Dentinogenesis imperfecta in Osteogenesis imperfecta type XI in South Africa: a genotype–phenotype correlation

BACKGROUND: The maxillofacial and dental manifestations of Osteogenesis imperfecta (OI) have significant implications in terms of management. Although the occurrence of abnormal dentine in some forms of OI is well documented, there is scant information on the association of abnormal dentine in the Black African persons with phenotypic OI III and genotypic OI XI in South Africa. METHODS: This was a cross-sectional analytic study. A series of 64 Black South African individuals with a confirmed phenotypic diagnosis of OI III, ages ranging from 3 months to 29 years, were assessed clinically, radiographically, and at a molecular level. RESULTS: A total number of 64 saliva samples were analyzed and 3 DNA variations were identified in exon 5 of the FKBP10 gene. The homozygous mutation, c.[831dupC]; [831dupC], was identified in 23 affected persons who had no clinically obvious features of DI in their primary and secondary teeth. Radiologically, mild features of DI were evident in 10 persons in whom radiographic images were obtained and were given a Clinical–radiological score of 2. A compound heterozygous mutation, c. [831delC]; [831dupC], was identified in three siblings. An intraoral examination of these affected persons revealed no clinically apparent features of DI in their primary and secondary teeth. Due to the lack of radiological facilities, the presence or absence of DI could not be confirmed or negated. A second compound heterozygous mutation, c.[831dupC]; [1400-4C>G], was identified in a female of 29 years belonging to the Xhosa linguistic group. Her teeth appeared clinically normal but it was not possible to obtain radiographs. In 37 affected individuals, no disease-causing mutations were identified. CONCLUSION: Black African individuals in SA with the homozygous mutation in the FKBP10 gene have clinically unaffected teeth yet exhibited radiographic features of DI to varying degrees. This characterization is suggestive of a relationship between the genetic abnormality and the clinical manifestations of DI. The authors suggest that this diagnosis must include teeth that are clinically and/or radiologically aberrant, and should not exclude the presence of other, milder, dentinal aberrations associated with OI. There was no correlation between severity of OI and DI in this cohort of individuals

Laboratory Studies of MEOR in the Micromodel as a Fractured System

Abstract Microbial enhanced oil recovery (MEOR) is receiving renewed interest worldwide in recent years as a viable method while not damaging the reservoir is proven to be remarkably effective, however to some extent costly. This method is based on microorganisms' activities to reduce residual oil of reservoirs, which is dependent on behavior of inherent microorganisms or injection of bio-product of external microorganisms. In this work, five bacterial species were taken from MIS crude oil that is one of the aging Persian fractured reservoirs. These microorganisms are substantially strong in increasing oil recovery especially by reducing IFT and other MEOR mechanisms such as change of wettability of rock at the favorable condition for the activities of these bacteria observed within the temperature range of 50°C to 90°C at the atmospheric pressure. Two series of visualization experiments were carried out to examine the behavior of microbial enhanced oil recovery in micromodels designed to resemble the fractured system: static and dynamic. In the static one, carbonate rock-glass micromodel is used to simulate the reservoir conditions and the latter is performed by a glass micromodel which has a fracture with 45 degree inclination. The image processing methodology is used to determine the recovery achieved by MEOR in the micromodel made of glass. Introduction A prevalent question in the oil industry is: what is the best method for improving the recovery factor of a certain reservoir? Jumping to the answer is not always an easy task. The effectiveness of a method in a specific reservoir does not necessarily guarantee the chance of success somewhere else. Essentially the prevailing condition of a reservoir is the determining factor in success or failure of a method. So, if the method is designed in a way the least affecting the reservoir, there would be a higher chance of success. MEOR is one of these lately high-profile methods. Even though, this method can be very powerful, but its associating problems are still to be taken into thorough consideration. MEOR has long been considered by hydrocarbon-related scientists and microbiologists as an effective method to recover tertiary oil from reservoirs. MEOR can recover tertiary oil by improving macroscopic sweep efficiency through microbially induced permeability profile modification; or reducing interfacial tension between oil and water with microbial bio-surfactants to lower the capillary trapping forces; or stimulating the reservoir porosity and permeability with microbial products such as acids, or combining all three mechanisms. This paper concentrates mainly on the application of bio-organisms which are also referred to as microorganisms throughout this study to recover residual oil trapped within the pores of a rock. The glass micromodels are largely used for visualization purposes in literature. In addition to conventional micromodels two other types were also utilized which could be considered as hybrid models of the reservoir rock and a micromodel. At the end of the water-flooding of reservoirs, a large quantity of oil may remain trapped within the reservoir. The oil is retained by capillary forces acting on oil globules within the porous medium. Surfactants reduce capillary forces by lowering the interfacial tension between oil and water. This allows any displacing force such as the viscous force of injected or flowing surfactant to recover some of this oil. Microbial bio-surfactants are similar to synthetic surfactants in terms of the oil recovery mechanism. What differentiates them from synthetic surfactants is that they are generated in situ, inside the reservoir, by microbes when sufficient nutrients and suitable conditions are present. Primary Microbial Culture A new surface sample of the MIS oil was taken at the well head and physical specifications were measured at the lab. This is fairly light oil with API gravity of 42.5. The respective specifications are according to the table 1. M. Nourani, H. Panahi, D. Biria, R. Roosta Azad, M. Haghighi and A. Mohebb

The mechanism of neutral red-mediated microbial electrosynthesis in Escherichia coli: menaquinone reduction

•The mechanism of electro-synthesis with neutral red in E. coli was identified.•Neutral red reduces menaquinone in the inner membrane.•Resulting menaquinol drives anaerobic respiration with multiple electron acceptors.•Sans electron acceptor, menaquinol reduces the arcB redox sensor.•Reduced arcB causes transcriptional changes that alter metabolite profiles. The aim of this work was to elucidate the mechanism of mediated microbial electrosynthesis via neutral red from an electrode to fermenting Escherichia coli cultures in a bioelectrochemical system. Chemical reduction of NAD+ by reduced neutral red did not occur as predicted. Instead, neutral red was shown to reduce the menaquinone pool in the inner bacterial membrane. The reduced menaquinone pool altered fermentative metabolite production via the arcB redox-sensing cascade in the absence of terminal electron acceptors. When the acceptors DMSO, fumarate, or nitrate were provided, as many as 19% of the electrons trapped in the reduced acceptors were derived from the electrode. These results demonstrate the mechanism of neutral red-mediated microbial electrosynthesis during fermentation as well as how neutral red enables microbial electrosynthesis of reduced terminal electron acceptors