Spontaneous dural tear leading to intracranial hypotension and tonsillar herniation in Marfan syndrome: a case report

Background  

We describe the case of a 38 year old male with Marfan syndrome who presented with orthostatic headaches and seizures.     

DNA barcoding of arid wild plants using rbcL gene sequences

DNA barcoding is currently gaining popularity due to its simplicity and high accuracy as compared to the complexity and subjective biases associated with morphology-based identification of taxa. The standard chloroplast DNA barcode for land plants recommended by the Consortium for the Barcode of Life (CBOL) plant working group needs to be evaluated for a wide range of plant species. We therefore tested the potential of the rbcL marker for the identification of wild plants belonging to diverse families of arid regions. Maximum likelihood tree analysis was performed to evaluate the discriminatory power of the rbcL gene. Our findings showed that using rbcL gene sequences enabled identification of the majority of the samples (92%) to genus level and only 17% to species level.     

Regulation of traffic and organelle architecture of the ER-Golgi interface by signal transduction

The components that control trafficking between organelles of the secretory pathway as well as their architecture were uncovered to a reasonable extent in the past decades. However, only recently did we begin to explore the regulation of the secretory pathway by cellular signaling. In the current review, we focus on trafficking between the endoplasmic reticulum and the Golgi apparatus. We highlight recent advances that have been made toward a better understanding of how the secretory pathway is regulated by signaling and discuss how this knowledge is important to obtain an integrative view of secretion in the context of other homeostatic processes such as growth and proliferation.     

Alcohol dehydrogenase expression as a biomarker of denitrification activity in activated sludge using methanol and glycerol as electron donors

Carbon sources such as methanol and glycerol are used for enhancing denitrification at wastewater treatment plants, which are required to meet increasingly stringent effluent nitrogen limits. Consequently, dosing strategies for these compounds could benefit from the development and application of molecular activity biomarkers to infer and distinguish between methanol- or glycerol-based denitrification in activated sludge. In this study, the applicability of genes coding for methanol dehydrogenase (mdh2 and mxaF) and glycerol dehydrogenase (dhaD) as potential biomarkers of denitrification activity using these specific substrates was explored and confirmed using a two-pronged approach. First, during short-term spikes of activated sludge biomass with glycerol, the ability of dhaD mRNA concentrations to closely track nitrate depletion profiles was demonstrated. Second, a high-degree of correlation of the mRNA concentrations of mdh2, mxaF and dhaD with methanol- and glycerol-based denitrification kinetics during long-term bioreactor operation using these substrates was also shown. Based on these results, expression of mdh2, mxaF and dhaD genes are promising biomarkers of in situ denitrification activity on methanol and glycerol, respectively, in mixed-culture engineered wastewater treatment processes.     

Modeling the Biodegradation Kinetics of Perchlorate in the Presence of Oxygen and Nitrate as Competing Electron Acceptors

A mathematical model was developed to describe the biodegradation kinetics of perchlorate in the presence of nitrate and oxygen as competing electron acceptors. The rate of perchlorate degradation is described as a function of the electron donor (acetate) degradation rate, the concentration of the alternate electron acceptors, and rates of biomass growth and decay. The kinetics of biomass growth are described using a modified Monod model, and inhibition factors are incorporated to describe the influence of oxygen and nitrate on perchlorate degradation. In order to develop input parameters for the model, a series of batch biodegradation studies were performed using Azospira suillum JPLRND, a perchlorate-degrading strain isolated from groundwater. This strain is capable of utilizing oxygen, nitrate, or perchlorate as terminal electron acceptors. The maximum specific growth rate (μ_max) and half-saturation constant (K _S ^don) for the bacterium when utilizing either perchlorate or nitrate were similar; 0.16 per h and 158 mg acetate/L, respectively. However, these parameters were different when the strain was growing on oxygen. In this case, μ_max and K _S ^don were 0.22 per h and 119 mg acetate/L, respectively. The batch experiments also revealed that nitrate inhibits perchlorate biodegradation by this strain. This finding was incorporated into the model by applying an inhibition coefficient (K _i ^nit) value of 25 mg nitrate/L. Combined with appropriate groundwater transport models, this model can be used to predict perchlorate biodegradation during in situ remediation efforts.