Human phagocytic cell response to histamine derived from potential probiotic strains of Lactobacillus reuteri.

Histamine derived from lactobacilli isolates is considered to be a potential immunomodulator able to interact with the host immune system. We tested the effect of pure histamine (0.413 mM) together with the effect of cell-culture supernatants (CCS) containing different concentration of histamine produced by two of Lactobacillus reuteri isolates on the activities of antioxidant enzyme, as well as on the phagocytic activity of human leucocytes (HL). Phagocytic activity represents the non-specific immune response of HL homogenate, in vitro. Analysed histamine-producers were represented by a goatling isolate named L. reuteri KO5 and a lamb isolate named L. reuteri E and histamine production was determined using HPLC method connected with UV detection. Concretely, the samples contained the mixture of isolated HL and the addition of lactobacilli CCS at three different final concentrations of histamine ∼ 0.1, 1.8 and 5.4 mM. It was found that pure histamine (0.413 mM) did not significantly influence the oxidant-antioxidant balance in HL demonstrated by unchanged degree of HL lipid peroxidation. However, at the same time, the final activity of catalase and superoxide dismutase were significantly changed (p ≤ 0.001). Moreover, the phagocytic index (p ≤ 0.01), lysozyme (p ≤ 0.05) and peroxidase activity (p ≤ 0.001), and production of IL-1ß significantly decreased. CCS containing different concentration of produced histamine were also able to modulate the host non-specific immune response together with the enzymatic activity of SOD and catalase too. However, our findings indicated that the impact of lactobacilli histamine is strictly strain-dependent and concentration dependent. Moreover, it seems that histamine is not the only one lactobacilli metabolite, which may play an important role in overall immunomodulatory and antioxidant potential of tested lactobacilli.

Analysis of antimicrobial and immunomodulatory substances produced by heterofermentative Lactobacillus reuteri.

Antimicrobial and immunomodulatory potential of various Lactobacillus reuteri strains is closely connected to their metabolite production profile under given cultivation conditions. We determined the in vitro production of antimicrobial substances such as organic acids, ethanol, and reuterin by four strains of L. reuteri (L. reuteri E, L. reuteri KO5, L. reuteri CCM 3625, and L. reuteri ATCC 55730). All studied L. reuteri strains showed the ability to produce lactic acid, acetic acid, and ethanol with concominant consumption of glucose and together with phenyllactic acid-a potent antifungal compound-with concominant consumption of phenylalanine. The reuterin production from glycerol was confirmed for all analyzed lactobacilli strains except L. reuteri CCM 3625. Production of organic acids, ethanol, and reuterin is significantly involved in antimicrobial activity of lactobacilli which was determined using the dual-culture overlay diffusion method against six indicator bacteria and five indicator moulds. In comparison to the referential L. reuteri ATCC 55730, the highest inhibition potential was observed against Escherichia coli CCM 3988 and Pseudomonas aeruginosa CCM 3955. Among analyzed indicators of moulds, the growth of Alternaria alternata CCM F-128 was the most inhibited by all four analyzed L. reuteri strains. Finally, the immunomodulatory potential of analyzed lactobacilli were proven by the determination of the in vitro production of biogenic amines histamine and tyramine. L. reuteri CCM 3625 was able to produce tyramine, and L. reuteri E and L. reuteri KO5 were able to produce histamine under given cultivation conditions.

Glucomannan in prevention of oxidative stress and inflammation occurring in adjuvant arthritis.

OBJECTIVES: The aim of this study was to evaluate the effects of a biological response modifier, glucomannan (GM), isolated from Candida utilis, on the progress of adjuvant arthritis in Lewis rats. METHODS: Adjuvant arthrithis was induced in Lewis rats by a single intradermal injection of Mycobacterium butyricum. GM was administered in two different doses of 5 and 7.5 mg/kg b.w. The treatment involved daily oral or intraperitoneal administration of the substance from day 0, i.e. the day of immunization to the end of the experiment - day 28. Cyclosporin A was used as a therapeutic standard in daily oral dose of 2.5 mg/kg b.w. The following parameters were monitored: hind paw volume, total antioxidant status, protein carbonyl groups, activity of N-acetyl-beta-D-glucosaminidase in plasma, lysozyme and peroxidase activity of peritoneal macrophages and activity of gamma-glutamyltransferase in homogenates of spleen, hind paw muscle and hind paw joint. RESULTS: Beneficial action of GM was revealed mainly in hind paw volume decrease. Further decrease of the activity of the enzyme gamma glutamyltransferase (GGT) in the spleen, hind paw joint and muscle tissue homogenates, decrease of the plasmatic activity of N-acetyl-beta-D-glucosaminidase (NAGA), and finally suppression of lysozyme and peroxidase activity assessed in peritoneal macrophages were observed in arthritic animals treated with GM. All these findings speak in favor of the anti-inflammatory activity of glucomannan. Moreover, a significant improvement of the arthritis induced suppression of total antioxidant status and decrease of the level of the arthritis-associated protein carbonyls in plasma were detected. CONCLUSIONS: The important characteristics of GM isolated from Candida utilis, such as good water solubility and relatively small molecular weight, along with the observed in vivo anti-inflammatory and antioxidant effects, appear to be promising features for its prospective use as a natural agent in prevention and supplementary therapy of rheumatoid arthritis.

Interaction of gemini surfactants butane-1,4-diyl-bis(alkyldimethylammonium bromide) with DNA.

The size and structure of aggregates formed by interaction of DNA with homologous series of cationic gemini surfactants butane-1,4-diyl-bis(alkyldimethylammonium bromide) (CnGS, n=10-16 is the number of alkyl carbons) were investigated using UV-vis turbidity, dynamic light scattering and small-angle synchrotron X-ray (SAX) diffraction. The detailed analysis of turbidity in the range of lambda=450-600 nm indicates an anomaly in the growth of CnGS+DNA aggregates with increasing concentration of CnGS, possibly involving changes of structure and size of aggregates. Using dynamic light scattering, changes of the effective diameter of CnGS+DNA (n=12 and 16) aggregates formed in the CnGS concentration range 0.002-0.140 mmol/l were observed. SAX diffractograms show the presence of long-range organization of CnGS+DNA (n=12, 13, 14 and 16) aggregates due to DNA interaction with CnGS above the critical micellar concentration. The CnGS+DNA (n=12, 13 and 14) aggregates at 25 degrees C are packed in a lattice of two-dimensional hexagonal symmetry. With increasing C14GS:DNA molar ratio the changes of the lattice parameter in the range of 4.80-5.27 nm are observed at 25 degrees C. The aggregates undergo structural changes induced by temperature in the range 60-95 degrees C, which are accompanied by changes of the diffraction patterns, namely in the region of reciprocal spacing s=0.15-0.30 nm(-1).

Effects of gemini surfactants on egg phosphatidylcholine bilayers in the fluid lamellar phase.

The influence of 1,4-butanediamonium-N,N'-dialkyl-N,N,N',N'-tetramethyl dibromides (CmA, m = 7-16 is the number of alkyl carbons) on the egg yolk phosphatidylcholine (EYPC) bilayer thickness and lipid surface area at the bilayer-aqueous phase interface is studied using X-ray diffraction on fluid lamellar CmA + EYPC + H2O phases as a function of CmA:EYPC and H2O:EYPC molar ratios and the alkyl chain length m. At the constant CmA:EYPC = 0.4 and H2O:EYPC = 18 molar ratios, the CmA induced bilayer thickness decrease shows a minimum and the lipid surface area increase a maximum at the alkyl chain length m = 9. The obtained results are discussed in the context of a structural perturbation model of the cut-off effect in biological potencies of surfactants which occurs when increasing the alkyl substituent chain length above the critical value.