Biology subjects

Yang, M. L.

Publications and source records attributed to Yang, M. L..

4 recordsLinked to original sources

bioRxiv2022

Understanding Vascular Endothelial Cell Behavior Using a Mechanical Strain Gradient Generated by an Electromagnetic Stretching Device

Cardiovascular diseases cause an estimated 17.9 million deaths globally each year (World Health Organization). Endothelial cells that line the vasculature and the endocardium are subjected to cyclic mechanical stretch. Deviation from physiological stretch can alter the endothelial function, having the risk of atherosclerosis and myocardial infarction. To understand the mechanical stretch effects, cell culture platforms that provide mechanical stretch have been developed. However, most of them have fixed strain and frequency, sometime not in the pathophysiological range. We thus developed a novel, electromagnetically driven, uniaxial stretching device, where cells were grown on a flexible polydimethylsiloxane (PDMS) membrane mounted onto a 3-D printed track. The strain of the membrane was readily controlled by tailoring the track design and the frequency was determined by electromagnetic actuation. Furthermore, the mechanical strain gradient was generated on a PDMS membrane with a tapered thickness. This strain gradient, ranging from 1.5% to 40%, covered both physiological and pathological vascular stretch ranges. When human vascular endothelial cells were subjected to the cyclic stretch, the cells exhibited strain-dependent cell and nuclear orientation and elongation perpendicular to the stretching direction, compared to the random cell and nuclear orientation under the static condition. However, the overstretching led to deviation from the aforementioned orientation and elongation, and impaired the tight junctions, leading to a leaky endothelium. This novel, versatile, cost-effective, pathophysiologically relevant stretching device provides a useful platform for advancement of vascular disease research and treatment.

bioengineering↗

bioRxiv2022

A synthetic bispecific antibody capable of neutralizing SARS-CoV-2 Delta and Omicron

Bispecific antibodies have emerged as a promising strategy for curtailing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immune escape. This brief report highlights RBT-0813 (also known as TB493-04), a synthetic, humanized, receptor-binding domain (RBD)-targeted bispecific antibody that retains picomolar affinity to the Spike (S) trimers of all major variants of concern and neutralizes both SARS-CoV-2 Delta and Omicron in vitro.

immunology↗

bioRxiv2020

Genomic characterization of a diazotrophic microbiota associated with maize aerial root mucilage

A geographically isolated maize landrace cultivated on nitrogen-depleted fields without synthetic fertilizer in the Sierra Mixe region of Oaxaca, Mexico utilizes nitrogen derived from the atmosphere and develops an extensive network of mucilage-secreting aerial roots that harbors a diazotrophic microbiota. Targeting these diazotrophs, we selected nearly 600 microbes from a collection isolated from these plants and confirmed their ability to incorporate heavy nitrogen (15N2) metabolites in vitro. Sequencing their genomes and conducting comparative bioinformatic analyses showed that these genomes had substantial phylogenetic diversity. We examined each diazotroph genome for the presence of nif genes essential to nitrogen fixation (nifHDKENB) and carbohydrate utilization genes relevant to the mucilage polysaccharide digestion. These analyses identified diazotrophs that possessed canonical nif gene operons, as well as many other operon configurations with concomitant fixation and release of >700 different 15N labeled metabolites. We further demonstrated that many diazotrophs possessed alternative nif gene operons and confirmed their genomic potential to derive chemical energy from mucilage polysaccharide to fuel nitrogen fixation. These results confirm that some diazotrophic bacteria associated with Sierra Mixe maize were capable of incorporating atmospheric nitrogen into their small molecule extracellular metabolites through multiple nif gene configurations while others were able to fix nitrogen without the canonical (nifHDKENB) genes. Data SummaryGenetic resources, including biological materials and nucleic acid sequences, were accessed under an Access and Benefit Sharing (ABS) Agreement between the Sierra Mixe community and the Mars Corporation, and with authorization from the Mexican government. An internationally recognized certificate of compliance has been issued by the Mexican government under the Nagoya Protocol for such activities (ABSCH-IRCC-MX-207343-3). Any party seeking access to the nucleic acid sequences underlying the analysis reported here is subject to the full terms and obligations of the ABS agreement and the authorization from the government of Mexico. Individuals wishing to access nucleic acid sequence data for scientific research activities should contact Mars Incorporated Chief Science Officer at CSO@effem.com.

genomics↗

bioRxiv2017

Identification and characterization of Gypsophila paniculata color morphs in Sleeping Bear Dunes National Lakeshore, MI, USA.

BackgroundGypsophila paniculata (babys breath) is an invasive species found throughout much of the northwest United States and western Canada. Recently, plants exhibiting a different color morphology were identified within the coastal dunes along eastern Lake Michigan. The common babys breath (G. paniculata) typically produces stems that are purple in color (purple morph), while the atypical morph has stems that are green-yellow (green-yellow morph). The purpose of this study was to characterize these newly identified morphs and determine if they are genetically distinct species from the common babys breath in order to assess whether alternative management strategies should be employed to control these populations.\n\nMethodsWe sequenced two chloroplast regions, rbcL and matK, and one nuclear region, ITS2, from the purple morphs and green-yellow morphs collected from Sleeping Bear Dunes National Lakeshore, MI, USA (SBDNL). Sequences were aligned to the reference sequences from other Gypsophila species obtained from the Barcode of Life (BOLD) and GenBank databases. We also collected seeds from wild purple morph and wild green-yellow morph plants in SBDNL. We grew the seeds in a common garden setting and characterized the proportion of green-yellow individuals produced from the two color morphs after five-months of growth.\n\nResultsPhylogenetic analyses based upon rbcL, matK, and ITS2 regions suggest that the two color morphs are not distinct species and they both belong to G. paniculata. Seeds collected from wild green-yellow morphs produced a significantly higher proportion of green-yellow individuals compared to the number produced by seeds collected from wild purple morphs. However, seeds collected from both color morphs produced more purple morphs than green-yellow morphs.\n\nDiscussionBased upon these results, we propose that the two color morphs are variants of G. paniculata. Given the significant difference in the number of green-yellow morphs produced from the seeds of each morph type, we also suggest that this color difference has some genetic basis. We propose that current management continue to treat the two color morphs in a similar manner in terms of removal to prevent the further spread of this species.

plant biology↗