A novel iron-containing blue protein, named neelaredoxin, was isolated from the sulfate-reducing bacterium Desulfovibrio gigas. It is a monomeric protein with a molecular mass of 15 kDa containing two iron atoms/molecule. The N-terminal sequence of neelaredoxin has similarity to the second domain of desulfofen-odoxin, a protein purified from Desulfovibrio vulgaris Hildenborough. This finding supports the hypothesis that the gene coding for desulfoferrodoxin (rbo) might have arisen from a gene fusion [Brumlik, M. J., Leroy, G., Bruschi, M. & Voordouw, G. (1990) J. Bacteriol. 172, 7289-72921. The visible spectrum exhibits a single band at 666 nm, responsible for the blue color of the protein, which is completely bleached upon reduction with sodium ascorbate. In the oxidized state the EPR spectrum is complex, exhibiting well-resolved features at g = 7.6, 7.0, 5.9, and 5.8 which are assigned to two high-spin (5' = 5/2) mononuclear-iron (111) centers with different rhombic distortions (EID = 0.05 and = 0.08). The two iron atoms contribute identically to the visible spectrum as judged from visible redox titrations, from which a reduction potential of +190 mV was determined for both iron sites at pH 7.5. At high pH the visible and the EPR spectra become pH-dependent with a pK, above 9 : the 666-nm band shifts to 590 nm and the EPR signals are converted into a signal with g, , , = 4.7. Neelaredoxin is readily reduced both by H2/hydrogenase/ cytochrome c3 and by NADWNADH -rubredoxin oxidoreductase.Sulfate-reducing bacteria are rich in electron-carrier proteins. These proteins can be classified into three groups : flavoproteins, hemoproteins, and non-heme iron proteins. Detailed discussions concerning these proteins can be found in recent reviews [I, 21. Within the group of non-heme-iron proteins, besides the iron-sulfur-containing ferredoxins, several redox proteins with no labile sulfur have been discovered containing mononuclear or dinuclear iron centers. These include rubredoxin, desulforedoxin, desulfoferrodoxin, rubrerythrin and nigerythrin.Rubredoxin is the smallest protein (Mr = 6000) found in sulfate-reducing bacteria including Desulfovibrio gigas [3], D. vulgaris Hildenborough [4], D. desulfuricans [5] and D.salexigens [6]. The structure of the protein has been well studied [7]. This protein contains one iron atodmolecule which links to four cysteinyl residues in the polypeptide chain. Its high reduction potential (-50 to 0 mV) made it difficult to find an appropriate place in any electron transfer chain. Recently, D. gigas rubredoxin was shown to function in an aerobic electron transfer chain which allows ATP formation from polyglucose [S, 91. Desulforedoxin is another [Fel-only-
Antioxidant supplements from plants are vital to count the oxidative damage in cells. We assessed the antioxidants and antibacterial activity of green hull of Juglans regia in this study. According to our results the maximum antibacterial activity was observed in ethanolic extract when compared to other extract. So, the ethanolic extract was studied for antioxidant activity which exhibited high antiradical activity against DPPH, hydroxyl, and nitric oxide radicals. In conclusion, green hull of J. regia showed strong reducing power activity and total antioxidant capacity. The results justify the therapeutic application of plant in the indigenous system of medicine.
PurposeMany changes that call for concerted social action were observed in society and business performance during the coronavirus 2019 (COVID-19) outbreak. The impact of digitization and customer participation was evident in providing medical guidelines, updates on government initiatives, education or the supply of essential services during lockdown in many countries. However, there were aberrations. The purpose of this study is to explore some consumers and firms' being better equipped for service co-creation than others, specifically during a pandemic; the different degrees of service co-creation and the possible outcomes of customer participation in the service context.Design/methodology/approachQualitative study with 35 in-depth interviews of supply- and demand-side actors, with coding and analysis of interview transcripts was conducted.FindingsThe authors identify two levels of service co-creation: (1) service co-development and (2) service co-evaluation that are affected by customer capabilities and firm/institutional barriers. The outcome of service co-creation lies in the social, economic and experiential values thus created. A pandemic strengthens the effect of antecedents (customer capabilities and firm capabilities) on the co-creation process.Practical implicationsManagers can refer to the findings to manage customer engagements and co-creations effectively, especially during a pandemic.Originality/valueThe impact of the pandemic on the service co-creation process in an emerging market, and the antecedents (firm- and customer-side) and consequences (mutual value outcomes) of service co-creation and actor participation are explored.
Aim: To investigate the relationship between caries etiological factors and occurrence of severe caries among adults in Kuwait. Methods: Forty-two adult patients with severe caries, attending Kuwait polyclinics, were compared with 36 caries-free subjects in a cross-sectional study. The patients with severe caries were aged 16 years or older and had a minimum of eight open coronal carious cavities, with the involvement of at least one anterior tooth. In addition, their salivary glands had not been compromised by disease or medication. The caries-free subjects had at least 24 standing teeth, and no carious cavities. Salivary flow rates, buffering capacity, frequency of sugar consumption, and oral hygiene index were measured. Mutans streptococci and Lactobacillus counts were determined by the dip-slide method. Results: Fisher’s exact test or χ2 test showed that the patients with severe caries had a significantly higher frequency of sugar consumption, plaque index, Lactobacillus and mutans streptococci counts, as compared with those who were caries-free. In contrast, no significant difference was observed in salivary flow rates or buffering capacity between the two groups of patients. In the multiple logistic regression analysis, only frequency of sugar consumption, oral hygiene, and mutans streptococci count were found to be significantly associated with the occurrence of severe caries. Conclusion: Severe caries may occur in Kuwait even among adults whose salivary gland functions have not been compromised.
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