scholarly journals Stress-Induced Hsp70 Gene Expression and Inactivation of Cryptosporidium parvum Oocysts by Chlorine-Based Oxidants

2010 ◽  
Vol 76 (6) ◽  
pp. 1732-1739 ◽  
Author(s):  
George Bajszár ◽  
Alexander Dekonenko
Keyword(s):  
Cryptosporidium Parvum ◽  
Pcr Amplification ◽  
Decay Rates ◽  
Free Chlorine ◽  
Heat Shock Gene ◽  
Molecular Diagnostic ◽  
Hsp70 Mrna ◽  
Reverse Transcription Pcr ◽  
Efficacy Assessment ◽  
Tubulin Mrna

ABSTRACT Our research on the mechanisms of action of chlorine-based oxidants on Cryptosporidium parvum oocysts in water revealed a dual-phase effect: (i) response to oxidative stress, which was demonstrated by induced expression of the Hsp70 heat shock gene, and (ii) oocyst inactivation as a result of long-term exposure to oxidants. The relative biocidal effects of sodium hypochlorite (bleach) and electrolytically generated mixed oxidant solution (MOS) on C. parvum oocysts were compared at identical free chlorine concentrations. Oocyst inactivation was determined by quantitative reverse transcription-PCR (qRT-PCR) amplification of the heat-induced Hsp70 mRNA and compared with tissue culture infectivity. According to both assays, within the range between 25 and 250 mg/liter free chlorine and with 4 h contact time, MOS exhibits a higher efficacy in oocyst inactivation than hypochlorite. Other RNA-based viability assays, aimed at monitoring the levels of β-tubulin mRNA and 18S rRNA, showed relatively slow decay rates of these molecules following disinfection by chlorine-based oxidants, rendering these molecular diagnostic viability markers inappropriate for disinfection efficacy assessment.

Unusual cryptosporidiosis cases in Swedish patients: extended molecular characterization ofCryptosporidium viatorumandCryptosporidiumchipmunk genotype I

Parasitology ◽  
2013 ◽  
Vol 140 (14) ◽  
pp. 1735-1740 ◽  
Author(s):  
MARIANNE LEBBAD ◽  
JESSICA BESER ◽  
MONA INSULANDER ◽  
LILLEMOR KARLSSON ◽  
JENS G. MATTSSON ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Cryptosporidium Parvum ◽  
Geographical Variation ◽  
Indian Subcontinent ◽  
Common Species ◽  
Diagnostic Methods ◽  
Molecular Diagnostic ◽  
Cryptosporidium Hominis ◽  
Genotype I ◽  
Protein Locus

SUMMARYMost human cases of cryptosporidiosis are caused byCryptosporidium parvumorCryptosporidium hominis, but the use of molecular diagnostic methods has revealed that several other less common species or genotypes can also be involved. Here, we describe two unusual causes of cryptosporidiosis, one being the recently described speciesCryptosporidium viatorumand the otherCryptosporidiumchipmunk genotype I. Two Swedish patients who were infected withC. viatorumhad travelled to Kenya and Guatemala, respectively, and two others had been infected withCryptosporidiumchipmunk genotype I in Sweden. None of these four patients were immunocompromised, and all four showed classical symptoms of cryptosporidiosis. We performed extensive molecular characterization, including analysis of four loci. The twoC. viatorumisolates were found to differ slightly at the 70-kDa heat shock protein locus, which may indicate a local geographical variation in this species that has previously been described exclusively on the Indian subcontinent.

scholarly journals Characterization of a Putative Founder Mutation that Accounts for the High Incidence of Cystinosis in Brittany

2001 ◽  
Vol 12 (10) ◽  
pp. 2170-2174
Author(s):  
VASILIKI KALATZIS ◽  
STÉPHANIE CHERQUI ◽  
GENEVIÈVE JEAN ◽  
BÉATRICE CORDIER ◽  
PIERRE COCHAT ◽  
...  
Keyword(s):  
Autosomal Recessive ◽  
Founder Mutation ◽  
Pcr Amplification ◽  
Splice Site Mutation ◽  
Autosomal Recessive Disorder ◽  
Site Mutation ◽  
Live Births ◽  
Reverse Transcription Pcr ◽  
High Incidence

Abstract. Cystinosis is an autosomal recessive disorder, characterized by an accumulation of intralysosomal cystine, with an incidence of 1 in 100,000 to 200,000 live births. A higher incidence of cystinosis, 1 in 26,000 live births, has been reported in the western French province of Brittany. PCR amplification and sequencing has identified a 27-bp deletion starting 3 bp before the end of exon 8 and continuing into intron 8, 898-900+24del27, which has only been detected in families from this region. Reverse transcription—PCR amplification of RNA from an affected individual has shown that this mutation is indeed a splice-site mutation and results in the production of aberrant transcripts. These transcripts are predicted to either severely truncate cystinosin or alter its topology, thus accounting for the severe phenotype of these individuals. The mutation 898-900+24del27 has been identified in 7 of 18 alleles studied. This mutation is likely to be a founder mutation and would account for the higher incidence of cystinosis in Brittany.1

Investigation of chlorine wall decay in an old, decommissioned metallic pipe using a pipe section reactor

2020 ◽  
Vol 20 (3) ◽  
pp. 953-962
Author(s):  
R. Tonev ◽  
G. Dimova
Keyword(s):  
Reaction Rate ◽  
Rate Coefficient ◽  
Tap Water ◽  
Decay Rates ◽  
Free Chlorine ◽  
Reaction Rate Coefficient ◽  
Pipe Section ◽  
Reaction Coefficient ◽  
Bulk Reaction ◽  
Series Of Experiments

Abstract The study investigates the kinetics of free chlorine depletion in tap water from the Sofia distribution network. The overall decay rates, the bulk reaction rate coefficient, the wall reaction rate coefficient and the influence of mass transfer have been determined in a laboratory pipe section reactor (PSR), testing an old decommissioned metallic pipe. In total, 23 series of experiments were performed under different initial free chlorine concentrations and different hydraulic conditions. The applicability of different chlorine decay mathematical models has been investigated. A new model was proposed, combining zero order bulk reactions and first order wall reactions, describing the laboratory results with Nash-Sutcliffe efficiency coefficients over 0.99. The obtained values for the wall reaction coefficient vary in the range 0.008–0.030 m/h, decreasing exponentially with increasing initial chlorine concentration.

Quantification of Cryptosporidium parvum in anaerobic digesters treating manure by (reverse-transcription) quantitative real-time PCR, infectivity and excystation tests

2006 ◽  
Vol 53 (8) ◽  
pp. 195-202 ◽  
Author(s):  
G. Garcés ◽  
M. Effenberger ◽  
M. Najdrowski ◽  
C. Wackwitz ◽  
A. Gronauer ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Real Time ◽  
Cryptosporidium Parvum ◽  
Reverse Transcription ◽  
Real Time Pcr ◽  
Combined Treatment ◽  
Quantitative Real Time Pcr ◽  
Anaerobic Digesters ◽  
Hsp70 Mrna ◽  
Cryptosporidium Parvum Oocysts

The survival of Cryptosporidium parvum oocysts in anaerobic digesters treating manure was investigated for mesophilic, thermophilic, and a combined treatment (mesophilic–thermophilic–mesophilic) under different retention times of oocysts in the reactors. C. parvum DNA was extracted with an optimised protocol, and its amount determined by quantitative real-time PCR (qPCR). Results indicated noteworthy differences in DNA content after the different treatments. DNA was not degraded during the process. However, excystation and infectivity tests showed a reduction of viable oocyst numbers of ≥2 and ≥5 log units after the thermophilic treatment in two different experiments. Thus qPCR-targeting DNA can overestimate the number of oocysts that survive and remain viable after anaerobic digestion. However, targeting DNA is suitable to indicate the presence or absence of oocysts. Reverse transcription qPCR (RT-qPCR) targeting C. parvum hsp70 mRNA successfully indicated the presence of viable fraction of oocysts.

Synergistic inactivation of Cryptosporidium parvum using ozone followed by free chlorine in natural water

2003 ◽  
Vol 37 (19) ◽  
pp. 4737-4747 ◽  
Author(s):  
Kaushik Biswas ◽  
Stephen Craik ◽  
Daniel W. Smith ◽  
Miodrag Belosevic
Keyword(s):  
Cryptosporidium Parvum ◽  
Natural Water ◽  
Free Chlorine

scholarly journals The effect of cyanuric acid on the disinfection rate of Cryptosporidium parvum in 20-ppm free chlorine

2008 ◽  
Vol 7 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Joan M. Shields ◽  
Michael J. Arrowood ◽  
Vincent R. Hill ◽  
Michael J. Beach
Keyword(s):  
Public Health ◽  
Cryptosporidium Parvum ◽  
Cyanuric Acid ◽  
Free Chlorine ◽  
Swimming Pool ◽  
Swimming Pools ◽  
Log10 Reduction ◽  
Chlorine Residual ◽  
Cryptosporidium Oocysts ◽  
Reduction Current

Cyanuric acid is used to stabilize free chlorine to reduce photodegradation in outdoor swimming pools. While there have been numerous studies examining its effect on the disinfection rates of bacteria and viruses, it is not known whether cyanuric acid can significantly impact the effectiveness of hyperchlorination for inactivating Cryptosporidium oocysts present in fecally-contaminated swimming pools. This study examined the effect of cyanuric acid on the disinfection rate of Cryptosporidium parvum under swimming pool hyperchlorination conditions (20 mg/ml free chlorine). When 50 mg/L cyanuric acid was present there was a 0.70-log10 reduction in oocyst viability after 10 hours as compared to a 3.7-log10 reduction without cyanuric acid. Aids to remediation, such as decreasing the pH to enhance the germicidal efficiency of the free chlorine and doubling the amount of free chlorine residual, were still unable to achieve a 3-log10 reduction. Current public health recommendations for hyperchlorination and pool remediation are insufficient for pools using cyanurate-stabilized chlorine to achieve a three log inactivation of the parasite.

scholarly journals A single editing event is a prerequisite for efficient processing of potato mitochondrial phenylalanine tRNA.

1996 ◽  
Vol 16 (7) ◽  
pp. 3504-3510 ◽  
Author(s):  
L Marechal-Drouard ◽  
A Cosset ◽  
C Remacle ◽  
D Ramamonjisoa ◽  
A Dietrich
Keyword(s):  
Plant Mitochondria ◽  
Pcr Amplification ◽  
Mitochondrial Trna ◽  
Processing Efficiency ◽  
Editing Event ◽  
Tertiary Structures ◽  
Reverse Transcription Pcr ◽  
Efficient Processing ◽  
Trna Editing

In bean, potato, and Oenothera plants, the C encoded at position 4 (C4) in the mitochondrial tRNA Phe GAA gene is converted into a U in the mature tRNA. This nucleotide change corrects a mismatched C4-A69 base pair which appears when the gene sequence is folded into the cloverleaf structure. C-to-U conversions constitute the most common editing events occurring in plant mitochondrial mRNAs. While most of these conversions introduce changes in the amino acids specified by the mRNA and appear to be essential for the synthesis of functional proteins in plant mitochondria, the putative role of mitochondrial tRNA editing has not yet been defined. Since the edited form of the tRNA has the correct secondary and tertiary structures compared with the nonedited form, the two main processes which might be affected by a nucleotide conversion are aminoacylation and maturation. To test these possibilities, we determined the aminoacylation properties of unedited and edited potato mitochondrial tRNAPhe in vitro transcripts, as well as the processing efficiency of in vitro-synthesized potato mitochondrial tRNAPhe precursors. Reverse transcription-PCR amplification of natural precursors followed by cDNA sequencing was also used to investigate the influence of editing on processing. Our results show that C-to-U conversion at position 4 in the potato mitochondrial tRNA Phe GAA is not required for aminoacylation with phenylalanine but is likely to he essential for efficient processing of this tRNA.

scholarly journals Interleukin 1 induces the expression of a heat-shock gene in chondrocytes

1991 ◽  
Vol 277 (2) ◽  
pp. 327-330 ◽  
Author(s):  
T F Cruz ◽  
R A Kandel ◽  
I R Brown
Keyword(s):  
Heat Shock ◽  
Interleukin 1 ◽  
Heat Shock Gene ◽  
Proteoglycan Synthesis ◽  
Hsp70 Mrna ◽  
Mrna Species ◽  
Shock Gene ◽  
Shock Proteins ◽  
Arthritic Joints

The presence of T cells and antibodies reactive with heat-shock proteins (hsps) in the joints of patients with rheumatoid arthritis may indicate a role of hsps in this disease. In the present study we examined whether increased temperature and interleukin 1 (IL 1), both of which are elevated in arthritic joints, induced the expression of two hsp70 genes in bovine chondrocyte cultures. We found that heat shock resulted in increased expression of constitutive and inducible hsp70 mRNA species. IL 1 and phorbol 12-myristate 13-acetate (PMA) also induced an increase in the constitutive hsp70 mRNA species, but without affecting the expression of the inducible hsp70 gene. The increase induced by IL 1 was observed only after 3 h, whereas increases induced by PMA were observed within 1 h. For all treatments, the hsp70 mRNA decreased by 24 h. Heat treatment of chondrocytes did not affect levels of collagenase and caseinase activity in the medium, nor did it alter proteoglycan synthesis by these cells.

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