In vitro Interactions between Hemocytes of the Eastern Oyster, Crassostrea virginica Gmelin, 1791 and Cryptosporidium parvum Oocysts

1997 ◽  
Vol 83 (5) ◽  
pp. 949 ◽  
Author(s):  
T. K. Graczyk ◽  
R. Fayer ◽  
E. J. Lewis ◽  
C. A. Farley ◽  
J. M. Trout
Keyword(s):  
Crassostrea Virginica ◽  
Cryptosporidium Parvum ◽  
Eastern Oyster ◽  
Cryptosporidium Parvum Oocysts ◽  
In Vitro Interactions

Vibrio vulnificus Load Reduction in Oysters after Combined Exposure to Vibrio vulnificus–Specific Bacteriophage and to an Oyster Extract Component†

2005 ◽  
Vol 68 (6) ◽  
pp. 1188-1191 ◽  
Author(s):  
WILLIAM PELON ◽  
RONALD B. LUFTIG ◽  
KENNETH H. JOHNSTON
Keyword(s):  
Health Risk ◽  
Crassostrea Virginica ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Load Reduction ◽  
Combined Exposure ◽  
In Vitro System ◽  
Iron Deficient ◽  
Specific Bacteriophage

Oysters infected with Vibrio vulnificus can present a serious health risk to diabetic, immunocompromised, and iron-deficient individuals. Numerous studies have been conducted with the goal of eliminating this organism from raw oysters. We utilized two natural oyster-associated components: pooled Vibrio vulnificus–specific bacteriophage and an extract of the eastern oyster (Crassostrea virginica) that contains an antimicrobial component we named anti–Vibrio vulnificus factor, which is bactericidal for V. vulnificus. Although each component alone can reduce V. vulnificus numbers independently, the simultaneous use of both components in an in vitro system successfully more effectively reduced V. vulnificus bacterial loads.

Aging of Cryptosporidium parvum oocysts in river water and their susceptibility to disinfection by chlorine and monochloramine

1998 ◽  
Vol 44 (12) ◽  
pp. 1154-1160 ◽  
Author(s):  
Christian Chauret ◽  
Kerry Nolan ◽  
Ping Chen ◽  
Susan Springthorpe ◽  
Syed Sattar
Keyword(s):  
Cryptosporidium Parvum ◽  
Environmental Fate ◽  
Water Environment ◽  
Water Disinfection ◽  
Ottawa River ◽  
In Situ Conditions ◽  
Cryptosporidium Parvum Oocysts ◽  
St Lawrence River

Cryptosporidium parvum oocysts were aged in waters from both the St. Lawrence River and the Ottawa River. In situ survival experiments were carried out by incubating the oocysts in either dialysis cassettes or microtubes floated into an overflow tank. A significant portion of the oocysts survived in the test waters for several weeks. Oocyst survival in the St. Lawrence River was better in membrane-filtered (0.2-µm-pore diameter) water than in unfiltered water, suggesting that biological antagonism may play a role in the environmental fate of the parasite. Oocysts aged in river waters under in situ conditions and control oocysts kept refrigerated in synthetic water (100 ppm as CaCO3; pH 7.0) were subjected to the same disinfection protocol. Aged oocysts were at least as resistant as, if not more resistant than, the control oocysts to disinfection. This indicates that the oocysts surviving in the water environment may be just as difficult to inactivate by potable water disinfection as freshly shed oocysts. Therefore, water treatment should not be based on the assumption that environmental oocysts may be more easily inactivated than freshly shed oocysts. First-order kinetics die-off rates varied from one river to another (from 0.013 to 0.039 log10·day-1) and from one experiment to another with water from the same river collected at different times. Calculation of the die-off rates based on either in vitro excystation or in vitro excystation in combination with total counts (overall die-off rates) showed that the assessment of oocyst viability by microscopic methods must account for the total oocyst loss observed during long-term inactivation assays of river waters.Key words: Cryptosporidium, survival, disinfection, biological antagonism.

scholarly journals Perkinsus marinus Extracellular Protease Modulates Survival of Vibrio vulnificus in Eastern Oyster (Crassostrea virginica) Hemocytes

1999 ◽  
Vol 65 (9) ◽  
pp. 4261-4263 ◽  
Author(s):  
B. D. Tall ◽  
J. F. La Peyre ◽  
J. W. Bier ◽  
M. D. Miliotis ◽  
D. E. Hanes ◽  
...  
Keyword(s):  
Serine Protease ◽  
Crassostrea Virginica ◽  
Time Course ◽  
Vibrio Vulnificus ◽  
Eastern Oyster ◽  
Intracellular Survival ◽  
Extracellular Protease ◽  
Perkinsus Marinus ◽  
In Vitro Effects

ABSTRACT The in vitro effects of the Perkinsus marinus serine protease on the intracellular survival of Vibrio vulnificusin oyster hemocytes were examined by using a time-course gentamicin internalization assay. Results showed that protease-treated hemocytes were initially slower to internalize V. vulnificus than untreated hemocytes. After 1 h, the elimination of V. vulnificus by treated hemocytes was significantly suppressed compared with hemocytes infected with invasive and noninvasive controls. Our data suggest that the serine protease produced byP. marinus suppresses the vibriocidal activity of oyster hemocytes to effectively eliminate V. vulnificus, potentially leading to conditions favoring higher numbers of vibrios in oyster tissues.

The effect of blueberry extracts on Giardia duodenalis viability and spontaneous excystation of Cryptosporidium parvum oocysts, in vitro

Methods ◽  
2007 ◽  
Vol 42 (4) ◽  
pp. 339-348 ◽  
Author(s):  
J.-P. Anthony ◽  
L. Fyfe ◽  
D. Stewart ◽  
G.J. McDougall ◽  
H.V. Smith
Keyword(s):  
Cryptosporidium Parvum ◽  
Giardia Duodenalis ◽  
Cryptosporidium Parvum Oocysts
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