The Complex Effects of Stimulated Climate Temperature Increase on the Social Amoeba Dictyostelium discoideum and Their Bacterial Endosymbionts

From the Washington University Office of Undergraduate Research Digest (WUURD), Vol. 13, 05-01-2018. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences Mentor(s): Joan Strassman

Waterlogging tolerance evaluation of fifteen poplar clones cultivated in the Jianghan Plain of China

To provide references for poplar cultivation in waterlogged prone area of Jianghan Plain of China, the waterlogging tolerance of 15 poplar clones widely cultivated in these areas were evaluated based on their responses to 45-day waterlogging stress followed by 15-day drainage recovery in morphology, growth, biomass accumulation, leaf gas exchange and chlorophyll fluorescence parameters. The results showed that the normal watered seedlings (CK) of the 15 clones grew vigorously during the experiment, and no defoliation and death occurred. For the seedlings under waterlogging treatment (water 10 cm above the soil surface), its morphology changed markedly, including slowing growth, chlorosis and abscission of leaves, development of hypertrophied lenticels and adventitious roots etc. Waterlogging stress significantly inhibited the seedling growth of height and ground diameter, biomass accumulation, as well as leaf gas exchange and chlorophyll fluorescence parameters of the 15 clones with varying degrees. The net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular CO2 concentration/ environmental CO2 concentration (Ci/Ca), variable fluorescence (Fv), variable fluorescence/ initial fluorescence (Fv/Fo) and PS Ⅱ primary light energy conversion efficiency (Fv/Fm) decreased gradually with the prolonged waterlogging, and reached their bottom on day 45. During the terminal recovery stage, the leaf gas exchange and chlorophyll fluorescence parameters of the most clones increased, but their recovery abilities were significantly different. At the end of the experiment, the highest survival rates (100%) were observed in DHY, HS-1, HS-2, I-72, I-69, I-63 and NL-895, and the lowest (zero) occurred in XYY. Survival rates of the other clones ranged from 33.33% to 83.33%. Both results of cluster analysis and membership function analysis showed that HS-1, I-69, DHY, NL-895 and HS-2 had the strongest waterlogging tolerance, XYY and HBY were the worst, and the other clones were moderate. These results would provide guidance not only for the selection of cultivated varieties in Jianghan Plain, but also for the selection of hybrid parents for waterlogging resistance breeding

Trans-arterial positive ICG staining-guided laparoscopic liver watershed resection for hepatocellular carcinoma

IntroductionAnatomical liver resection is the optimal treatment for patients with resectable hepatocellular carcinoma (HCC). Laparoscopic Couinaud liver segment resection could be performed easily as liver segments could be stained by ultrasound-guided indocyanine green (ICG) injection into the corresponding segment portal vein. Several smaller liver anatomical units (liver watersheds) have been identified (such as S8v, S8d, S4a, and S4b). However, since portal veins of liver watersheds are too thin to be identified under ultrasound, the boundaries of these liver watersheds could not be stained intraoperatively, making laparoscopic resection of these liver watersheds demanding. Digital subtraction angiography (DSA) could identify arteries of liver watersheds with a diameter of less than 2 mm. Yet, its usage for liver watershed staining has not been explored so far.PurposeThe aim of this study is to explore the possibility of positive liver watershed staining via trans-arterial ICG injection under DSA examination for navigating laparoscopic watershed-oriented hepatic resection.MethodsWe describe, in a step-by-step approach, the application of trans-arterial ICG injection to stain aimed liver watershed during laparoscopic anatomical hepatectomy. The efficiency and safety of the technique are illustrated and discussed in comparison with the laparoscopic anatomical liver resection via ultrasound-guided liver segment staining.ResultsEight of 10 HCC patients received successful trans-arterial liver watershed staining. The success rate of the trans-artery staining approach was 80%, higher than that of the ultrasound-guided portal vein staining approach (60%). Longer surgical duration was found in patients who underwent the trans-artery staining approach (305.3 ± 23.2 min vs. 268.4 ± 34.7 min in patients who underwent the ultrasound-guided portal vein staining approach, p = 0.004). No significant difference was found in major morbidity, reoperation rate, hospital stay duration, and 30-day and 90-day mortality between the 2 groups.ConclusionsTrans-arterial ICG staining is safe and feasible for staining the aimed liver watershed, navigating watershed-oriented hepatic resection under fluorescence laparoscopy for surgeons

Local Adaptation and the Role of Carried Symbionts to Thermal Stress in a Social Amoeba Dictyostelium discoideum

From the Washington University Office of Undergraduate Research Digest (WUURD), Vol. 12, 05-01-2017. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Lindsey Paunovich, Editor; Helen Human, Programs Manager and Assistant Dean in the College of Arts and Sciences. Mentor: Joan Strassman

RELIABILITY ALLOCATION OF A ROTARY MACHINE BASED ON GREY EVALUATION THEORY

A comprehensive reliability allocation method, which is applicable to the cases of lack of data in design stage, as well as the complexity of the influence factors and uncertainty of expert evaluation, is presented based on the grey system theory. The key of this method is to modify the weights of influence factors which are associated with expert scoring data by grey correlation analysis before reliability indices are assigned linearly to each subsystem.Based on grey evaluation with 4 levels, the application of this method is illustrated with the reliability allocation of a rotary machine under the consideration that complexity, technical level, importance and environment condition are chosen as influence factors. Compared with the actual faults statistics results, the validity and feasibility of the method is verified

Lipid Nanoparticle (LNP) Delivery Carrier-Assisted Targeted Controlled Release mRNA Vaccines in Tumor Immunity

In recent years, lipid nanoparticles (LNPs) have attracted extensive attention in tumor immunotherapy. Targeting immune cells in cancer therapy has become a strategy of great research interest. mRNA vaccines are a potential choice for tumor immunotherapy, due to their ability to directly encode antigen proteins and stimulate a strong immune response. However, the mode of delivery and lack of stability of mRNA are key issues limiting its application. LNPs are an excellent mRNA delivery carrier, and their structural stability and biocompatibility make them an effective means for delivering mRNA to specific targets. This study summarizes the research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity. The role of LNPs in improving mRNA stability, immunogenicity, and targeting is discussed. This review aims to systematically summarize the latest research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity to provide new ideas and strategies for tumor immunotherapy, as well as to provide more effective treatment plans for patients

The SNP Rs915014 in MTHFR Regulated by MiRNA Associates with Atherosclerosis

Background/Aims: The association between the genetic polymorphisms located in either the exon or untranslated region of MTHFR and the risk of human atherosclerosis has been well-documented. This study analyzed MTHFR polymorphisms at the 3’-untranslated region for association with risk and outcome of atherosclerosis in a Chinese Han population. Methods: The hospital based case-control study was conducted with 500 patients and 600 healthy volunteers as control enrolled. The genotyping was conducted by using Taqman probe. The potential interaction was predicted by multiple bioinformatics analysis. The relative expression of MTHFR was detected by qRT-PCR. Further confirmation was determined by dual-luciferase assay. The plasma homocysteine levels were assayed by ELISA. Results: Cigarette smoking, alcohol consumption, diabetes, hypertension and low levels of serum high-density lipoprotein-C were associated with an increased risk of developing ischemic stroke. MTHFR rs915014 AG and GG genotypes were significantly associated with increased risk of rs915014 compared with the GG genotype. The qRT-PCR confirmed that MTHFR rs915014 AG or GG genotypes could facilitate miR-2861 binding leading to decreased MTHFR levels in cells. In addition, patients carrying the MTHFR rs915014 AG or GG genotypes were associated with accumulation of circulating tHcy volume and a poor atherosclerosis consequence. Conclusions: This study demonstrates that the MTHFR rs915014 is associated with increased risk of atherosclerosis and might be a shot term outcome biomarker for atherosclerosis patients

Efficient Escherichia coli (E. coli) Trapping and Retrieval from Bodily Fluids via a Three-Dimensional (3D) Microbeads Stacked Nano-Device

A micro- and nano-fluidic device stacked with magnetic beads is developed to efficiently trap, concentrate, and retrieve Escherichia coli (E. coli) from bacteria suspensionand pig plasma. The small voids between the magnetic beads are used to physically isolate the bacteria in the device. We use computational fluid dynamics (CFD), 3Dtomography technology, and machine learning to probe and explain the bead stacking in a small 3D space with various flow rates. A combination of beads with different sizes is utilized to achieve a high capture efficiency of ~86% with a flow rate of 50 μL/min. Leveraging the high deformability of this device, the E. coli sample is retrieved from the designated bacteria suspension by applying a higher flow rate, followed by rapid magnetic separation. This unique function is also utilized to concentrate E. coli from the original bacteria suspension. An on-chip concentrationfactor of ~11× is achieved by inputting 1,300 μL of the E. coli sample and then concentrating it in 100 μL buffer.Importantly, this multiplexed, miniaturized, inexpensive, and transparent device is easy to fabricate and operate, making it ideal for pathogen separation in both laboratory and pointof- care (POC) settings.</div