Effect of polymer/nanosilver composite packaging on long-term microbiological status of Iranian saffron (Crocus sativus L.)

Crocus sativus L. (saffron) is a valuable plant which is native to Iran. Saffron is the dried stigmata of the flowering part of the plant that is usually contaminated with different bacteria and fungi through production process. Antimicrobial properties of silver nanoparticles are well recognized. To survey the effects of nanosilver packaging on microbiological status of spiked, saffron samples over a six month period were chosen. Saffron samples from five regions of Khorasan province were purchased and de novo frequencies of microbial contaminants were determined using standard procedures. Totally 35 g of saffron was spiked with known numbers of four bacterial and two fungal species and packaged into one gram packets. The packaging materials consisted of polyethylene polymers containing 0, 400, 800, 1200 or 4000 ppm nanosilver (as Ag). Total and differential numbers of spiked microorganisms in the packaged saffrons were enumerated at initial and at six time points of seven, 14, 28, 64, 90 and 180 days. Baird-Parker agar (BP agar), Kenner Fecal (KF), Salmonella–Shigella agar (SS agar), Violet Red Bile Glucose Agar (VRBGA), and Sabouraud Dextrose agar (SD agar) media were used for enumeration of the six spiked microorganisms including Staphylococcus aureus, Enterococcus faecalis, Salmonella Enteritidis, Enterobacter species and Escherichia coli, Fusarium oxysporum and Aspergillus flavus, respectively. Direct antibacterial activity of the composites was also determined. De novo frequencies of microorganisms in five saffron samples were at acceptable levels with dominance of fungi species. Nanosilver embedded packages accelerated the reduction in live microbial numbers in saffron samples and the efficacy was the best in packages containing 4000 ppm nanosilver particles. Nanosilver packaging can significantly reduce microbial burden of saffron.     

The anti-biofouling effect of Lactobacillus fermentum-derived biosurfactant against Streptococcus mutans

Biofouling in the oral cavity often causes serious problems. The ability of Streptococcus mutans to synthesize extracellular glucans from sucrose using glucosyltransferases (gtfs) is vital for the initiation and progression of dental caries. Recently, it was demonstrated that some biological compounds, such as secondary metabolites of probiotic bacteria, have an anti-biofouling effect. In this study, S. mutans was investigated for the anti-biofouling effect of Lactobacillus fermentum (L.f.)-derived biosurfactant. It was hypothesized that two enzymes produced by S. mutans, glucosyltransferases B and C, would be inhibited by the L.f.-biosurfactant. When these two enzymes were inhibited, fewer biofilms (or none) were formed. RNA was extracted from a 48-h biofilm of S. mutans formed in the presence or absence of L.f. biosurfactant, and the gene expression level of gtfB/C was quantified using the real-time polymerase chain reaction (RT-PCR). L.f. biosurfactant showed substantial anti-biofouling activity because it reduced the process of attachment and biofilm production and also showed a reduction in gtfB/C gene expression (P value?相似文献   

The impact of encroachment of mangroves into saltmarshes on saltwater mosquito habitats

Will mangrove encroachment into saltmarshes affect saltwater mosquito habitats? To address this, we synthesized information from two perspectives: 1) at a detailed level, the immature mosquito habitat within mangroves; 2) at a more general or regional level, changes due to mangrove expansion into saltmarshes. This is a synthesis of two research projects. One showed that mosquito larval habitats in mangroves are complex, related to the detailed interactions between topography and tidal patterns and that not all parts of a mangrove forest are suitable habitat. The other, based on remote sensing and analysis of rainfall data, showed that mangrove encroachment in eastern Australia is related to both climate and human land use over several decades (1972–2004). An important question emerged: when mangroves encroach into saltmarshes will they displace saltmarsh immature mosquito habitats or will they replace them with mangrove ones? There is no simple answer: it will vary with climate change and sea level scenario and how these affect the system. We conclude that mosquito management, which is locally implemented, needs to be integrated with land use planning systems, which often operate at a more general level.     

Oral TNFα Modulation Alters Neutrophil Infiltration,Improves Cognition and Diminishes Tau and Amyloid Pathology in the 3xTgAD Mouse Model

Cytokines such as TNFα can polarize microglia/macrophages into different neuroinflammatory types. Skewing of the phenotype towards a cytotoxic state is thought to impair phagocytosis and has been described in Alzheimer’s Disease (AD). Neuroinflammation can be perpetuated by a cycle of increasing cytokine production and maintenance of a polarized activation state that contributes to AD progression. In this study, 3xTgAD mice, age 6 months, were treated orally with 3 doses of the TNFα modulating compound isoindolin-1,3 dithione (IDT) for 10 months. We demonstrate that IDT is a TNFα modulating compound both in vitro and in vivo. Following long-term IDT administration, mice were assessed for learning & memory and tissue and serum were collected for analysis. Results demonstrate that IDT is safe for long-term treatment and significantly improves learning and memory in the 3xTgAD mouse model. IDT significantly reduced paired helical filament tau and fibrillar amyloid accumulation. Flow cytometry of brain cell populations revealed that IDT increased the infiltrating neutrophil population while reducing TNFα expression in this population. IDT is a safe and effective TNFα and innate immune system modulator. Thus small molecule, orally bioavailable modulators are promising therapeutics for Alzheimer’s disease.     

Computational approach to suggest a new multi-target-directed ligand as a potential medication for Alzheimer’s disease

Abstract

Acetylcholinesterase (AChE) enzyme and myeloid differentiation 2 protein (MD2) are two critical proteins involved in Alzheimer’s disease (AD). Since the nature of the active site of AChE and the binding pocket of MD2 are similar, some ligands can inhibit both of them appropriately. Oxidative stress has also been known as an important cause of AD. Designing an effective common inhibitor with antioxidant activity to inhibit AChE and MD2 proteins is the main goal of this work. In this regard, we used tacrine molecule with a high ligand efficiency (LE) and dehydrozingerone (DHZ) with anti-inflammatory, antioxidant and anti-Alzheimer activities. Some modifications on DHZ structure can increase its antioxidant activity. So, tacrine molecule was combined with modified DHZ to present a new multi-target-directed ligand (MTDL). The ability of the designed ligand to inhibit AChE and MD2 proteins was confirmed by molecular docking, molecular dynamics (MD) simulation, and binding-free energy calculations. Therefore, the designed ligand can target two proteins involved in AD. It can also act as a potent antioxidant. In general, three important causative agents of AD are targeted by the designed ligand. Moreover, the inhibition of MD2, as the main source of oxidative stress, significantly reduces the production of free radicals.     

Antihemolytic and antioxidant activities of <Emphasis Type="Italic">Allium paradoxum</Emphasis>

Antioxidant activity of the aerial part and bulbs of Allium paradoxum was investigated by eight in vitro assay systems. Extracts showed good antioxidant activity. IC₅₀ for 1,1-diphenyl-2-picryl hydrazyl radical-scavenging activity was 890.9±43.2 and 984.9±33.5 μg/ml for the aerial part and bulbs, respectively. The aerial parts have better reducing power than bulb extracts but not comparable with Vitamin C (P>0.001). Extracts showed weak Fe²⁺ chelating ability, the IC₅₀ being 959±47 and 530±24 μg/ml for bulbs and aerial parts, respectively. Both tested extracts exhibited good hydrogen peroxide scavenging in a concentration dependent manner. They exhibited good antioxidant activity against the hemoglobin-induced linoleic acid system that was comparable with vitamin C (P>0.01). They showed good activity against cumene hydro peroxide induced hemolysis in RBCs. In addition, they possessed antihemolytic activity. The extract from aerial parts had significantly higher total phenol and flavonoid content than did bulbs. Amounts of eight elements (Cu, Mn, Zn, Fe, Ni, Pb, Cd and Cr) were also determined in the bulb and aerial part using atomic absorption spectroscopy. They contained higher Fe and Mn contents than other elements.     

Protective Effects of Curcumin against Sodium Fluoride-Induced Toxicity in Rat Kidneys

In the present study, the protective effect of curcumin against sodium fluoride-induced nephrotoxicity was evaluated in rats. Renal injury was induced by daily administration of 600 ppm sodium fluoride in drinking water for 1 week. One week before the administration of fluoride, the animals selected as study group were given curcumin (10 and 20 mg/kg body weight, intraperitoneally). After 1 week, lipid peroxidation level, activities of superoxide dismutase, catalase, and level of glutathione in kidney homogenate were measured. Blood serum samples were examined for creatinine, serum urea, and blood urea nitrogen levels. Another group of rats received vitamin C (10 mg/kg) as standard antioxidant. The results show that curcumin and vitamin C treatment prior to fluoride administration normalized the levels of serum creatinine, serum urea, and blood urea nitrogen. Moreover, curcumin and vitamin C administrations prevented the antioxidant enzyme decreasing and lipid peroxidation levels imbalance. In conclusion, curcumin treatment at the doses of 10 and 20 mg/kg (intraperitoneally) showed significant nephroprotective effects.