scholarly journals Production and Characterization of Antibodies against Each of the Three Subunits of the Bacillus cereus Nonhemolytic Enterotoxin Complex

2005 ◽  
Vol 71 (12) ◽  
pp. 8214-8220 ◽  
Author(s):  
Richard Dietrich ◽  
Maximilian Moravek ◽  
Christine Bürk ◽  
Per Einar Granum ◽  
Erwin Märtlbauer
Keyword(s):  
Bacillus Cereus ◽  
Rabbit Antiserum ◽  
Food Poisoning ◽  
Cross Reactivity ◽  
Terminal Part ◽  
Complete Set ◽  
Different Strains ◽  
First Time ◽  
Three Components

ABSTRACT The nonhemolytic enterotoxin (Nhe) is one of the two three-component enterotoxins which are responsible for diarrheal food poisoning syndrome caused by Bacillus cereus. To facilitate the detection of this toxin, consisting of the subunits NheA, NheB, and NheC, a complete set of high-affinity antibodies against each of the three components was established and characterized. A rabbit antiserum specific for the C-terminal part (15 amino acids) of NheC was produced using a respective synthetic peptide coupled to a protein carrier for immunization. Using purified B. cereus exoprotein preparations as immunogens, one monoclonal antibody against NheA and several antibodies against NheB were obtained. No cross-reactivity with other proteins produced by different strains of B. cereus was observed. Antibodies against the NheB component were able to neutralize the cytotoxic activity (up to 98%) of Nhe. Based on indirect enzyme immunoassays, the antibodies developed in this study were successfully used in the characterization of the enterotoxic activity of several B. cereus strains. For the first time, it could be shown that strains carrying the nhe genes usually express the complete set of the three components, including NheC. However, the amount of toxin produced varies considerably between the different strains.

scholarly journals Production and Characterization of Monoclonal Antibodies against the Hemolysin BL Enterotoxin Complex Produced byBacillus cereus

1999 ◽  
Vol 65 (10) ◽  
pp. 4470-4474 ◽  
Author(s):  
R. Dietrich ◽  
C. Fella ◽  
S. Strich ◽  
E. Märtlbauer
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Bacillus Cereus ◽  
Cell Lines ◽  
Cross Reactivity ◽  
Uncharacterized Protein ◽  
Hybridoma Cell Lines ◽  
Different Strains ◽  
Hemolysin Bl

ABSTRACT A total of five hybridoma cell lines that produced monoclonal antibodies against the components of the hemolysin BL (HBL) enterotoxin complex and sphingomyelinase produced by Bacillus cereuswere established and characterized. Monoclonal antibody 2A3 was specific for the B component, antibodies 1A12 and 8B12 were specific for the L2 component, and antibody 1C2 was specific for the L1 protein of the HBL enterotoxin complex. No cross-reactivity with other proteins produced by different strains ofB. cereus was observed for monoclonal antibodies 2A3, 1A12, and 8B12, whereas antibody 1C2 cross-reacted with an uncharacterized protein of approximately 93 kDa and with a 39-kDa protein, which possibly represents one component of the nonhemolytic enterotoxin complex. Antibody 2A12 finally showed a distinct reactivity withB. cereus sphingomyelinase. The monoclonal antibodies developed in this study were also successfully applied in indirect enzyme immunoassays for the characterization of the enterotoxic activity of B. cereus strains. About 50% of the strains tested were capable of producing the HBL enterotoxin complex, and it could be demonstrated that all strains producing HBL were also highly cytotoxic.

scholarly journals Incidence and characterisation of Bacillus cereus bacteriophages from Thua Nao, a Thai fermented soybean product

2021 ◽  
Vol 12 (1) ◽  
pp. 85-93
Author(s):  
Wallapat Phongtang ◽  
Ekachai Chukeatirote
Keyword(s):  
Bacillus Cereus ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Morphological Analysis ◽  
Food Poisoning ◽  
Fermented Soybean ◽  
Foodborne Pathogenic Bacteria ◽  
Ph Range ◽  
Potential Use

Abstract Bacillus cereus is considered to be an important food poisoning agent causing diarrhea and vomiting. In this study, the occurrence of B. cereus bacteriophages in Thai fermented soybean products (Thua Nao) was studied using five B. cereus sensu lato indicator strains (four B. cereus strains and one B. thuringiensis strain). In a total of 26 Thua Nao samples, there were only two bacteriophages namely BaceFT01 and BaceCM02 exhibiting lytic activity against B. cereus. Morphological analysis revealed that these two bacteriophages belonged to the Myoviridae. Both phages were specific to B. cereus and not able to lyse other tested bacteria including B. licheniformis and B. subtilis. The two phages were able to survive in a pH range between 5 and 12. However, both phages were inactive either by treatment of 50°C for 2 h or exposure of UV for 2 h. It should be noted that both phages were chloroform-insensitive, however. This is the first report describing the presence of bacteriophages in Thua Nao products. The characterization of these two phages is expected to be useful in the food industry for an alternative strategy including the potential use of the phages as a biocontrol candidate against foodborne pathogenic bacteria.

scholarly journals Characterization of Each St and Y Genome Chromosome of Roegneria grandis Based on Newly Developed FISH Markers

2021 ◽  
pp. 213-222
Author(s):  
Dandan Wu ◽  
Xiaoxia Zhu ◽  
Lu Tan ◽  
Haiqin Zhang ◽  
Lina Sha ◽  
...  
Keyword(s):  
Structural Changes ◽  
Distribution Patterns ◽  
Proximal Region ◽  
Genome Chromosome ◽  
High Affinity ◽  
Complete Set ◽  
Genome Analyses ◽  
First Time ◽  
Homoeologous Chromosomes

The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of <i>Roegneria</i> C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among <i>Roegneria</i> species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of <i>R. grandis</i> (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.

scholarly journals The CasKR Two-Component System Is Required for the Growth of Mesophilic and Psychrotolerant Bacillus cereus Strains at Low Temperatures

2014 ◽  
Vol 80 (8) ◽  
pp. 2493-2503 ◽  
Author(s):  
Sara Esther Diomandé ◽  
Stéphanie Chamot ◽  
Vera Antolinos ◽  
Florian Vasai ◽  
Marie-Hélène Guinebretière ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Two Component System ◽  
Diverse Range ◽  
Component System ◽  
Content Type ◽  
Two Component ◽  
Temperature Ranges ◽  
Different Strains

ABSTRACTThe different strains ofBacillus cereuscan grow at temperatures covering a very diverse range. SomeB. cereusstrains can grow in chilled food and consequently cause food poisoning. We have identified a new sensor/regulator mechanism involved in low-temperatureB. cereusgrowth. Construction of a mutant of this two-component system enabled us to show that this system, called CasKR, is required for growth at the minimal temperature (Tmin). CasKR was also involved in optimal cold growth aboveTminand in cell survival belowTmin. Microscopic observation showed that CasKR plays a key role in cell shape during cold growth. Introducing thecasKRgenes in a ΔcasKRmutant restored its ability to grow atTmin. Although it was first identified in the ATCC 14579 model strain, this mechanism has been conserved in most strains of theB. cereusgroup. We show that the role of CasKR in cold growth is similar in otherB. cereus sensu latostrains with different growth temperature ranges, including psychrotolerant strains.

scholarly journals Characterization of Bacillus cereus in Dairy Products in China

Toxins ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 454 ◽  
Author(s):  
Xiao-Ye Liu ◽  
Qiao Hu ◽  
Fei Xu ◽  
Shuang-Yang Ding ◽  
Kui Zhu
Keyword(s):  
Bacillus Cereus ◽  
Virulence Factors ◽  
Prevalence Rate ◽  
Dairy Products ◽  
Foodborne Pathogen ◽  
Food Poisoning ◽  
Intervention Strategies ◽  
Epidemiological Characteristics ◽  
Shed Light

Bacillus cereus is a common and ubiquitous foodborne pathogen with an increasing prevalence rate in dairy products in China. High and unmet demands for such products, particularly milk, raise the risk of B. cereus associated contamination. The presence of B. cereus and its virulence factors in dairy products may cause food poisoning and other illnesses. Thus, this review first summarizes the epidemiological characteristics and analytical assays of B. cereus from dairy products in China, providing insights into the implementation of intervention strategies. In addition, the recent achievements on the cytotoxicity and mechanisms of B. cereus are also presented to shed light on the therapeutic options for B. cereus associated infections.

scholarly journals Can proteomics of snake venoms help drug discovery? A study on the venom of spectacled cobra (Naja naja) from the Western Ghats

2021 ◽  
Author(s):  
Muralidharan Vanuopadath ◽  
Dileepkumar Raveendran ◽  
Bipin Gopalakrishnan Nair ◽  
Sudarslal Sadasivan Nair
Keyword(s):  
Glutathione Peroxidase ◽  
Western Ghats ◽  
De Novo ◽  
Cross Reactivity ◽  
Cobra Venom ◽  
Venom Protein ◽  
Naja Naja ◽  
First Time ◽  
The Western Ghats

AbstractVenom proteome profiling is important to understand the toxicology and treatment of persons poisoned by animal venoms. An in depth understanding of the pharmacological mechanisms induced by venom toxins could help in the discovery of novel drug molecules. In the current study, we aimed to delineate the venom toxins of Indian cobra (Naja naja) from the Western Ghats of India through SDS-PAGE and reversed-phase HPLC followed by Q-TOF LC-MS/MS analysis, incorporating PEAKS and Novor assisted de novo sequencing methodologies. A total of 143 proteins distributed across 17 different enzymatic and non-enzymatic venom protein families were identified. The de novo analysis exclusively yielded 59 peptides representing 28 venom protein families. Among these, glutathione peroxidase and endonuclease were reported for the first time in Indian cobra venom. Immunological cross-reactivity of cobra venom assessed using Indian polyvalent antivenoms suggested that VINS showed better EC50 (2.48 µg/mL) values than that of PSAV (6.04 µg/mL) and Virchow (6.03 µg/mL) antivenoms. Also, immunoaffinity chromatography performed using VINS antivenom indicated that it failed to detect few low molecular mass proteins (<10 kDa) that include three-finger toxins, phospholipase A2s and kunitz-type serine protease inhibitors. Taken together, the present study enabled a large-scale characterization of the venom proteome of Naja naja that offers valuable insights on the possible pharmacological mechanisms and future therapeutic potential of hitherto unexplored snake venom constituents.SignificanceThe present work describes the venom proteome characterization of Naja naja collected from the Western Ghats region in India, incorporating conventional proteomics approaches as well as de novo sequencing methods. Interestingly, we were able to determine proteins belong to glutathione peroxidase and endonuclease family, which was not reported in any of the previous studies on Naja naja venom. Notably, our study has reported the highest number of proteins from cobra venom so far. Also, the current study highlights the importance of developing region-specific antivenoms for improving the specificity and cross-neutralization potential of antivenoms.HighlightsProteomics of cobra venom resulted in the identification of 143 proteins.De novo approaches exclusively yielded 59 peptides representing 28 proteins.Glutathione peroxidase and endonuclease were identified for the first time in Indian cobra venom.Indian polyvalent antivenoms showed varying cross-reactivity towards cobra venom.VINS antivenom failed to detect few low molecular mass proteins (< 10 kDa).

Characterization and Exposure Assessment of Emetic Bacillus cereus and Cereulide Production in Food Products on the Dutch Market

2016 ◽  
Vol 79 (2) ◽  
pp. 230-238 ◽  
Author(s):  
ELISABETH G. BIESTA-PETERS ◽  
SERGE DISSEL ◽  
MARTINE W. REIJ ◽  
MARCEL H. ZWIETERING ◽  
PAUL H. in 't VELD
Keyword(s):  
Bacillus Cereus ◽  
Exposure Assessment ◽  
Food Poisoning ◽  
Food Product ◽  
Food Products ◽  
Food Samples ◽  
Two Samples ◽  
Contaminated Food ◽  
Germination And Growth

ABSTRACT The emetic toxin cereulide, which can be produced by Bacillus cereus, can be the cause of food poisoning upon ingestion by the consumer. The toxin causes vomiting and is mainly produced in farinaceous food products. This article includes the prevalence of B. cereus and of cereulide in food products in The Netherlands, a characterization of B. cereus isolates obtained, cereulide production conditions, and a comparison of consumer exposure estimates with those of a previous exposure assessment. Food samples (n = 1,489) were tested for the presence of B. cereus; 5.4% of the samples contained detectable levels (&gt;102 CFU/g), and 0.7% contained levels above 105 CFU/g. Samples (n = 3,008) also were tested for the presence of cereulide. Two samples (0.067%) contained detectable levels of cereulide at 3.2 and 5.4 μg/kg of food product. Of the 481 tested isolates, 81 produced cereulide and/or contained the ces gene. None of the starch-positive and hbl-containing isolates possessed the ces gene, whereas all strains contained the nhe genes. Culture of emetic B. cereus under nonoptimal conditions revealed a delay in onset of cereulide production compared with culture under optimal conditions, and cereulide was produced in all cases when B. cereus cells had been in the stationary phase for some time. The prevalence of cereulide-contaminated food approached the prevalence of contaminated products estimated in an exposure assessment. The main food safety focus associated with this pathogen should be to prevent germination and growth of any B. cereus present in food products and thus prevent cereulide production in foods.

scholarly journals Genomic and antigenic characterization of the newly emerging Chinese duck egg-drop syndrome flavivirus: genomic comparison with Tembusu and Sitiawan viruses

2012 ◽  
Vol 93 (10) ◽  
pp. 2158-2170 ◽  
Author(s):  
Peipei Liu ◽  
Hao Lu ◽  
Shuang Li ◽  
Gregory Moureau ◽  
Yong-Qiang Deng ◽  
...  
Keyword(s):  
Egg Production ◽  
Cross Reactivity ◽  
Coding Regions ◽  
Evolutionary Origins ◽  
Glycosylation Sites ◽  
Antigenic Characterization ◽  
Close Relationship ◽  
Duck Egg ◽  
First Time

Duck egg-drop syndrome virus (DEDSV) is a newly emerging pathogenic flavivirus causing avian diseases in China. The infection occurs in laying ducks characterized by a severe drop in egg production with a fatality rate of 5–15 %. The virus was found to be most closely related to Tembusu virus (TMUV), an isolate from mosquitoes in South-east Asia. Here, we have sequenced and characterized the full-length genomes of seven DEDSV strains, including the 5′- and 3′-non-coding regions (NCRs). We also report for the first time the ORF sequences of TMUV and Sitiawan virus (STWV), another closely related flavivirus isolated from diseased chickens. We analysed the phylogenetic and antigenic relationships of DEDSV in relation to the Asian viruses TMUV and STWV, and other representative flaviviruses. Our results confirm the close relationship between DEDSV and TMUV/STWV and we discuss their probable evolutionary origins. We have also characterized the cleavage sites, potential glycosylation sites and unique motifs/modules of these viruses. Additionally, conserved sequences in both 5′- and 3′-NCRs were identified and the predicted secondary structures of the terminal sequences were studied. Antigenic cross-reactivity comparisons of DEDSV with related pathogenic flaviviruses identified a surprisingly close relationship with dengue virus (DENV) and raised the question of whether or not DEDSV may have a potential infectious threat to man. Importantly, DEDSV can be efficiently recognized by a broadly cross-reactive flavivirus mAb, 2A10G6, derived against DENV. The significance of these studies is discussed in the context of the emergence, evolution, epidemiology, antigenicity and pathogenicity of the newly emergent DEDSV.

scholarly journals Isolation and characterization of staphylococcus aureus from two large-scale food poisoning outbreaks in Vietnam

2020 ◽  
pp. 139-147
Author(s):  
Lam Quoc Hung ◽  
◽  
Huong Minh Nguyen ◽  
Ta Thi Yen ◽  
Le Vinh Hoa ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Food Production ◽  
Large Scale ◽  
Virulence Genes ◽  
Food Poisoning ◽  
Isolation And Characterization ◽  
Food Borne ◽  
Different Strains ◽  
Spa Type

In Vietnam and around the world, Staphylococcus aureus remains a major hazard of food safety and food poisoning. S. aureus is present in many places and easily contaminates food production during processing chains. In this study, we successfully isolated S. aureus strains from suspected samples of two food borne poisoning outbreaks in Ha Giang and Vinh Phuc in 2017 and 2018, respectively. The collected samples were examined for presence of staphylococcal enterotoxins (SEs) by using 3MTMTECRATM Staph Enterotoxin kit, from there all the samples were positive with SEs. Different strains of S. aureus were isolated and then confirmed by MALDI-TOF technique. Those strains then were stored in Brain heart solution with 15% glycerol until further analysis. Our results identified three STs, ST96, ST88 (spa type t7558), and ST72 (spa type t3092), were responsible for two outbreaks. Two virulence genes detected from the above strains were sea and sec. Furthermore, these strains are test for antibiotic resistance susceptibility with commonly antibiotics. Penicillin are found to be resisted by all three STs, in particularly, ST96 and ST88 are both resistant to erythromycin while ST72 is resistant to gentamicin. Taken together, our study highlights the usefulness of molecular characterization to study and monitor bacterial pathogens associated with food poisoning outbreaks in Vietnam.

scholarly journals Characterization of LysBC17, a Lytic Endopeptidase from Bacillus cereus

Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 155 ◽  
Author(s):  
Swift ◽  
Etobayeva ◽  
Reid ◽  
Waters ◽  
Oakley ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Food Poisoning ◽  
Lytic Activity ◽  
Bacillus Species ◽  
Gram Positive ◽  
Gene Encoding ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Alternative Antimicrobials

Bacillus cereus, a Gram-positive bacterium, is an agent of food poisoning. B. cereus is closely related to Bacillus anthracis, a deadly pathogen for humans, and Bacillus thuringenesis, an insect pathogen. Due to the growing prevalence of antibiotic resistance in bacteria, alternative antimicrobials are needed. One such alternative is peptidoglycan hydrolase enzymes, which can lyse Gram-positive bacteria when exposed externally. A bioinformatic search for bacteriolytic enzymes led to the discovery of a gene encoding an endolysin-like endopeptidase, LysBC17, which was then cloned from the genome of B. cereus strain Bc17. This gene is also present in the B. cereus ATCC 14579 genome. The gene for LysBC17 encodes a protein of 281 amino acids. Recombinant LysBC17 was expressed and purified from E. coli. Optimal lytic activity against B. cereus occurred between pH 7.0 and 8.0, and in the absence of NaCl. The LysBC17 enzyme had lytic activity against strains of B. cereus, B. anthracis, and other Bacillus species.

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