scholarly journals THE ENHANCEMENT OF MACROPHAGE BACTERIOSTASIS BY PRODUCTS OF ACTIVATED LYMPHOCYTES

1973 ◽  
Vol 138 (4) ◽  
pp. 952-964 ◽  
Author(s):  
Robert E. Fowles ◽  
Ileana M. Fajardo ◽  
Jacques L. Leibowitch ◽  
John R. David
Keyword(s):  
Listeria Monocytogenes ◽  
Guinea Pig ◽  
Concanavalin A ◽  
Bactericidal Activity ◽  
Culture Supernatant ◽  
Cell Adherence ◽  
Activated Lymphocytes ◽  
Glucose Carbon ◽  
Lymphocyte Cultures ◽  
By Products

It was reported previously that the incubation of normal guinea pig macrophages with partially purified products of activated lymphocytes resulted in altered macrophage function including increased cell adherence to culture vessels, spreading, phagocytosis, and glucose carbon-1 oxidation. Studies reported here demonstrate that such macrophages also exhibit enhanced bacteriostasis. Lymphocytes were stimulated with concanavalin A, the culture supernatant was chromatographed over Sephadex G-100 and the fraction of mol wt 25,000–55,000, rich in lymphocyte mediators, was cultured with normal guinea pig macrophages for 1–3 days. Macrophages incubated with fractions from unstimulated lymphocyte cultures served as controls. The resulting macrophage monolayers were infected with Listeria monocytogenes. Macrophages incubated with mediator-rich fractions exhibited 2- to 10-fold enhanced bacteriostasis compared to controls. Further studies indicate that this enhancement was attributable to intrinsic changes in the macrophages and not simply a consequence of the number of macrophages on the monolayers. The studies support the concept that macrophage bacteriostasis can be enhanced by lymphocyte mediators. However, macrophages, which have been preincubated directly with sensitive lymphocytes and antigen exhibit even greater bacteriostasis and sometimes bactericidal capacity, suggesting that either a labile lymphocyte factor or direct lymphocyte macrophage interaction may also be involved in bactericidal activity.

Ultrastructural and chemical evidences of heterogeneity and hormone dependence of certain glycocalyces

1978 ◽  
Vol 36 (2) ◽  
pp. 322-323
Author(s):  
B. Monis ◽  
D. Lis ◽  
I. Parlanti ◽  
A. R. Eynard ◽  
M. A. Valentich ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Concanavalin A ◽  
Ruthenium Red ◽  
Transitional Epithelium ◽  
Membrane Material ◽  
Hormone Dependence ◽  
Cellulose Acetate Electrophoresis ◽  
Electrophoretic Data ◽  
Fat Globule ◽  
Collecting Tubules

We are gathering evidences which indicate ultrastructural variations and chemical heterogeneity of certain glycocalyces as well as hormone dependence of some of them. Thus, in the lumenal glycocalyx of renal collecting tubules of the guinea-pig granular and filamentous structures were seen (1, fig. 1). By isolation, chemical analysis and cellulose acetate electrophoresis in various buffers of tubular membrane material, glycopeptides and glycosaminoglycans were identified (fig. 2).Guinea-pig and rat transitional epithelium of urinary tract showed a filamentous lumenal glycocalyx demonstrable with ruthenium red (fig. 3) but which only in part stained with concanavalin A. Chemical and electrophoretic data indicated that urothelium contains glycoproteins, glycosaminoglycans and glycolipids.The glycocalyx of the fat globule membrane of milk of several species has a granular appearance as shown by cationic dyes and by concanavalin A (2, 3, fig. 4 and 5). Also, several glycoproteins were isolated and identified on polyacrilamide gel electrophoresis (fig. 6). Glycosaminoglycans and certain glycolipids such as sulfatides were chemically identified in this glycocalyx.

scholarly journals Listeria adhesion protein-expressing bioengineered probiotics prevent fetoplacental transmission of Listeria monocytogenes in a pregnant Guinea pig model

2021 ◽  
Vol 151 ◽  
pp. 104752
Author(s):  
Valerie E. Ryan ◽  
Taylor W. Bailey ◽  
Dongqi Liu ◽  
Tracy Vemulapalli ◽  
Bruce Cooper ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Guinea Pig ◽  
Pig Model ◽  
Adhesion Protein ◽  
Listeria Adhesion Protein ◽  
Guinea Pig Model

Listeria monocytogenes strains encoding premature stop codons in inlA invade mice and guinea pig fetuses in orally dosed dams

2013 ◽  
Vol 62 (12) ◽  
pp. 1799-1806 ◽  
Author(s):  
Anne Holch ◽  
Hanne Ingmer ◽  
Tine Rask Licht ◽  
Lone Gram
Keyword(s):  
Listeria Monocytogenes ◽  
Guinea Pig ◽  
Food Processing ◽  
Guinea Pigs ◽  
Stop Codon ◽  
Fetal Liver ◽  
Fatal Case ◽  
Premature Stop Codon ◽  
Tissue Samples ◽  
Pregnant Mice

Listeria monocytogenes is an important food-borne bacterial pathogen and listeriosis can result in abortions in pregnant women. The bacterium can colonize food-processing environments, where specific molecular subtypes can persist for years. The purpose of this study was to determine the virulence potential of a group of food-processing persistent L. monocytogenes strains encoding a premature stop codon in inlA (encoding internalin A) by using two orally dosed models, pregnant mice and pregnant guinea pigs. A food-processing persistent strain of L. monocytogenes invaded placentas (n = 58; 10 % positive) and fetuses (3 % positive) of pregnant mice (n = 9 animals per strain), similar to a genetically manipulated murinized strain, EGD-e InlA m* (n = 61; 3 and 2 %, respectively). In pregnant guinea pigs (n = 9 animals per bacterial strain), a maternofetal strain (from a human fetal clinical fatal case) was isolated from 34 % of placenta samples (n = 50), whereas both food-processing persistent strains were found in 5 % of placenta samples (n = 36 or 37). One of the food-processing persistent strains, N53-1, was found in up to 8 % of guinea pig fetal liver and brain samples, whereas the maternofetal control was found in 6 % of fetal tissue samples. As the food-processing persistent strains carry a premature stop codon in inlA but are invasive in orally dosed pregnant mice and guinea pigs, we hypothesize that listerial crossing of the placental barrier can occur by a mechanism that is independent of an interaction between E-cadherin and InlA.

Changes in Heat Resistance Resulting from pH and Nutritional Shifts of Acid-Adapted and Non–Acid-Adapted Listeria monocytogenes Scott A†

2004 ◽  
Vol 67 (2) ◽  
pp. 316-321 ◽  
Author(s):  
DARRELL O. BAYLES
Keyword(s):  
Listeria Monocytogenes ◽  
Heat Resistance ◽  
Frequency Distribution ◽  
Culture Supernatant ◽  
Physiological State ◽  
Distribution Data ◽  
Treatment Conditions ◽  
Lower Heat ◽  
Full Factorial ◽  
Cell Free Culture Supernatant

Stationary-phase Listeria monocytogenes cells that were either pH dependent acid adapted or not acid adapted were heat challenged at 60°C in a two-level full factorial design for three variables. The three variables and the levels consisted of tryptic soy broth (TSB) and sterile cell-free culture supernatant (sterile TSB), the presence and absence of 1% added glucose, and pH 4.8 and pH 7. Non–acid-adapted cells were most heat resistant when challenged in TSB (mean decimal reduction times at 60°C: D60 = 1.16 min). In the absence of added glucose, non–acid-adapted cells had similar D60-values for inactivations at pH 4.8 and pH 7; however, the presence of glucose caused non–acid-adapted cells challenged at pH 4.8 to be more heat sensitive (D60 = 0.65 min) than those inactivated at pH 7 (D60 = 1.03 min), indicating an interaction between glucose and pH. Overall, the significantly decreased heat resistance of the acid-adapted cells was due to the presence of glucose (D60 = 0.78 min without glucose, D60 = 0.59 min with glucose). Acid-adapted cells heat challenged in TSB had similar D60-values for inactivations at pH 4.8 and pH 7; however, acid-adapted cells in sterile TSB challenged at pH 4.8 (D60 = 0.52 min) had significantly lower heat resistance than did cells challenged at pH 7 (D60 = 0.76 min), indicating an interaction between the medium and pH. The L. monocytogenes survivor data were modeled to extract information on the frequency distribution of heat resistance within heat-challenged populations, and the frequency distribution characteristics of mean, mode, and variance were compared among treatment conditions. Significant differences in the frequency distribution data were compared with the D60-values. These data indicated that the presence and level of cross-protection is highly dependent on the physiological state of the cells and nutrient availability at the time of heat challenge. Such conditions should be considered to ensure that stressed pathogens in foods are destroyed or inactivated.

Inactivation of Pathogenic Bacteria by Cucumber Volatiles (E,Z)-2,6-Nonadienal and (E)-2-Nonenal†

2004 ◽  
Vol 67 (5) ◽  
pp. 1014-1016 ◽  
Author(s):  
M. J. CHO ◽  
R. W. BUESCHER ◽  
M. JOHNSON ◽  
M. JANES
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Bactericidal Activity ◽  
Pathogenic Bacteria ◽  
Brain Heart Infusion ◽  
Escherichia Coli O157 ◽  
Infusion Solution ◽  
E Coli ◽  
Log Reduction

The effects of (E,Z)-2,6-nonadienal (NDE) and (E)-2-nonenal (NE) on Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium were investigated. A suspension of each organism of 6 to 9 log CFU/ml was incubated for 1 h at 37° C in brain heart infusion solution that contained 0 to 500 or 1,000 ppm of NDE or NE. Depending on concentration, exposure to either NDE or NE caused a reduction in CFU of each organism. Treatment with 250 and 500 ppm NDE completely eliminated viable B. cereus and Salmonella Typhimurium cells, respectively. L. monocytogenes was the most resistant to NDE, showing only about a 2-log reduction from exposure to 500 ppm for 1 h. Conversely, this concentration of NDE caused a 5.8-log reduction in E. coli O157:H7 cells. NE was also effective in inactivating organisms listed above. A higher concentration of NE, 1,000 ppm, was required to kill E. coli O157:H7, L. monocytogenes, or Salmonella Typhimurium compared with NDE. In conclusion, both NDE and NE demonstrated an apparent bactericidal activity against these pathogens.

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