共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
Maria E. Rodriguez Analia L. Samo Daniela F. Hozbor Osvaldo M. Yantorno 《Journal of industrial microbiology & biotechnology》1993,12(2):103-108
Summary The production ofBordetella pertussis extracytoplasmic filamentous haemagglutinin (FHA) and pertussis toxin (PT) in a bioreactor under stirring conditions was studied in order to investigate the effect of hydromechanical forces on yields of both antigens. It was shown that FHA loses its haemagglutinin activity when the power transmitted by the agitator and the aerator per unit volume increases, whereas PT production is not affected. The loss of FHA activity can be explained by the action of shear forces on the filamentous structure of this antigen.Nomenclature C*
dissolved oxygen saturation concentration
- C1
dissolved oxygen concentration
- D
impeller diameter
-
power transmitted by the agitator and the aerator per unit of liquid volume
- Em
maximum local energy dissipation rate per unit of liquid volume
- KLa
volumetric oxygen transfer coefficient
- N
impeller speed
- Pg
power input in aerated system
- qO2m
maximum specific oxygen consumption rate
- Re
Reynold number (D2N /)
- VVM
volume of air per volume of fermentation broth per minute
- Xm
maximum of biomass concentration
- o
Kolmogorov-microscale
-
fermentation broth viscosity
-
fermentation broth kinematic viscosity
-
fermentation broth density
- expt
experiment 相似文献
3.
Rob J. L. Willems Cecile Geuijen Han G. J. van der Heide Genevieve Renauld Philippe Berlin Willem M. R. van den Akker Camille Locht Frits R. Mooi 《Molecular microbiology》1994,11(2):337-347
The chromosome of Bordetella pertussis harbours a region of 27 contiguous kb, which contains the bvg, fha and flm genes, involved in the co-ordinate regulation of virulence genes, FHA production and fimbriae production, respectively. The linkage of FHA and fimbrial genes has resulted in some confusion concerning the existence and location of genes required for the production of FHA and the function of the fimbrial genes fimB-D, which were proposed to be involved in both FHA and fimbriae biosynthesis. Through the use of non-polar mutations in each of these genes, we found that fimB-D are required for the production of both serotype 2 and 3 fimbriae, but not for FHA biosynthesis. Furthermore, a large open reading frame, designated fhaC, was identified downstream of fimD. It was shown that fhaC is essential for FHA production but not for fimbriae biogenesis. We propose that insertion mutations in fimB-D affect FHA production because of polar effects on fhaC expression. An insertion in the region downstream of fhaC had only a slight effect on FHA and fimbriae production. The fhaC gene product shows homology with ShIB and HpmB, two outer membrane proteins involved in export and activation of the haemolysins, ShIA and HpmA, of Serratia marcescens and Proteus mirabilis, respectively. Homology is also observed between the N-termini of FHA, ShIA and HpmA. Export of the haemolysins requires the Af-termini of these molecules, and when this region was removed from FHA by an in-frame deletion, FHA biosynthesis was abolished. These results suggest that the N-terminus of FHA interacts with FhaC, and that as a result FHA is transported across the outer membrane. 相似文献
4.
FhaC is an outer membrane transporter from Bordetella pertussis belonging to the t wo‐ p artner s ecretion (TPS) pathway with its primary role being the secretion of the virulence factor f ilamentous h aem a gglutinin (FHA). FhaC serves as a model transporter of the TPS pathway and significant work has been done to characterize the role of FhaC in FHA secretion. Recent studies characterized interactions between FHA and the POTRA domains of FhaC, suggesting that secretion may involve a successive translocation mechanism mediated by β‐augmentation and/or electrostatic interactions. Moreover, it was also shown that reconstituted FhaC is necessary and sufficient to transport FHA into proteoliposomes. While the crystal structure of FhaC clearly suggests a role in transport, the putative transport pore is plugged by an N‐terminal α‐helix (H1 helix) that occludes access by FHA. Therefore, it has been proposed that the H1 helix must be expelled from the pore in order for secretion of FHA to occur. However, this has yet to be shown experimentally. Guérin et al. (2014) report the first direct experimental evidence to show that the FhaC H1 helix is quite dynamic and exchanges between closed and open states upon interaction with FHA. 相似文献
5.
Activation of hypersensitive cell death by pathogen-induced receptor-like protein kinases from <Emphasis Type="Italic">Arabidopsis</Emphasis> 总被引:1,自引:0,他引:1
In Arabidopsis, there is a family of receptor-like protein kinases (RLKs) containing novel cysteine-rich repeats in their extracellular domains. Genes encoding many of these cysteine-rich RLKs (CRKs) are induced by pathogen infection, suggesting a possible role in plant defense responses. We have previously generated Arabidopsis plants expressing four pathogen-regulated CRK genes (CRK5, 6, 10 and 11) under control of a steroid-inducible promoter and found that induced expression of CRK5, but not the other three CRK genes, triggered hypersensitive response-like cell death in transgenic plants. In the present study, we have analyzed the structural relationship of the CRK family and identified three CRKs (CRK4, 19 and 20) that are structurally closely related to CRK5. Genes encoding these three CRKs are all induced by salicylic acid and pathogen infection. Furthermore, induced expression of CRK4, 19and 20 all activates rapid cell death in transgenic plants. Thus, the activity of inducing rapid cell death is shared by these structurally closely related CRKs. We have also performed yeast two-hybrid screens and identified proteins that interact with the kinase domains of CRKs. One of the identified CRK-interacting proteins is the kinase-associated type 2C protein phospohatase known to interact with a number of other RLKs through its kinase-interacting FHA domain. Other CRK-interacting proteins include a second protein with a FHA domain and another type 2C protein phosphatase. Interactions of CRKs with these three proteins in vivo were demonstrated through co-immunoprecipitation. These CRK-interacting proteins may play roles in the regulation and signaling of CRKs. 相似文献
6.
The filamentous haemagglutinin, a multifaceted adhesin produced by virulent Bordetella spp. 总被引:3,自引:3,他引:0
Camille Locht Philippe Berlin Franco D. Menozzi Genevieve Renauld† 《Molecular microbiology》1993,9(4):653-660
Filamentous haemagglutinin (FHA) is the major attachment factor produced by virulent Bordetella spp. Similar to the other virulence factors, its production is tightly regulated by a two-component system in response to environmental changes. Although of impressive size (c. 220 kDa), it is very efficiently released into the culture supernatant of Bordetella pertussis. Its biogenesis involves complex processing of a larger precursor with a calculated molecular mass of 370 kDa. Export of FHA into the culture medium depends on an outer membrane protein homologous to haemolysin accessory proteins. Purified extracellular FHA is able to increase the adherence of other pathogens to the host, which may contribute to super-infection in whooping cough. Although FHA- mutants colonize lungs as efficiently as the wild-type parent strains, immune responses against FHA appear to protect against colonization. Unlike many other adhesins, FHA expresses at least three different attachment activities, one specific for the CR3 integrins of macrophages, one involving a carbohydrate-binding site, specific for interactions with cilia, and a heparin-binding activity that may be important for interaction of B. pertussis with epithelial cells or extracellular matrices. 相似文献
7.
Steven M. Julio Carol S. Inatsuka Joseph Mazar Christine Dieterich David A. Relman Peggy A. Cotter 《Molecular microbiology》2009,71(6):1574-1590
Bacteria of the Bordetella genus cause respiratory tract infections. Both broad host range (e.g. Bordetella bronchiseptica) and human‐adapted (e.g. Bordetella pertussis) strains produce a surface‐exposed and secreted protein called filamentous haemagglutinin (FHA) that functions in adherence and immunomodulation. Previous studies using B. pertussis and cultured mammalian cells identified several FHA domains with potential roles in host cell interactions, including an Arg‐Gly‐Asp (RGD) triplet that was reported to bind integrins on epithelial cells and monocytes to activate host signalling pathways. We show here that, in contrast to our previous report, the fhaB genes of B. pertussis and B. bronchiseptica are functionally interchangeable, at least with regard to the various in vitro and in vivo assays investigated. This result is significant because it indicates that information obtained studying FHA using B. bronchiseptica and natural‐host animal models should apply to B. pertussis FHA as well. We also show that the C‐terminus of mature FHA, which we name the MCD, mediates adherence to epithelial and macrophage‐like cells and is required for colonization of the rat respiratory tract and modulation of the inflammatory response in mouse lungs. We could not, however, detect a role for the RGD in any of these processes. 相似文献
8.
Christopher R. Noël Joseph Mazar Jeffrey A. Melvin Jessica A. Sexton Peggy A. Cotter 《Molecular microbiology》2012,86(4):988-1006
Two‐partner secretion (TPS) systems use β‐barrel proteins of the Omp85‐TpsB superfamily to transport large exoproteins across the outer membranes of Gram‐negative bacteria. The Bordetella FHA/FhaC proteins are prototypical of TPS systems in which the exoprotein contains a large C‐terminal prodomain that is removed during translocation. Although it is known that the FhaB prodomain is required for FHA function in vivo, its role in FHA maturation has remained mysterious. We show here that the FhaB prodomain is required for the extracellularly located mature C‐terminal domain (MCD) of FHA to achieve its proper conformation. We show that the C‐terminus of the prodomain is retained intracellularly and that sequences within the N‐terminus of the prodomain are required for this intracellular localization. We also identify sequences at the C‐terminus of the MCD that are required for release of mature FHA from the cell surface. Our data support a model in which the intracellularly located prodomain affects the final conformation of the extracellularly located MCD. We hypothesize that maturation triggers cleavage and degradation of the prodomain. 相似文献
9.
The mammalian pathogen Bordetella bronchiseptica was grown under controlled batch conditions with glutamate as the primary carbon and nitrogen source. First, a Box-Behnken statistical design quantified the effect of Mg, sulfate, and nicotinate on the antigen filamentous hemagglutinin (FHA) formation. Using lactic acid as a secondary carbon source for pH control, Mg, and SO4 each negatively affected antigen expression, while nicotinate positively affected antigen expression. Sulfate had a stronger negative effect than Mg with 10 mM eliminating FHA altogether; the highest FHA expression (about 1,000 ng/mL) occurred when either Mg concentration or SO4 concentration, but not both, was about 0.1 mM. Using two Mg and SO4 compositions modeled to yield the greatest antigen expression, three other organic acids were compared as the secondary carbon source: acetate, citrate, and succinate. Mixtures of acetate and glutamate resulted in the greatest organic acid consumption, OD, and FHA concentration (about 1,500 ng/mL), although significant acetate accumulated during these batch processes. The mechanism leading to elevated FHA expression when acetate is the secondary carbon source is unknown, particularly since these cultures were most prone to phase shift to Bvg? cultures. 相似文献
10.
Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro
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Casandra Hoffman Joshua Eby Mary Gray F. Heath Damron Jeffrey Melvin Peggy Cotter Erik Hewlett 《Molecular microbiology》2017,103(2):214-228
Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous haemagglutinin (FHA), a surface‐displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT‐FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro. Exogenous ACT inhibits biofilm formation in a concentration‐dependent manner and the N‐terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C‐terminal segment of FHA with ~650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C‐terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host‐directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT. 相似文献
11.
Maria T. Panteva Reza Salari Monica Bhattacharjee Lillian T. Chong 《Biophysical journal》2011,100(9):L50
Using explicit solvent molecular dynamics simulations, we were able to obtain direct observations of shifts in the hydrogen-bonding register of an intermolecular β-sheet protein-peptide complex. The β-sheet is formed between the FHA domain of cancer marker protein Ki67 (Ki67FHA) and a peptide fragment of the hNIFK signaling protein. Potential encounter complexes of the Ki67FHA receptor and hNIFK peptide are misregistered states of the β-sheet. Rearrangements of one of these misregistered states to the native state were captured in three independent simulations. All three rearrangements occurred by a common mechanism: an aromatic residue of the peptide (F263) anchors into a transient hydrophobic pocket of the receptor to facilitate the formation of native hydrogen bonds. To our knowledge, these simulations provide the first atomically detailed visualizations of a mechanism by which nature might correct for errors in the alignment of intermolecular β-sheets. 相似文献
12.
Spatial, seasonal and species variations of harmful algal blooms in the South Yellow Sea and East China Sea 总被引:12,自引:0,他引:12
DanLing Tang BaoPing Di Guifeng Wei I-Hsun Ni Im Sang Oh SuFen Wang 《Hydrobiologia》2006,568(1):245-253
The occurrences of harmful algal blooms (HABs), in terms of frequency and area in the Chinese coastal waters, have been increasing
since 1980s and caused considerable economic losses. In the present study, we have analyzed spatial and seasonal characteristics
of HAB events in the southern Yellow Sea and East China Sea along Chinese coast from 1933 to 2004. With a total 435 HAB records,
the most frequent HAB occurrence area (FHA) is off the Yangtze River mouth and another two FHA areas are located south of
the Yangtze River estuary along about isobaths of 30–60 m coastal water in the East China Sea. The time of HAB occurrence
shifted during our study period: from autumn (August–October) before 1980s to July–August in 1980s, during May–July in 1990s,
and May–June for the period of 2000–2004. Causative species were found to be different: Noctiluca scintillans and Skeletonema costatum were dominant causative species prior to 2000; and Prorocentrum donghaiense Lu was dominant from 2000 to 2004 and also caused large blooms in May. Trichodesmium sp. caused many HABs in autumn (August–October) prior to 1980s with only one HAB between 1980 and 2004. The changes of the
dominant HAB species may have affected the timings of HAB occurrence, as well as the increasing HAB-affected areas in recent
years. 相似文献
13.
Jinyong Z Xiaoli Z Weijun Z Ying G Gang G Xuhu M Quanming Z 《Molecular biology reports》2011,38(3):1957-1963
Mutants of pertussis toxin (PT) S1 subunit and filamentous hemagglutinin (FHA) type I immunodominant domain from Bordetella pertussis (B. pertussis) are considered to be effective candidate antigens for acellular pertussis vaccines; however, the substantial progress is
hampered in part for the lack of a suitable in vitro expression system. In this paper, the gene sequences of a S1 mutant C180-R9K/E129G
(mS1) and a truncated peptide named Fs from FHA type I immunodominant domain were linked together and constructed to pET22b
expression vector as a fusion gene; after inducing with IPTG, it was highly expressed in E. coli BL21 (DE3) as inclusion body. The fusion protein FsmS1 was purified from cell lysates and refolded successfully. The result
of Western blotting indicate that it was able to react with both anti-S1 and anti-FHA McAbs; antiserum produced from New Zealand
white rabbits immunized with this protein was able to recognize both native PT and FHA antigens as determined by western blotting.
These data have provided a novel feasible method to produce PT S1 subunit and FHA type I immunodominant domain in large scale
in vitro, which is implicated for the development of multivalent subunit vaccines candidate against B. pertussis infection. 相似文献
14.
Françcoise Jacob-Dubuisson Corinne Buisine Nathalie Mielcarek Eve Clément Franco D. Menozzi Camille Locht 《Molecular microbiology》1996,19(1):65-78
The 220 kDa filamentous haemagglutinin (FHA) is a major adhesin of Bordetella pertussis and is produced from a large precursor designated FhaB. Although partly surface associated, it is also very efficiently secreted into the extracellular milieu. Its secretion depends on the outer membrane accessory protein FhaC. An 80 kDa N-terminal derivative of FHA, named Fha44, can also be very efficiently secreted in a FhaC-dependent manner, indicating that all necessary secre tion signals are localized in the N-terminal region of FhaB. A comparison of predicted and apparent sizes of FHA derivatives, in addition to immunoblot analyses of cell-associated and secreted FHA polypeptides, indicated that FhaB undergoes N-terminal maturation by the cleavage of an 8–9 kDa segment. However, phenotypic analyses of translational lacZ and phoA fusions showed that this segment does not function as a typical signal peptide. Co-expression of the Fha44-encoding gene with fhaC also did not allow for secretion of Fha44 in Escherichia coli. High levels of secretion could, however, be observed when the OmpA signal peptide was fused to the N-terminal end of Fha44. Regardless of the OmpA signal peptide-Fha44 fusion point, the E. coli-secreted Fha44 had the same Mr as that secreted by B. pertussis, indicating that the N-terminal proteolytic maturation does not require a B. perfussis-specific factor. Similar to FHA, the B. pertussis-secreted Fha44 contains an as yet uncharacterized modification at its N-terminus. This modification did not occur in E. coli and is therefore not required for secretion. The N-terminus of Fha44 secreted by E. coli was determined and found to correspond to the 72nd residue after the first in-frame methionine of FhaB. The N-terminal modification was also found not to be required for haemagglutination or interaction with sulphated glycoconjugates. 相似文献
15.
Birgit An der Lan James L. Cowell Don G. Burstyn Charles R. Manclark Andreas Chrambach 《Molecular and cellular biochemistry》1986,70(1):31-55
Summary A highly purified preparation of filamentous hemagglutinin (FHA) from Bordetella pertussis was analyzed for its protein composition by gel electrophoretic methods. In this preparation of FHA the following native species could be detected by polyacrylamide gel electrophoresis (PAGE) at pH 3.2: S, and S2 (inactive subunits or fragments); two monomers, a major form designated Ia (144K), and a minor form lb, differing only in net charge; and three oligomeric forms, designated II (213K), III (595K) and IV (1064K). Hemagglutinating activity was associated predominantly with component Ia. PAGE of FHA after derivatization with sodium dodecyl sulfate (SDS) showed there to be three major species, designated A, C and D. According to estimated molecular weight values, A, C and D are likely to correspond to S2, Ia and II respectively. Isolated components II, III and IV yield all three SDS-species upon derivatization with SDS. Both moving boundary electrophoresis and gel electrofocusing showed hemagglutinating FHA to be a basic protein. Its apparent pI is 8.1. 相似文献
16.
Colombi D Oliveira ML Campos IB Monedero V Pérez-Martinez G Ho PL 《Current microbiology》2006,53(6):462-466
Filamentous haemagglutinin adhesin (FHA) is an important virulence factor from Bordetella pertussis related to the adhesion and spread of the bacteria through the respiratory tract. Three distinct domains have been characterized
in mature FHA, and among them, the FHA442–863 fragment was suggested to be responsible for the heparin-binding activity. In this study, we cloned the gene encoding the
HEP fragment (FHA430–873) in a Lactobacillus casei–inducible expression vector based on the lactose operon. The recombinant bacteria, transformed with the resulting construct
(L. casei-HEP), were able to express the heterologous protein depending on the sugar added to the culture. Subcutaneous inoculation
of L. casei-HEP in Balb/C mice, using the cholera toxin B subunit as adjuvant, induced systemic anti-HEP antibodies that were able to
inhibit in vitro erythrocyte haemagglutination induced by FHA. This is the first example of a B. pertussis antigen produced in lactic acid bacteria and opens new perspectives for alternative vaccine strategies against whooping cough. 相似文献
17.
Analyses of dental function are an essential component of the study of human evolution. However, with few exceptions, they have utilized the traditional analogizing method of comparative anatomy, and have assumed rather than demonstrated that proposed adaptive characters confer a performance benefit. Since food reduction is a mechanical process, it is appropriate to measure performance using mechanical parameters, specifically the ability of a given morphology to induce failure in food particle by either of the two major regimes: crush and shear, corresponding to simple stresses (tensile and compressive) and shear stress, respectively. We apply finite elements stress analysis to model the relationship between the angulation of the intercuspal occlusal surfaces in a “puncture crushing” mode of mastication. On the basis of morphological data acquired from sectioned great ape molars, we have predicted the nature, magnitude and distribution of stress in a standard food particle by models representing each morphotype. Results indicate that the blunt-cusped molars ofHomo, the gradually-sloping supporting (buccal) cusps but high-angled guiding (lingual) cusps of the lower molars ofPan, and the high angled occlusal surfaces ofGorillaare all more likely to fracture small food particles by shear, while the gradually sloping occlusal surfaces ofPongomolars are more likely to break them down by “crush”. Mechanisms of food failure induced by molars ofPanandHomowill vary according to the orientation of the tooth–food contacting surfaces, which in turn will vary according to the size of the food particle. These genera may be able to break food down either by shear or by “crush”. 相似文献
18.
In order to control suitable mycelium morphology to obtain high lipase productivity by Rhizopus chinensis in submerged fermentation, the effects of fungal morphology on the lipase production by this strain both in shake flask and
fermentor were investigated. Different inoculum level and shear stress were used to develop distinctive morphologies. Analyses
and investigations both on micromorphology and macromorphology were performed. Study of micromorphology reveals that micromorphologies
for dispersed mycelia and aggregated mycelia are different in cell shape, biosynthetic activity. Macromorphology and broth
rheology study in fermentor indicate that pellet formation results in low broth viscosity. Under this condition, the oil can
disperse sufficiently in broth which is very important for lipase production. These results indicate that morphology changes
affected the lipase production significantly for R. chinensis and the aggregated mycelia were suggested to achieve high lipase production. 相似文献
19.
Nilesh Patel Viviane Choy Philippe Malouf Jules Thibault 《Process Biochemistry》2009,44(10):1164-1171
A series of fed-batch experiments at different agitation speeds were performed using the industrially important strain Trichoderma reesei RUT C-30 in two different bioreactors to understand the close relationship that exists between the shear field within a bioreactor, the morphology of the microorganism, the rheology of cultivation broth, and the process performance. The two bioreactors, stirred tank bioreactor (STB) and reciprocating plate bioreactor (RPB), are characterized by a significantly different shear field to which microorganisms are exposed. Highest biomass concentration (ca. 15 g l−1) was obtained at higher agitation rates in both bioreactors due to better oxygen supply. However, better filter paper activities per mg of protein were obtained at lower agitation in both bioreactors. In both bioreactors, young and healthier fungi in the batch phase were not affected by shear even at higher agitation rates. However, during the fed-batch phase, higher degree of fragmentation of clump morphology at high agitation intensity was confirmed by image analysis. Also, the rheological analysis showed an increase in apparent viscosity during the batch phase and early fed-batch phase due to the increase in the biomass concentration. During the late stages of cultivation, the apparent viscosity decreased due to cell lysis and spore formation. 相似文献
20.
Mohammadhossein Esnaashary Mohammadhossein Fathi Mahdi Ahmadian 《Biotechnology letters》2014,36(6):1343-1347
The effect of the fluorine content and nano-structure of fluoridated hydroxyapatite (FHA) on human osteoblast-like (HO) cell behavior were investigated. FHA nanopowders and bulk nanostructured FHA, produced via mechanical alloying and two-step sintering, respectively, were used. The cytotoxicity of FHA nanopowders was assessed by MTT. Cell attachment to the surface of the bulk nanostructured FHA was evaluated by culturing of HO cells. Although HO cells proliferated 10 % more in contact with FHA nanopowders compared to culture medium without FHA nanopowders, an increase in the fluorine content of FHA caused a delay in the cell proliferation by about 2 days. Cell attachment on the bulk nanostructured FHA did not change the fluorine content. 相似文献