scholarly journals Casuarina Root Exudates Alter the Physiology, Surface Properties, and Plant Infectivity of Frankia sp. Strain CcI3

2011 ◽  
Vol 78 (2) ◽  
pp. 575-580 ◽  
Author(s):  
Nicholas J. Beauchemin ◽  
Teal Furnholm ◽  
Julien Lavenus ◽  
Sergio Svistoonoff ◽  
Patrick Doumas ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Surface Properties ◽  
Root Exudates ◽  
Host Plants ◽  
Growth Yield ◽  
Content Type ◽  
Bacterial Surface ◽  
Legume Symbiosis ◽  
Red Dye ◽  
Strain Cci3

ABSTRACTThe actinomycete genusFrankiaforms nitrogen-fixing symbioses with 8 different families of actinorhizal plants, representing more than 200 different species. Very little is known about the initial molecular interactions betweenFrankiaand host plants in the rhizosphere. Root exudates are important inRhizobium-legume symbiosis, especially for initiating Nod factor synthesis. We measured differences inFrankiaphysiology after exposure to host aqueous root exudates to assess their effects on actinorhizal symbioses.Casuarina cunninghamianaroot exudates were collected from plants under nitrogen-sufficient and -deficient conditions and tested onFrankiasp. strain CcI3. Root exudates increased the growth yield ofFrankiain the presence of a carbon source, butFrankiawas unable to use the root exudates as a sole carbon or energy source. Exposure to root exudates caused hyphal “curling” inFrankiacells, suggesting a chemotrophic response or surface property change. Exposure to root exudates altered Congo red dye binding, which indicated changes in the bacterial surface properties at the fatty acid level. Fourier transform infrared spectroscopy (FTIR) confirmed fatty acid changes and revealed further carbohydrate changes.Frankiacells preexposed toC. cunninghamianaroot exudates for 6 days formed nodules on the host plant significantly earlier than control cells. These data support the hypothesis of early chemical signaling between actinorhizal host plants andFrankiain the rhizosphere.

scholarly journals A Caleosin-Like Protein with Peroxygenase Activity Mediates Aspergillus flavus Development, Aflatoxin Accumulation, and Seed Infection

2015 ◽  
Vol 81 (18) ◽  
pp. 6129-6144 ◽  
Author(s):  
Abdulsamie Hanano ◽  
Ibrahem Almousally ◽  
Mouhnad Shaban ◽  
Elizabeth Blee
Keyword(s):  
Fatty Acid ◽  
Aspergillus Flavus ◽  
Polyunsaturated Fatty Acid ◽  
Calcium Binding ◽  
Antioxidant Activities ◽  
Fungal Growth ◽  
Oxidation Reactions ◽  
Content Type ◽  
Fatty Acid Hydroperoxides

ABSTRACTCaleosins are a small family of calcium-binding proteins endowed with peroxygenase activity in plants. Caleosin-like genes are present in fungi; however, their functions have not been reported yet. In this work, we identify a plant caleosin-like protein inAspergillus flavusthat is highly expressed during the early stages of spore germination. A recombinant purified 32-kDa caleosin-like protein supported peroxygenase activities, including co-oxidation reactions and reduction of polyunsaturated fatty acid hydroperoxides. Deletion of the caleosin gene prevented fungal development. Alternatively, silencing of the gene led to the increased accumulation of endogenous polyunsaturated fatty acid hydroperoxides and antioxidant activities but to a reduction of fungal growth and conidium formation. Two key genes of the aflatoxin biosynthesis pathway,aflRandaflD, were downregulated in the strains in whichA. flavusPXG(AfPXG) was silenced, leading to reduced aflatoxin B1 productionin vitro. Application of caleosin/peroxygenase-derived oxylipins restored the wild-type phenotype in the strains in whichAfPXGwas silenced.PXG-deficientA. flavusstrains were severely compromised in their capacity to infect maize seeds and to produce aflatoxin. Our results uncover a new branch of the fungal oxylipin pathway and may lead to the development of novel targets for controlling fungal disease.

scholarly journals The Unique Structure of Haemophilus influenzae Protein E Reveals Multiple Binding Sites for Host Factors

2012 ◽  
Vol 81 (3) ◽  
pp. 801-814 ◽  
Author(s):  
Birendra Singh ◽  
Tamim Al-Jubair ◽  
Matthias Mörgelin ◽  
Marjolein M. Thunnissen ◽  
Kristian Riesbeck
Keyword(s):  
Haemophilus Influenzae ◽  
Disulfide Bridge ◽  
Lung Epithelial Cells ◽  
Binding Region ◽  
Content Type ◽  
Bacterial Surface ◽  
Hydrogen Bonding Pattern ◽  
Functional Regions ◽  
C Terminus ◽  
Α Helix

ABSTRACTHaemophilus influenzaeprotein E (PE) is a multifunctional adhesin involved in direct interactions with lung epithelial cells and host proteins, including plasminogen and the extracellular matrix proteins vitronectin and laminin. We recently crystallized PE and successfully collected X-ray diffraction data at 1.8 Å. Here, we solved the structure of a recombinant version of PE and analyzed different functional regions. It is a dimer in solution and in the asymmetric unit of the crystals. The dimer has a structure that resembles a flattened β-barrel. It is, however, not a true β-barrel, as there are differences in both the hydrogen-bonding pattern and the shape. Each monomer consisted of a 6-stranded antiparallel β-sheet with a rigid α-helix at the C terminus tethered to the concave side of the sheet by a disulfide bridge. The laminin/plasminogen binding region (residues 41 to 68) is exposed, while the vitronectin binding region (residues 84 to 108) is partially accessible in the dimer. The dimerized PE explains the simultaneous interaction with laminin and vitronectin. In addition, we found this unique adhesin to be present in many bacterial genera of the familyPasteurellaceaeand also orthologues in other, unrelated species (Enterobacter cloacaeandListeria monocytogenes). Peptides corresponding to the surface-exposed regions PE 24 to 37, PE 74 to 89, and PE 134 to 156 were immunogenic in the mouse. Importantly, these peptide-based antibodies also recognized PE at the bacterial surface. Taken together, our detailed structure of PE explains how this important virulence factor ofH. influenzaesimultaneously interacts with host vitronectin, laminin, or plasminogen, promoting bacterial pathogenesis.

scholarly journals A New Bacterial Disease on Mandevilla sanderi, Caused by Pseudomonas savastanoi: Lessons Learned for Bacterial Diversity Studies

2012 ◽  
Vol 78 (23) ◽  
pp. 8492-8497 ◽  
Author(s):  
Namis Eltlbany ◽  
Zsa-Zsa Prokscha ◽  
M. Pilar Castañeda-Ojeda ◽  
Ellen Krögerrecklenfort ◽  
Holger Heuer ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Host Plants ◽  
Detection Method ◽  
Lessons Learned ◽  
Bacterial Disease ◽  
Content Type ◽  
Restriction Patterns ◽  
Diversity Studies

ABSTRACTLeaf lesions ofMandevilla sanderiwere shown to be caused byPseudomonas savastanoi. While BOX fingerprints were similar forP. savastanoiisolates from different host plants, plasmid restriction patterns and sequencing of plasmid-located pathogenicity determinants revealed thatMandevillaisolates contained similar plasmids distinct from those of other isolates. ArepA-based detection method was established.

Long-chain n-3 polyunsaturated fatty acids contained in liver and muscle tissues of Okinawan long-spine porcupinefish (Diodon holocanthus Linnaeus 1758)

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yutaka Tashiro
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Ryukyu Islands ◽  
Okinawa Island ◽  
Content Type ◽  
Muscle Tissues ◽  
The Ryukyu Islands ◽  
Total Fatty Acids ◽  
Long Chain

Purpose This study aimed to analyze the lipid content and fatty acid composition in the liver and muscle of a porcupinefish species inhabiting waters around the Ryukyu Islands to investigate their potential as a source of long-chain n-3 polyunsaturated fatty acids (LC-PUFAs). Design/methodology/approach Porcupinefish were collected along the Okinawa Island coast. The composition of fatty acids and cholesterol in both liver and muscle were analyzed using a gas chromatograph mass spectrometer. Findings The liver of Okinawan long-spine porcupinefish was rich in lipids whose content correlated to the proportion of liver/body weight. Fatty acid compositions in their liver and muscles were similar to each other. LC-PUFAs occupied 44% of total fatty acids, with docosahexaenoic acid (DHA) being the dominant (42%), whereas eicosapentaenoic acid occupied 2.4%. The liver contained 1,690 mg of cholesterol and 14.8 g of DHA per 100 g, whose proportion decreased in summer compared to other seasons (p = 0.036). Originality/value The liver of Okinawan long-spine porcupinefish, which has not yet been commercially used although its non-toxicity is claimed, can be an excellent source of LC-PUFAs, especially DHA, accentuating its potential in food supplements’ production.

scholarly journals An Exopolysaccharide-Deficient Mutant of Lactobacillus rhamnosus GG Efficiently Displays a Protective Llama Antibody Fragment against Rotavirus on Its Surface

2015 ◽  
Vol 81 (17) ◽  
pp. 5784-5793 ◽  
Author(s):  
Beatriz Álvarez ◽  
Kasper Krogh-Andersen ◽  
Christian Tellgren-Roth ◽  
Noelia Martínez ◽  
Gökçe Günaydın ◽  
...  
Keyword(s):  
Developing Countries ◽  
Alternative Therapy ◽  
Lactobacillus Rhamnosus ◽  
Antibody Fragment ◽  
Genomic Analysis ◽  
Developed Countries ◽  
Content Type ◽  
Infantile Diarrhea ◽  
Bacterial Surface ◽  
Mouse Pup

ABSTRACTRotavirus is the leading cause of infantile diarrhea in developing countries, where it causes a high number of deaths among infants. Two vaccines are available, being highly effective in developed countries although markedly less efficient in developing countries. As a complementary treatment to the vaccines, aLactobacillusstrain producing an anti-rotavirus antibody fragment in the gastrointestinal tract could potentially be used. In order to develop such an alternative therapy, the effectiveness ofLactobacillus rhamnosusGG to produce and display a VHH antibody fragment (referred to as anti-rotavirus protein 1 [ARP1]) on the surface was investigated.L. rhamnosusGG is one of the best-characterized probiotic bacteria and has intrinsic antirotavirus activity. Among fourL. rhamnosusGG strains [GG (CMC), GG (ATCC 53103), GG (NCC 3003), and GG (UT)] originating from different sources, only GG (UT) was able to display ARP1 on the bacterial surface. The genomic analysis of strain GG (UT) showed that the geneswelEandwelFof the EPS cluster are inactivated, which causes a defect in exopolysaccharide (EPS) production, allowing efficient display of ARP1 on its surface. Finally, GG (UT) seemed to confer a level of protection against rotavirus-induced diarrhea similar to that of wild-type GG (NCC 3003) in a mouse pup model, indicating that the EPS may not be involved in the intrinsic antirotavirus activity. Most important, GG (EM233), a derivative of GG (UT) producing ARP1, was significantly more protective than the control strainL. caseiBL23.

The role of the interplay between polymer architecture and bacterial surface properties on the microbial adhesion to polyoxazoline-based ultrathin films

Biomaterials ◽  
2010 ◽  
Vol 31 (36) ◽  
pp. 9462-9472 ◽  
Author(s):  
Bidhari Pidhatika ◽  
Jens Möller ◽  
Edmondo M. Benetti ◽  
Rupert Konradi ◽  
Ekaterina Rakhmatullina ◽  
...  
Keyword(s):  
Surface Properties ◽  
Ultrathin Films ◽  
Polymer Architecture ◽  
Microbial Adhesion ◽  
Bacterial Surface

scholarly journals Response of Fatty Acid Synthesis Genes to the Binding of Human Salivary Amylase by Streptococcus gordonii

2012 ◽  
Vol 78 (6) ◽  
pp. 1865-1875 ◽  
Author(s):  
Anna E. Nikitkova ◽  
Elaine M. Haase ◽  
M. Margaret Vickerman ◽  
Steven R. Gill ◽  
Frank A. Scannapieco
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Protein A ◽  
Acid Synthesis ◽  
Differentially Expressed ◽  
Streptococcus Gordonii ◽  
Bacterial Survival ◽  
Salivary Amylase ◽  
Content Type

ABSTRACTStreptococcus gordonii, an important primary colonizer of dental plaque biofilm, specifically binds to salivary amylase via the surface-associated amylase-binding protein A (AbpA). We hypothesized that a function of amylase binding toS. gordoniimay be to modulate the expression of chromosomal genes, which could influence bacterial survival and persistence in the oral cavity. Gene expression profiling by microarray analysis was performed to detect genes inS. gordoniistrain CH1 that were differentially expressed in response to the binding of purified human salivary amylase versus exposure to purified heat-denatured amylase. Selected genes found to be differentially expressed were validated by quantitative reverse transcription-PCR (qRT-PCR). Five genes from the fatty acid synthesis (FAS) cluster were highly (10- to 35-fold) upregulated inS. gordoniiCH1 cells treated with native amylase relative to those treated with denatured amylase. AnabpA-deficient strain ofS. gordoniiexposed to amylase failed to show a response in FAS gene expression similar to that observed in the parental strain. Predicted phenotypic effects of amylase binding toS. gordoniistrain CH1 (associated with increased expression of FAS genes, leading to changes in fatty acid synthesis) were noted; these included increased bacterial growth, survival at low pH, and resistance to triclosan. These changes were not observed in the amylase-exposedabpA-deficient strain, suggesting a role for AbpA in the amylase-induced phenotype. These results provide evidence that the binding of salivary amylase elicits a differential gene response inS. gordonii, resulting in a phenotypic adjustment that is potentially advantageous for bacterial survival in the oral environment.

scholarly journals A Novel Method of Serum Resistance by Escherichia coli That Causes Urosepsis

mBio ◽  
2018 ◽  
Vol 9 (3) ◽  
Author(s):  
Carrie F. Coggon ◽  
Andrew Jiang ◽  
Kelvin G. K. Goh ◽  
Ian R. Henderson ◽  
Mark A. Schembri ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Serum Resistance ◽  
Gram Negative ◽  
Content Type ◽  
Bacterial Surface ◽  
O Antigen ◽  
High Prevalence ◽  
Novel Method ◽  
Inhibitory Antibodies

ABSTRACT Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection, which in some patients can develop into life-threatening urosepsis. Serum resistance is a key virulence trait of strains that cause urosepsis. Recently, we identified a novel method of serum resistance in patients with Pseudomonas aeruginosa lung infections, where patients possessed antibodies that inhibited complement-mediated killing (instead of protecting against infection). These inhibitory antibodies were of the IgG2 subtype, specific to the O-antigen component of lipopolysaccharide (LPS) and coated the bacterial surface, preventing bacterial lysis by complement. As this mechanism could apply to any Gram-negative bacterial infection, we hypothesized that inhibitory antibodies may represent an uncharacterized mechanism of serum resistance in UPEC. To test this, 45 urosepsis patients with paired blood culture UPEC isolates were screened for serum titers of IgG2 specific for their cognate strain’s LPS. Eleven patients had sufficiently high titers of the antibody to inhibit serum-mediated killing of UPEC isolates by pooled healthy control sera. Depletion of IgG or removal of O-antigen restored sensitivity of the isolates to the cognate patient serum. Importantly, the isolates from these 11 patients were more sensitive to killing by serum than isolates from patients with no inhibitory antibodies. This suggests the presence of inhibitory antibodies may have allowed these strains to infect the bloodstream. The high prevalence of patients with inhibitory antibodies (24%) suggests that this phenomenon is an important mechanism of UPEC serum resistance. LPS-specific inhibitory antibodies have now been identified against three Gram-negative pathogens that cause disparate diseases. IMPORTANCE Despite improvements in the early detection and management of sepsis, morbidity and mortality are still high. Infections of the urinary tract are one of the most frequent sources of sepsis with Escherichia coli the main causative agent. Serum resistance is vital for bacteria to infect the bloodstream. Here we report a novel method of serum resistance found in patients with UPEC-mediated sepsis. Antibodies in sera usually protect against infection, but here we found that 24% of patients expressed “inhibitory antibodies” capable of preventing serum-mediated killing of their infecting isolate. Our data suggest that these antibodies would allow otherwise serum-sensitive UPEC strains to cause sepsis. The high prevalence of patients with inhibitory antibodies in this cohort suggests that this is a widespread mechanism of resistance to complement-mediated killing in urosepsis patients, invoking the potential for the application of new methods to prevent and treat sepsis.

scholarly journals Important Late-Stage Symbiotic Role of theSinorhizobium melilotiExopolysaccharide Succinoglycan

2018 ◽  
Vol 200 (13) ◽  
pp. e00665-17 ◽  
Author(s):  
Markus F. F. Arnold ◽  
Jon Penterman ◽  
Mohammed Shabab ◽  
Esther J. Chen ◽  
Graham C. Walker
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Late Stage ◽  
Sinorhizobium Meliloti ◽  
Antimicrobial Action ◽  
Protective Function ◽  
Content Type ◽  
Early Stages ◽  
Symbiotic Interactions ◽  
Legume Symbiosis

ABSTRACTSinorhizobium melilotienters into beneficial symbiotic interactions withMedicagospecies of legumes. Bacterial exopolysaccharides play critical signaling roles in infection thread initiation and growth during the early stages of root nodule formation. After endocytosis ofS. melilotiby plant cells in the developing nodule, plant-derived nodule-specific cysteine-rich (NCR) peptides mediate terminal differentiation of the bacteria into nitrogen-fixing bacteroids. Previous transcriptional studies showed that the intensively studied cationic peptide NCR247 induces expression of theexogenes that encode the proteins required for succinoglycan biosynthesis. In addition, genetic studies have shown that someexomutants exhibit increased sensitivity to the antimicrobial action of NCR247. Therefore, we investigated whether the symbiotically activeS. melilotiexopolysaccharide succinoglycan can protectS. melilotiagainst the antimicrobial activity of NCR247. We discovered that high-molecular-weight forms of succinoglycan have the ability to protectS. melilotifrom the antimicrobial action of the NCR247 peptide but low-molecular-weight forms of wild-type succinoglycan do not. The protective function of high-molecular-weight succinoglycan occurs via direct molecular interactions between anionic succinoglycan and the cationic NCR247 peptide, but this interaction is not chiral. Taken together, our observations suggest thatS. melilotiexopolysaccharides not only may be critical during early stages of nodule invasion but also are upregulated at a late stage of symbiosis to protect bacteria against the bactericidal action of cationic NCR peptides. Our findings represent an important step forward in fully understanding the complete set of exopolysaccharide functions during legume symbiosis.IMPORTANCESymbiotic interactions between rhizobia and legumes are economically important for global food production. The legume symbiosis also is a major part of the global nitrogen cycle and is an ideal model system to study host-microbe interactions. Signaling between legumes and rhizobia is essential to establish symbiosis, and understanding these signals is a major goal in the field. Exopolysaccharides are important in the symbiotic context because they are essential signaling molecules during early-stage symbiosis. In this study, we provide evidence suggesting that theSinorhizobium melilotiexopolysaccharide succinoglycan also protects the bacteria against the antimicrobial action of essential late-stage symbiosis plant peptides.

scholarly journals Thailandamide, a Fatty Acid Synthesis Antibiotic That Is Coexpressed with a Resistant Target Gene

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Christopher E. Wozniak ◽  
Zhenjian Lin ◽  
Eric W. Schmidt ◽  
Kelly T. Hughes ◽  
Theodore G. Liou
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Target Gene ◽  
Gene Clusters ◽  
Acid Synthesis ◽  
Inducible Promoter ◽  
Content Type ◽  
Uncharacterized Gene ◽  
Fatty Acid Synthesis Pathway ◽  
Genetic Techniques

ABSTRACTMicrobes encode many uncharacterized gene clusters that may produce antibiotics and other bioactive small molecules. Methods for activating these genes are needed to explore their biosynthetic potential. A transposon containing an inducible promoter was randomly inserted into the genome of the soil bacteriumBurkholderia thailandensisto induce antibiotic expression. This screen identified the polyketide/nonribosomal peptide thailandamide as an antibiotic and discovered its regulator, AtsR. Mutants ofSalmonellaresistant to thailandamide had mutations in theaccAgene for acetyl coenzyme A (acetyl-CoA) carboxylase, which is one of the first enzymes in the fatty acid synthesis pathway. A second copy ofaccAin the thailandamide synthesis gene cluster keepsB. thailandensisresistant to its own antibiotic. These genetic techniques will likely be powerful tools for discovering other unusual antibiotics.

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