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1.
Synergistic Inactivation of Spores of Proteolytic Clostridium botulinum Strains by High Pressure and Heat Is Strain and Product Dependent
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M. K. Bull S. A. Olivier R. J. van Diepenbeek F. Kormelink B. Chapman 《Applied microbiology》2009,75(2):434-445
The combined high pressure and heat resistances of spores of five proteolytic Clostridium botulinum strains and of the nonpathogenic surrogate strain Clostridium sporogenes PA3679 were compared with their heat-only resistances on the basis of equivalent accumulated thermal lethality, expressed as equivalent minutes at a reference temperature of 105°C (F105°C). Comparisons were made with three model (i.e., diluted) products, namely, 30% (wt/wt) Bolognese sauce, 50% (wt/wt) cream sauce, and rice water agar. Pressure was determined to act synergistically with heat during high-pressure thermal (HPT) processing for C. botulinum FRRB 2802 (NCTC 7273) and C. botulinum FRRB 2804 (NCTC 3805 and 62A) in the Bolognese and cream sauces and for C. botulinum FRRB 2807 (213B) in the Bolognese sauce only. No synergy was observed for C. botulinum FRRB 2803 (NCTC 2916) or FRRB 2806 (62A) or C. sporogenes FRRB 2790 (NCTC 8594 and PA3679) in any of the model products. No significant protective effect of pressure against spore inactivation was determined for any Clostridium strain in any product. Because synergy was not consistently observed among strains of C. botulinum or among products, the prediction of inactivation of C. botulinum spores by HPT sterilization (HPTS) for the present must assume a complete lack of synergy. Therefore, any HPTS process for low-acid shelf-stable foods must be at least thermally equivalent to an F0 process of 2.8 min, in line with current good manufacturing practices. The results of this study suggest that the use of C. sporogenes PA3679 as a surrogate organism may risk overestimating inactivation of C. botulinum by HPT processing. 相似文献
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Background
In Malaysia, researchers and medical practitioners are unfamiliar with Naegleria infections. Thus little is known about the existence of pathogenic Naegleria fowleri, and the resultant primary amoebic meningoencephalitis (PAM) is seldom included in the differential diagnosis of central nervous system infections. This study was conducted to detect the presence of Naegleria species in various environmental samples.Methods/Findings
A total of 41 Naegleria-like isolates were isolated from water and dust samples. All these isolates were subjected to PCR using two primer sets designed from the ITS1-ITS2 regions. The N. fowleri species-specific primer set failed to produce the expected amplicon. The Naegleria genus-specific primers produced amplicons of 408 bp (35), 450 bp (2), 457 bp (2) or 381 bp (2) from all 41 isolates isolated from aquatic (33) and dust (8) samples. Analysis of the sequences from 10 representative isolates revealed that amplicons with fragments 408, 450 and 457 bp showed homology with non-pathogenic Naegleria species, and 381 bp showed homology with Vahlkampfia species. These results concurred with the morphological observation that all 39 isolates which exhibited flagella were Naegleria, while 2 isolates (AC7, and AC8, JN034055) that did not exhibit flagella were Vahlkampfia species. JN034056Conclusion
To date, pathogenic species of N. fowleri have not been isolated from Malaysia. All 39 isolates that produced amplicons (408, 450 and 457 bp) from the genus-specific primers were identified as being similar to nonpathogenic Naegleria. Amplicon 408 bp from 5 representative isolates showed 100% and 99.7% identity to Naegleria philippinensis isolate RJTM () and is thus believed to be the most common species in our environment. Amplicons 450 bp and 457 bp were respectively believed to be from 2 new species of Naegleria, since representative isolates showed lower homology and had a longer base pair length when compared to the reference species in the Genbank, Naegleria schusteri ( AM167890) and Naegleria laresi ( AJ566626), respectively. AJ566630相似文献3.
Mui-Keng Tan Harsh Raman Grant Chambers Indu Sharma Zhiliang Chen Nandan Deshpande Marc R. Wilkins 《PloS one》2016,11(11)
Tilletia indica causes the disease Karnal bunt in wheat. The disease is under international quarantine regulations. Comparative mitochondrial (mt) genome analysis of T. indica ( and KX394364) and T. walkeri ( DQ993184) has found 325 to 328 SNPs, 57 to 60 short InDels (from 1 to 13 nt), two InDels (30 and 61 nt) and five (>200 nt) presence/absence variations (PAVs) between the two species. The mt genomes of both species have identical gene order. The numbers of SNPs and InDels between the mt genomes of the two species are approximately nine times of the corresponding numbers between the two T. indica isolates. There are eight SNPs between T. indica and T. walkeri that resulted in amino acid substitutions in the mt genes of cob, nad2 and nad5. In contrast, there is no amino acid substitution in the mt genes of the T. indica isolates from the SNPs found. The five PAVs present in T. indica ( EF536375) are absent in T. walkeri. Four PAVs are more than 1 kb and are not present in every T. indica isolate. Analysis of their presence and absence separates a collection of T. indica isolates into 11 subgroups. Two PAVs have ORFs for the LAGLIDAG endonuclease and two have ORFs for the GIY-YIG endonuclease family, which are representatives of homing endonuclease genes (HEGs). These intron- encoded HEGs confer intron mobility and account for their fluid distribution in T. indica isolates. The small PAV of 221 bp, present in every T. indica isolate and unique to the species, was used as the genetic fingerprint for the successful development of a rapid, highly sensitive and specific loop mediated isothermal amplification (LAMP) assay. The simple procedure of the LAMP assay and the easy detection formats will enable the assay to be automated for high throughput diagnosis. DQ993184相似文献
4.
Background
Proteolytic Clostridium botulinum is the causative agent of botulism, a severe neuroparalytic illness. Given the severity of botulism, surprisingly little is known of the population structure, biology, phylogeny or evolution of C. botulinum. The recent determination of the genome sequence of C. botulinum has allowed comparative genomic indexing using a DNA microarray.Results
Whole genome microarray analysis revealed that 63% of the coding sequences (CDSs) present in reference strain ATCC 3502 were common to all 61 widely-representative strains of proteolytic C. botulinum and the closely related C. sporogenes tested. This indicates a relatively stable genome. There was, however, evidence for recombination and genetic exchange, in particular within the neurotoxin gene and cluster (including transfer of neurotoxin genes to C. sporogenes), and the flagellar glycosylation island (FGI). These two loci appear to have evolved independently from each other, and from the remainder of the genetic complement. A number of strains were atypical; for example, while 10 out of 14 strains that formed type A1 toxin gave almost identical profiles in whole genome, neurotoxin cluster and FGI analyses, the other four strains showed divergent properties. Furthermore, a new neurotoxin sub-type (A5) has been discovered in strains from heroin-associated wound botulism cases. For the first time, differences in glycosylation profiles of the flagella could be linked to differences in the gene content of the FGI.Conclusion
Proteolytic C. botulinum has a stable genome backbone containing specific regions of genetic heterogeneity. These include the neurotoxin gene cluster and the FGI, each having evolved independently of each other and the remainder of the genetic complement. Analysis of these genetic components provides a high degree of discrimination of strains of proteolytic C. botulinum, and is suitable for clinical and forensic investigations of botulism outbreaks. 相似文献5.
Enrico Lavezzo Stefano Toppo Luisa Barzon Claudio Cobelli Barbara Di Camillo Francesca Finotello Elisa Franchin Denis Peruzzo Gianna Maria Toffolo Marta Trevisan Giorgio Palù 《Journal of bacteriology》2010,192(19):5270-5271
Neisseria meningitidis is a human-specific pathogen known for its capability to cause sepsis and meningitis. Here we report the availability of 2 draft genome sequences obtained from patients infected during the same epidemic outbreak. Both bacterial isolates belong to serogroup C, but their genome sequences show local and remarkable differences compared with each other or with the reference genome of strain FAM18.Neisseria meningitidis is found as a commensal organism of the human nasopharynx in 8 to 25% of the adult population (9), but sporadically, it is able to cross the mucosa and reach the bloodstream, causing severe septicemia and meningitis. Even though the reasons triggering these pathogenic outbreaks are not well understood, several factors related either to the host or the bacterium have been proposed 3, 8).So far, complete genome sequences for N. meningitidis serogroups A (strain Z2491 [GenBank accession no. ]) ( AL1579594), B (strain MC58 [GenBank accession no. ]) ( AE00209810), and C (strains FAM18, 8013, and 053442 [GenBank accession no. , AM421808, and FM999788, respectively]) ( CP0003811, 5, 6) have been reported, together with the unencapsulated strain α14 (GenBank accession no. ) ( AM8891367). Here we announce the availability of 2 draft genome sequences for N. meningitidis serogroup C, strains K1207 and S0108, isolated from the same epidemic cluster which occurred in the Veneto region in northern Italy during the 2007-2008 winter (2).The genomes were sequenced using 454 pyrosequencing (Roche), combining shotgun and 30-kb paired-end strategies, according to the manufacturer''s recommendations. The coverage was nearly 27×, and assemblies were performed with Newbler. We obtained 223 and 226 contigs for the 2 genomes, which were finally mapped in 17 and 16 scaffolds, respectively. From both samples, we also isolated a 7-kb plasmid, whose sequence was nearly identical to that of pJS-B, already available in GenBank (accession no. ).The first analysis was performed by comparing sequences of the two isolates with the most similar complete genome available, strain FAM18. This analysis showed that the genome lengths were almost identical (about 2.2 Mb) and GC contents were comparable (51.91% in both isolates versus 51.62% of strain FAM18). Then, to identify potential differences in coding sequence content, the contigs obtained for both isolates were aligned with those for strain FAM18 using MEGABLAST ( NC_00475811) and LASTZ tools, which showed that in the genomes of the two N. meningitidis isolates, several genes were missing or nonfunctional because of the presence of insertions or deletions. For example, a couple of FAM18 outer membrane proteins (NMC0214 and NMC0215) were completely missing in both genomes, due to a 3-kb deletion, and no homologues were present in other genomic regions.Sequences that did not map on the genome of strain FAM18 were investigated by performing a BLAST analysis on a nonredundant database. Interestingly, besides genes or partial genes belonging to the other completely sequenced N. meningitidis serogroup C strain 053442, the genomes of our isolates contained coding sequences from N. meningitidis serogroups A and B, from other Neisseria species, such as N. gonorrhoeae, N. cinerea, and N. mucosa, and even from other bacterial species, such as cobyrinic acid ac-diamide synthase from Shewanella baltica, attesting once more to the great capability of horizontal gene transfer, which is peculiar to this microorganism.A detailed report of our two isolates will be included in a future publication, with the results of a full comparative analysis between the genomes. 相似文献
6.
Sanjib Kumar Sardar Ajanta Ghosal Yumiko Saito-Nakano Shanta Dutta Tomoyoshi Nozaki Sandipan Ganguly 《The Korean journal of parasitology》2021,59(4):409
In this study, we have collected and screened a total of 268 stool samples from diarrheal patients admitted to an Infectious disease hospital in Kolkata for the presence of Cryptosporidium spp. The initial diagnosis was carried out by microscopy followed by genus specific polymerase chain reaction assays based on 70 kDa heat shock proteins (HSP70). DNA sequencing of the amplified locus has been employed for determination of genetic diversity of the local isolates. Out of 268 collected samples, 12 (4.48%) were positive for Cryptosporidium spp. Sequences analysis of 70 kDa heat shock proteins locus in 12 Cryptosporidium local isolates revealed that 2.24% and 1.86% of samples were showing 99% to 100% identity with C. parvum and C. hominis. Along with the other 2 major species one recently described globally distributed pathogenic species Cryptosporidium viatorum has been identified. The HSP70 locus sequence of the isolate showed 100% similarity with a previously described isolate of C. viatorum (Accession No. , JX978274.1, and JX978273.1) present in GenBank. JN846706.1相似文献
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Braarudosphaera bigelowii (Prymnesiophyceae) is a coastal coccolithophore with a long fossil record, extending back to the late Cretaceous (ca. 100 Ma). A recent study revealed close phylogenetic relationships between B. bigelowii, Chrysochromulina parkeae (Prymnesiophyceae), and a prymnesiophyte that forms a symbiotic association with the nitrogen-fixing cyanobacterium UCYN-A. In order to further examine these relationships, we conducted transmission electron microscopic and molecular phylogenetic studies of B. bigelowii. TEM studies showed that, in addition to organelles, such as the nucleus, chloroplasts and mitochondria, B. bigelowii contains one or two spheroid bodies with internal lamellae. In the 18S rDNA tree of the Prymnesiophyceae, C. parkeae fell within the B. bigelowii clade, and was close to B. bigelowii Genotype III (99.89% similarity). Plastid 16S rDNA sequences obtained from B. bigelowii were close to the unidentified sequences from the oligotrophic SE Pacific Ocean (e.g. ) (99.86% similarity). Bacterial16S rDNA sequences obtained from B. bigelowii were identical to the UCYN-A sequence HM133411 from Arabian Sea, and fell in the UCYN-A clade. From these results, we suggest that; 1) C. parkeae is the alternate life cycle stage of B. bigelowii sensu stricto or that of a sibling species of B. bigelowii, and 2) the spheroid body of B. bigelowii originated from endosymbiosis of the nitrogen-fixing cyanobacterium UCYN-A. AY621693相似文献
9.
Highly polymorphic markers such as simple sequence repeats (SSRs) or microsatellites are very useful for genetic mapping. In this study novel SSRs were identified in BAC-end sequences (BES) from non-contigged, non-overlapping bacterial artificial clones (BACs) in common bean (Phaseolus vulgaris L.). These so called “singleton” BACs were from the Andean gene pool physical map and the new BES-SSR markers were used for the saturation of the inter-gene pool, DOR364× G19833 genetic map. A total of 899 SSR loci were found among the singleton BES, but only 346 loci corresponded to the single di- or tri-nucleotide motifs that were likely to be polymorphic (ATT or AG motifs, principally) and useful for primer design and individual marker mapping. When these novel SSR markers were evaluated in the DOR364× G19833 population parents, 136 markers revealed polymorphism and 106 were mapped. Genetic mapping resulted in a map length of 2291 cM with an average distance between markers of 5.2 cM. The new genetic map was compared to the most recent cytogenetic analysis of common bean chromosomes. We found that the new singleton BES-SSR were helpful in filling peri-centromeric spaces on the cytogenetic map. Short genetic distances between some new singleton-derived BES-SSR markers was common showing suppressed recombination in these regions compared to other parts of the genome. The correlation of singleton-derived SSR marker distribution with other cytogenetic features of the bean genome is discussed. G19833相似文献
10.
Jason Brunt June Plowman Duncan J. H. Gaskin Manoa Itchner Andrew T. Carter Michael W. Peck 《PLoS pathogens》2014,10(9)
Clostridium botulinum is a dangerous pathogen that forms the highly potent botulinum toxin, which when ingested causes a deadly neuroparalytic disease. The closely related Clostridium sporogenes is occasionally pathogenic, frequently associated with food spoilage and regarded as the non-toxigenic equivalent of Group I C. botulinum. Both species form highly resistant spores that are ubiquitous in the environment and which, under favourable growth conditions germinate to produce vegetative cells. To improve the control of botulinum neurotoxin-forming clostridia, it is imperative to comprehend the mechanisms by which spores germinate. Germination is initiated following the recognition of small molecules (germinants) by a specific germinant receptor (GR) located in the spore inner membrane. The present study precisely defines clostridial GRs, germinants and co-germinants. Group I C. botulinum ATCC3502 contains two tricistronic and one pentacistronic GR operons, while C. sporogenes ATCC15579 has three tricistronic and one tetracistronic GR operons. Insertional knockout mutants, allied with characterisation of recombinant GRs shows for the first time that amino acid stimulated germination in C. botulinum requires two tri-cistronic encoded GRs which act in synergy and cannot function individually. Spore germination in C. sporogenes requires one tri-cistronic GR. Two other GRs form part of a complex involved in controlling the rate of amino-acid stimulated germination. The suitability of using C. sporogenes as a substitute for C. botulinum in germination studies and food challenge tests is discussed. 相似文献
11.
Lisa F. Dawson Esmeralda Valiente Alexandra Faulds-Pain Elizabeth H. Donahue Brendan W. Wren 《PloS one》2012,7(12)
Clostridium difficile is a Gram-positive anaerobic, spore-forming bacillus that is the leading cause of nosocomial diarrhoea worldwide. We demonstrate that C. difficile aggregates and forms biofilms in vitro on abiotic surfaces. These polymicrobial aggregates are attached to each other and to an abiotic surface by an extracellular polymeric substance (EPS). The EPS matrix provides the scaffold bonding together vegetative cells and spores, as well as forming a protective barrier for vegetative cells against oxygen stress. The master regulator of sporulation, Spo0A, may play a key role in biofilm formation, as genetic inactivation of spo0A in strain exhibits decreased biofilm formation. Our findings highlight an important attribute of C. difficile pathogenesis, which may have significant implications for infection, treatment and relapse. R20291相似文献
12.
Sarah Jamali Annick Salzmann Nader Perroud Magali Ponsole-Lenfant Jennifer Cillario Patrice Roll Nathalie Roeckel-Trevisiol Ariel Crespel Jorg Balzar Kurt Schlachter Ursula Gruber-Sedlmayr Ekaterina Pataraia Christoph Baumgartner Alexander Zimprich Fritz Zimprich Alain Malafosse Pierre Szepetowski 《PloS one》2010,5(9)
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Xun-Li Xia Guang-Xiao Yang Guang-Yuan He 《Physiology and Molecular Biology of Plants》2009,15(1):99-102
A tandem gene cluster CHS-CHI-IFS (rIFS) for secondary metabolites of plant isoflavones was constructed by using the chalcone synthase (CHS), chalcone isomerase (CHI), and isoflavone synthase (IFS) (GenBank accession numbers , EU526827, EU526829) in a single recombination event with the pET22b vector. The resulting expression vector pET-rIFS was heterogeneously expressed. The highlights of the vector include ease of handling, high efficiency and universal application among diverse plant species. To the best of our knowledge, this is the first attempt at developing a novel method of constructing tandem gene cluster for future research involving secondary metabolism of isoflavones and isoflavones engineering.Key words: EU526830Isoflavones biosynthesis, Novel method, Secondary metabolism, Tandem gene cluster 相似文献
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Xiaolu Shi Yiman Lin Yaqun Qiu Yinghui Li Min Jiang Qiongcheng Chen Yixiang Jiang Jianhui Yuan Hong Cao Qinghua Hu Shenghe Huang 《PloS one》2016,11(3)
Proteus mirabilis is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in P. mirabilis genomes. Three strains of P. mirabilis / C02011/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C04010 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria. C02011相似文献
18.
Mohamed A. Hassan Sarah Abd El-Aziz Horeya M. Elbadry Samy A. El-Aassar Tamer M. Tamer 《Saudi Journal of Biological Sciences》2022,29(4):2978
Multi-drug resistant (MDR) bacteria associated with wounds are extremely escalating. This study aims to survey different wounds in Alexandria hospitals, North Egypt, to explore the prevalence and characteristics of MDR bacteria for future utilization in antibacterial wound dressing designs. Among various bacterial isolates, we determined 22 MDR bacteria could resist different classes of antibiotics. The collected samples exhibited the prevalence of mono-bacterial infections (60%), while 40% included poly-bacterial species due to previous antibiotic administration. Moreover, Gram-negative bacteria showed dominance with a ratio of 63.6%, while Gram-positive bacteria reported 36.4%. Subsequently, the five most virulent bacteria were identified following the molecular approach by 16S rRNA and physiological properties using the VITEK 2 automated system. They were deposited in GenBank as Staphylococcus haemolyticus MST1 (), Pseudomonas aeruginosa MST2 ( KY550377), Klebsiella pneumoniae MST3 ( KY550378), Escherichia coli MST4 ( KY550379), and Escherichia coli MST5 ( KY550380). In terms of isolation source, S. haemolyticus MST1 was isolated from a traumatic wound, while P. aeruginosa MST2 and E. coli MST4 were procured from hernia surgical wounds, and K. pneumoniae MST3 and E. coli MST5 were obtained from diabetic foot ulcers. Antibiotic sensitivity tests exposed that K. pneumoniae MST3, E. coli MST4, and E. coli MST5 are extended-spectrum β-lactamases (ESBLs) bacteria. Moreover, S. haemolyticus MST1 belongs to the methicillin-resistant coagulase-negative staphylococcus (MRCoNS), whereas P. aeruginosa MST2 exhibited resistance to common empirical bactericidal antibiotics. Overall, the study provides new insights into the prevalent MDR bacteria in Egypt for further use as specific models in formulating antibacterial wound dressings. KY550381相似文献
19.
Anusri Tripathi Sudip Kumar Dutta Monalisa Majumdar Lena Dhara Debolina Banerjee Krishnangshu Roy 《Indian journal of microbiology》2012,52(4):557-564
Pathogenic Klebsiella pneumoniae, resistant to beta-lactam and quinolone drugs, is widely recognized as important bacteria causing array of diseases. The resistance property is obtained by acquisition of plasmid encoded blaTEM, blaSHV, blaCTX-M, QNRA, QNRB and QNRS genes. The aim of this study was to document the prevalence and association of these resistant genes in K. pneumoniae infecting patients in India. Approximately 97 and 76.7 % of the 73 K. pneumoniae isolates showed resistance towards beta-lactam and quinolone drugs respectively. Bla genes were detected in 74 % of K. pneumoniae isolates; with prevalence in the following order: blaTEM > blaSHV > blaCTXM. QNR genes were detected in 67 % samples. Chi-square analysis revealed significant association between presence of bla and qnr genes in our study (P value = 0.000125). Sequence analysis of some blaTEM, blaSHV, blaCTX-M and QNRB PCR products revealed presence of blaTEM1 (GenBank accession: ), blaTEM116 ( JN193522 and JN193523), blaSHV11, blaCTXM72 variants ( JN193524) and QNRB1 ( JF523199 and JN193526) in our samples. JN193527相似文献
20.
A novel isolate belonging to the genus Streptomyces, strain SL-4T, was isolated from soil sample collected from a sanitary landfill, New Delhi, India. The taxonomic status of this isolate was studied by polyphasic approach including morphological, physiological and chemo-taxonomic characterization. Spore chains of SL-4T were open loops, hooks or extended spirals of wide diameter (retinaculiperti). The cell wall peptidoglycan of the isolate SL-4T contained L,L-diaminopimelic acid, suggesting that the strain has a cell wall of chemotype-I. The polar lipid profile of the isolate was of Type II, with phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The 16SrRNA gene sequence similarity between SL-4T and its phylogenetic relatives Streptomyces atrovirens NRRLB 16357T (), S. albogriseolus NRRLB 1305T ( DQ026672), S viridodiastaticus NBRC 13106T ( AJ494865), S. caelestis NRRL 2418T ( AB184317), S. flavoviridis NBRC 12772T ( X80824), S. pilosus NBRC 12807T ( AB184842) and S. longispororuber NBRC 13488T ( AB184161) was 99.65, 99.65, 99.64, 99.23, 99.15, 99.14 and 99.13 % respectively. Subsequent DNA–DNA hybridization experiments with the test strain and its clade members showed 55.27, 44.27, 36.86, and 15.65 % relatedness between SL-4T and its relatives S. atrovirens,S. albogriseolus, S. viridodiastaticus and S. longispororuber respectively. The genotypic and phenotypic data was analyzed to verify possibility of the isolate SL-4T representing novel member of the genus Streptomyces, for which the name S. antibioticalis is being proposed. The type strain is SL-4T (=CCM 7434T=MTCC 8588T). AB184440相似文献