Plant antimicrobial peptides

Plant antimicrobial peptides (AMPs) are a component of barrier defense system of plants. They have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. Thus, plant AMPs are considered as promising antibiotic compounds with important biotechnological applications. Plant AMPs are grouped into several families and share general features such as positive charge, the presence of disulfide bonds (which stabilize the structure), and the mechanism of action targeting outer membrane structures.     

The Effects of Antihypertensive Drugs on Chromium Status, Glucose Metabolism, and Antioxidant and Inflammatory Indices in Spontaneously Hypertensive Rats

The long-term use of hypotensive drugs may cause side effects, including impaired glucose metabolism and mineral status. This study tested the hypothesis that some hypotensive drugs can affect tissular chromium levels and indices of glucose metabolic and antioxidant potential in rats. The experiment was performed on 40 male spontaneously hypertensive rats (SHRs), which were assigned to five groups: control (C), with perindopril (PR), with metoprolol (MT), with indapamide (ID), and with amlodipine (AM). All rats were provided ad libitum standard diet (with or without drugs) and distilled water for 45 days. Glucose and insulin levels, along with total antioxidant status (TAS) and concentrations of TNF-alpha and C-reactive protein, were assayed in serum. Chromium concentrations in the liver and kidney were determined using the flame atomic absorption spectrometry method. Detailed statistical analysis was performed using Statistica for Windows 10.0 (StatSoft, Poland). One-way analysis of variance (ANOVA), followed by a post hoc Tukey test, was used to compare the data between groups. Treatment with indapamide and amlodipine resulted in significantly higher chromium concentrations in the liver and kidney (AM) of the rats, compared with the control group. A markedly higher concentration of glucose was found in the ID group. Treatment with amlodipine significantly increased TAS levels in serum and decreased TNF-alpha concentration in serum of the rats. A significant positive correlation between chromium concentration in tissues and serum TAS level was observed, as was a significant negative correlation between chromium concentration in the kidneys, and TNF-alpha and glucose levels in serum. In conclusion, the administration of amlodipine may lead to an increase in chromium accumulation in the internal organs, which is associated with increased antioxidant status and suppression of the inflammatory response of cells in SHRs.     

Coordinate induction of dissimilatory ammonification and fermentative pathways in rhizobia

Dissimilatory ammonification was indicated as the common feature of ten rhizobial strains representing six species and three genera. In the absence of external electron acceptors, all investigated strains were capable of ethanolic fermentation. However, induction of anaerobic nitrite reduction was shown to be coupled with a shift of fermentation towards acetate in all the strains tested. Three metabolic groups could be distinguished with regard to nitrite regulation of ethanolic fermentation. It was shown for Bradyrhizobium sp. strain USDA 3045 that nitrite is the signal for switching between fermentative pathways although both ammonia and acetate excretion could not accelerate until nitrate had been utilized first. In the absence of N oxyanions, ethanol was indicated as the main product of mannitol fermentation, five-fold more abundant than acetate. An inverse composition was found in nitrite-amended cultures, due to a four-fold increase in acetate excretion whereas ethanol was kept at low level. Nitrite-supported fermentation towards acetate has not been previously reported for rhizobia. This benefit of this pathway was a two-fold shorter doubling time on 1% mannitol and 2.5 mM nitrite compared to no-nitrite media variants but also enabled fermentation of the more reduced carbon compound glycerol.     

Toxoplasma gondii: The immunogenic and protective efficacy of recombinant ROP2 and ROP4 rhoptry proteins in murine experimental toxoplasmosis

Toxoplasmosis is a one of the most world-wide spread zoonosis representing a very serious clinical and veterinary problem. In the presented study, we evaluated the protective efficacy of a combined recombinant ROP2 and ROP4 subunit vaccine in a chronic Toxoplasma gondii infection in mice. The recombinant ROP2 (rROP2) and ROP4 (rROP4) proteins were cloned and expressed in Escherichia coli and then used for the immunization of C3H/HeJ mice. Both antigens generated a strong systemic mixed Th1/Th2 response polarized towards IgG1 antibody isotype. In contrast to rROP2 stimulating only the specific IL-2 release, rROP4 and crude toxoplasma lysate antigen (TLA) used as a source of native forms of the parasite proteins induced significant proliferation of splenocytes and specific production of IFN-γ as well as IL-2, the Th1-type cytokines. Challenge of rROP2 and rROP4-vaccinated mice with cysts of low virulent T. gondii DX strain resulted in a partial protection effect with a significantly lower brain parasites load when compared with control animals. In the immunized group of mice the brain cysts number was reduced by nearly 46% as was determined in two independent experiments. These results suggest that, similar to ROP2, rhoptry protein ROP4 could be a very good candidate for future anti-T. gondii multicomponent vaccine based on the recombinant forms of different parasite proteins.     

Vacuolization of HeLa cells by a partially purified Clostridium histolyticum cytotoxin

Clostridium histolyticum vacuolating cytotoxin was partially purified from culture broth using ammonium sulfate precipitation, gel filtration and hydrophobic interaction chromatography. The toxin caused vacuolization of HeLa cells visible under a light microscope after 2 h and distinct after 8 h. Transmission electron microscopy revealed the presence of numerous vacuoles, condensation of the mitochondrial matrix, increased cytoplasm density and increased amounts of heterochromatin. Apoptosis was not detected either by electron microscopy or by an apoptosis/necrosis discrimination assay with fluorescein-labeled annexin V and propidium iodide, or DNA fragmentation assay. Calcium ion influx was detected by flow cytometry after labeling cells with Fluo-4 AM. Vacuolation of HeLa cells by C. histolyticum cytotoxin was inhibited by bafilomycin A1, suggesting involvement of H+ -ATPase in the formation of vacuoles.     

The chimpanzee-specific pericentric inversions that distinguish humans and chimpanzees have identical breakpoints in Pan troglodytes and Pan paniscus

Seven of nine pericentric inversions that distinguish human (HSA) and chimpanzee karyotypes are chimpanzee-specific. In this study we investigated whether the two extant chimpanzee species, Pan troglodytes (common chimpanzee) and Pan paniscus (bonobo), share exactly the same pericentric inversions. The methods applied were FISH with breakpoint-spanning BAC/PAC clones and PCR analyses of the breakpoint junction sequences. Our findings for the homologues to HSA 4, 5, 9, 12, 16, and 17 confirm for the first time at the sequence level that these pericentric inversions have identical breakpoints in the common chimpanzee and the bonobo. Therefore, these inversions predate the separation of the two chimpanzee species 0.86-2 Mya. Further, the inversions distinguishing human and chimpanzee karyotypes may be regarded as early acquisitions, such that they are likely to have been present at the time of human/chimpanzee divergence. According to the chromosomal speciation theory the inversions themselves could have promoted human speciation.     

Structural characterization and binding properties of the hemopexin-like domain of the matrixmetalloproteinase-19

The matrixmetalloproteinase-19 (MMP-19) belongs to the superfamily of the zinc-dependent endopeptidases, which are secreted by cells and are involved in the remodeling of the extracellular matrix. The full-length protein consists of a signal peptide, a propeptide, a catalytic domain and a C-terminal hemopexin-like domain. For other members of this superfamily, the hemopexin-like domain has been described to be involved in substrate recognition. In this study, the hemoxpexin domain of MMP-19 was expressed in Escherichia coli, refolded, and purified. For structural characterization, circular dichroism and NMR spectroscopy were used. We show that the hemopexin-like domain of MMP-19 is able to bind calcium and this binding induces a conformational change and an increase in the thermal stability of the domain. MMP-19 promotes proliferation of keratinocytes by cleaving the insulin-like-growth factor binding protein-3, thereby causing the release of IGF-1, which is a potent growth factor for these cells. By plasmon resonance experiments, we show that the isolated hemopexin-like domain is able to bind to the insulin-like-growth factor binding protein-3. These results provide a basis for further structural investigations that could be used for the rational design of potential agonists and antagonists.     

Species specificity,surface exposure,protein expression,immunogenicity, and participation in biofilm formation of <Emphasis Type="Italic">Porphyromonas gingivalis</Emphasis> HmuY

Background  

Porphyromonas gingivalis is a major etiological agent of chronic periodontitis. The aim of this study was to examine the species specificity, surface exposure, protein expression, immunogenicity, and participation in biofilm formation of the P. gingivalis heme-binding protein HmuY.