Protective and Therapeutic Capacities of Lactic Acid Bacteria Postmetabolites against Koi Herpesvirus Infection In Vitro.

BACKGROUND: The accumulation of data on beneficial biological effects of probiotics and their metabolic products favors their potential use in the prevention and treatment of various malaises. METHODS: Nine postmetabolites from Lactic acid bacteria (LAB) of human or dairy origin and their antiviral activity were studied using the cytopathic effect inhibition test. The virucidal capacity, their influence on the adsorption stage of Koi herpes virus (KHV) and their preventive role against subsequent viral challenge on intact Common carp brain (CCB) cells were also determined by titration assay. Residual viral infectivity in postmetabolites-treated samples was compared to mock-treated controls and Δlgs were calculated. RESULTS: When administered during KHV replication, the microbial products isolated from Lactiplantibacillus plantarum showed remarkable activity with a selectivity index (SI) between 26.5 and 221.4, as those effects were dependent on the sample-virus incubation time. Postmetabolites from Lactobacillus gasseri and Lactiplantibacillus plantarum also demonstrated significant inhibition of KHV replication with SI of 24 and 16, respectively. The bioactive metabolites isolated from Limosilactobacillus fermentum had a minor effect on the viral replicative cycle. Compounds, produced during the fermentation by lactobacilli, grown on different nutritive media and collected at different time points, significantly inhibited extracellular KHV virions. All investigated postmetabolites remarkably blocked KHV attachment to the host cell (CCB), leading to a drop in viral titers by Δlg = 4.25-5.25, and exerted protective effects on CCB cells before they were subjected to viral infection. CONCLUSIONS: Our results open new horizons and promote LAB and their postbiotic products to be used in the prophylaxis and therapy of viral infections.

Anti-herpes virus activity of lactobacillus' postbiotics.

Background: Recently various lactic acid bacteria (LAB) and their post-metabolites have shown many positive effects on human and animal welfare. They appear to be beneficial in different disorders and pathological conditions, including in a broad-spectrum of infectious diseases. Aim: To estimate in vitro the anti-herpes simplex activity of 11 postbiotic samples (lysates or cell-free supernatants - CFS) produced during the fermentation of six candidate-probiotic Lactobacillus strains isolated from Bulgarian fermented milk products. Materials and methods: In vitro protocols for assessment of different LAB samples on the Herpes simplex virus type 1 (HSV-1) replication, adsorption and virucidal effects were applied using MDBK cells. Results: Four of the studied LAB samples expressed a statistically significant inhibition of the replication of HSV-1. The highest selective index (79.75) was calculated for the post-metabolites of Lactiplantibacillus plantarum, followed by a high molecular fraction of cell-derived fragments of Limosilactobacillus fermentum culture (S6) (SI = 34.63), CFS from late exponential L. plantarum (SI = 28.26) and neutralized CFS from L. fermentum (SI = 28.11). Pronounced virucidal activities of the postbiotics S1, S11 (L. fermentum), S3 (L. plantarum) and S6 (L. fermentum) were recorded, too. The inhibitory effect of the majority of the samples on the stage of adsorption of the virus to MDBK cells was remarkable. In addition, almost all of the postbiotics exerted a protective effect on healthy cells and significantly reduced viral yield at subsequent infection. Conclusion: Pre-selected Lactobacillus strains demonstrated strain-specific effects against HSV-1. These postbiotics influence different stages of viral infection in cell cultures and their promising characteristics are currently evaluated.

Vibration-Induced Kinesthetic Illusions and Corticospinal Excitability Changes.

The authors' aim was to investigate the changes of corticospinal excitability during kinesthetic illusions induced by tendon vibration. Motor-evoked potentials in response to transcranial magnetic stimulation were recorded from the vibrated flexor carpi radialis and its antagonist, extensor carpi radialis. The illusions were evoked under vision conditions without feedback for the position of the wrist (open or closed eyes). In these two conditions motor-evoked potential changes during vibration in the antagonist were not identical. This discrepancy may be a result of 2 simultaneously acting, different and opposite influences and the balance between them depends on visual conditions. Thus, the illusion was accompanied by the facilitation of corticospinal excitability in both vibrated muscle and its antagonist.

The effect of muscle vibration on short latency intracortical inhibition in humans.

PURPOSE: The purpose of the present study was to investigate the effect of muscle vibration (MV) on short latency intracortical inhibition (SICI) and facilitation (ICF) assessed by paired-pulse transcranial magnetic stimulation (TMS). METHODS: Nineteen right-handed healthy subjects were investigat ed without and with MV of the right extensor carpi radialis (ECR), using single- and paired-pulse TMS with interstimulus interval (ISI) of 3 and 13 ms. Intensities of the conditioning and test stimulus were 70 and 120 % of the motor threshold at rest. The motor-evoked potentials (MEPs) were recorded simultaneously from the vibrated ECR and its antagonist flexor carpi radialis (FCR). RESULTS: In all the subjects a SICI of similar strength could be observed at 3 ms, at rest and during MV both in the vibrated muscle as well as in its antagonist. The subjects were divided in two groups according to the changes in MEP response to paired-pulse TMS with 13 ms ISI observed during MV. In nine subjects SICI was evident also at 13 ms when vibration was applied, while in another ten subjects vibration induced ICF at 13 ms. CONCLUSIONS: The effect of MV is not just a facilitation of SICI, but a stronger prolongation of the effect of intracortical inhibition to an ISI at which ICF is well pronounced, when the intensity of the conditioning stimulus exceeds the threshold for intracortical facilitation.