Correlation of "K" plane to occlusal plane and three different ala-tragal lines in dentulous subjects with different skeletal forms: A cephalometric study.

Aim: Orientation of the occlusal plane is an important clinical procedure for complete denture fabrication. An attempt had been made to reconstruct the occlusal plane using a different reference plane. The aim of this study was to find the correlation of the "K" plane to the occlusal plane and to assess the angular deviation between the K-plane to the occlusal plane (KO) with different skeletal forms. Settings and Design: An in vivo observational study was conducted on dentulous subjects having Class I dental occlusion with different skeletal forms undergoing orthodontic treatment. Materials and Methods: The study was conducted on 54 subjects aged 18-30 years. Metallic balls (3 mm in diameter) were attached to the desired landmarks, and a lateral cephalogram was taken for each subject. Cephalometric analysis was done using the Dolphin Imaging software, and the values obtained were recorded and subjected to statistical analysis. Statistical Analysis Used: The values obtained were recorded and subjected to statistical analysis using simple descriptive analysis, Shapiro-Wilk test, Mann-Whitney U-test, and Pearson's correlation. Results: A positive correlation was found between KO with a mean angular deviation of 8.59° ± 3.05°. The angle was found to be steeper in skeletal Class II subjects. Conclusions: Clinical application of the K-plane to use as a reference plane to orient the posterior occlusal plane can enhance the treatment outcome for a removable prosthesis. The results of this study provide a theoretical foundation for the practical restoration of the occlusal plane in different skeletal forms.

Macroscopic to Microscopic - A Case of Crohn's Disease Progressing to Collagenous Colitis.

The association between microscopic colitis (MC) and inflammatory bowel disease (IBD) is uncertain and infrequently reported. Rare cases in the literature consist of simultaneous MC and IBD, or progression of one condition to the other. We present a unique case of clinically and endoscopically diagnosed and successfully treated IBD that revealed MC on histology months later due to reappearance of diarrhea. Common pathophysiologic mechanisms, such as tumor necrosis factor α and T helper type 1 cells, may explain the MC and IBD relationship. During endoscopy, a prompt biopsy should be taken if suspicious for MC, thus decreasing the duration of patient's symptoms and saving healthcare costs.

Urea and urine are a viable and cost-effective nitrogen source for Yarrowia lipolytica biomass and lipid accumulation.

Yarrowia lipolytica is an industrial yeast that has been used in the sustainable production of fatty acid-derived and lipid compounds due to its high growth capacity, genetic tractability, and oleaginous properties. This investigation examines the possibility of utilizing urea or urine as an alternative to ammonium sulfate as a nitrogen source to culture Y. lipolytica. The use of a stoichiometrically equivalent concentration of urea in lieu of ammonium sulfate significantly increased cell growth when glucose was used as the carbon source. Furthermore, Y. lipolytica growth was equally improved when grown with synthetic urine and real human urine. Equivalent or better lipid production was achieved when cells are grown on urea or urine. The successful use of urea and urine as nitrogen sources for Y. lipolytica growth highlights the potential of using cheaper media components as well as exploiting and recycling non-treated human waste streams for biotechnology processes.

Engineering xylose utilization in Yarrowia lipolytica by understanding its cryptic xylose pathway.

BACKGROUND: The oleaginous yeast, Yarrowia lipolytica, has been utilized as an industrial host for about 60 years for various applications. Recently, the metabolic engineering of this host has become increasingly popular due to its ability to accumulate lipids as well as improvements made toward developing new genetic tools. Y. lipolytica can robustly metabolize glucose, glycerol, and even different lipid classes. However, little is known about its xylose metabolizing capability. Given the desirability of having a robust xylose utilizing strain of Y. lipolytica, we performed a comprehensive investigation and elucidation of the existing components of its xylose metabolic pathway. RESULTS: A quick and efficient means of determining functionality of the candidate xylose pathway genes (XYR, XDH, and XKS) from Y. lipolytica was desirable. We challenged Escherichia coli mutants lacking either the xylose isomerase (xylA) gene or the xylulose kinase (xylB) gene to grow on xylose minimal media by expressing the candidate genes from Y. lipolytica. We showed that the XKS of Y. lipolytica is able to rescue xylose growth of E. coli ΔxylB, and the XDH enabled growth on xylitol, but not on xylose, of E. coli ΔxylA. Overexpression of XKS and XDH in Y. lipolytica improved growth on xylitol, indicating that expression of the native enzymes was limiting. Overexpression of XKS and XDH in Y. lipolytica also enables robust growth on xylose under high nitrogen conditions without the need for adaptation. These results prove that a complete xylose pathway exists in Y. lipolytica, but the pathway is poorly expressed. To elucidate the XYR gene, we applied the E. coli ΔxylA xylose growth challenge with 14 candidate XYR genes and XDH. The XYR2 candidate was able to rescue growth of E. coli ΔxylA xylose on minimal media. CONCLUSIONS: While a native xylose pathway exists in Y. lipolytica, the microorganism's inability to grow robustly on xylose is an effect of cryptic genetic circuits that control expression of key enzymes in the metabolic pathway. We have characterized the key enzymes associated with xylose metabolism and demonstrated that gene regulatory issues can be overcome using strong hybrid promoters to attain robust growth on xylose without adaptation.

Synthetic RNA Polymerase III Promoters Facilitate High-Efficiency CRISPR-Cas9-Mediated Genome Editing in Yarrowia lipolytica.

The oleaginous yeast Yarrowia lipolytica is a valuable microbial host for chemical production because it has a high capacity to synthesize, modify, and store intracellular lipids; however, rapid strain development has been hampered by the limited availability of genome engineering tools. We address this limitation by adapting the CRISPR-Cas9 system from Streptococcus pyogenes for markerless gene disruption and integration in Y. lipolytica. Single gene disruption efficiencies of 92% and higher were achieved when single guide RNAs (sgRNA) were transcribed with synthetic hybrid promoters that combine native RNA polymerase III (Pol III) promoters with tRNA. The Pol III-tRNA hybrid promoters exploit endogenous tRNA processing to produce mature sgRNA for Cas9 targeting. The highest efficiencies were achieved with a SCR1'-tRNA(Gly) promoter and Y. lipolytica codon-optimized Cas9 expressed from a UAS1B8-TEF promoter. Cotransformation of the Cas9 and sgRNA expressing plasmid with a homologous recombination donor plasmid resulted in markerless homologous recombination efficiency of over 64%. Homologous recombination was observed in 100% of transformants when nonhomologous end joining was disrupted. The end result of these studies was the development of pCRISPRyl, a modular tool for markerless gene disruption and integration in Y. lipolytica.