Biology subjects

Cheng, B.

Publications and source records attributed to Cheng, B..

41 records · Page 3Linked to original sources

bioRxiv2019

Genome-wide variations analysis of special waxy sorghum cultivar Hongyingzi for brewing Moutai liquor

AbstractsHongyingzi is a special waxy sorghum (Sorghum bicolor L. Moench) cultivar for brewing Moutai liquor. For an overall understanding of the whole genome of Hongyingzi, we performed whole-genome resequencing technology with 56.10 X depth to reveal its comprehensive variations. Compared with the BTx623 reference genome, 2.48% of genome sequences were altered in the Hongyingzi genome. Among these alterations, there were 1885774 single nucleotide polymorphisms (SNPs), 309381 small fragments insertions and deletions (Indels), 31966 structural variations (SVs), and 217273 copy number variations (CNVs). These alterations conferred 29614 genes variations. It was also predicted that 35 genes variations were related to the multidrug and toxic efflux (MATE) transporter, chalcone synthase (CHS), ATPase isoform 10 (AHA10) transporter, dihydroflavonol-4-reductase (DFR), the laccase 15 (LAC15), flavonol 3'-hydroxylase (F3'H), flavanone 3-hydroxylase (F3H), O-methyltransferase (OMT), flavonoid 3'5' hydroxylase (F3'5'H), UDP-glucose:sterol-glucosyltransferase (SGT), flavonol synthase (FLS), and chalcone isomerase (CHI) involved in the tannin synthesis. These results would provide theoretical supports for the molecular markers developments and gene function studies related to the liquor-making traits, and the genetic improvement of waxy sorghum based on the genome editing technology.

genomics↗

bioRxiv2019

Three dimensional nanoscopy of whole cells and tissues with in situ point spread function retrieval

Single-molecule localization microscopy is a powerful tool in visualizing organelle structures, interactions, and protein functions in biological research. However, whole-cell and tissue specimens challenge the achievable resolution and depth of nanoscopy methods. As imaging depth increases, photons emitted by fluorescent probes, the sole source of molecular positions, were scattered and aberrated, resulting in image artifacts and rapidly deteriorating resolution. We propose a method to allow constructing the in situ 3D response of single emitters directly from single-molecule dataset and therefore allow pin-pointing single-molecule locations with limit-achieving precision and uncompromised fidelity through whole cells and tissues. This advancement expands the routine applicability of super-resolution imaging from selected cellular targets near coverslips to intra- and extra-cellular targets deep inside tissues. We demonstrate this across a range of cellular-tissue architectures from mitochondrial networks, microtubules, and nuclear pores in 2D and 3D cultures, amyloid-{beta} plaques in mouse brains to developing cartilage in mouse forelimbs.

biophysics↗

bioRxiv2019

Visual speed compensation of pitch-constrained blue-bottle flies under retinal-image velocity perturbation in a flight mill

In the presence of wind or background image motion, flies are able to maintain a constant retinal-image velocity via regulating flight speed to the extent permitted by their locomotor capacity. Here we investigated the speed regulation of semi-tethered blue-bottle flies (Calliphora vomitoria) flying along an annular corridor in a magnetically levitated flight mill enclosed by two motorized cylindrical walls. We perturbed the flies retinal-image motion via spinning the cylindrical walls, generating bilaterally-averaged velocity perturbations from -0.3 to 0.3 m{middle dot}s-1. Flies compensated retinal-image velocity perturbations by adjusting airspeed up to 20%, thereby maintaining a relatively constant retinal-image velocity. When the retinal-image velocity perturbation became greater than [~]0.1 m{middle dot}s-1, the compensation weakened as airspeed plateaued, suggesting that flies were unable to further change airspeed. The compensation gain, i.e., the ratio of airspeed compensation and retinal-image velocity perturbation, depended on the spatial frequency of the grating patterns, being the largest at 12 m-1.

bioengineering↗

bioRxiv2019

Effects of transcranial alternating-current stimulation to secondary motor areas on cortical oscillations in stroke patients

BackgroundThere is growing evidence that secondary motor areas are relevant for recovery after motor stroke. Communication among brain areas occurs via synchronization of oscillatory activity which can potentially be modulated via transcranial alternating-current stimulation (tACS).\n\nHypothesisWe hypothesized that tACS to secondary motor areas of the stroke-lesioned hemisphere leads to modulation of task-related connectivity among primary and secondary motor areas, reflected in metrics of EEG coupling in the frequency domain.\n\nMethodsWe applied focal tACS at 1mA peak-to-peak intensity to ipsilesional ventral premotor cortex (PMv) and supplementary motor area (SMA) in chronic stroke patients while they moved their impaired hand. To probe effects of stimulation on cortical oscillations, several task-related EEG-based connectivity metrics (coherence, imaginary coherence, phase-locking value, mutual information) were assessed before and after each stimulation.\n\nResultsOverall, we found significant but weak modulations of the motor network by tACS. Stimulation of PMv reduced task-related coupling between (i) both primary motor cortices (M1) (coherence, -0.0514{+/-}0.0665 (mean{+/-}SD, active stimulation) vs. 0.0085{+/-}0.0888 (sham), p=0.0029) and (ii) between ipsilesional M1 and contralesional PMv (coherence, - 0.0386{+/-}0.0703 vs. 0.0226{+/-}0.0694, p=0.0283; phase-locking value, -0.0363{+/-}0.0581 vs. 0.0036{+/-}0.0497, p=0.0097) compared with sham stimulation.\n\nConclusionsIn this exploratory analysis, tACS to the ipsilesional PMv induced a weak decrease of task-related connectivity between ipsilesional M1 and contralesional M1 and PMv. As an excess of interhemispheric coupling is under discussion as maladaptive phenomenon of motor reorganization after stroke (e.g., bimodal balance-recovery model), tACS-induced reduction of coupling might be an interesting approach to assist re-normalization of the post-stroke motor network.

neuroscience↗

bioRxiv2018

Speed Control and Force-Vectoring of Blue Bottle Flies in a Magnetically-Levitated Flight Mill

Flies fly at a broad range of speeds and produce sophisticated aerial maneuvers with precisely controlled wing movements. Remarkably, only subtle changes in wing motion are used by flies to produce aerial maneuvers, resulting in little directional tilt of aerodynamic force vector relative to the body. Therefore, it is often considered that flies fly according to a helicopter model and control speed mainly via force-vectoring enabled primarily by body-pitch change. Here we examine the speed control of blue bottle flies using a magnetically-levitated (MAGLEV) flight mill, as they fly at different body pitch and with different augmented aerodynamic damping. We identify wing kinematic contributors to the changes of estimated aerodynamic force through testing two force-vectoring models. Results show that in addition to body pitch, flies also use a collection of wing kinematic variables to control both force magnitude and direction, the roles of which are analogous to those of throttle, collective and cyclic pitch of helicopters. Our results also suggest that the MAGLEV flight mill system can be potentially used to study the roles of visual and mechanosensory feedback in insect flight control.\n\nSummary statement: This paper elucidates how files control flight speed while flying in a magnetically-levitated (MAGLEV) flight mill, which enables the manipulation of body pitch and aerodynamic load.

bioengineering↗