The Effect of Lactobacillus salivarius SGL03 on Clinical and Microbiological Parameters in Periodontal Patients

The destruction of periodontal tissues during periodontitis is the result of the immune-inflammatory reactions to the bacteria of dental biofilm. Probiotics may reduce dysbiosis by the modification of the dental microbiome, which can influence the immune-inflammatory mechanisms. The aim of this study was to estimate the clinical and microbiological parameters, before and after 30 days of application of the dietary supplement containing Lactobacillus salivarius SGL03 or placebo. The study was conducted in 51 patients with stage I or II periodontitis during the maintenance phase of treatment. The clinical parameters and the number of colony forming units (CFU) of bacteria in supragingival plaque were assessed before and after 30 days of the oral once daily administration of the dietary supplement in the form of suspension containing L. salivarius SGL03 or placebo. There were no changes in the PI scores between and within the groups. The value of BOP decreased in both groups. In the study group the significant reduction of the mean pocket depth was revealed (from 2.5 to 2.42, p = 0,027) but without the difference between the groups. There were no significant changes in the number of bacteria within the groups. In the control, but not the study group, positive correlations were observed between the clinical parameters (variables) and the number of bacteria. The use of the dietary supplement containing L. salivarius SGL03 may reduce pocket depth despite the lack of changes in other clinical parameters and the number of bacteria in supragingival plaque.Key words: probiotics, periodontal treatment, Lactobacillus salivarius     

Cellulases released during the germination of Dictyostelium discoideum spores.

Dormant spores of Dictyostelium discoideum contained cellulase at a specific activity of 130 to 140 U/mg of protein; when heat activated, the spores germinated, progressively releasing the cellulase activity into the extracellular medium. The cellulase release was a selective process and resulted in recovery of the cellulase activity at a specific activity of 2,000 U/mg of protein; beta-glucosidase in the spores remained completely associated with the emerging amoebae. Release of the cellulase required heat activation of the spores and occurred during the swelling stage of germination; inhibition of the emergence stage with cycloheximide had no effect on the release of the cellulase. The cellulase activity released consisted of two enzymes whose molecular weights were 136,000 and 69,000. Studies of their pH optima, heat lability, and of their sensitivity to inhibition revealed no distinctive differences between these two proteins. Analysis on diethylaminoethyl-Sephadex columns showed that the higher-molecular-weight protein could be converted into the lower-molecular-weight component in vitro.     

Direct spectrophotometric observation of ribulese-1,5-bisphosphate carboxylase activity

The catalytic conversion of ribulose biphosphate by ribulosebiphosphate carboxylase (EC 4.1.1.39) to 3-phosphoglycerate has been measured based on the disappearance of a chromophore of ribulose biphosphate (RuBP) absorbing at 280 nm. The rate of disappearance of this chromophore matches perfectly with the rate of appearance of 3-phosphoglycerate as measured by ¹⁴CO₂ assay. The rate of disappearance of RuBP, as shown by the rate of A₂₈₀ decrease, correlates well with the rate of disappearance of pentose, as measured by the orcinol-HCl reaction. Use of the above methods as well as a coupled enzyme assay led to a molar absorptivity for RuBP of approximately 48 m^?1 cm^?1. The ultraviolet absorption spectrum of RuBP is discussed.     

Molecular recognition between oligopeptides and nucleic acids. Specificity of binding of a monocationic bis-furan lexitropsin to DNA deduced from footprinting and 1H NMR studies

MPE-Fe(EDTA) footprinting of a novel monocationic bis-furan lexitropsin 6 on a HindIII/EcoRI restriction fragment of pBR322 DNA revealed a series of four-base binding sites (all 5'----3') of (primary) TGTA, TGAA, AAAT, ACAA, TTAT, and (secondary) CTAA, TCGT, TGTA, GTCA, and GGTT. Thus 6 can accept a GC pair at positions 1, 2 or 3 of the binding site with a strict 3' (4 position) AT requirement. Marked enhancement of cleavage, particularly at GC rich sequences, is observed at regions flanking or even up to 18 base pairs remote from a given binding site. The non-exchangeable and imino 1H NMR resonances of the 1:1 complex and d-[CATGGCCATG]2 were assigned using a combination of NOE differences, NOESY and COSY techniques. 1H NMR studies (ligand induced chemical shifts and NOE differences) of Lexitropsin 6 with d-[CATGGCCATG]2 show unambiguously the location and orientation of the N to C termini of 6 on the sequence 5'-G5C6C7A8-3', with the C terminus oriented to A8. This orientation of 6 in the minor groove of 5'-GCCA is confirmed by an NOE observed between H1 2a of 6 and AH8(8). This preference for binding of 6 to the sequence 5'-GCCA when challenged with d-[CATGGCCATG]2 is in accord with the conclusions of the footprinting experiments wherein GC base pairs can be accepted in the first three positions and with a strict 3' terminus AT reading requirement. Collectively the data support the inference of a GC recognizing capacity for a 2,5-substituted furan moiety within a lexitropsin. The 1H NMR data indicate that the decadeoxyribonucleotide duplex exists in the B conformation in both the 1:1 complex and the free form. The apparent binding constant of 6 to calf thymus DNA is 1.68 X 10(5) M-1 whereas netropsin under similar conditions gives a value of 1.85 X 10(7) M-1. This suggests that if advantage is to be taken of the GC recognizing property of a 2,5-substituted furan in longer lexitropsins it should be flanked by more strongly bound moieties.     

Sequence dependent conformation and local geometry of the conserved branch site sequence element d(TpApCpTpApApC), essential for yeast mRNA splicing, deduced from high resolution 1H-NMR

The conserved sequence element and branch site splice signal d(TpApCpTpApApC) has been synthesized by a solid phase procedure. All the non-exchangeable protons have been assigned using a combination of one-dimensional and two-dimensional 1H-NMR analytical procedures. On the basis of the low NOE intensities in the 1D-NOE and NOESY experiments, the heptamer exists in solution as a random coil. The deoxyribose rings towards the 5' terminus exist predominantly in the S form (2'-endo-3'-exo) while residues on or adjacent to the 2' branch site in the eventual lariat structure [A(6) of TACTAAC] show more N-character (3'endo-2'-exo). In addition unique propeller twisting at contiguous AT base pairs in the consensus 5'-splice site occurs in the region in which there is partial complementarity with the branch splice signal TACTAAC. These subtle structural features, if carried over to the corresponding RNA, may have significance either as a recognition signals or for stereochemical reasons in the formation of the lariat intermediate in the maturation process of mRNA.     

Cytarabine-Induced Destabilization and Bending of a Model Okazaki Fragment

Abstract

The effects of cytarabine on the structural and thermodynamic properties of an Okazaki fragment were investigated using UV hyperchromicity and 2D ¹H NMR. Cytarabine significantly decreased the stability of this model Okazaki fragment, decreasing the melting temperature from 46.8 °C to 42.4 °C at 1.33 × 10^?5M. Cytarabine also markedly increased the bend angle of the Okazaki fragment duplex from 20° to 42°. Changes to the structures and stabilities of Okazaki fragments may cause the biological effects of cytarabine.