipient immune cells. Exosomes may find their way into the therapeutic realm of islet transplantation, as exosomes isolated from mesenchymal stem cells have shown promising results in early studies that have seen increased viability and functionality of isolated and grafted islets in vitro as well as in vivo. With the study of exosomes still in its infancy, continued research on the role of exosomes in islet transplantation will be paramount to understanding beta cell regeneration and improving long-term graft function.

scholarly journals Role of HrcA and CIRCE in the Heat Shock Regulatory Network of Bradyrhizobium japonicum

2000 ◽  
Vol 182 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Alexander C. Minder ◽  
Hans-Martin Fischer ◽  
Hauke Hennecke ◽  
Franz Narberhaus
Keyword(s):  
Heat Shock ◽  
Bradyrhizobium Japonicum ◽  
Target Genes ◽  
Specific Binding ◽  
Regulatory Function ◽  
In The Wild ◽  
Number Of Bacteria

ABSTRACT A large number of bacteria regulate chaperone gene expression by the CIRCE-HrcA system in which a DNA element called CIRCE serves as binding site for the repressor protein HrcA under non-heat-shock conditions. We have cloned the two consecutive genes hrcAand grpE of Bradyrhizobium japonicum by using a complementation approach that screened for GrpE function. In vivo and in vitro transcript mapping demonstrated that both genes are transcribed separately from RpoH (ς32)-dependent promoters. To investigate the supposed negative regulatory function of HrcA, we compared the expression of putative target genes in the wild type with that in an hrcA mutant. Transcription of the CIRCE-associated chaperonin operons groESL 4 andgroESL 5, as well as the β-galactosidase activity derived from corresponding groE-lacZ fusions, was strongly elevated in the hrcA mutant even at physiological temperatures. Expression of other heat shock regulons (RpoH or ROSE dependent) was not affected. To study the activity of HrcA in vitro, we purified a histidine-tagged version of the protein under nondenaturing conditions. Specific binding to the CIRCE element was obtained with a soluble fraction of HrcA in gel retardation experiments.

Stress is a critical player in CYP3A, CYP2C, and CYP2D regulation: role of adrenergic receptor signaling pathways

2012 ◽  
Vol 303 (1) ◽  
pp. E40-E54 ◽  
Author(s):  
Evangelos P. Daskalopoulos ◽  
Foteini Malliou ◽  
Georgia Rentesi ◽  
Marios Marselos ◽  
Matti A. Lang ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Adrenergic Receptor ◽  
Drug Efficacy ◽  
Stress System ◽  
Wide Range ◽  
Repeated Restraint Stress ◽  
Pharmacological Manipulations

Stress is a critical player in the regulation of the major cytochrome P-450s ( CYPs) that metabolize the majority of the prescribed drugs. Early in life, maternal deprivation (MD) stress and repeated restraint stress (RS) modified CYP expression in a stress-specific manner. In particular, the expression of CYP3A1 and CYP2C11 was increased in the liver of MD rats, whereas RS had no significant effect. In contrast, hepatic CYP2D1/2 activity was increased by RS, whereas MD did not affect it. The primary effectors of the stress system, glucocorticoids and epinephrine, highly induced CYP3A1/2. Epinephrine also induced the expression of CYP2C11 and CYP2D1/2. Further investigation indicated that AR-agonists may modify CYP regulation. In vitro experiments using primary hepatocyte cultures treated with the AR-agonists phenylephrine, dexmedetomidine, and isoprenaline indicated an AR-induced upregulating effect on the above-mentioned CYPs mediated by the cAMP/protein kinase A and c-Jun NH2-terminal kinase signaling pathways. Interestingly though, in vivo pharmacological manipulations of ARs using the same AR-agonists led to a suppressed hepatic CYP expression profile, indicating that the effect of the complex network of central and peripheral AR-linked pathways overrides that of the hepatic ARs. The AR-mediated alterations in CYP3A1/2, CYP2C11, and CYP2D1/2 expressions are potentially connected with those observed in the activation of signal transducer and activator of transcription 5b. In conclusion, stress and AR-agonists may modify the expression of the major CYP genes involved in the metabolism of drugs used in a wide range of diseases, thus affecting drug efficacy and toxicity.

scholarly journals OmpR phosphorylation regulates ompS1 expression by differentially controlling the use of promoters

Microbiology ◽  
2014 ◽  
Vol 160 (4) ◽  
pp. 733-741 ◽  
Author(s):  
Mario Alberto Flores-Valdez ◽  
Marcos Fernández-Mora ◽  
Miguel Ángel Ares ◽  
Jorge A. Girón ◽  
Edmundo Calva ◽  
...  
Keyword(s):  
Regulatory Sequence ◽  
Dependent Manner ◽  
In The Wild ◽  
P2 Promoter ◽  
Regulatory Effects ◽  
Encoding Genes ◽  
Effect Of Glucose

The Salmonella enterica ompS1 gene encodes a quiescent porin that belongs to the OmpC/OmpF family. In the present work we analysed the regulatory effects of OmpR phosphorylation on ompS1 expression. We found that in vivo, OmpR in its phosphorylated form (OmpR-P) was important in the regulation of the two ompS1 promoters: OmpR-P activated the P1 promoter and repressed the P2 promoter in an EnvZ-dependent manner; expression occurs from the P2 promoter in an ompR mutant. In vitro, OmpR-P had a higher DNA-binding-affinity to the ompS1 promoter region than OmpR and OmpRD55A, showing an affinity even higher than that of equivalent DNA regions in the 5′-upstream regulatory sequence of the major porin-encoding genes ompC and ompF. By analysing different environmental conditions, we found that glucose and glycerol enhanced ompS1 expression in the wild-type strain. Interestingly the stimulation by glycerol was OmpR-dependent while the effect of glucose was still observed in the absence of OmpR. Acetyl phosphate produced by the AckA-Pta pathway did not influence ompS1 regulation. These data indicate the important role of the phosphorylation in the activity of OmpR on the differential regulation of both ompS1 promoters and its impact on the pathogenesis.

scholarly journals Interaction of Bacillus subtilis CsaA with SecA and precursor proteins

2000 ◽  
Vol 348 (2) ◽  
pp. 367-373 ◽  
Author(s):  
Jörg P. MÜLLER ◽  
Jörg OZEGOWSKI ◽  
Stefan VETTERMANN ◽  
Jelto SWAVING ◽  
Karel H. M. VAN WELY ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Specific Interaction ◽  
Membrane Vesicles ◽  
Protein Export ◽  
E Coli ◽  
Bacterium Bacillus Subtilis ◽  
Bacterium Bacillus

CsaA from the Gram-positive bacterium Bacillus subtilis has been identified previously as a suppressor of the growth and protein-export defect of Escherichia coli secA(Ts) mutants. CsaA has chaperone-like activities in vivo and in vitro. To examine the role of CsaA in protein export in B. subtilis, expression of the csaA gene was repressed. While export of most proteins remained unaffected, export of at least two proteins was significantly reduced upon CsaA depletion. CsaA co-immunoprecipitates and co-purifies with the SecA proteins of E. coli and B. subtilis, and binds the B. subtilis preprotein prePhoB. Purified CsaA stimulates the translocation of prePhoB into E. coli membrane vesicles bearing the B. subtilis translocase, whereas it interferes with the SecB-mediated translocation of proOmpA into membrane vesicles of E. coli. The specific interaction with the SecA translocation ATPase and preproteins suggests that CsaA acts as a chaperone that promotes the export of a subset of preproteins in B. subtilis.

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