Humic Acid, a Polyphenolic Substance, Decreases Alveolar Bone Loss in Experimental Periodontitis in Rats

The purpose of this study was to evaluate the biochemical, morphometric, and histopathological changes associated with experimental periodontitis in rats in response to local administration of humic acid. Thirty-eight Wistar rats were divided into 5 experimental groups: nonligated (NL) group, ligature-only (LO) group, and ligature + local administration of humic acid (20, 80, and 150 mg/kg body weight per day for 15 days, respectively; L-20, L-80, and L-150 groups). Changes in alveolar bone levels were clinically measured as the distance from the cementoenamel junction to the alveolar bone crest with a stereomicroscope. Tissues were histopathologically examined to assess the osteoclast numbers, osteoblastic activity, and inflammatory cell infiltration among the study groups. Enzyme-linked immunosorbent assay interleukin1β (IL-1β) and IL-10 levels in serum and gingival homogenates were evaluated. At the end of 15 days, the alveolar bone loss was significantly higher in the LO group compared to the NL, L-20, and L-150 groups (P < .05). The osteoclast number in the LO group was significantly higher than the NL, L-20, and L-150 groups (P < .05). Inflammatory cell infiltration was significantly higher in the LO and L-80 groups than the other groups (P < .05). The highest serum and gingival homogenate IL-10 levels were determined in the NL group (P < .05). The serum and gingival homogenate IL-1β levels in LO group were significantly higher than the NL, L-20, and L-150 groups (P < .05). Within the limits of this study, it can be suggested that humic acid, when administered locally at 20 and 80 mg/kg doses, may prevent alveolar bone loss in the rat model.

Serosurvey of Coxiella burnetii in high risk population in Turkey, endemic to Crimean-Congo haemorrhagic fever virus

Background & objectives

Q fever caused by Coxiella burnetii is a zoonotic infection that spreads to human beings from animals. This study was aimed to demographically examine the C. burnetii seroprevalence in the people living in villages where Crimean-Congo haemorrhagic fever virus (CCHFV) is endemic, in terms of various risk factors such as tick bites, tick contact, and occupational groups.

Methods

A total of 440 serum samples from those living in rural areas of Sivas and Tokat regions in Turkey were included in the study as a risk group; 387of them were serologically CCHFV positive (as confirmed in our previous research). Serums of the control group composed of 110 people living in urban areas. In all serum samples, IgG antibodies of C. burnetii against phase-I and phase-II antigens were diagnosed using the ELISA method.

Results

Coxiella burnetii seropositivity was detected in 19.09% of those living in rural areas and 4.55% of those living in urban areas (p < 0.001, OR = 4.96). In terms of their approach to the ticks, no statistical difference was observed between the risk groups in the chi-square test (p = 0.787). However, according to univariate analysis, the absorbance means of antibodies reactive to C. burnetii was statistically higher for the rural people who have made contact with ticks than those who have not (p = 0.017). No seroepidemiological relation was found between CCHFV and C. burnetii serology (p = 0.787), and the rate of co-seropositivity between them was 5.43% (21/387).

Interpretation & conclusion

The findings of the study showed that C. burnetii infection is epidemic especially in the people living in rural areas. Contact with ticks in various ways might have resulted in the increased risk of C. burnetii infection in the study. Personal protective measures against tick bites may be important for reducing Q fever risk as in other tick-borne infectious disease.

Investigating the Effects of Systemically Administered Strontium Ranelate on Alveolar Bone Loss Histomorphometrically and Histopathologically on Experimental Periodontitis in Rats

BACKGROUND

The aim of this study is to investigate effects of strontium ranelate (SR) on alveolar bone loss (ABL) in rats with experimental periodontitis.

METHODS

Forty Wistar rats were randomly divided into five groups: 1) control (n = 8); 2) ligated (n = 8); 3) 300 mg/kg SR (SR300, n = 8); 4) 625 mg/kg SR (SR625, n = 8); and 5) 900 mg/kg SR (SR900, n = 8). To create experimental periodontitis, 4/0 silk ligatures were inserted submarginally around first molars at the right mandible. After 11 days, rats were sacrificed. ABL was calculated by measuring cemento-enamel junction and alveolar crest distance. Interleukin (IL)-1β, osteoprotegerin (OPG), and bone-specific alkaline phosphatase (BALP) serum levels were determined by enzyme-linked immunosorbent assay. Histopathologic analysis was used to evaluate inflammatory cell infiltration, numbers of osteoblasts and osteoclasts, and receptor activator of nuclear factor-kappa B ligand (RANKL) activity.

RESULTS

ABL was significantly lower in SR900 group than in the ligated group (P <0.05). Osteoclast numbers in ligated group were significantly higher than in the control, SR300, and SR900 groups (P <0.05). In ligated, SR625, and SR900 groups, significantly higher osteoblast numbers were detected than in control group (P <0.05). Osteoblast numbers in SR625 group were significantly higher than in the SR300 group (P <0.05). RANKL activities in SR900 and control groups were close to each other (P >0.05). Serum IL-1β, OPG, and BALP levels revealed no significant difference (P >0.05).

CONCLUSION

It can be concluded that SR can reduce RANKL activity and osteoclast numbers, as well as ABL.

Crystal structures of the kinase domain of the sulfate-activating complex in Mycobacterium tuberculosis

In Mycobacterium tuberculosis the sulfate activating complex provides a key branching point in sulfate assimilation. The complex consists of two polypeptide chains, CysD and CysN. CysD is an ATP sulfurylase that, with the energy provided by the GTPase activity of CysN, forms adenosine-5’-phosphosulfate (APS) which can then enter the reductive branch of sulfate assimilation leading to the biosynthesis of cysteine. The CysN polypeptide chain also contains an APS kinase domain (CysC) that phosphorylates APS leading to 3’-phosphoadenosine-5’-phosphosulfate, the sulfate donor in the synthesis of sulfolipids. We have determined the crystal structures of CysC from M. tuberculosis as a binary complex with ADP, and as ternary complexes with ADP and APS and the ATP mimic AMP-PNP and APS, respectively, to resolutions of 1.5 Å, 2.1 Å and 1.7 Å, respectively. CysC shows the typical APS kinase fold, and the structures provide comprehensive views of the catalytic machinery, conserved in this enzyme family. Comparison to the structure of the human homolog show highly conserved APS and ATP binding sites, questioning the feasibility of the design of specific inhibitors of mycobacterial CysC. Residue Cys556 is part of the flexible lid region that closes off the active site upon substrate binding. Mutational analysis revealed this residue as one of the determinants controlling lid closure and hence binding of the nucleotide substrate.

Design of a specific colonic mucus marker using a human commensal bacterium cell surface domain

Imaging living cells and organs requires innovative, specific, efficient, and well tolerated fluorescent markers targeting cellular components. Such tools will allow proceeding to the dynamic analysis of cells and the adaptation of tissues to environmental cues. In this study, we have identified and synthesized a novel non-toxic fluorescent marker allowing a specific fluorescent staining of the human colonic mucus. Our strategy to identify a molecule able to specifically bind to the human colonic mucus was on the basis of the mucus adhesion properties of commensal bacteria. We identified and characterized the mucus-binding property of a 70-amino acid domain (MUB(70)) expressed on the surface of Lactobacillus strains. The chemical synthesis of MUB(70) was achieved using the human commensal bacterium Lactobacillus reuteri AF120104 protein as a template. The synthesized Cy5-conjugated MUB(70) marker specifically stained the colonic mucus on fixed human, rabbit, and guinea pig tissues. Interestingly, murine tissue was not stained, suggesting significant differences in the composition of the murine colonic mucus. In addition, this marker stained the mucus of living cultured human colonic cells (HT29-MTX) and human colonic tissue explants. Using a biotinylated derivative of MUB(70), we demonstrated that this peptide binds specifically to Muc2, the most abundant secreted mucin, through its glycosylated moieties. Hence, Cy5-MUB(70) is a novel and specific fluorescent marker for mammalian colonic mucus. It may be used for live imaging analysis but also, as demonstrated in this study, as a marker for the diagnosis and the prognosis of colonic mucinous carcinomas.