Detection of plasmid-mediated quinolone resistance in clinical isolates of Enterobacteriaceae strains in Hamadan,West of Iran

Plasmid mediated quinolone resistance (PMQR) determinants have arisen as a significant concern in recent years. The aim of this study was screening of resistant-clinical isolates to fluoroquinolone antibiotics and detection of qnr and aac(6′)-Ib-cr genes.For this purpose we collected 100 fluoroquinolone-resistant Enterobacteriaceae which were from 3 hospitals in Hamadan, west provinces of Iran, between October 2012 and June 2013. The all samples were identified by biochemical tests and confirmed by PCR method. Antimicrobial susceptibility to 14 antimicrobial agents including levofloxacin and ciprofloxacin were determined by disk diffusion methods and ciprofloxacin MIC was obtained by broth microdilution method as Clinical Laboratory Standards Institute (CLSI) recommendations. The isolates were screened for the presence of qnrA, qnrB, qnrS and aac(6′)-Ib-cr genes using PCR assay. Among the screened isolates, 64 strains (64%) of Escherichia coli, 23 strains (23%) of Klebsiella pneumoniae, 13 strains (13%) of Proteus mirabilis were collected as quinolone-resistant isolates. out of 100 isolates, two (2%) were positive for qnrS, seventeen (17%) isolates were positive for qnrB and we did not find qnrA gene in any of the isolates. There were also 32 positive isolates for aac(6′)-Ib-cr determinant. We described the prevalence of qnr and aac(6′)-Ib-cr genes in fluoroquinolone-resistant Enterobacteriaceae in Hamadan city. The carriage rate of multidrug-resistant Enterobacteriaceae in healthy people in Hamadan City is extremely high. Moreover, genes encoding transferable quinolones, in particular aac(6′)-Ib-cr, are highly prevalent in these strains.     

Effect of the Heavy Metals on the Developmental Stages of Ovule and Seed Proteins in Chenopodium botrys L. (Chenopodiaceae)

Excessive amounts of heavy metals adversely affect plant growth and development. Also, the presence of elevated levels of heavy metal ions triggers a wide range of cellular responses including changes in gene expression and synthesis of metal-detoxifying peptides. The overall objective of this research was to elucidate some microscopic effects of heavy metals on the formation, development, and structure of ovule and seed storage proteins in Chenopodium botrys L. To achieve this purpose, the surrounding area of Hame-Kasi iron and copper mine (Hamedan, Iran) was chosen as a polluted area where the amount of some heavy metals was several times higher than the natural soils. Flowers and young pods were removed from nonpolluted and polluted plants, fixed in FAA 70 and subjected to developmental studies. Our results showed that heavy metals can cause some abnormalities during the ovule developmental process. Decreasing the size of embryo sac, quick growth of inner integument, quick degradation of embryonic sac cells, accumulation of dark particles, irregularity, and even blockage of the nuclear envelope formation and increasing of embryonic sac cytoplasm concentration were the effects of heavy metals. Reduction of ovule number was also seen in the plants collected from polluted area. For protein studies, mature seeds were harvested from nonpolluted and polluted plants at the same time. Seed storage proteins (water soluble ones) were extracted and studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after being prepared. The results revealed that there were no significant differences between seed protein bands of polluted and nonpolluted samples, but the quantity of protein bands was different, and there was a slight quantitative increase of bands with molecular mass of 35 and 15 kD and decrease of a band with molecular mass of 17 kD in the plants collected from the mine area.     

Structure,chaperone activity,and aggregation of wild-type and R12C mutant αB-crystallins in the presence of thermal stress and calcium ion – Implications for role of calcium in cataract pathogenesis

The current study was performed with the aim to evaluate the chaperoning ability, structural features, and aggregation propensity of wild-type and R12C mutant αB-crystallins (αB-Cry) under thermal stress and in the presence of calcium ion. The results of different spectroscopic analyses suggest that wild-type and mutant αB-Cry have dissimilar secondary and tertiary structures. Moreover, αB-Cry indicates slightly improved chaperone activity upon the R12C mutation. Thermal stress and calcium, respectively, enhance and reduce the extent of solvent-exposed hydrophobic surfaces accompanying formation of ordered and non-ordered aggregate entities in both proteins. Compared to the wild-type protein, the R12C mutant counterpart shows significant resistance against thermal and calcium-induced aggregation. In addition, in the presence of calcium, significant structural variation was accompanied by reduction in the solvent-exposed hydrophobic patches and attenuation of chaperone activity in both proteins. Additionally, gel mobility shift assay indicates the intrinsic propensity of R12C mutant αB-Cry for disulfide bridge-mediated protein dimerization. Overall, the results of this study are of high significance for understanding the molecular details of different factors that are involved in the pathomechanism of cataract disorders.     

Specialized Plant Metabolism Characteristics and Impact on Target Molecule Biotechnological Production

Plant secondary metabolism evolved in the context of highly organized and differentiated cells and tissues, featuring massive chemical complexity operating under tight environmental, developmental and genetic control. Biotechnological demand for natural products has been continuously increasing because of their significant value and new applications, mainly as pharmaceuticals. Aseptic production systems of plant secondary metabolites have improved considerably, constituting an attractive tool for increased, stable and large-scale supply of valuable molecules. Surprisingly, to date, only a few examples including taxol, shikonin, berberine and artemisinin have emerged as success cases of commercial production using this strategy. The present review focuses on the main characteristics of plant specialized metabolism and their implications for current strategies used to produce secondary compounds in axenic cultivation systems. The search for consonance between plant secondary metabolism unique features and various in vitro culture systems, including cell, tissue, organ, and engineered cultures, as well as heterologous expression in microbial platforms, is discussed. Data to date strongly suggest that attaining full potential of these biotechnology production strategies requires being able to take advantage of plant specialized metabolism singularities for improved target molecule yields and for bypassing inherent difficulties in its rational manipulation.     

Sphagnum divinum (sp. nov.) and S. medium Limpr. and their relationship to S. magellanicum Brid.

Sphagnum magellanicum has been viewed as being a predominantly circumpolar species in the northern hemisphere, but it occurs in the southern hemisphere and was originally described from the southern parts of Chile. It is an ecologically important species in mire ecosystems and has been extensively used as a model to study processes of growth, carbon sequestration and peat decomposition. Molecular and experimental studies have, however, revealed genetic structure within S. magellanicum, and morphological differences associated with these genetic groups. Here we describe Sphagnum divinum in Sphagnum subgenus Sphagnum (Sphagnaceae, Bryophyta) as a new species, based on molecular and morphological evidence. Sphagnum medium is reinstated as a distinct species and is epitypified. Consequently, a new species concept of S. magellanicum is presented including an epitypification. Important morphological characters to separate these three species in the field and under the microscope are presented. Ecology and distribution differ among the species; S. divinium has a wide habitat range including mire margin, forested peatlands and moist heaths, and a circumpolar distribution around the northern hemisphere. Sphagnum medium seems to be more restricted to ombrotrophic mire expanse habitats and shows an amphi-Atlantic distribution in the northern hemisphere. Sphagnum magellanicum has a very broad ecological niche in peatlands and is found in most mire habitats in Tierra del Fuego on the southern tip of South America.     

Effects of Irrigation Regime and Foliar Application of Salicylic Acid and Spermine on the Contents of Essential Oil and Caffeic Acid Derivatives in Echinacea purpurea L.

Journal of Plant Growth Regulation - This study investigated the effect of irrigation regimes and the foliar application of salicylic acid (SA) and spermine (SPM) on the content of essential oil...     

Monophosphoryl Lipid A and Pam3Cys Prevent the Increase in Seizure Susceptibility and Epileptogenesis in Rats Undergoing Traumatic Brain Injury

Five percent of all epilepsy cases are attributed to traumatic brain injury (TBI), which are known as post-traumatic epilepsy (PTE). Finding preventive strategies for PTE is valuable. Remarkable feature of TBI is activation of microglia and subsequent neuroinflammation, which provokes epileptogenesis. The toll-like receptor agonists monophosphoryl lipid A (MPL) and tri-palmitoyl-S-glyceryl-cysteine (Pam3Cys) are safe, well-tolerated and effective adjuvants existing in prophylactic human vaccines. We examined the impact of early injection of MPL and Pam3Cys to rats, on the rate of kindled seizures acquisition following TBI. Rats received a single dose (1 µg/rat) of MPL or Pam3Cys through intracerebroventricular injection. 5 days later, trauma was exerted to temporo-parietal cortex of rats by controlled cortical impact device. After 24 h, traumatic rats underwent amygdala kindling. Brain level of the inflammatory cytokine tumor necrosis factor-alpha (TNF-α) was also measured in traumatic rats by immunoblotting. Compared to non-traumatic (sham-operated) rats, traumatic rats showed three times lower seizure threshold (133?±?5 µA vs. 416.3?±?16 µA, p?<?0.001); about three times less number of stimuli to become kindled (5?±?1 vs. 14?±?2, p?<?0.01); longer duration of kindled seizure parameters including entire seizure behavior, generalized seizures, and afterdischarges (p?<?0.001); and a two times increase in the TNF-α level. MPL and Pam3Cys did not change kindling rate and the seizure parameters in sham-operated rats. The MPL- and Pam3Cys-pretreated traumatic rats displayed seizure threshold, speed of kindling, and duration of kindled seizure parameters, similar to the non-traumatic rats. Pretreatment by MPL and Pam3Cys prevented the increase in TNF-α level by trauma. Given that MPL and Pam3Cys currently have clinical use as well-tolerated vaccines with reliable safety, they have the potential to be used in prevention of PTE.