The effect of melatonin on bacterial translocation following ischemia/reperfusion injury in a rat model of superior mesenteric artery occlusion

Background: Acute mesenteric ischemia is a life-threatening vascular emergency resulting in tissue destruction due to ischemia-reperfusion injury. Melatonin, the primary hormone of the pineal gland, is a powerful scavenger of reactive oxygen species (ROS), including the hydroxyl and peroxyl radicals, as well as singlet oxygen, and nitric oxide. In this study, we aimed to investigate whether melatonin prevents harmful effects of superior mesenteric ischemia-reperfusion on intestinal tissues in rats. Methods: Rats were randomly divided into three groups, each having 10 animals. In group I, the superior mesenteric artery (SMA) was isolated but not occluded. In group II and group III, the SMA was occluded immediately distal to the aorta for 60 minutes. After that, the clamp was removed and the reperfusion period began. In group III, 30 minutes before the start of reperfusion, 10 mg/kg melatonin was administered intraperitonally. All animals were sacrified 24 hours after reperfusion. Tissue samples were collected to evaluate the I/R-induced intestinal injury and bacterial translocation (BT). Results: There was a statistically significant increase in myeloperoxidase activity, malondialdehyde levels and in the incidence of bacterial translocation in group II, along with a decrease in glutathione levels. These investigated parameters were found to be normalized in melatonin treated animals (group III). Conclusion: We conclude that melatonin prevents bacterial translocation while precluding the harmful effects of ischemia/reperfusion injury on intestinal tissues in a rat model of superior mesenteric artery occlusion. © 2015 Ozban et al.; licensee BioMed Central

Uptake, accumulation and some biochemical responses in Raphanus sativus L. to zinc stress

The responses of radish (Raphanus sativus L.) to increasing concentrations of ZnCl2 (1, 5 and 10 mM) in Hoagland nutrient medium were studied. Under the conditions of these increasing zinc concentrations, the highest zinc accumulation was obtained in the roots of the plants treated with 10 mM applications. The zinc concentration in the vegetative parts, was highest in the root and was lowest in the cotyledons. The highest bioconcentration factor (BCF) value was detected in the roots in 5 mM zinc applications. When compared with the control, total zinc uptake was observed to increase in 1, 5 and 10 mM ZnCl2 treatments. The total accumulation rate (TAR) for zinc was highest in 10 mM ZnCl2 treatment, while the lowest TAR was observed in radish plants exposed to 1 mM ZnCl2. Plants treated with 5, 10 mM ZnCl2 showed significant decreases in chlorophyll (Chl a, Chl b, Chl a/b) and carotenoid content compared with the control. Peroxidase (POD) activity especially in radish roots increased significantly with increasing concentrations of ZnCl2 (5 and 10 mM) while the total protein amount decreased when compared with the control. The results of this study showed that, radish plants could tolerate the negative effects of zinc stress up to 1 mM ZnCl2 concentration and that in zinc concentrations of 5 mM and above toxic effects were existent.Key words: Radish, Raphanus sativus, zinc, metal toxicity, uptake, accumulation, peroxidase, pigment

Systemic and local antibiotic prophylaxis in the prevention of Staphylococcus epidermidis graft infection

BACKGROUND: The aim of the study was to investigate the in vivo efficacy of local and systemic antibiotic prophylaxis in the prevention of Staphylococcus (S.) epidermidis graft infection in a rat model and to evaluate the bacterial adherence to frequently used prosthetic graft materials. METHODS: Graft infections were established in the subcutaneous tissue of 120 male Wistar rats by implantation of Dacron/ePTFE grafts followed by topical inoculation with 2 × 10(7 )CFUs of clinical isolate of methicillin-resistant S. epidermidis. Each of the graft series included a control group, one contaminated group that did not receive any antibiotic prophylaxis, two contaminated groups that received systemic prophylaxis with teicoplanin or levofloxacin and two contaminated groups that received teicoplanin-soaked or levofloxacin-soaked grafts. The grafts were removed 7 days after implantation and evaluated by quantitative culture. RESULTS: There was significant bacterial growth inhibition in the groups given systemic or local prophylaxis (P < 0.05). Methicillin-resistant S. epidermidis had greater affinity to Dacron graft when compared with ePTFE graft in the untreated contaminated groups (P < 0.05). CONCLUSION: The study demonstrated that the usage of systemic or local prophylaxis and preference of ePTFE graft can be useful in reducing the risk of vascular graft infections caused by staphylococcal strains with high levels of resistance

Deciphering the Multifactorial Nature of Acinetobacter baumannii Pathogenicity

Background: Acinetobacter baumannii is an emerging bacterial pathogen that causes a broad array of infections, particularly in hospitalized patients. Many studies have focused on the epidemiology and antibiotic resistance of A. baumannii, but little is currently known with respect to its virulence potential. Methodology/Principal Findings: The aim of this work was to analyze a number of virulence-related traits of four A. baumannii strains of different origin and clinical impact for which complete genome sequences were available, in order to tentatively identify novel determinants of A. baumannii pathogenicity. Clinical strains showed comparable virulence in the Galleria mellonella model of infection, irrespective of their status as outbreak or sporadic strains, whereas a non-human isolate was avirulent. A combined approach of genomic and phenotypic analyses led to the identification of several virulence factors, including exoproducts with hemolytic, phospholipase, protease and iron-chelating activities, as well as a number of multifactorial phenotypes, such as biofilm formation, surface motility and stress resistance, which were differentially expressed and could play a role in A. baumannii pathogenicity. Conclusion/Significance: This work provides evidence of the multifactorial nature of A. baumannii virulence. While A. baumannii clinical isolates could represent a selected population of strains adapted to infect the human host, subpopulations of highly genotypically and phenotypically diverse A. baumannii strains may exist outside the hospita

Comparison of the flower colour and the pigment content of Mirabilis jalapa L.

In this study a correlation was found between the flower colour and the pigment content of Mirabilis jalapa L. We tried to prove that the heredity of the flower colours of M. jalapa, which are seen at fenotype, is related to plastids as well as the existence of anthocyanin in the vacuole. Moreover the amount of chlorophyll, peroxidase activity and total protein content were determined by means of biochemical methods. As a result it was proved that there is an inverse connection between the amount of chlorophyll and the anthocyanin content, the peroxidase activity, which is an antioxidant enzyme, increases especially in the storage root of the plant known to be chemotherapeutic potential

INVESTIGATION ON THE RELATIONSHIP BETWEEN SENESCENCE AND NITRIC OXIDE IN SUNFLOWER (HELIANTHUS ANNUUS L.) SEEDLINGS

In this study, the effects of NO (nitric oxide) on senescence occurring in the cotyledons of Helianthus annuus L. (sunflower) seedlings, were examined. Following germination of the sunflower the seedlings were grown in perlit for 10 days and then transferred into hydroponic culture containing 1/4 Hoagland solution. At day 23 approximately when senescence started occurring, 0.1, 1, 10, 100 and 400 mu M concentrations of Sodium nitroprusside prepared in 1/4 Hoagland solution used as NO donor were applied to the seedlings. The cotyledons of both control and experimental groups were harvested when the avarage green area in the control group reached 50%. Effects of NO in senescence process were determinated by measuring parameters such as Peroxidase activity, amount of chlorophyll and total soluble protein