In vitro investigation of ?-amylase release from the digestive cells of the bivalve mollusc Pecten maximus: effect of second messengers and biogenic amines

1995 ◽  
Vol 164 (7) ◽  
Author(s):  
W. Giard ◽  
P. Favrel ◽  
E. Boucaud-Camou
2002 ◽  
Vol 87 (4) ◽  
pp. 2043-2051 ◽  
Author(s):  
Hisashi Koda ◽  
Kazue Mizumura

Hyperalgesia to mechanical stimulation and heat is commonly observed in inflamed conditions. Although sensitization to heat is well documented and its mechanism has also been well studied, it remains unclear whether and how nociceptors are sensitized to mechanical stimulation. Therefore we conducted in vitro investigation of which inflammatory mediators (bradykinin, histamine, prostaglandin E2, and protons) sensitize nociceptors to suprathreshold mechanical stimulation and at what concentrations. In addition, we studied the effects of possible second messengers for these mediators downstream of the receptors and also the effects of mild burn. Single polymodal receptor activities were recorded in canine testis-spermatic nerve preparations excised from deeply anesthetized dogs. Mechanical stimulation was applied to the identified receptive field for 10 s with a servo-controlled mechanical stimulator. Bradykinin at 0.001 μM induced neither excitation nor facilitation of the mechanical response; however, it facilitated the mechanical response at 0.01 μM and higher, levels at which significant excitation was also induced by bradykinin alone. Histamine excited the nociceptor and sensitized it to mechanical stimulation at 10 μM and higher. PG E2 also sensitized the mechanical response, but starting at 1 μM, without inducing excitation by itself. The effects of two possible intracellular messengers for these mediators were studied using forskolin (10 μM), which increases intracellular cAMP, and a protein-kinase-C-stimulating phorbol ester, phorbol 12,13-dibutyrate (0.1 μM). Both substances reversibly facilitated the mechanical response of testicular polymodal receptors. In contrast, low-pH solution (pH: 6.6–4.5) seldom induced excitation and failed to facilitate the mechanical response. After 55°C, 30-s heat stimulation, testicular polymodal receptors were sensitized to mechanical stimulation. These results demonstrated that inflammatory mediators and burn sensitized nociceptor responses to mechanical stimulation and provide support for the idea that peripheral nociceptor sensitization is a mechanism involved in hyperalgesia to mechanical stimulation in inflamed tissues.


2008 ◽  
Vol 35 (S 01) ◽  
Author(s):  
H Leske ◽  
A Baiker ◽  
C Schichor ◽  
J.C Tonn ◽  
R Goldbrunner ◽  
...  

2010 ◽  
Vol 51 (8) ◽  
pp. 4151 ◽  
Author(s):  
Henri Sueke ◽  
Stephen B. Kaye ◽  
Timothy Neal ◽  
Amanda Hall ◽  
Stephen Tuft ◽  
...  

2020 ◽  
Vol 21 (12) ◽  
pp. 2718-2728
Author(s):  
Elsayed M. Abdel Bary ◽  
Ammar N. Harmal ◽  
Mona E. Ibrahim ◽  
Moustafa A. Gouda

2020 ◽  
Vol 9 (1) ◽  
pp. 28
Author(s):  
Johannes Delgado-Ospina ◽  
Laura Acquaticci ◽  
Junior Bernardo Molina-Hernandez ◽  
Kalliopi Rantsiou ◽  
Maria Martuscelli ◽  
...  

Yeast starters for cocoa fermentation are usually tested according to their enzymatic activities in terms of mucilage degradation and flavor improvement, disregarding their influence on the production or elimination of toxic compounds as biogenic amines (BAs), important for human health. In this work, we tested 145 strains belonging to 12 different yeast species and isolated from the Colombian fermented cocoa beans (CB) for their capability of producing BAs in vitro. Sixty-five strains were able to decarboxylate at least one of the amino acids tested. Pichia kudriavzevii ECA33 (Pk) and Saccharomyces cerevisiae 4 (Sc) were selected to evaluate their potential to modulate BAs, organic acids, and volatile organic compounds (VOCs) accumulation during a simulated cocoa fermentation. The growth of Sc or Pk in the presence of CB caused a significant reduction (p < 0.05) of 2-phenylethylamine (84% and 37%) and cadaverine (58% and 51%), and a significant increase of tryptamine and putrescine with a strong influence of temperature in BA formation and degradation. In addition, our findings pointed out that Pk induced a major production of fatty acid- and amino acid-derived VOCs, while Sc induced more VOCs derived from fatty acids metabolism. Our results suggest the importance of considering BA production in the choice of yeast starters for cocoa fermentation.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4538
Author(s):  
Scarlett Puebla-Barragan ◽  
Emiley Watson ◽  
Charlotte van der Veer ◽  
John A. Chmiel ◽  
Charles Carr ◽  
...  

Lactobacillus crispatus is the dominant species in the vagina of many women. With the potential for strains of this species to be used as a probiotic to help prevent and treat dysbiosis, we investigated isolates from vaginal swabs with Lactobacillus-dominated and a dysbiotic microbiota. A comparative genome analysis led to the identification of metabolic pathways for synthesis and degradation of three major biogenic amines in most strains. However, targeted metabolomic analysis of the production and degradation of biogenic amines showed that certain strains have either the ability to produce or to degrade these compounds. Notably, six strains produced cadaverine, one produced putrescine, and two produced tyramine. These biogenic amines are known to raise vaginal pH, cause malodour, and make the environment more favourable to vaginal pathogens. In vitro experiments confirmed that strains isolated from women with a dysbiotic vaginal microbiota have higher antimicrobial effects against the common urogenital pathogens Escherichia coli and Enterococcus faecium. The results indicate that not all L. crispatus vaginal strains appear suitable for probiotic application and the basis for selection should not be only the overall composition of the vaginal microbiota of the host from which they came, but specific biochemical and genetic traits.


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