The antinociceptive effect of hydro-alcoholic extract of leave Mentha pulegium in formalin test in male rat

Background and aim: Drug researchers believe that pain relief medicines, because of their side effects and in some cases because of their inabilities are not useful. Therefore, it is necessary to do more research to find out new antinociceptive drugs. In the present study, antinociceptive effect of hydro-alcoholic extract of Mentha pulegium leave has been evaluated in male rats. Methods: In this experimental study, 40 adult male wistar rats, in the weight range of 220- 230 g were used. Antinociceptive response was evaluated by formalin test in five groups of 8 animals. Three experimental groups received 3 different doses of hydro alcoholic extract from the leaves of Mentha pulegium (400, 800, 1600 mg/kg, respectively). Sham group received distilled water and formalin only and the control group received no drugs. The extracts were injected intraperitoneally (i.p.), 15 minutes before the formalin test. Minutes 0-5 and 15-60 were designated as the acute and chronic phase of pain, respectively. After recording behavioral responses, the average pain scores in experimental groups and control group were statistically evaluated using t-test and Tukey’s test. Results: A significant difference was seen in mean pain scores between 3 experimental groups in the acute stage of formalin test. In the chronic stage, the only significant difference was seen between the experimental group which had been received 1600 mg/kg Mentha pulegium and two other groups (sham and control group) (P<0.05). Conclusion: According to the results of this research, the hydro-alcoholic extract of the leaves of Mentha pulegium reduces the pain in the acute stage more than chronic stage. However, more research is needed to find out the effective antinociceptive compounds in Mentha pulegium

Development of antiseptic adaptation and cross-adapatation in selected oral pathogens in vitro

There is evidence that pathogenic bacteria can adapt to antiseptics upon repeated exposure. More alarming is the concomitant increase in antibiotic resistance that has been described for some pathogens. Unfortunately, effects of adaptation and cross-adaptation are hardly known for oral pathogens, which are very frequently exposed to antiseptics. Therefore, this study aimed to determine the in vitro increase in minimum inhibitory concentrations (MICs) in oral pathogens after repeated exposure to chlorhexidine or cetylpyridinium chloride, to examine if (cross-)adaptation to antiseptics/antibiotics occurs, if (cross-)adaptation is reversible and what the potential underlying mechanisms are. When the pathogens were exposed to antiseptics, their MICs significantly increased. This increase was in general at least partially conserved after regrowth without antiseptics. Some of the adapted species also showed cross-adaptation, as shown by increased MICs of antibiotics and the other antiseptic. In most antiseptic-adapted bacteria, cell-surface hydrophobicity was increased and mass-spectrometry analysis revealed changes in expression of proteins involved in a wide range of functional domains. These in vitro data shows the adaptation and cross-adaptation of oral pathogens to antiseptics and antibiotics. This was related to changes in cell surface hydrophobicity and in expression of proteins involved in membrane transport, virulence, oxidative stress protection and metabolism

Gene Erosion Can Lead to Gain-of-Function Alleles That Contribute to Bacterial Fitness

Despite our extensive knowledge of the genetic regulation of heat shock proteins (HSPs), the evolutionary routes that allow bacteria to adaptively tune their HSP levels and corresponding proteostatic robustness have been explored less. In this report, directed evolution experiments using the Escherichia coli model system unexpectedly revealed that seemingly random single mutations in its tnaA gene can confer significant heat resistance. Closer examination, however, indicated that these mutations create folding-deficient and aggregation-prone TnaA variants that in turn can endogenously and preemptively trigger HSP expression to cause heat resistance. These findings, importantly, demonstrate that even erosive mutations with disruptive effects on protein structure and functionality can still yield true gain-of-function alleles with a selective advantage in adaptive evolution

PROTEIN AGGREGATION AS A NEW STRATEGY TO COMBAT GRAM NEGATIVE BACTERIA

Protein homeostasis (proteostasis) is an important key to cell viability and its breakdown can lead to protein misfolding and protein aggregation, which is associated with neurodegenerative diseases. Accordingly, the interruption of bacterial proteostasis was proposed as a valuable drug target. We here present a novel designer antibiotics paradigm that exploits protein aggregation to kill pathogenic E. coli by widespread proteostatic collapse. In order to induce multi-targeted protein aggregation we designed P2, a synthetic peptide containing a short aggregation-nucleating sequence that is highly redundant in the E. coli proteome. P2 is readily internalized by the bacteria and does not cause bacterial membrane lysis but induces the rapid formation of large polar inclusions. Proteomics analysis of these inclusion bodies demonstrates P2 co-aggregates with several bacterial proteins containing our target sequence resulting in a lethal aggregation cascade involving more than 300 proteins. P2 is active in vivo, effectively reducing bacterial load in a mouse bladder infection model without adverse effect to its host. Finally, our results indicate slow development of resistance, suggesting that multi-targeted protein aggregation constitutes a tight proteostatic deadlock. This method could therefore represent a novel and rationally designable therapeutic approach for combatting difficult to treat pathogenic bacteria.nrpages: 149status: publishe

Detection of Biofilm Phenotype of Isolated Staphylococcus epidermidis from Respiratory Catheters of Hospitalized Patients and Evaluation the Effect of Antibodies against SesC Protein on Biofilm Formation

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sesC as a genetic marker for easy identification of Staphylococcus epidermidis from other isolates

Staphylococcus epidermidis is one of the major concerns with respect to hospital-acquired infections. Therefore, a rapid and easy method to identify at species level S. epidermidis isolates out of a broad range of bacteria is necessary. Based on earlier studies, the sesC gene encoding a S. epidermidis surface protein revealed to be a highly conserved gene in this species. By means of an easy and inexpensive PCR assay, the presence of sesC was checked in 438 clinical staphylococcal isolates. Results showed that sesC is specifically present in all S. epidermidis. In conclusion, the sesC gene can be exploited as a genetic marker in order to distinguish S. epidermidis from other isolates.publisher: Elsevier articletitle: sesC as a genetic marker for easy identification of Staphylococcus epidermidis from other isolates journaltitle: Infection, Genetics and Evolution articlelink: http://dx.doi.org/10.1016/j.meegid.2016.05.037 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved.status: publishe

Ses proteins as possible targets for vaccine development against Staphylococcus epidermidis infections

OBJECTIVES: The opportunistic pathogen Staphylococcus epidermidis is progressively involved in device-related infections. Since these infections involve biofilm formation, antibiotics are not effective. Conversely, a vaccine can be advantageous to prevent these infections. In view of vaccine development, predicted surface proteins were evaluated on their potential as a vaccine target. METHODS: Immunoglobulins directed against S. epidermidis surface proteins SesB, M, O, Q and R were used to firstly affirm their surface location. Further, inhibitory effects of these IgGs on biofilm formation were determined in vitro on polystyrene and polyurethane surfaces and in vivo using a subcutaneous catheter mouse model. We also examined the opsonophagocytotic capacity of these IgGs. RESULTS: Surface localization of the five Ses proteins was demonstrated both for planktonic and sessile cells, though to a variable extent. Ses-specific IgGs added to planktonic cells had a variable inhibitory effect on cell adhesion to polystyrene, while only anti-SesO IgGs decreased cell attachment to polyurethane catheters. Although phagocytic killing was only obtained after opsonization with SesB-specific IgGs, a significant reduction of in vivo formed biofilms was observed after administration of SesB-, SesM- and SesO-specific IgGs. CONCLUSIONS: Regardless of their characterization or function, S. epidermidis surface proteins can be adequate targets for vaccine development aiming the prevention of device-related infections caused by invasive S. epidermidis strains.status: publishe

Development of antiseptic adaptation and cross-adapatation in selected oral pathogens in vitro

There is evidence that pathogenic bacteria can adapt to antiseptics upon repeated exposure. More alarming is the concomitant increase in antibiotic resistance that has been described for some pathogens. Unfortunately, effects of adaptation and cross-adaptation are hardly known for oral pathogens, which are very frequently exposed to antiseptics. Therefore, this study aimed to determine the in vitro increase in minimum inhibitory concentrations (MICs) in oral pathogens after repeated exposure to chlorhexidine or cetylpyridinium chloride, to examine if (cross-)adaptation to antiseptics/antibiotics occurs, if (cross-)adaptation is reversible and what the potential underlying mechanisms are. When the pathogens were exposed to antiseptics, their MICs significantly increased. This increase was in general at least partially conserved after regrowth without antiseptics. Some of the adapted species also showed cross-adaptation, as shown by increased MICs of antibiotics and the other antiseptic. In most antiseptic-adapted bacteria, cell-surface hydrophobicity was increased and mass-spectrometry analysis revealed changes in expression of proteins involved in a wide range of functional domains. These in vitro data shows the adaptation and cross-adaptation of oral pathogens to antiseptics and antibiotics. This was related to changes in cell surface hydrophobicity and in expression of proteins involved in membrane transport, virulence, oxidative stress protection and metabolism.status: publishe

Pituitary adenylate cyclase-activating polypeptide (PACAP) in zebrafish models of nephrotic syndrome

Pituitary adenylate cyclase-activating polypeptide (PACAP) is an inhibitor of megakaryopoiesis and platelet function. Recently, PACAP deficiency was observed in children with nephrotic syndrome (NS), associated with increased platelet count and aggregability and increased risk of thrombosis. To further study PACAP deficiency in NS, we used transgenic Tg(cd41:EGFP) zebrafish with GFP-labeled thrombocytes. We generated two models for congenital NS, a morpholino injected model targeting nphs1 (nephrin), which is mutated in the Finnish-type congenital NS. The second model was induced by exposure to the nephrotoxic compound adriamycin. Nephrin RNA expression was quantified and zebrafish embryos were live-screened for proteinuria and pericardial edema as evidence of renal impairment. Protein levels of PACAP and its binding-protein ceruloplasmin were measured and GFP-labeled thrombocytes were quantified. We also evaluated the effects of PACAP morpholino injection and the rescue effects of PACAP-38 peptide in both congenital NS models. Nephrin downregulation and pericardial edema were observed in both nephrin morpholino injected and adriamycin exposed congenital NS models. However, PACAP deficiency was demonstrated only in the adriamycin exposed condition. Ceruloplasmin levels and the number of GFP-labeled thrombocytes remained unchanged in both models. PACAP morpholino injections worsened survival rates and the edema phenotype in both congenital NS models while injection with human PACAP-38 could only rescue the adriamycin exposed model. We hereby report, for the first time, PACAP deficiency in a NS zebrafish model as a consequence of adriamycin exposure. However, distinct from the human congenital NS, both zebrafish models retained normal levels of ceruloplasmin and thrombocytes. We further extend the renoprotective effects of the PACAP-38 peptide against adriamycin toxicity in zebrafish.status: publishe

Enhanced therapeutic window for antimicrobial Pept-ins by investigating their structure-activity relationship.

The overconsumption and inappropriate use of antibiotics is escalating antibiotic resistance development, which is now one of the 10 top threats to global health. Introducing antibiotics with a novel mode of action into clinical use is urgently needed to address this issue. Deliberately inducing aggregation of target proteins and disrupting protein homeostasis in bacteria via amyloidogenic peptides, also called Pept-ins (from peptide interferors), can be lethal to bacteria and shows considerable promise as a novel antibiotic strategy. However, the translation of Pept-ins into the clinic requires further investigation into their mechanism of action and improvement of their therapeutic window. Therefore, we performed systematic structure modifications of 2 previously discovered Pept-ins, resulting in 179 derivatives, and investigated the corresponding impact on antimicrobial potency, cellular accumulation, and ability to induce protein aggregation in bacteria, in vitro aggregation property, and toxicity on mammalian cells. Our results show that both Pept-in accumulation and aggregation of target proteins in bacteria are requisite for Pept-in mediated antimicrobial activity. Improvement of these two parameters can be achieved via increasing the number of arginine residues, increasing Pept-in aggregation propensity, optimizing the aggregate core structure, adopting β-turn linkers, or forming a disulphide bond. Correspondingly, improvement of these two parameters can enhance Pept-in antimicrobial efficacy against wildtype E. coli BL21 used in the laboratory as well as clinically isolated multidrug-resistant strain E. coli ATCC, A. baumannii, and K. pneumoniae