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61.
Banada PP Guo S Bayraktar B Bae E Rajwa B Robinson JP Hirleman ED Bhunia AK 《Biosensors & bioelectronics》2007,22(8):1664-1671
We demonstrate here the development of a non-invasive optical forward-scattering system, called 'scatterometer' for rapid identification of bacterial colonies. The system is based on the concept that variations in refractive indices and size, relative to the arrangement of cells in bacterial colonies growing on a semi-solid agar surface will generate different forward-scattering patterns. A 1.2-1.5mm colony size for a 1mm laser beam and brain heart infusion agar as substrate were used as fixed variables. The current study is focused on exploring identification of Listeria monocytogenes and other Listeria species exploiting the known differences in their phenotypic characters. Using diffraction theory, we could model the scattering patterns and explain the appearance of radial spokes and the rings seen in the scattering images of L. monocytogenes. Further, we have also demonstrated development of a suitable software for the extraction of the features (scalar values) calculated from images of the scattering patterns using Zernike moment invariants and principal component analysis and were grouped using K-means clustering. We achieved 91-100% accuracy in detecting different species. It was also observed that substrate variations affect the scattering patterns of Listeria. Finally, a database was constructed based on the scattering patterns from 108 different strains belonging to six species of Listeria. The overall system proved to be simple, non-invasive and virtually reagent-less and has the potential for automated user-friendly application for detection and differentiation of L. monocytogenes and other Listeria species colonies grown on agar plates within 5-10 min analysis time. 相似文献
62.
(S)-1-Phenylethanol derivatives, which are the precursors of many pharmacological products, have also been used as anti-Alzheimer drugs. Bioreduction experiments were performed in a batch and packed-bed bioreactor. Then, the kinetics constants were determined by examining the reaction kinetics in the batch system with free and immobilized carrot cells. Also, the effective diffusion coefficient (De) of acetophenone in calcium alginate-immobilized carrot cells was investigated. Kinetics constants for free cells, which are intrinsic values, are reaction rate Vmax?=?0.052?mmol?L?1?min?1, and constants of the Michaelis–Menten KM?=?2.31?mmol?L?1. Kinetics constants for immobilized cells, which are considered apparent values, are Vmax, app?=?0.0407?mmol?L?1 min?1, KM, app?=?3.0472?mmol?L?1 for 2?mm bead diameter, and Vmax, app?=?0.0453?mmol?L?1 min?1, KM, app?=?4.9383?mmol?L?1 for 3?mm bead diameter. Average value of effective diffusion coefficient of acetophenone in immobilized beads was determined as 1.97?×?10?6?cm2?s?1. Using immobilized carrot cells in an up-flow packed-bed reactor, continuous production of (S)-1-phenylethanol through asymmetric bioreduction of acetophenone was performed. The effects of the residence time and concentrations of substrate were investigated at pH 7.6 and 33°C. Enantiomerically pure (S)-1-phenylethanol (ee?>?99%) was produced with 75% conversion at 4-hr residence time. 相似文献
63.
Mehmet Yucel Aysegul Kucuk Aslihan Cavunt Bayraktar Murat Tosun Soner Yalcinkaya Namik Kemal Hatipoglu Nilufer Erkasap Mustafa Kavutcu 《Molecular biology reports》2013,40(10):5733-5740
The aim of the present study was to evaluate the protective effects of the NF-кB inhibition with pyrrolidine-dithiocarbamate (PDTC) in ischemia–reperfusion (I/R) injury in the rat bladder. Twenty-four Sprague-Dawley male rats were divided into three groups. Group I; (n = 8) control, group II; (n = 8) I/R group; group III (n = 8) I/R and PDTC treatment. Superoxide dismutase (SOD), catalase (CAT), and gluatathione-S-transferase (GST) enzymes was studied in bladder tissue. Lipid peroxidation (as TBARS) levels in tissue homogenate were measured with thiobarbituric acid reaction. All the slides were stained with NF-кB, p53 and HSP60 immunohistochemistry for detection genome destruction and tissue stress, respectively. Our results show that the mean TBARS levels were significantly higher in group II (p < 0.05). The TBARS levels were significantly decreased in group III compared with the group II (p < 0.05). CAT, SOD and GST activities were decreased in group II, but these enzymes levels were significantly increased in group III according to the group II (p < 0.05). Under microscopic evaluation NF-кB expression increased significantly in group II compared to the group I (p < 0.05) and then decreased in group III (p < 0.05). HSP60 and p53 expression in group II was increased significantly compared with group I. Under microscopic evaluation we detected that HSP60 and p53 expression was increased significantly in group II compared with group I. In group III PDTC administration was decreased the HSP60 and p53 expression, this difference was statistically significant (p < 0.05). The results of the present study have demonstrated that NF-кB inhibition with PDTC protects and provides beneficial effects on ischemia/reperfusion stress related bladder tissue destruction. 相似文献
64.
65.
Alton G; Hasilik M; Niehues R; Panneerselvam K; Etchison JR; Fana F; Freeze HH 《Glycobiology》1998,8(3):285-295
Direct utilization of mannose for glycoprotein biosynthesis has not been
studied because cellular mannose is assumed to be derived entirely from
glucose. However, animal sera contain sufficient mannose to force uptake
through glucose-tolerant, mannose-specific transporters. Under
physiological conditions this transport system provides 75% of the mannose
for protein glycosylation in human hepatoma cells despite a 50- to 100-fold
higher concentration of glucose. This suggests that direct use of mannose
is more important than conversion from glucose. Consistent with this
finding the liver is low in phosphomannose isomerase activity
(fructose-6-P<->mannose-6-P), the key enzyme for supplying
glucose-derived mannose to the N-glycosylation pathway. [2- 3H] Mannose is
rapidly absorbed from the intestine of anesthetized rats and cleared from
the blood with a t1/2of 30 min. After a 30 min lag, label is incorporated
into plasma glycoproteins, and into glycoproteins of all organs during the
first hour. Most (87%) of the initial incorporation occurs in the liver,
but this decreases as radiolabeled plasma glycoproteins increase.
Radiolabel in glycoproteins also increases 2- to 6-fold in other organs
between 1-8 h, especially in lung, skeletal muscle, and heart. These organs
may take up hepatic- derived radiolabeled plasma glycoproteins.
Significantly, the brain, which is not exposed to plasma glycoproteins,
shows essentially no increase in radiolabel. These results suggest that
mammals use mannose transporters to deliver mannose from blood to the liver
and other organs for glycoprotein biosynthesis. Additionally, contrary to
expectations, most of the mannose for glycoprotein biosynthesis in cultured
hepatoma cells is derived from mannose, not glucose. Extracellular mannose
may also make a significant contribution to glycoprotein biosynthesis in
the intact organism.
相似文献
66.
67.
Christina Spilker Sven Nullmeier Katarzyna M. Grochowska Anne Schumacher Ioana Butnaru Tamar Macharadze Guilherme M. Gomes PingAn Yuanxiang Gonca Bayraktar Carolin Rodenstein Carolin Geiseler Angela Kolodziej Jeffrey Lopez-Rojas Dirk Montag Frank Angenstein Julia B?r Wolfgang D’Hanis Thomas Roskoden Marina Mikhaylova Eike Budinger Frank W. Ohl Oliver Stork Ana C. Zenclussen Anna Karpova Herbert Schwegler Michael R. Kreutz 《PLoS genetics》2016,12(3)
68.
Botrytis disease of tea was reported for the first time from Rize, Turkey. The causal agent was identified as Botrytis cinerea based on morphological and cultural characteristics. Also, the species‐specific PCR assays confirmed the identification of all B. cinerea isolates. The pathogen caused blight of shoots, buds, flowers and young leaves, shoot canker and leaf spots. The disease was observed in Rize central district and Derepazar?, Çaml?hem?in, Çayeli, Pazar, Hem?in, ?kizdere, Arde?en and ?yidere districts. 相似文献
69.
Optically active 1-phenyl 1-propanol is used as a chiral building block and synthetic intermediate in the pharmaceutical industries. In this study, the enantioselective production of 1-phenyl 1-propanol was investigated systematically using response surface methodology (RSM). Before RSM was applied, the effects of the enzyme source, the type of acyl donor, and the type of solvent on the kinetic resolution of 1-phenyl 1-propanol were studied. The best results were obtained with Candida antartica lipase (commercially available as Novozym 435), vinyl laurate as the acyl donor, and isooctane as the solvent. In the RSM, substrate concentration, molar ratio of acyl donor to the substrate, amount of enzyme, temperature, and stirring rate were chosen as independent variables. The predicted optimum conditions for a higher enantiomeric excess (ee) were as follows: substrate concentration, 233 mM; molar ratio of acyl donor to substrate, 1.5; enzyme amount, 116 mg; temperature, 47 °C; and stirring rate, 161 rpm. A verification experiment conducted at these optimized conditions for maximum ee yielded 91% for 3 hr, which is higher than the predicted value of 83%. The effect of microwave on the ee was also investigated and ee reached 87% at only 5 min. 相似文献
70.
The phylogeny and substitution rates of the mammalian X chromosome- located
and autosomal phosphoglycerate kinase and pyruvate dehydrogenase genes were
investigated. Compatibility analysis was used to show reticulate evolution
in these genes. Analysis of the marsupial, mouse, and human
phosphoglycerate kinase genes suggests that at least two recombination
events have taken place, one occurring about the time of the
placental-marsupial split involving exons 1-5 and the other before the
primate-rodent split involving exons 9-10. Similar analysis of the pyruvate
dehydrogenase genes indicates a recombination event involving exons 2-3 at
a time before the primate-rodent split and a gene conversion between exons
3-4 in the human somatic and testis- specific pyruvate dehydrogenase genes
after the primate-rodent split. This demonstrates that genetic exchange can
occur between paralogous genes at widely separated chromosomal locations.
Estimation of nucleotide substitution rates in these genes confirmed a
higher substitution rate in the pyruvate dehydrogenase genes. In the
phosphoglycerate kinase genes, there is no difference between the
substitution rates in mice and humans and between the X chromosome- and
autosome-located genes. A greater substitution rate was noted in the mouse
autosomal pyruvate dehydrogenase gene when compared with the other mouse
and human genes. This may be a result of either directional natural
selection or a relaxation of functional constraint at this specific gene.
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