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Bacterial Challenge (bacterial + challenge)
Selected AbstractsInfluence of Vitamin E Source and Dietary Supplementation Level on Production Performance of Sunshine Bass, Morone chrysops , × Morone saxatilis ,, Fillet Tocopherol Content, and Immunocompetency during Stress and Bacterial ChallengeJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2008Jesse T. Trushenski We evaluated the effects of dietary vitamin E concentration and source on production performance and immunocompetency of sunshine bass, Morone chrysops × Morone saxatilis, following stress and disease challenge. Four diets were formulated to contain requisite levels (1×) or five times (5×) the vitamin E requirement of sunshine bass as met by synthetic vitamin E (SYNE) or natural source vitamin E (NSVE). Each diet was fed to juvenile sunshine bass for 8 wk prior to experimental challenges. Replicate tanks within each dietary treatment were challenged with stressor exposure (chasing with dip net), incidental Flavobacterium columnare exposure, or both; control groups were not challenged. Pathogen and/or stressor exposure largely resulted in significant reductions in immunological performance. Although significant independent dietary effects were not observed among immunological parameters, suppression of complement and macrophage respiratory burst activities was numerically lower within the 5× NSVE treatment. Production performance was largely unaffected by dietary vitamin E source or level. Fillet ,-tocopherol concentration was significantly higher among fish fed the 5× diets (40.7/41.6 vs. 12.2/14.5 ,g/g dry tissue for 1× diets); however, the dietary concentration required to achieve these levels was lower for NSVE. Although super-requirement levels of either source of vitamin E were apparently beneficial, NSVE was effective at ,50% lower supplementation levels. [source] Bacterial challenge stimulates innate immune responses in extra-embryonic tissues of tobacco hornworm eggsINSECT MOLECULAR BIOLOGY, Issue 1 2004M. J. Gorman Abstract Innate immunity protects juvenile and adult vertebrates and invertebrates against potential pathogens; however, it is unknown when developing embryos become immune competent and just how they are guarded from infection. To address these questions, we studied the effect of immune challenge on early stage eggs of the tobacco hornworm, Manduca sexta. We detected many immune-related proteins and mRNAs in naive eggs. Upon immune challenge, antimicrobial protein genes were up-regulated, and antibacterial activity increased. Antimicrobial protein mRNAs and lysozyme were present in the extra-embryonic tissues of immune-challenged eggs; in addition, melanization in response to bacteria occurred in the yolk but not embryonic tissues. We conclude that the extra-embryonic tissues of early stage M. sexta eggs are immune competent and likely protect the developing embryo from infection. We suggest that innate immune responses of extra-embryonic tissues may be a common mechanism for protecting early embryos. [source] Identification of crucial residues for the antibacterial activity of the proline-rich peptide, pyrrhocoricinFEBS JOURNAL, Issue 17 2002Goran Kragol Members of the proline-rich antibacterial peptide family, pyrrhocoricin, apidaecin and drosocin appear to kill responsive bacterial species by binding to the multihelical lid region of the bacterial DnaK protein. Pyrrhocoricin, the most potent among these peptides, is nontoxic to healthy mice, and can protect these animals from bacterial challenge. A structure,antibacterial activity study of pyrrhocoricin against Escherichia coli and Agrobacterium tumefaciens identified the N-terminal half, residues 2,10, the region responsible for inhibition of the ATPase activity, as the fragment that contains the active segment. While fluorescein-labeled versions of the native peptides entered E. coli cells, deletion of the C-terminal half of pyrrhocoricin significantly reduced the peptide's ability to enter bacterial or mammalian cells. These findings highlighted pyrrhocoricin's suitability for combating intracellular pathogens and raised the possibility that the proline-rich antibacterial peptides can deliver drug leads into mammalian cells. By observing strong relationships between the binding to a synthetic fragment of the target protein and antibacterial activities of pyrrhocoricin analogs modified at strategic positions, we further verified that DnaK was the bacterial target macromolecule. Inaddition, the antimicrobial activity spectrum of native pyrrhocoricin against 11 bacterial and fungal strains and the binding of labeled pyrrhocoricin to synthetic DnaK D-E helix fragments of the appropriate species could be correlated. Mutational analysis on a synthetic E. coli DnaK fragment identified a possible binding surface for pyrrhocoricin. [source] Territorial behaviour and immunity are mediated by juvenile hormone: the physiological basis of honest signalling?FUNCTIONAL ECOLOGY, Issue 1 2009Jorge Contreras-Garduño Summary 1The role of the juvenile hormone (JH) as a potential mediator in the trade-off between male,male competition and immune response has not been tested, but its study could reveal a potential mechanism that mediates resource allocation between these two traits. 2Controlling for body size, we tested whether males of the territorial damselfly Calopteryx virgo administrated with methoprene acid, an analog of the JH (JHa), compared to control males, increased their aggression and occupation time on territories but decreased their phenoloxidase (PO) activity (a key enzyme used during immune response after a bacterial challenge). We found an increase in aggression in JHa treated males compared to control males, but the opposite was found for PO activity. 3As fat load and muscle mass are also important traits during a contest, we tested whether JHa males compared to control males showed more fat and muscle content 2 h after JHa administration. Our results did not show a significant difference between both male groups, suggesting that JHa only increased aggression. 4These results and a review of other published articles, which have documented an effect of JH on a variety of functions in insects, suggest that JH may be a target of sexual selection: this hormone not only promotes the expression of secondary sexual characters but also seems condition-dependent and so its titers may indicate male condition. [source] Cloning and molecular characterization of two invertebrate-type lysozymes from Anopheles gambiaeINSECT MOLECULAR BIOLOGY, Issue 3 2008S. M. Paskewitz Abstract We sequenced and characterized two novel invertebrate-type lysozymes from the mosquito Anopheles gambiae. Alignment and phylogenetic analysis of these and a number of related insect proteins identified through bioinformatics strategies showed a high degree of conservation of this protein family throughout the Class Insecta. Expression profiles were examined for the two mosquito genes through semiquantitative and real-time PCR analysis. Lys i-1 transcripts were found in adult females in the fat body and Malpighian tubules, whereas Lys i-2 was detected only in fat bodies. Blood-feeding resulted in significantly increased transcript abundance for both genes in the midguts. Neither gene was upregulated following bacterial challenge. [source] Molecular characterization of a prophenoloxidase cDNA from the malaria mosquito Anopheles stephensiINSECT MOLECULAR BIOLOGY, Issue 2 2000L. Cui Abstract Some refractory anopheline mosquitoes are capable of killing Plasmodium, the causative agent of malaria, by melanotic encapsulation of invading ookinetes. Phenoloxidase (PO) appears to be involved in the formation of melanin and toxic metabolites in the surrounding capsule. A cDNA encoding Anopheles stephensi prophenoloxidase (Ans-proPO) was isolated from a cDNA library screened with an amplimer produced by reverse transcriptase polymerase chain reaction (RT-PCR) with degenerate primers designed against conserved proPO sequences. The 2.4-kb-long cDNA has a 2058 bp open reading frame encoding Ans-proPO of 686 amino acids. The deduced amino acid sequence shows significant homology to other insect proPO sequences especially at the two putative copper-binding domains. In A. stephensi, Ans-proPO expression was detected in larval, pupal and adult stages. The Ans-proPO mRNA was detected by RT-PCR and in situ hybridization in haemocytes, fat body and epidermis of adult female mosquitoes. A low level of expression was detected in the ovaries, whereas no expression was detected in the midguts. Semi-quantitative RT-PCR analysis of Ans-proPO mRNA showed that its expression was similar in adult female heads, thoraxes and abdomens. No change in the level of Ans-proPO expression was found in adult females after blood feeding, bacterial challenge or Plasmodium berghei infection. However, elevated PO activity was detected in P. berghei -infected mosquitoes, suggesting that in non-selected permissive mosquitoes PO may be involved in limiting parasite infection. Genomic Southern blot and immunoblots suggest the presence of more than one proPO gene in the A. stephensi genome, which is consistent with the findings in other Diptera and Lepidoptera species. The greatest similarity in sequence and expression profile between Ans-proPO and A. gambiae proPO6 suggests that they might be homologues. Our results demonstrate that Ans-proPO is constitutively expressed through different developmental stages and under different physiological conditions, implying that other factors in the proPO activation cascade regulate melanotic encapsulation. [source] Infectious gastroenteritis caused by Vibrio harveyi (V. carchariae) in cultured red drum, Sciaenops ocellatusJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2003P.-C. Liu Summary An outbreak of serious mortality among the cultured red drum Sciaenops ocellatus (L.) characterized by a swollen intestine containing transparent yellow fluid (ascites and gastroenteritis) occurred in July 2000 in Taiwan. A motile strain Rd 0700 was isolated from head kidney and/or the intestinal yellow fluid on tryptone soya agar (TSA) supplemented with 2% (w/v) NaCl and/or thiosulfate citrate bile salt (TCBS) sucrose agar plates. Applying biochemical characteristics, this strain was characterized and identified as Vibrio harveyi (V. carchariae). The bacteria could be re-isolated from kidney, liver, and the transparent yellow fluid of swollen intestine of fish after bacterial challenge. The LD50 values of the organism and its extracellular products (ECP) were 2.9×107 colony forming units (CFU) and 3.85 ,g protein g,1 fish body weight, respectively. All moribund/dead fish exhibited gastroenteritis except those killed within 12 h. This is a first report showing that intraperitoneal (i.p.) injection of the ECP from V. carchariae is lethal to red drum and can reproduce gastroenteritis in the fish. [source] Interleukin-1, levels in gingival crevicular fluid and serum under naturally occurring and experimentally induced gingivitisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2010Leonardo Trombelli Trombelli L, Scapoli C, Carrieri A, Giovannini G, Calura G, Farina R. Interleukin-1, levels in gingival crevicular fluid and serum under naturally occurring and experimentally induced gingivitis. J Clin Periodontol 2010; 37: 697-704 doi: 10.1111/j.1600-051X.2010.01573.x. Abstract Aims: To evaluate the interleukin-1, (IL-1,) levels in gingival crevicular fluid (GCF) and serum in either naturally occurring (N-O) or experimentally induced (E-I) plaque-associated gingivitis. Material and Methods: Thirty-seven periodontally healthy subjects were evaluated in real life conditions (N-O gingivitis) as well as after 21 days of experimental gingivitis trial (E-I gingivitis). During the experimental gingivitis trial, in one maxillary quadrant (test quadrant), gingival inflammation was induced by oral hygiene abstention, while in the contralateral (control) quadrant, oral hygiene was routinely continued. IL-1, concentrations in N-O and E-I gingivitis were investigated for IL-1B+3954 and IL-1B,511 gene polymorphisms. Results: (i) GCF IL-1, concentrations in E-I gingivitis were significantly higher compared with N-O gingivitis; (ii) an intra-individual correlation between GCF concentrations of IL-1, detected in N-O and E-I gingivitis was observed in control quadrants, but not in test quadrants; (iii) IL-1, concentration in GCF was associated with IL-1B+3954 genotype only at test quadrants; (iv) IL-1, was detectable in serum only at low levels in a limited number of subjects, without difference between gingivitis conditions. Conclusions: Aspects of the bacterial challenge to the gingival tissues, such as the amount of plaque deposits and plaque accumulation rate, appear to affect the IL-1, levels in GCF in subjects with a specific IL-1B genotype. [source] Granulocyte elastase, matrix metalloproteinase-8 and prostaglandin E2 in gingival crevicular fluid in matched clinical sites in smokers and non-smokers with persistent periodontitisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2002B. Söder Abstract Background/aims: Smokers with persistent periodontitis may have granulocytes with impaired function. This study aimed to determine the levels of granulocyte elastase, matrix metalloproteinase-8 (MMP-8) and prostaglandin E2 (PGE2) in gingival crevicular fluid (GCF) in smokers and non-smokers with persistent periodontitis. Methods: We analyzed GCF from 70 matched sites in 29 periodontitis and 6 gingivitis sites in 34 subjects, 17 smokers, and 17 non-smokers. We also analyzed separately GCF from 28 of these subjects, 14 smokers and 14 non-smokers in 14 matched periodontitis sites. The following measurements were made: elastase complexed to ,1 -antitrypsin (EA-,1AT) and MMP-8 with ELISA, functional elastase with a chromogenic substrate, and PGE2 with radioimmunoassay (125I RIA). The significance of the findings was determined with Mann-Whitney test. Results: In the 29 matched periodontitis sites, smokers had significantly more functional elastase (p<0.005) and more EA-,1AT (p<0.05) than non-smokers. In the 14 matched periodontitis sites in 14 smokers and 14 non-smokers, the former had significantly more functional elastase than the latter (p<0.001). A significant correlation was found between EA-,1AT and MMP-8 in smokers (p<0.05) and non-smokers (p<0.001) and a positive correlation between levels of functional elastase and MMP-8 in non-smokers (r2=0.98; p<0.001). Conclusions: Granulocyte function seems to be impaired in smokers with persistent periodontitis. The cells react to the bacterial challenge by releasing serine proteases, which reflect the degradation of connective tissue. The risk of progression of the disease is therefore higher in smokers with persistent periodontitis than in non-smokers. Zusammenfassung Hintergrund, Ziele: Raucher mit bestehender Parodontitis haben möglicherweise Granulozyten mit beeinträchtigter Funktion. Diese Studie zielt auf die Bestimmung der Levels von Granulozytenelastase, Matrix-Metalloproteinase-8 (MMP-8) und Prostaglandin E2 (PGE2) in der krevikulären gingivalen Flüssigkeit (GCF) bei Rauchern und Nichtrauchern mit bestehender Parodontitis. Methoden: Wir analysierten GCF von 70 entsprechenden Flächen bei 29 Parodontitis und 6 Gingivitisflächen von 34 Personen, 17 Rauchern und 17 Nichtrauchern. Wir analysierten zusätzlich getrennt die GCF von 28 dieser Personen: 14 Raucher und 14 Nichtraucher von 14 entsprechenden parodontalen Flächen. Die folgenden Messungen wurden vorgenommen: Elastasekomplex zu ,1 -Antitrypsin (EA-,1AT) und MMP-8 mit ELISA, funktionelle Elastase mit chromogenem Substrat und PGE2 mit Radioimmunoassay (125I RIA). Die Signifikanz der Ergebnisse wurde mit dem Mann-Whitney Test bestimmt. Ergebnisse: In den 29 entsprechenden parodontalen Flächen hatten die Raucher signifikant mehr funktionelle Elastase (p<0.005) und mehr EA-,1At (p<0.05) als Nichtraucher. Bei den 14 entsprechenden parodontalen Flächen der 14 Raucher und 14 Nichtraucher hatten die ersten signifikant mehr funktionelle Elastase als die letzteren (p<0.001). Eine signifikante Korrelation wurde zwischen EA-,1AT und MMP-8 bei Rauchern (p<0.05) und Nichtrauchern (p<0.001) gefunden und eine positive Korrelation zwischen den Levels der funktionellen Elastase und MMP-8 bei Nichtrauchern (r2=0.98; p<0.001) festgestellt. Schlussfolgerungen: Die Granulozytenfunktion scheint bei Rauchern mit bestehender Parodontitis beeinträchtigt zu sein. Die Zellen reagieren auf die bakterielle Herausforderung durch Freisetzung von Serinproteasen, die die Degradation von Bindegewebe reflektiert. Das Risiko einer Progression dieser Erkrankung ist deshalb bei Rauchern mit bestehender Parodontitis höher als bei Nichtrauchern. Résumé Origine, but: Les fumeurs avec parodontite persistante pourraient avoir des granulocytes ayant des fonctions déréglées. Cette étude a eu pour but de déterminer les niveaux d'élastase granulocytaire, de la métallo-protéinase-8 de la matrice (MMP-8) et de la prostaglandine E2 (PGE2) dans le fluide créviculaire gingival (GCF) chez les fumeurs et les non-fumeurs avec parodontite persistante. Méthodes: Le GCF a été prélevé de 70 sites équivalents dans 29 parodontites et 6 sites avec gingivite chez 34 sujets, 17 fumeurs et 17 non-fumeurs. Le GCF de 28 de ces sujets a été analysé séparément, 14 fumeurs et 14 non-fumeurs dans 14 sites équivalents du point de vue parodontite. Les mesures suivantes ont été relevées: l'élastase avec ,1 -antitrypsine (EA-,1AT) et MMP-8 par ELISA, l'élastase fonctionnelle avec un substrat chromogénique, et PGE2 avec un essai radio-immunitaire (125I RIA). La signification de ces découvertes a été par l'utilisation du test de Mann-Whitney. Résultats: Dans les 29 sites équivalents, les fumeurs avaient significativement plus d'élastase functionnelle (p<0.005) et plus de EA-,1AT (p<0.05) que les non-fumeurs. Dans les 14 sites équivalents du point de vue parodontite, les 14 fumeurs avaient significativement plus d'élastase fonctionnelle que les 14 non-fumeurs (p<0.001). Une relation significative a étéétablie entre EA-,1AT et MMP-8 chez les fumeurs (p<0.05) et les non-fumeurs (p<0.001) et une relation positive entre les niveaux d'élastase fonctionnelle et de MMP-8 chez les non-fumeurs (r2=0.98; p<0.001). Conclusions: La fonction granulocytaire semble être altérée chez les fumeurs avec parodontite persistante. Les cellules réagissent à l'attaque bactérienne en relâchant des protéases sérine, ce qui démontre une dégradation du tissu conjonctif. Le risque de progression de la maladie est ainsi plus élevé chez les fumeurs avec parodontite persistante que chez les non-fumeurs. [source] Susceptibility of channel catfish, Ictalurus punctatus (Rafinesque), to Edwardsiella ictaluri challenge following copper sulphate exposureJOURNAL OF FISH DISEASES, Issue 10 2007B R Griffin Abstract Channel catfish, Ictalurus punctatus (Rafinesque), with or without a preliminary 24 h exposure to 2 mg copper sulphate L,1, were challenged with 7.5 × 106 colony forming units L,1 of Edwardsiella ictaluri to determine the effect of copper sulphate on disease resistance. Catfish previously exposed to copper sulphate were significantly more resistant to the bacterial challenge than those not exposed. Catfish not exposed to copper sulphate suffered 35.5% mortality while catfish exposed to copper sulphate experienced 14.1% mortality. Copper concentrations were the same in tank waters of both exposed and control fish at the time of challenge, eliminating the possibility that copper in the water may have been toxic to bacteria. Copper concentrations in freeze dried and ground tissues of unexposed, exposed, and purged channel catfish were highest in fish before copper sulphate exposures suggesting that elevated tissue levels of copper were not responsible for the increased resistance to bacterial challenge. Competition for sites of bacterial attachment to gill or epithelial cells may account for the reduction in mortality; although this is not supported by the low copper content of fish tissue after copper exposure. [source] Acute columnaris infection in channel catfish, Ictalurus punctatus (Rafinesque): efficacy of practical treatments for warmwater aquaculture pondsJOURNAL OF FISH DISEASES, Issue 1 2004S Thomas-Jinu Abstract Columnaris disease was induced in channel catfish, Ictalurus punctatus (Rafinesque), by bath exposure to four highly virulent isolates of Flavobacterium columnare. In untreated controls, mortality began 20 h after exposure and reached 100% by 48 h. Mortality in channel catfish given antibiotic treatments with oxytetracycline or a combination of sulphadimethoxine and ormetoprim in feed prior to bacterial challenge was zero with all four strains of F. columnare. Diquat® (Zeneca Agricultural Products, Wilmington, DE, USA) was the most effective bath treatment; mortality with all four strains was zero. With potassium permanganate, chloramine-T, hydrogen peroxide and copper sulphate, bath treatment efficacy varied significantly among strains (P = 0.0346) and among treatments (P = 0.0033). Bath treatments with chloramine-T and potassium permanganate significantly reduced (P < 0.05) mortality from 100 to 75 and 69%, respectively, but copper sulphate and hydrogen peroxide treatments were not effective. Based on our results, oral antibiotics prevented columnaris disease but, of the bath treatments, only Diquat® produced a dramatic reduction in the mortality of acutely infected fish. Diquat® is labelled for aquatic use as an herbicide in the USA but in large ponds it is prohibitively expensive. [source] Comparative challenge model of Flavobacterium columnare using abraded and unabraded channel catfish, Ictalurus punctatus (Rafinesque)JOURNAL OF FISH DISEASES, Issue 8 2003J A Bader Abstract The early entry of the fish pathogen Flavobacterium columnare and enhancement by abrasion was studied in channel catfish, Ictalurus punctatus (Rafinesque), using the polymerase chain reaction and a species-specific primer set for a bacterial 16S rRNA gene product. Evaluations were conducted following an abrasion bath immersion challenge with F. columnare. Abrasion, a practice which has historically been used prior to bacterial challenge, had significant effects on the early entry of the pathogen and on cumulative percent survival (CPS). The FvpF1,FvpR1 primer set was useful in detecting the early entry of F. columnare in mucus, skin, gill, blood, liver and trunk kidney tissues in both abraded and unabraded fish following immersion challenge at 29 ± 2 °C. Bacteria were detected earlier in all tissues in abraded fish, except in the trunk kidney. These differences were not significant, except in the case of blood. Mucus, skin and gill tissues were positive for F. columnare earliest regardless of treatment (after 5 min in abraded fish and after 15 min in unabraded fish). CPS following challenge with F. columnare was significantly affected by abrasion, which supports the use of abrasion for the F. columnare challenge model for channel catfish. [source] Characterization of serum and mucosal antibody responses and relative per cent survival in rainbow trout, Oncorhynchus mykiss (Walbaum), following immunization and challenge with Flavobacterium psychrophilumJOURNAL OF FISH DISEASES, Issue 12 2002B R LaFrentz Abstract Serum and mucosal antibody responses of juvenile rainbow trout, Oncorhynchus mykiss, were characterized by enzyme-linked immunosorbent assay (ELISA) following immunization with various preparations of formalin-killed Flavobacterium psychrophilum cells. The protective nature of these preparations was then determined by immunizing rainbow trout fry and challenging with the bacterium. Juvenile rainbow trout immunized intraperitoneally (i.p.) with formalin-killed F. psychrophilum emulsified with Freund's complete adjuvant (FCA), and i.p. with formalin-killed F. psychrophilum either with or without culture supernatant generated significant serum antibody responses by 6 and 9 weeks, respectively. Significant mucosal antibody responses were detected by 9 weeks only in fish immunized i.p. with killed F. psychrophilum/FCA. Following immunization and bacterial challenge of rainbow trout fry, protective immunity was conferred in F. psychrophilum/FCA and saline/FCA groups with relative per cent survival values of up to 83 and 51, respectively. Significant protection was not observed in treatment groups immunized by immersion or i.p. without adjuvant at the challenge doses tested. Results suggest that stimulation of non-specific immune factors enhances the ability of fish to mount a protective immune response, but specific antibody appears necessary to provide near complete protection. In this study, an ELISA was developed to monitor anti- F. psychrophilum antibody production in trout. The relationship of such responses to protective immunity suggests that future vaccination strategies against coldwater disease may require stimulation of both the innate and adaptive arms of the immune response. [source] Influence of a standardized closed soft tissue trauma on resistance to local infection.JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2003An experimental study in rats Abstract Purpose: The etiology of local posttraumatic infection in the locomotor system depends on the amount, virulence and pathogenicity of the inoculated microorganisms and the local/systemic host damage due to the type and extent of the accident or iatrogenic trauma. The relative effect of these factors remains unclear. In particular, it is still unclear today whether,in presence of microorganisms,soft tissue damage and its pathophysiological consequences lead to infection after soft tissue trauma, or whether the bacterial contamination is the primarily cause for posttraumatic infection. The aim of the project was to gain information on the consequences of a soft tissue injury in terms of resistance to local infection. Since clinical populations are too heterogeneous, the problem was investigated in a standardized, reduced (no surgery or implants) experimental in vivo model. Method: In female Sprague-Dawley-rats with a standardized closed soft tissue trauma to the tibialis anterior muscle (group I: n = 13) or without (group II: n = 13), we compared the incidence of local infection after a pairwise local, percutaneously injected bacterial challenge with various concentrations of Staphylococcus aureus (2 × 104 -2 × 106 colony forming units, CFU). The standardized closed soft tissue trauma was created by application of a specially designed, computer controlled impact device. The contaminated soft tissue and the underlying bone were removed under sterile conditions after five days and quantitatively evaluated for bacterial growths. Infection was defined as positive bacterial growth at the soft tissue and/or bone. A stepwise experimental design with an ,up-and-down" dosage technique was used to adjust the bacterial challenge in the area of the ID50 (50% infection dose). Statistical evaluation of the difference between the infection rates of both groups was performed by two-sided fisher exact test (p<0.05). Results: The overall infection rate was 46%. For the group with soft tissue trauma the ID50 was 1.32 × 105 CFU and 1.05 × 106 CFU for the group without soft tissue trauma. The infection rate was 69% (9 of 13 animals) for the group with soft tissue trauma and 23% (3 of 13 animals) for the group without soft tissue trauma. This difference is statistically significant (p = 0.047). Conclusions: The infection rate after a standardized closed soft tissue injury was significantly higher and the ID50 lower than without soft tissue trauma. Our results demonstrate that in presence of microorganisms it is not primarily the bacterial contamination but rather the soft tissue damage and its pathophysiological consequences resulting in decreased infection resistance that secondarily lead to infection. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Localized antimicrobial peptide expression in human gingivaJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2001Beverly A. Dale The stratified epithelia of the oral cavity are continually exposed to bacterial challenge that is initially resisted by innate epithelial factors and by the recruitment of neutrophils. Antimicrobial peptides from phagocytes and epithelia contribute to this antimicrobial barrier. Using antibodies and in situ hybridization, we explored antimicrobial peptide expression in the varied epithelia of the periodontium and in cultured gingival epithelial cells. In gingival tissue, mRNA for the ,-defensins, human beta-defensin 1 (hBD-1) and human beta-defensin 2 (hBD-2) was predominately localized in suprabasal stratified epithelium and the peptides were detected in upper epithelial layers consistent with the formation of the stratified epithelial barrier. In cultured epithelial cells, both hBD-1 and -2 peptides were detected only in differentiating, involucrin-positive epithelial cells, although hBD-2 required stimulation by proinflammatory mediators or bacterial products for expression. ,-defensins were not detected in junctional epithelium (JE) that serves as the attachment to the tooth surface. In contrast, ,-defensins and cathelicidin family member LL-37 were detected in polymorphonuclear neutrophils (PMNs) that migrate through the JE, a localization that persists during inflammation, when the JE and surrounding tissue are highly infiltrated with PMNs. Thus, the undifferentiated JE contains exogenously expressed ,-defensins and LL-37, and the stratified epithelium contains endogenously expressed ,-defensins. These findings show that defensins and other antimicrobial peptides are localized in specific sites in the gingiva, are synthesized in different cell types, and are likely to serve different roles in various regions of the periodontium. [source] Dietary Supplementation of a Purified Nucleotide Mixture Transiently Enhanced Growth and Feed Utilization of Juvenile Red Drum, Sciaenops ocellatusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2007Peng Li Thus, we investigated effects of a purified nucleotide mixture on growth and health of young red drum. The nucleotide premix, containing salts of cytidine, uridine, adenosine, and guanidine, was coated with binders, freeze-dried, and grounded to powder. A fish-meal-based diet was supplemented with 0.03, 0.1, or 0.3% by weight of the coated nucleotide mixture or with 0.2% Optimûn® (Chemoforma Co., Basel, Switzerland), a commercial nucleotide product. The experimental diets were maintained isonitrogenous and isocaloric by adjusting amounts of casein, gelatin, and alanine. Five replicate groups of 12 juvenile red drum (10.2 ± 0.2 g/fish, mean ± SD) were fed each experimental diet for 4 wk, followed by an assay of neutrophil oxidative radical production and a bacterial challenge via intraperitoneal injection of Vibrio harveyi at 2.9 × 107 colony-forming units/g fish. Fish fed all diets supplemented with various levels of purified nucleotides showed significantly (P < 0.01) enhanced weight gain and feed efficiency during the first week of feeding compared to fish fed the basal diet. However, the dietary effects became less significant during the following 3 wk of feeding. The transient growth-enhancing effect of dietary nucleotides observed in the present study may explain the conventional controversy about nucleotide effects on fish growth. Dietary supplementation with nucleotides had no influence on terminal whole-body composition. [source] Expression of MHC Class II, CD70, CD80, CD86 and pro-inflammatory cytokines is differentially regulated in oral epithelial cells following bacterial challengeMOLECULAR ORAL MICROBIOLOGY, Issue 6 2003D. C. Han Oral epithelium may play a regulatory role in local immune responses when interacting with bacteria. The present study was undertaken to investigate the effects of selected bacterial pathogens found in periodontal and endodontic infections on oral epithelial cells. Expression of cell surface molecules (major histocompatibility complex (MHC) Class II, CD54, CD70, CD80 and CD86) and secretion of inflammatory cytokines (interleukin (IL)-1,, IL-6, and tumor necrosis factor (TNF)-,) in response to selected bacterial challenge were examined on an immortalized oral epithelial cell line, HOK-18A and a skin epithelial cell line, HaCaT. Actinomyces viscosus, Actinomyces israelii, Fusobacterium nucleatum lipopolysaccharide (LPS) or primary human periradicular exudate from a granuloma were co-cultured with epithelial cells for 4 or 24 h. Subsequently, cell surface expression of MHC Class II, CD54, CD70, CD80 and CD86, along with pro-inflammatory cytokine levels were determined using flow cytometry, ELISA and RT-PCR. Results indicated that the selected oral bacteria have greater effects on oral versus skin epithelial cells. F. nucleatum increased MHC Class II and CD54 (ICAM-1) cell surface expression on HOK-18A and HaCaT cells. A. israelii also had enhancing effects on the expression of CD54 and MHC Class II. A. israelii and LPS induced a 2.8-fold (P < 0.001) and 4.4-fold (P < 0.005) TNF-, secretion, respectively, while F. nucleatum and LPS induced a 10-fold (P < 0.0004) and 6-fold (P < 0.01) IL-1, secretion, respectively by HOK-18A. Interestingly, CD70, CD80, and CD86 were generally decreased upon bacteria and LPS challenge on HOK-18A. The effects of increased MHC Class II and decreased CD70 were also evident with challenge of human periradicular exudate on HOK-18A. The implications of the study are unique in that oral epithelial cells may play both activating and inhibitory roles in the host immune response towards infection by oral bacteria. We introduce a concept of ,dormancy' where the differential expression of key cell surface antigens on oral epithelial cells may keep the recruited immune effector cells in a state of unresponsiveness, thus contributing to the long term quiescent period observed in many periodontal and endodontic lesions. [source] Type III effectors orchestrate a complex interplay between transcriptional networks to modify basal defence responses during pathogenesis and resistanceTHE PLANT JOURNAL, Issue 1 2006William Truman Summary To successfully infect a plant, bacterial pathogens inject a collection of Type III effector proteins (TTEs) directly into the plant cell that function to overcome basal defences and redirect host metabolism for nutrition and growth. We examined (i) the transcriptional dynamics of basal defence responses between Arabidopsis thaliana and Pseudomonas syringae and (ii) how basal defence is subsequently modulated by virulence factors during compatible interactions. A set of 96 genes displaying an early, sustained induction during basal defence was identified. These were also universally co-regulated following other bacterial basal resistance and non-host responses or following elicitor challenges. Eight hundred and eighty genes were conservatively identified as being modulated by TTEs within 12 h post-inoculation (hpi), 20% of which represented transcripts previously induced by the bacteria at 2 hpi. Significant over-representation of co-regulated transcripts encoding leucine rich repeat receptor proteins and protein phosphatases were, respectively, suppressed and induced 12 hpi. These data support a model in which the pathogen avoids detection through diminution of extracellular receptors and attenuation of kinase signalling pathways. Transcripts associated with several metabolic pathways, particularly plastid based primary carbon metabolism, pigment biosynthesis and aromatic amino acid metabolism, were significantly modified by the bacterial challenge at 12 hpi. Superimposed upon this basal response, virulence factors (most likely TTEs) targeted genes involved in phenylpropanoid biosynthesis, consistent with the abrogation of lignin deposition and other wall modifications likely to restrict the passage of nutrients and water to the invading bacteria. In contrast, some pathways associated with stress tolerance are transcriptionally induced at 12 hpi by TTEs. [source] The responsive expression of heat shock protein 22 gene in zhikong scallop Chlamys farreri against a bacterial challengeAQUACULTURE RESEARCH, Issue 2 2010Lei Zhang Abstract HSP22 is a member of a small HSP subfamily contributing to the growth, transformation and apoptosis of the cell as well as acting as a molecular chaperone. In the present study, CfHSP22 cDNA was cloned from Chlamys farreri by the rapid amplification of cDNA ends technique. The full-length cDNA of CfHSP22 was of 1279 bp, consisting of a 5,-terminal untranslated region (5,UTR) of 122 bp, a 3,UTR of 581 bp with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame of 576 bp encoding a polypeptide with a molecular mass of 22.21 kDa and a predicted isoelectric point of 9.69. There was an ,-crystallin domain, a hallmark of the sHSP subfamily, in the C-terminus, and the deduced amino acid sequence of CfHSP22 showed high similarity to previously identified HSP22s. CfHSP22 was constitutively expressed in the haemocyte, muscle, kidney, gonad, gill, heart and hepatopancreas, and the expression level in the hepatopancreas was higher than that in the other tissues. CfHSP22 transcription was up-regulated and reached a maximal level at 12 h after the bacterial challenge, and then declined progressively to the original level at 48 h. These results suggested that CfHSP22 perhaps play a critical role in response to the bacterial challenge in haemocytes of scallop C. farreri. [source] Dose-dependent influences of dietary ,-1,3-glucan on innate immunity and disease resistance of hybrid striped bass Morone chrysops×Morone saxatilisAQUACULTURE RESEARCH, Issue 14 2009Peng Li Abstract To investigate potential use of dietary ,-1,3-glucan for health management of hybrid striped bass, juvenile fish were fed diets supplemented with yeast glucan (MacroGuard®) at 0.05%, 0.1% or 0.2% of diet for 4 weeks, followed by immune response assays and a bath challenge with Streptococcus iniae. Dietary glucan significantly (P<0.05) enhanced neutrophil oxidative radical production, and fish fed 0.1% glucan had a significant (P<0.05) reduction in mortality (10%) after bacterial challenge compared with fish fed the control diet (46.7%). However, accumulative mortality of fish fed 0.2% glucan was not significantly different from that of fish fed the control diet. To further elucidate this observation, macrophages from sub-adult hybrid striped bass were isolated and cultured in L-15 medium with 10% foetal calf serum and penicillin/streptomycin supplemented with 0.2, 0.5, 1, 2, 5, 20 and 100 ,g soluble glucan (MacroGuard®) mL,1 for 24 and 48 h. Intracellular superoxide anion production was significantly (P<0.001) increased by 0.5 ,g glucan mL,1, but significantly (P<0.001) suppressed by doses >5 ,g glucan mL,1. It is concluded that dietary yeast glucan has potential for use in diet formulations of hybrid striped bass to limit the adverse effects of S. iniae, but dosage should be an important consideration in administration. [source] Expression profiling of novel bacteria-induced genes from the silkworm, Bombyx moriARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2010Hiromitsu Tanaka Abstract In this study, we have newly identified three bacteria-induced genes from the silkworm Bombyx mori by quantitative reverse transcriptase-polymerase chain reaction. One of these, eukaryotic initiation factor 4E-1 (eIF4E-1), is assumed to encode an eIF4E family, which plays a role in the initiation of translation as a mRNA cap-binding protein. The second gene is BmFOXG1, belonging to a family of forkhead transcription factors, FOXG1. The third gene is MBF2-related (MBF2-R) whose product has high homology to a co-activator protein MBF2 from B. mori. Although BmFOXG1 was up-regulated in the fat body in response to three kinds of bacteria, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, eIF4E-1 and MBF2-R were up-regulated by E. coli and B. subtilis, but not S. aureus, suggesting that bacteria possessing meso-diaminopimelic acid-containing peptidoglycan but not lysine-containing peptidoglycan activate eIF4E-1 and MBF2-R, probably through a conserved immune deficiency pathway. We further profiled the expression of three genes in different tissues and a silkworm cell line, NIAS-Bm-aff3, in response to bacteria, and at different times after bacterial challenge in the fat body. © 2010 Wiley Periodicals, Inc. [source] Trade-off between immune stimulation and expression of storage protein genesARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2009Anete P. Lourenço Abstract Proteins stored in insect hemolymph may serve as a source of amino acids and energy for metabolism and development. The expression of the main storage proteins was assessed in bacterial-challenged honey bees using real-time (RT)-PCR and Western blot. After ensuring that the immune system had been activated by measuring the ensuing expression of the innate immune response genes, defensin-1 (def-1) and prophenoloxidase (proPO), we verified the expression of four genes encoding storage proteins. The levels of vitellogenin (vg) mRNA and of the respective protein were significantly lowered in bees injected with bacteria or water only (injury). An equivalent response was observed in orally-infected bees. The levels of apolipophorin II/I (apoLp-II/I) and hexamerin (hex 70a) mRNAs did not significantly change, but levels of Hex 70a protein subunit showed a substantial decay after bacterial challenge or injury. Infection also caused a strong reduction in the levels of apoLp-III transcripts. Our findings are consistent with a down-regulation of the expression and accumulation of storage proteins as a consequence of activation of the immune system, suggesting that this phenomenon represents a strategy to redirect resources to combat injury or infection. © 2009 Wiley Periodicals, Inc. [source] Pulpal responses to bacterial contamination following dentin bridging beneath hard-setting calcium hydroxide and self-etching adhesive resin systemDENTAL TRAUMATOLOGY, Issue 2 2008Yuichi Kitasako Class V cavities were prepared on 30 monkey teeth, and the pulps were exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with either DY or 2V. The cavities were restored with a hybrid resin composite. The resin composite was removed at 180 days after capping, and then cavities were left open to the oral environment for 2 weeks to obtain bacteria contamination DY (BDY) and 2V (B2V; n = 10). A non-bacterial-contaminated group capped with DY was used as control. After bacterial challenges, inflammatory cell infiltration, incidence and differentiation of dentin bridges were evaluated histologically. There were significant differences in the presence of inflammatory cell infiltration among all groups (P < 0.05). No moderate or severe inflammatory reaction was found in Group DY. Group BDY showed moderate or severe inflammatory cell infiltration in 50%, and showed four necrotic specimens. Although no statistically significant difference was found in the formation and differentiation of dentin bridges among all groups, tunnel defects in dentin bridges were detected in 70% (DY), 80% (BDY), and 50% (B2V). Group B2V showed a significantly lower presence of inflammatory cell infiltration than Group BDY (P < 0.05). Bonding agent is supposed to seal the exposure site, and the remaining bonding agent on the cavities was effective as the barrier in the dentin bridges after bacterial challenges. [source] Antibacterial Coatings: Genetically Engineered Phage Fibers and Coatings for Antibacterial Applications (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Mater. Genetic manipulation of viruses can be used to fabricate antibacterial fibers and coatings comprising crosslinked M13 bacteriophages, which are modified to bind silver ions. On page 209, Krystyn Van Vliet and co-workers demonstrate the bactericidal effects of such silverized phage fibers against several types of bacterial challenges including those potentially arising from use as wound dressings or antibacterial textiles. [source] Vancomycin covalently bonded to titanium alloy prevents bacterial colonizationJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2007Valentin Antoci Jr. Abstract Periprosthetic infection is a devastating consequence of implant insertion and can arise from hematogenous sources or surgical contamination. Microbes can preferentially colonize the implant surface and, by forming a biofilm, escape immune surveillance. We hypothesized that if an antibiotic can be tethered to a titanium alloy (Ti) surface, it will inhibit bacterial colonization, prevent biofilm formation, and avert late-stage infection. To test this hypothesis, a Ti rod was covalently derivatized with vancomycin. Reaction efficiencies were evaluated by colorimetric and spectrophotometric measurements. The vancomycin-modified surface was stable in aqueous solutions over extended time periods and maintained antibiotic coverage, even after press-fit insertion into a cadaverous rat femora. When evaluated using fluorescently labeled bacteria, or by direct colony counts, the surface-bound antibiotic prevented bacterial colonization in vitro after: (1) exposure to high levels of S. aureus; (2) extended incubation in physiological buffers; and (3) repeated bacterial challenges. Importantly, whereas the vancomycin-derivitized pins prevented bacterial colonization, S. aureus adhered to control pins, even in the presence of concentrations of vancomycin that exceeded the strain MIC. These results demonstrate that we have effectively engineered a stable, bactericidal Ti surface. This new surface holds great promise in terms of mitigating or preventing periprosthetic infection. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:858,866, 2007 [source] Eicosanoids influence in vitro elongation of plasmatocytes from the tobacco hornworm, Manduca sextaARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2005Jon S. Miller Abstract Nodule formation is the predominant insect cellular defense reaction to bacterial challenges, responsible for clearing the largest proportion of infecting bacteria from hemolymph circulation. Hemocyte spreading behavior is a critical step in the nodulation process. It has been suggested that eicosanoids mediate several steps in the process. However, the influence of eicosanoids on hemocyte spreading has not been investigated in detail. To test the hypothesis that eicosanoids mediate hemocyte spreading behavior, I treated larvae of the tobacco hornworm, Manduca sexta, with eicosanoid biosynthesis inhibitors and later assessed plasmatocyte elongation on glass slides. Plasmatocytes from larvae treated with dexamethasone did not elongate to the extent of plasmatocytes from untreated control larvae. The dexamethasone effect on plasmatocyte elongation was expressed in a dose-dependent manner and was reversed by injecting dexamethasone-treated larvae with the eicosanoid-precursor fatty acid, arachidonic acid. Palmitic acid, which is not substrate for eicosanoid biosynthesis, did not reverse the influence of dexamethasone on plasmatocyte elongation. Finally, plasmatocytes from larvae treated with a range of eicosanoid biosynthesis inhibitors did not elongate to the extent of plasmatocytes from control larvae. Plasmatocyte width did not appear to be influenced in this study. These findings strongly support the idea that insect plasmatocyte elongation is influenced by eicosanoids. Arch. Insect Biochem. Physiol. 59:42,51, 2005. © 2005 Wiley-Liss, Inc. [source] | |||||||||||||||||||