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Pathogenic Strains (pathogenic + strain)

Distribution by Scientific Domains

Life Sciences	45%
Medical Sciences	25%
Earth and Environmental Science	15%
Chemistry	15%

Selected Abstracts

Anthrax toxins inhibit immune cell chemotaxis by perturbing chemokine receptor signalling

CELLULAR MICROBIOLOGY, Issue 4 2007
Silvia Rossi Paccani
Summary Pathogenic strains of Bacillus anthracis produce two potent toxins, lethal toxin (LT), a metalloprotease that cleaves mitogen-activated protein kinase kinases, and oedema toxin (ET), a calcium/calmodulin-dependent adenylate cyclase. Emerging evidence indicates a role for both toxins in suppressing the initiation of both innate and adaptive immune responses, which are essential to keep the infection under control. Here we show that LT and ET inhibit chemotaxis of T-cells and macrophages by subverting signalling by both CXC and CC chemokine receptors. The data highlight a novel strategy of immunosuppression by B. anthracis based on inhibition of immune cell homing. [source]

Seeking a second opinion: uncertainty in disease ecology

ECOLOGY LETTERS, Issue 6 2010
Brett T. McClintock
Ecology Letters (2010) 13: 659,674 Abstract Analytical methods accounting for imperfect detection are often used to facilitate reliable inference in population and community ecology. We contend that similar approaches are needed in disease ecology because these complicated systems are inherently difficult to observe without error. For example, wildlife disease studies often designate individuals, populations, or spatial units to states (e.g., susceptible, infected, post-infected), but the uncertainty associated with these state assignments remains largely ignored or unaccounted for. We demonstrate how recent developments incorporating observation error through repeated sampling extend quite naturally to hierarchical spatial models of disease effects, prevalence, and dynamics in natural systems. A highly pathogenic strain of avian influenza virus in migratory waterfowl and a pathogenic fungus recently implicated in the global loss of amphibian biodiversity are used as motivating examples. Both show that relatively simple modifications to study designs can greatly improve our understanding of complex spatio-temporal disease dynamics by rigorously accounting for uncertainty at each level of the hierarchy. [source]

Interactions of microorganisms isolated from gilthead sea bream, Sparus aurata L., on Vibrio harveyi, a pathogen of farmed Senegalese sole, Solea senegalensis (Kaup)

JOURNAL OF FISH DISEASES, Issue 9 2005
M Chabrillón
Abstract Four bacterial isolates from farmed gilthead sea bream, Sparus aurata, included in a previous study as members of the Vibrionaceae and Pseudomonodaceae and the genus Micrococcus, have been evaluated for their adhesive ability to skin and intestinal mucus of farmed Senegalese sole, Solea senegalensis, and their antagonistic effect on Vibrio harveyi, a pathogen of sole. These isolates showed higher adhesion to sole mucus than the pathogenic strains of V. harveyi assayed. Only two of the isolates showed antagonistic activity to V. harveyi. Interactions of the four isolates with V. harveyi in respect of adhesion to skin and intestinal mucus under exclusion, competition and displacement conditions were studied. Three isolates were able to reduce the attachment to skin and intestinal sole mucus of a pathogenic strain of V. harveyi under displacement and exclusion conditions, but not under competition conditions. The in vivo probiotic potential of isolate Pdp11 was assessed by oral administration followed by challenge with the pathogenic V. harveyi strain Lg14/00. A group of 50 Senegalese sole received a commercial diet supplemented with 108 cfu g,1 of lyophilized Lg14/00 for 15 days. A second group of fish received a non-supplemented commercial diet. After challenge the mortality of the fish receiving the diet supplemented with the potential probiotic isolate was significantly lower than that in the fish receiving the non-supplemented commercial diet. This study has shown that the ability to interfere with attachment of pathogens, as well as the adhesion to host surfaces, are suitable criteria for selection of candidate probiotics for use in the culture of Senegalese sole. [source]

Pharmacokinetics and pharmacokinetic/pharmacodynamic integration of orbifloxacin in Korean Hanwoo cattle

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2009
G. ELIAS
The pharmacokinetics and pharmacodynamics of orbifloxacin were studied in six clinically healthy Hanwoo cows after intravenous (i.v.) and intramuscular (i.m.) administration at a dose of 3 mg/kg. Orbifloxacin concentrations were determined by high performance liquid chromatography with fluorescence detection. Steady-state volume of distribution and clearance of orbifloxacin after i.v. administration were 0.92 L/kg and 0.24 L/h·kg, respectively. Following i.m. administration, a slow and complete absorption with absolute bioavailability of 101.4%, and a maximum concentration (Cmax) of 1.17 ,g/mL at 1.04 h were observed. The in vitro serum protein binding was 14.76%. The in vitro antibacterial activity of orbifloxacin against a pathogenic strain of Mannheimia haemolytica (M. haemolytica), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was determined. The ex vivo activity of orbifloxacin against M. haemolytica strain was also determined, and these data were integrated with the ex vivo bacterial counts to establish AUC24h/MIC values producing bacteriostatic action, bactericidal action and elimination of bacteria. Mean values were 32.7, 51.6 and 102.6 h, respectively. From these data, we predict that orbifloxacin, when administered i.m. at a dosage of 2.5,5 mg/kg once a day, would be effective against bovine pathogens, such as M. haemolytica. Additional studies may be needed to confirm its efficacy in a clinical setting, and to evaluate the penetration of the drug in diseased tissues. [source]

Pharmacokinetics and pharmacokinetic/pharmacodynamic integration of marbofloxacin in calf serum, exudate and transudate

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 3 2002
F. SHOJAEE ALIABADI
Aliabadi, F. S., Lees, P. Pharmacokinetics and pharmacokinetic/pharmacodynamic integration of marbofloxacin in calf serum, exudate and transudate. J. vet. Pharmacol. Therap.25, 161,174. Marbofloxacin is a fluoroquinolone antimicrobial drug used in cattle for the treatment of respiratory infections. In this investigation the pharmacokinetics (PK) of marbofloxacin were determined after intravenous and intramuscular dosing at a dosage of 2 mg/kg. In addition the ex vivo pharmacodynamics (PD) of the drug were determined in serum and three types of tissue cage fluid (transudate, inflammatory exudate generated by carrageenan and exudate generated by lipopolysaccharide). Marbofloxacin PK was characterized by a high volume of distribution after dosing by both routes (1.28 L/kg intravenous and 1.25 L/kg intramuscular). Corresponding area under the concentration,time curve (AUC) and elimination half-life (t½el) values were 9.99 and 10.11 ,g h/mL and 4.23 and 4.33 h, respectively. Values of AUC for carrageenan-induced exudate, lipopolysaccharide-induced exudate and transudate were, respectively, 8.28, 7.83 and 7.75 ,g h/mL after intravenous and 8.84, 8.53 and 8.52 ,g h/mL after intramuscular dosing. Maximum concentration (Cmax) values were similar for the three tissue cage fluids after intravenous and intramuscular dosing. For in vivo PK data values of AUC: minimum inhibitory concentration (MIC) (AUIC) ratio for serum were 250 and 253, respectively, after intravenous and intramuscular dosing of marbofloxacin against a pathogenic strain of Mannheimia haemolytica (MIC=0.04 ,g/mL). For all tissue cage fluids AUIC values were >194 and >213 after intravenous and intramuscular dosing, and Cmax/MIC ratios were 9 or greater, indicating a likely high level of effectiveness in clinical infections caused by M. haemolytica of MIC 0.04 ,g/mL or less. This was confirmed by both in vitro (serum) and ex vivo (serum, exudate and transudate) measurements, which demonstrated a concentration-dependent killing profile for marbofloxacin against M. haemolytica. Ex vivo, after 24-h incubation, virtually all bacteria were killed (<10 cfu/mL) in all samples collected up to 9 h (serum), 24 h (carrageenan-induced exudate and transudate) and 36 h (lipopolysaccharide-induced exudate). Application of the sigmoid Emax equation to the ex vivo antibacterial data provided, for serum, AUIC24 h values of 37.1 for bacteriostasis, 46.3 for bactericidal activity and 119.6 for elimination of bacteria. These data may be used as a rational basis for setting dosing schedules which optimize clinical efficacy and minimize the opportunities for emergence of resistant organisms. [source]

Penaeus monodon larvae can be protected from Vibrio harveyi infection by pre-emptive treatment of a rearing system with antagonistic or non-antagonistic bacterial probiotics

AQUACULTURE RESEARCH, Issue 6 2010
Srinivas Somnath Pai
Abstract This study shows that the disease resistance and survival rate of Penaeus monodon in a larval rearing systems can be enhanced by supplementing with antagonistic or non-antagonistic probiotics. The antagonistic mode of action of Pseudomonas MCCB 102 and MCCB 103 against vibrios was demonstrated in larval mesocosm with cultures having sufficient concentration of antagonistic compounds in their culture supernatant. Investigations on the antagonistic properties of Bacillus MCCB 101, Pseudomonas MCCB 102 and MCCB 103 and Arthrobacter MCCB 104 against Vibrio harveyi MCCB 111 under in vitro conditions revealed that Pseudomonas MCCB 102 and MCCB 103 were inhibitory to the pathogen. These inhibitory properties were further confirmed in the larval rearing systems of P. monodon. All these four probionts significantly improved larval survival in long-term treatments as well as when challenged with a pathogenic strain of V. harveyi MCCB 111. We could demonstrate that Pseudomonas MCCB 102 and MCCB 103 accorded disease resistance and a higher survival rate in P. monodon larval rearing systems through active antagonism of vibrios, whereas Bacillus MCCB 101 and Arthrobacter MCCB 104 functioned as probiotics through immunostimulatory and digestive enzyme-supporting modes of action. [source]

Investigation of virulence genes in clinical isolates of Yersinia enterocolitica

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2008
Haoxuan Zheng
Abstract In this study, we aimed to investigate the distribution of virulence genes in clinical isolates of pathogenic Yersinia enterocolitica. Two thousand six hundred stool samples were collected from 2600 patients with diarrhea, and were tested using the culture method and real-time PCR. Then, all isolates of pathogenic Y. enterocolitica cultured from the culture method were examined for virulence genes (inv, ail, ystA, ystB, ystC, yadA, virF) by PCR and for the presence of plasmid by four phenotypic tests. As a result, 160 pathogenic strains were successfully detected by the culture method, including bio/serotype 1A/unknown (4), 1B/unknown (8), 2/O:9 (39), 2/unknown (7), 3/O:3 (22), 3/unknown (6), 4/O:3 (55), 4/unknown (10) and 5/unknown (9). The positive rate of virulence genes tested in 160 isolates was inv (100%), ail (94%), ystA (93%), ystB (7.5%), ystC (5%), yadA (89%) and virF (82%) while the phenotypic test included autoagglutination (87%), binding of crystal violet (89%), calcium-dependent growth (74%) and Congo red absorption (78%), respectively. Finally, we found that not all pathogenic Y. enterocolitica necessarily carry all traditional virulence genes in both chromosomes and plasmids to cause illness. Perhaps, some of them, lacking some traditional virulence genes, contain other unknown virulence markers that interact with each other and play an important role in the diverse pathogenesis of pathogenic Y. enterocolitica. [source]

The new mycobacteria: an update

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2006
Enrico Tortoli
Abstract The continuous evolution of mycobacterial taxonomy may represent a source of confusion for laboratories and clinicians. Apart from the obvious pathogenic strains of the Mycobacterium tuberculosis complex, Mycobacterium leprae and Mycobacterium ulcerans, the role of other mycobacteria may be associated with varying conditions ranging from contamination to specific disease processes. Of the more than 120 mycobacterial species recognized currently, very few have not been reported as pathogenic in humans or animals. Although the attempt to keep pace with the steadily increasing number of mycobacterial species seems hopeless, a careful review of the recent literature relevant to the newly described species may be advantageous. The aim of this present update is to provide epidemiological and clinical information along with major phenotypic and genotypic characteristics of the species described in the last 3 years. [source]

Essential oil composition and antimicrobial activity of tuberous roots of Pimpinella tirupatiensis Bal.

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2002
& Subr., India, an endemic taxon from eastern ghats
Abstract The tuberous roots of Pimpinella tirupatiensis (Apiaceae) were subjected to sequential extraction with different polar solvents and the extracts were tested against eight bacterial and three fungal pathogenic strains for antimicrobial activity. The minimum inhibitory concentration of active extracts against six bacterial and two fungal strains were determined. The hexane and ethyl acetate fractions exhibited a broad spectrum of antimicrobial activity and were analysed for different phytochemicals. The active extracts contained significant amounts of alkaloids, flavonols, flavones and volatile oils. The hexane extract yielded an essential oil when subjected to GC with FID. The compounds were identified based on their retention indices and yielded 24 known compounds and one unknown compound. The major compounds are ,-bisabolene (9.2%), ,-3-carene (8.9%), cis -carveol (6.7%), elemol (5.8%), ,-cadinol (4.4%), methyl geranate (4.3%) and ,-nonalactone (3.4%). Copyright © 2002 John Wiley & Sons, Ltd. [source]

Diagnosis of Helicobacter pylori Infection

HELICOBACTER, Issue 2004
Athanasios Makristathis
ABSTRACT While there are some attempts to improve culture of Helicobacter pylori, molecular methods have been the main focus of this interest. Their main application concerns the development of rapid tests also allowing the determination of bacterial resistance, i.e. real-time polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH), or to genotype the strains. Attempts to improve, simplify or explain the discrepancies of urea breath test results have been made and new generation of stool antigen test with monoclonal antibodies either using the standard ELISA format or rapid immunoenzymatic detection have confirmed their value. With regard to serology, studies have mainly focused on the distinction of infections with more pathogenic strains and the ability to diagnose atrophic gastritis with the Gastropanel. [source]

Probiotic lactic acid bacteria from Kung-Som: isolation, screening, inhibition of pathogenic bacteria

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2010
Noraphat Hwanhlem
Summary Lactic acid bacteria (LAB) were isolated from Kung-Som at various fermentation periods. Only ten strains, named D2SM22, D6SM3, D6SM24, D6SM26, D8SM21, D10SM5, D10SM11, D10SM16, D10SM20 and D16SM26 showed a survival rate of more than 50% under the simulated gastric juice. After being subjected to simulated gastric juice, four strains (D6SM3, D8SM21, D10SM16 and D10SM20) showed a survival rate of more than 50% in simulated small intestinal juices. Growth of strain D6SM3, D8SM21 and D10SM16 under micro-aerobic and anaerobic conditions was not different. Tested pathogenic strains (Escherichia coli, Staphylococcus aureus, Bacillus cereus, Vibrio parahaemolyticus and Salmonella sp.) were inhibited by probiotic LAB. However, none of strains could produce bacteriocins. All strains were identified as Lactobacillus plantarum. No differences in pH, acidity, LAB count and liking scores between Kung-Som produced with starter culture and conventional method were observed (P > 0.01). [source]

Assessment of survival of Listeria monocytogenes, Salmonella Infantis and Enterococcus faecalis artificially inoculated into experimental waste or compost

JOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2010
N. Paniel
Abstract Aims:, To evaluate survival of pathogenic strains, Listeria monocytogenes and Salmonella Infantis and a sanitation indicator Enterococcus faecalis in composts at different stages of the composting process and during storage. Methods and Results:, The studied pathogenic and indicator strains, originally isolated from compost, were inoculated into compost samples from the various stages of the composting process. During incubation, indigenous microflora diversity was monitored with DGGE analysis. After 90 days of incubation, strain survival was observed in compost sampled before the beginning of the cooling phase, and DGGE analysis demonstrated an increase of microbial diversity up to the cooling phase. However, inoculated strains were not detected in composts after 30, 60 or 90 days of incubation in compost sampled after the start of the cooling phase. Microbial diversity also became stable, and DGGE profiles reached a maximum number of bands at this stage. Conclusions:, Strain survival was not observed in stabilized composts. The cooling phase seems to be the turning point for pathogen survival and at this stage the indigenous microflora appeared to play a significant role in suppression. Significance and Impact of the Study:, The importance of indigenous microflora in the survival of pathogens in four different composts was demonstrated. Stabilized composts were recommended for spreading on land. [source]

Interactions of microorganisms isolated from gilthead sea bream, Sparus aurata L., on Vibrio harveyi, a pathogen of farmed Senegalese sole, Solea senegalensis (Kaup)

Biocontrol and Plant Pathogenic Fusarium oxysporum -Induced Changes in Phenolic Compounds in Tomato Leaves and Roots

JOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2007
Y. Panina
Abstract The biocontrol fungus Fusarium oxysporum strain CS-20 was previously shown to reduce the incidence of Fusarium wilt of tomato through an uncharacterized host-mediated response. As phenolic compounds are involved in the defence response of tomato to pathogens and other stressors, this work was undertaken to determine whether biocontrol strains induced changes in phenolic compounds in leaves and roots of tomato seedlings in the presence and absence of pathogenic F. oxysporum f. sp. lycopersici. Roots of intact tomato seedlings were placed in water or aqueous fungal spore suspensions. Two biocontrol F. oxysporum strains [CS-20 (host-mediated mechanism) and 85SK-1 (control mechanism unknown)] and two plant pathogenic strains of F. oxysporum f. sp. lycopersici Race 1 were used. After 24 or 72 h exposure, phenolic compounds were extracted from leaves and roots before identification by HPLC. There were significant qualitative and quantitative differences between the two sampling times. Compared with the control treatment, strain CS-20 significantly altered (usually increasing) the ferulic, caffeic and vanillic acid contents, and concentrations once unidentified phenolic compounds recovered from leaves and roots. In another experiment, tomato seedlings growing in sterile sand were drenched with spores of strain CS-20 the day before treating them with varying concentrations of spores of the pathogen for 24 or 72 h. The amount of pathogen present did not significantly affect the plant phenolic response to the presence of strain CS-20. This work demonstrates that tomato responds within 24 h to the presence of the biocontrol strain CS-20 by alterations in secondary metabolism that are typical of resistance responses in tomato. [source]

Type IV pili-mediated secretion modulates Francisella virulence

MOLECULAR MICROBIOLOGY, Issue 1 2006
Anthony J. Hager
Summary Francisella tularensis are the causative agent of the zoonotic disease, tularaemia. Among four F. tularensis subspecies, ssp. novicida (F. novicida) is pathogenic only for immunocompromised individuals, while all four subspecies are pathogenic for mice. This study utilized proteomic and bioinformatic approaches to identify seven F. novicida secreted proteins and the corresponding Type IV pilus (T4P) secretion system. The secreted proteins were predicted to encode two chitinases, a chitin binding protein, a protease (PepO), and a ,-glucosidase (BglX). The transcription of F. novicida pepO and bglX was regulated by the virulence regulator MglA. Intradermal infection of mice with F. novicida mutants defective in T4P secretion system or PepO resulted in enhanced F. novicida spread to systemic sites. Infection with F. novicida pepO mutants also resulted in increased neutrophil infiltration into the mouse airways. PepO is a zinc protease that is homologous to mammalian endothelin-converting enzyme ECE-1. Therefore, secretion of PepO likely results in increased production of endothelin and increased vasoconstriction at the infection site in skin that limits the F. novicida spread. Francisella human pathogenic strains contain a mutation in pepO predicted to abolish its secretion. Loss of PepO function may have contributed to evolution of highly virulent Francisellae. [source]

Genetic analysis of Escherichia coli K1 gastrointestinal colonization

MOLECULAR MICROBIOLOGY, Issue 6 2000
J. Martindale
Strains of Escherichia coli expressing the K1 polysaccharide capsule colonize the large intestine of newborn infants, and are the leading cause of Gram-negative septicaemia and meningitis in the neonatal period. We used signature-tagged mutagenesis (STM) to identify genes that E. coli K1 requires to colonize the gastrointestinal (GI) tract. A total of 2140 mTn5 mutants was screened for their capacity to colonize the GI tract of infant rats, and 16 colonization defective mutants were identified. The mutants have transposon insertions in genes affecting the synthesis of cell surface structures, membrane transporters, transcriptional regulators, enzymes in metabolic pathways, and in genes of unknown function, designated dgc (defective in GI colonization). Three dgcs are absent from the whole genome sequence of E. coli K-12, although related sequences are found in other pathogenic strains of E. coli and in Shigella flexneri. Additionally, immunohistochemistry was used to define the nature of the colonization defect in five mutants including all dgc mutants. STM was successfully applied to examine the factors involved in E. coli K1 colonization, and the findings are relevant to the pathogenesis of other enteric infections. [source]

N- Benzylsalicylthioamides: Highly Active Potential Antituberculotics

ARCHIV DER PHARMAZIE, Issue 2 2009
Rafael Dole
Abstract A gseries of 29 new derivatives of N -benzylsalicylthioamides was synthesized and the compounds were tested for in-vitro antimycobacterial activity against Mycobacterium tuberculosis, Mycobacterium kansasii, and Mycobacterium avium. The activity was analyzed by quantitative structure-activity relationship (QSAR). Activity increased with increasing lipophilicity and electron donating effect of the substituents in the acyl moiety and decreased with the electrophilic superdelocalizability of the molecules. The most active compounds are more active than isoniazid (INH) and are active against INH-resistant potential pathogenic strains of mycobacterium. [source]

Die Geschichte der Kolibakterien.

BIOLOGIE IN UNSERER ZEIT (BIUZ), Issue 3 2010
Vom Darmbewohner zum Bioreaktor
Abstract Das von Theodor Escherich vor 125 Jahren entdeckte E. coli -Bakterium hat wie kein anderes die Entwicklung der molekularbiologischen Forschung und der medizinischen und industriellen Biotechnologie beeinflusst. Vor allem die Eigenschaften des K12-Stammes im Hinblick auf Apathogenität, Kultivierbarkeit und Transformierbarkeit haben E. coli zum "Haustier" der Genetiker und Molekularbiologen gemacht. Die Leichtigkeit, mit der gentechnisch veränderte E. coli hergestellt werden können, ließen dieses Bakterium zum beliebten Produktionsorganismus in der modernen Biotechnologie zur Erzeugung von Medikamenten und Feinchemikalien werden. Als physiologischer Darmbewohner von Menschen und Tieren wird E. coli als Indikatororganismus für fäkale Verunreinigungen von Grund- und Trinkwasser verwendet. Neben seiner mikroökologischen Rolle im Magen-Darm-Trakt kommt ihm in Form von pathogenen Stämmen auch eine Bedeutung als Erreger von Durchfallerkrankungen zu. The history of colibacteria The E. coli bacterium discovered by Theodor Escherich 125 years ago has influenced the development of molecular-biological research and medicinal and industrial biotechnology like no other bacterium. In particular, the characteristics of the K12-strain with respect to apathogenicity, culturability and transformability made E. coli the "workhorse" of geneticists and molecular biologists. The easiness with which genetically modified E. coli can be made let this bacterium become a popular production organism of modern biotechnology for the making of drugs and fine chemicals. As a physiological inhabitant of the intestine of humans and animals, E. coli is used as an indicator organism of faecal pollution of ground and drinking water. Alongside its micro-ecological role in the gastrointestinal tract, the E. coli bacterium, in terms of pathogenic strains, also has significance as a causative agent of diarrhoeal diseases. [source]

Cell surface display of highly pathogenic avian influenza virus hemagglutinin on the surface of Pichia pastoris cells using ,-agglutinin for production of oral vaccines ,

BIOTECHNOLOGY PROGRESS, Issue 2 2010
Jamie L. Wasilenko
Abstract Yeast is an ideal organism to express viral antigens because yeast glycosylate proteins more similarly to mammals than bacteria. Expression of proteins in yeast is relatively fast and inexpensive. In addition to the convenience of production, for purposes of vaccination, yeast has been shown to have natural adjuvant activity making the expressed proteins more immunogenic when administered along with yeast cell wall components. Development of genetic systems to display foreign proteins on the surface of yeast via fusion to glycosylphosphatidylinositol-anchored (GPI) proteins has further simplified the purification of recombinant proteins by not requiring harsh treatments for cellular lysis or protein purification. We have expressed the hemagglutinin protein from a highly pathogenic avian influenza (HPAI) virus [A/Egret/HK/757.2/02], subtype H5N1, on the surface of the yeast strain Pichia pastoris, as an anchored C-terminal fusion with the Saccharomyces cerevisiae GPI-anchored cell wall protein, ,-agglutinin. Surface expression of the hemagglutinin fusion protein was demonstrated by immunofluorescence microscopy. Functionally, the fusion protein retained hemagglutinin agglutinating activity, and oral vaccination with the yeast resulted in production of virus neutralizing antibodies. This study represents the first steps in the generation of a yeast-based vaccine for protection against highly pathogenic strains of avian influenza. Published 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]

Neisseria gonorrhoeae downregulates expression of the human antimicrobial peptide LL-37

CELLULAR MICROBIOLOGY, Issue 7 2005
Peter Bergman
Summary Neisseria gonorrhoeae is a human pathogen causing the sexually transmitted disease gonorrhoeae. The bacteria preferentially attach to and invade epithelial cells of the genital tract. As these cells previously have been shown to express the human cathelicidin LL-37, we wanted to investigate the role of LL-37 during N. gonorrhoeae infection. The cervical epithelial cell line ME180 was utilized and the expression of LL-37 was confirmed on both peptide and transcriptional levels. Moreover, LL-37 exhibited potent in vitro activity ,against ,N. ,gonorrhoeae.,Interestingly, ,the transcript and peptide levels of LL-37 were downregulated ,during ,infection, ,according ,to ,quantitative real-time polymerase chain reaction (PCR) and immunocyto-chemistry. The downregulation was most prominent with pathogenic strains of Neisseria, while non-pathogenic strains such as Neisseria lactamica and Escherichia coli only exhibited moderate effects. Heat-killed N. gonorrhoeae had no impact on the downregulation, emphasizing the importance of live bacteria. The results in this study suggest that pathogenic Neisseria may gain a survival advantage in the female genital tract by downregulating LL-37 expression. [source]