The identification of a low molecular mass bacteriocin, rhamnosin A, produced by Lactobacillus rhamnosus strain 68

AIMS

This study focuses on the isolation and characterization of a peptide with bacteriocin-like properties isolated from Lactobacillus rhamnosus strain 68, previously identified by 16S rRNA gene sequencing and originating from human gastrointestinal flora.

METHODS AND RESULTS

The peptide was isolated from a supernatant of bacteria maintained under restrictive conditions by a combination of ethanol precipitation and reversed-phase chromatography. The molecular mass of the peptide as assessed by mass spectrometry was 6433.8 Da. An isoelectric point of 9.8 was determined by 2D-PAGE. The peptide designated rhamnosin A inhibited Micrococcus lysodeikticus ATCC 4698 but did not inhibit Lactobacillus plantarum 8014 or Lact. plantarum 39268. Inhibitory activity against M. lysodeikticus at concentrations used in this study was shown to be bacteriostatic rather than bacteriolytic or bactericidal. Rhamnosin A retained biological activity after heat treatment (95 degrees C, 30 min) but was sensitive to proteolytic activity of pepsin and trypsin.

CONCLUSIONS

The N-terminal sequence of rhamnosin A, as determined by Edman degradation and in more detail by blast analysis, did not show identity with any currently available Lact. rhamnosus HN001-translated protein sequences, nor any significant similarity with other sequences in the nonredundant protein sequence database. Being a small, heat-stable, nonlanthionine-containing peptide, rhamnosin A should be categorized as a class II bacteriocin.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study describes a partial bacteriocin sequence isolated from Lact. rhamnosus 68 and broadens our understanding of bacteriocins.

HD phenocopies--possible role of Saitohin gene

Saitohin (STH) is located in the intron of the human gene for microtubule-associated protein tau. Q7R polymorphism has been identified in the STH gene. Some neurodegenerative disorders were found to be associated with the presence of certain STH allele. This study genotyped 37 subjects with diagnosis of Huntington's disease, but lacking mutations in HD, PRNP, JPH-3, and FTL genes for STH polymorphism. It was determined that Q allele of STH gene was over-represented in a tested group of patients (P > Pt). Over-representation of Q allele in a group of patients might be considered as genetic risk factor for HD like diseases.

Biological and chemical quality control of spermicidal raw material nonoxynol-9 and nonoxynol-9 containing vaginal contraceptive (ABF contraceptive film): determination of spermicidal activity and assay of nonoxynol-9

The paper presents a routine biological and chemical quality control of nonoxynol-9 raw material and pharmaceutical formulation containing nonoxynol-9 (ABF contraceptive film). The biological control performed based on the determination and comparison of the spermicidal activities different dilutions of the standard raw materials solution and assay raw material or nonoxynol-9 pharmaceutical formulation solution on the human or breeding bull sperm using a modified Sander-Cramer method. The test preparations of the nonoxynol-9 raw materials or pharmaceutical formulation should show equal or higher spermicidal activity than the standard. The spermicidal activity should not be lower than dilution 1:90. The chemical control is performed based on the determination and comparison of nonoxynol-9 content in the standard raw material solution and assay raw material or nonoxynol-9 pharmaceutical formulation solution using UV-spectrophotometric method determining and comparing the absorbances at the maximum absorbance wavelength (275 nm). The content of nonoxynol-9 in the raw material assay solution or pharmaceutical formulation (ABF contraceptive film) should be within 90-110% of the declared value.

[Septic encephalopathy--prognostic value of the intensity of consciousness disorder to the outcome of sepsis]

Septic encephalopathy (SE) is a common term indicating the development of signs of progressing cerebral dysfunction and is associated with the presence of microorganisms and their toxins in the blood. Aim of this investigation was to analyze the frequency of this complication considering the consciousness disorders in quantitative sense and prognosis of the survival in patients with SE. The investigation comprised patients (n = 54) with positive hemoculture and signs of septic syndrome by the accepted criteria (fever, clinical signs of infection, respiratory frequency, heart rate, plasma lactate, oliguria). Patients with confirmed cerebral injury, hemorrhage or cerebral ischemia were excluded from the study. Lumbar punction and CT-scan of the brain were performed in all patients in order to exclude visible lesions of cerebral parenchyma and eventual presence of cerebral nervous system (CNS) infection as the causes of sepsis. Results of the investigation demonstrated that in 30 (55%) of patients existed mild consciousness disorder at the level of somnolescence, in 18 (33%) consciousness disorder at the level of sopor and in 6 (11%) consciousness disorder at the level of deep coma. Level of consciousness disorder was in positive correlation with the outcome of sepsis syndrome, which was additionally confirmed by the fact that only in the group of patients with deep coma lethal outcome was observed in 3 cases (50% of this subgroup) regardless of intensive antibiotic, metabolically active and symptomatic therapy. It can be concluded that SE syndrome has a favorable prognosis if macroscopic lesion and dissemination of microorganisms in CNS are not present, and simultaneously it represents changes in metabolic-electrolytic state with early presentation of consciousness disorders that represent clinically significant indicator for sepsis syndrome outcome.